During the last decade, Professor P. Anninos of Greece and neurologist R. Sandyk M.D. have been fabulously successful treating neurological disorders using A/C magnetic fields transcranially. Electromagnetic field therapy may be the world's most effective and versatile panacea as it is being discovered that its beneficial biological effects upon the organism appear to be nearly unlimited especially where neurological and endocrine malfunction is a root cause of the disease condition.
While PEMF's have been studied and used for several decades on chronic pain, musculoskeletal, neuromuscular and orthopedic applications, research since the late 1980's into neurological and psychological effects of transcranial magnetic stimulation / transcranially applied PEMFs upon brain and neuroendocrine system are very EXCITING to say the least.
This type of therapy called repetitive transcranial magnetic stimulation (rTMS) or transcranial magnetic stimulation (TMS - or - sometimes called slow TMS if under 1 pulse per second) is gaining a strong reputation for being extremely safe and providing measurable and perceptible benefits in users. Even though these TMS/rTMS studies show therapeutic effects warranting further studies, most use TMS/rTMS strictly for diagnostic purposes. We have omitted most of these diagnostic studies from this resource.
Canada is close to approving rTMS / TMS for psychological / anti depressive effects at 100's or 1000's of Gauss magnetic field density. Ludicrous, since the discovery by Anninos and Sandyk that pico tesla fields (millions of times less dense @ 10-13 Tesla) have substantial neurological benefits. Meanwhile in January '07 the FDA Advisors rejected rTMS use for depression.
Peer reviewed journal abstracts libraried by the National Institutes of Health (NIH) indicate rTMS / TMS are beneficial and without perceptible expected or unexpected adverse reactions in epilepsy, Parkinson's disease, MS, Alzheimer's, migraine headache, cluster headache, severe PMS, depression, ADD/ADHD and others.
Several hundred pulsed electromagnetic field therapy citations contained in our research bibliographies are linked directly to PubMed a service of the U.S. National Library of Medicine and the U.S. National Institutes of Health.
These studies are offered for your education only and are not intended as promotional material for EarthPulse™ Technologies, LLC.
See also; Sandyk R, Anninos PA , Jacobson JI; three pioneers of electromagnetic field therapy to treat Parkinson's, Alzheimer's and epilepsy.
PEMF Background:
introduction to electromedicine
brain wave entrainment
brain wave entrainment II
Research Bibliographies:
arthritis and pulsed electromagnetic field therapy research
athletic performance enhancement and pulsed electromagnetic field therapy research
Alzheimer's disease and pulsed electromagnetic field therapy research
back pain and EarthPulse™ v.2.3
bone / connective tissue regeneration and pulsed electromagnetic field therapy research
depression and pulsed electromagnetic field therapy research
EMF - electropollution research (your brain and your wireless technologies)
epilepsy and pulsed electromagnetic field therapy research
fibromyalgia and pulsed electromagnetic field therapy research
insomnia and pulsed electromagnetic field therapy researchmigraine headache and pulsed electromagnetic field therapy research
multiple sclerosis and pulsed electromagnetic field therapy research
nerve regeneration and pulsed electromagnetic field therapy research
neuropathy and pulsed electromagnetic field therapy research
osteoporosis and pulsed electromagnetic field therapy research
pain and pulsed electromagnetic field therapy research
Parkinson's disease and pulsed electromagnetic field therapy researchstroke and pulsed electromagnetic field therapy research
tinnitus and pulsed electromagnetic field therapy research
transcranial magnetic stimulation (rTMS / TMS) research
EarthPulse research:
video evidence
client feedback forms
chronic lower back pain/sleep
news
J Psychiatr Res. 2007 Oct;41(7):606-15. Epub 2006 Apr 4.
Metabolic alterations in the dorsolateral prefrontal cortex after treatment with high-frequency repetitive transcranial magnetic stimulation in patients with unipolar major depression.
Department of Psychiatry, Charite - Universitatsmedizin Berlin, Campus Benjamin Franklin, Eschenallee 3, D-14050 Berlin, Germany.
J Psychiatr Res. 2007 Aug;41(5):395-403. Epub 2006 Mar 22.
Disturbed Sleep is predictor for antidepressive response to prefrontal repetitive transcranial magnetic stimulation (rTMS).
Department of Psychiatry and Psychotherapy, Charite - Universitatsmedizin Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
Psychiatry Res. 2007 Mar 30;150(2):181-6. Epub 2007 Feb 14. Links
Long-lasting effects of high frequency repetitive transcranial magnetic stimulation in major depressed patients.
Casa di Cura "Villa S. Chiara", Verona, Italy.
Clin Neurophysiol. 2006 Jul;117(7):1536-44. Epub 2006 Jun 5.
Transcranial magnetic stimulation for pain control. Double-blind study of different frequencies against placebo, and correlation with motor cortex stimulation efficacy.Andre-Obadia N, Peyron R, Mertens P, Mauguiere F, Laurent B, Garcia-Larrea L. University Hospital Lyon Sud, Lyon, France; INSERM EMI 342; UCLB1 Lyon & UJM, Saint-Etienne, France.
OBJECTIVE: To assess, using a double-blind procedure, the pain-relieving effects of rTMS against placebo, and their predictive value regarding the efficacy of implanted motor cortex stimulation (MCS). METHODS: Three randomised, double-blinded, 25min sessions of focal rTMS (1Hz, 20Hz and sham) were performed in 12 patients, at 2 weeks intervals. Effects on pain were estimated from daily scores across 5 days before, and 6 days after each session. Analgesic effects were correlated with those of subsequent implanted motor cortex stimulation (MCS). RESULTS: Immediately after the stimulating session, pain scores were similarly decreased by all rTMS modalities.
Clin Neurophysiol. 2006 Jun 20; [Epub ahead of print]
Motor cortical excitability studied with repetitive transcranial magnetic stimulation in patients with Huntington's disease.
Lorenzano C, Dinapoli L, Gilio F, Suppa A, Bagnato S, Curra A, Inghilleri M, Berardelli A.
Department of Neurological Sciences, University of Rome 'La Sapienza', Rome, Italy.
Pain. 2006 May;122(1-2):22-7. Epub 2006 Feb 21.
Reduction of intractable deafferentation pain by navigation-guided repetitive transcranial magnetic stimulation of the primary motor cortex. Hirayama A, Saitoh Y, Kishima H, Shimokawa T, Oshino S, Hirata M, Kato A, Yoshimine T.
Department of Neurosurgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
The precentral gyrus (M1) is a representative target for electrical stimulation therapy of pain. To date, few researchers have investigated whether pain relief is possible by stimulation of cortical areas other than M1. According to recent reports, repetitive transcranial magnetic stimulation (rTMS) can provide an effect similar to that of electrical stimulation. With this in mind, we therefore examined several cortical areas as stimulation targets using a navigation-guided rTMS and compared the effects of the different targets on pain. Twenty patients with intractable deafferentation pain received rTMS of M1, the postcentral gyrus (S1), premotor area (preM), and supplementary motor area (SMA). Each target was stimulated with ten trains of 10-s 5-Hz TMS pulses, with 50-s intervals in between trains. Intensities were adjusted to 90% of resting motor thresholds. Thus, a total of 500 stimuli were applied. Sham stimulations were undertaken at random. The effect of rTMS on pain was rated by patients using a visual analogue scale (VAS) and the short form of the McGill Pain Questionnaire (SF-MPQ). Ten of the 20 patients (50%) indicated that stimulation of M1, but not other areas, provided significant and beneficial pain relief (p<0.01). Results indicated a statistically significant effect lasting for 3 hours after the stimulation of M1 (p<0.05). Stimulation of other targets was not effective. The M1 was the sole target for treating intractable pain with rTMS, in spite of the fact that M1, S1, preM, and SMA are located adjacently.Psychother Psychosom.
Exp Brain Res. 2006 May 9; [Epub ahead of print]
The effects of repetitive transcranial magnetic stimulation on cortical inhibition in healthy human subjects.
Daskalakis ZJ, Moller B, Christensen BK, Fitzgerald PB, Gunraj C, Chen R.
Centre for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada.
Clin Neurophysiol. 2006 Jan;117(1):103-9. Epub 2005 Dec 20.
Altered response to rTMS in patients with Alzheimer's disease.
Inghilleri M, Conte A, Frasca V, Scaldaferri N, Gilio F, Santini M, Fabbrini G, Prencipe M, Berardelli A.
Department of Neurological Sciences, University of Rome La Sapienza, Viale dell'Universita, 30, 00185 Rome, Italy.
Stroke. 2005 Dec;36(12):2681-6. Epub 2005 Oct 27.
Repetitive transcranial magnetic stimulation of contralesional primary motor cortex improves hand function after stroke.
Takeuchi N, Chuma T, Matsuo Y, Watanabe I, Ikoma K.Department of Rehabilitation Medicine, Hokkaido University Graduate School of Medicine, Sapporo 060-0814, Japan.
BACKGROUND AND PURPOSE: A recent report has demonstrated that the contralesional primary motor cortex (M1) inhibited the ipsilesional M1 via an abnormal transcallosal inhibition (TCI) in stroke patients. We studied whether a decreased excitability of the contralesional M1 induced by 1 Hz repetitive transcranial magnetic stimulation (rTMS) caused an improved motor performance of the affected hand in stroke patients by releasing the TCI.CONCLUSIONS: We have demonstrated that a disruption of the TCI by the contralesional M1 virtual lesion caused a paradoxical functional facilitation of the affected hand in stroke patients; this suggests a new neurorehabilitative strategy for stroke patients.
J Neurophysiol. 2005 Sep;94(3):1668-75. Epub 2005 May 4.
Effect of low-frequency repetitive transcranial magnetic stimulation on interhemispheric inhibition.
Pal PK, Hanajima R, Gunraj CA, Li JY, Wagle-Shukla A, Morgante F, Chen R.
Divsion of Neurology and Krembil Neuroscience Centre, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada.
Mov Disord. 2005 Sep;20(9):1178-84.
Effect of repetitive TMS and fluoxetine on cognitive function in patients with Parkinson's disease and concurrent depression. Boggio PS, Fregni F, Bermpohl F, Mansur CG, Rosa M, Rumi DO, Barbosa ER, Odebrecht Rosa M, Pascual-Leone A, Rigonatti SP, Marcolin MA, Araujo Silva MT. Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Sao Paulo, SP, Brazil.
We compared the cognitive effects of two types of antidepressant treatments in PD patients: fluoxetine (20 mg/day) versus repetitive transcranial magnetic stimulation (rTMS, 15 Hz, 110% above motor threshold, 10 daily sessions) of the left dorsolateral prefrontal cortex. Patients in both groups had a significant improvement of Stroop (colored words and interference card) and Hooper and Wisconsin (perseverative errors) test performances after both treatments. Furthermore, there were no adverse effects after either rTMS or fluoxetine in any neuropsychological test of the cognitive test battery. The results show that rTMS could improve some aspects of cognition in PD patients similar to that of fluoxetine. The mechanisms for this cognitive improvement are unclear, but it is in the context of mood improvement.
Neurol Neurochir Pol. 2005 Sep-Oct;39(5):389-96.
[The diagnostic and therapeutic application of transcranial magnetic stimulation] [Article in Polish] Derejko M, Niewiadomska M, Rakowicz M. Zaklad Neurofizjologii Klinicznej, Instytut Psychiatrii i Neurologii, ul. Sobieskiego 9, 02-957 Warszawa.
The functional abnormalities of the central motor structures and its contribution of rigidity, tremor and bradykinesia in Parkinson's disease seem mainly due to the degeneration of the nigro-striatal pathway. Recent reviews on the basic mechanisms of TMS in Parkinson's disease show reduced inhibitory motor network at the cortical and spinal level. The observed changes are thought to be in relation with a dysfunction of subcortico-cortical and subcortico-spinal pathways. Observations made using TMS give new pathophysiological insights in functioning of the central motor structures in Parkinson's disease and started new form of TMS - repetitive TMS (rTMS) as a treatment of the Parkinson's disease motor signs. A few studies using rTMS with repetition rate of 0.2, 1, and 5 Hz showed improvement of motor signs in the Parkinson's disease patients. Although these results support the beneficial effects of rTMS on parkinsonian symptoms, long-term studies with large numbers of subjects should be conducted to assess the efficacy of the rTMS on Parkinson's disease in future.
J Clin Psychiatry. 2005 Jul;66(7):930-7.
Add-on rTMS for medication-resistant depression: a randomized, double-blind, sham-controlled trial in Chinese patients.
Su TP, Huang CC, Wei IH. Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan. tpsu@vghtpe.gov.tw
BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has been developed as a novel tool for improving depression by delivering magnetic stimulation to the brain. However, the apparent effects of rTMS on depression have been varied in different studies. The aims of this study were to determine whether left dorsolateral prefrontal cortex rTMS can alleviate medication-resistant depression in Chinese patients and to investigate what demographic variables or clinical features may predict better response. METHOD: We designed a 2-week randomized, double-blind, sham-controlled study of add-on rTMS. A total of 30 medication-resistant patients with DSM-IV major depressive disorder or bipolar disorder, depressed episode completed 10 sessions of active or sham rTMS-10 patients at each of 2 frequencies, faster (20 Hz) or slower (5 Hz) at 100% motor threshold, and 10 patients at sham stimulation. RESULTS: Patients at both stimulation frequencies demonstrated a superior reduction of depression severity compared to sham stimulation (active = 55.7% vs. sham = 16.3%). The response rate for active rTMS was 60%, in contrast to 10% for the sham treatment. No difference in clinical response was observed between 5 Hz and 20 Hz active rTMS.
Int J Neuropsychopharmacol. 2005 Jun;8(2):223-33. Epub 2004 Nov 30.
Antidepressant effects of different schedules of repetitive transcranial magnetic stimulation vs. clomipramine in patients with major depression: relationship to changes in cortical excitability. Chistyakov AV, Kaplan B, Rubichek O, Kreinin I, Koren D, Feinsod M, Klein E.
Laboratory of Clinical Neurosciences, Department of Neurosurgery, Rambam Medical Center, B. Rappaport Faculty of Medicine, The Technion, Israel Institute of Technology, Haifa, Israel
J Neurol Neurosurg Psychiatry. 2005 Jun;76(6):833-8. Related Articles, Links
Longlasting antalgic effects of daily sessions of repetitive transcranial magnetic stimulation in central and peripheral neuropathic pain. Khedr EM, Kotb H, Kamel NF, Ahmed MA, Sadek R, Rothwell JC. Department of Neurology, Assiut University Hospital, Assiut, Egypt
BACKGROUND AND OBJECTIVE: A single session of repetitive transcranial magnetic stimulation (rTMS) over motor cortex had been reported to produce short term relief of some types of chronic pain. The present study investigated whether five consecutive days of rTMS would lead to longer lasting pain relief in unilateral chronic intractable neuropathic pain. PATIENTS AND METHODS: Forty eight patients with therapy resistant chronic unilateral pain syndromes (24 each with trigeminal neuralgia (TGN) and post-stroke pain syndrome (PSP)) participated. Fourteen from each group received 10 minutes real rTMS over the hand area of motor cortex (20 Hz, 10x10 s trains, intensity 80% of motor threshold) every day for five consecutive days. The remaining patients received sham stimulation. CONCLUSION: These results confirm that five daily sessions of rTMS over motor cortex can produce longlasting pain relief in patients with TGN or PSP.
J Neurol Sci. 2005 Mar 15;229-230:157-61. Epub 2004 Dec 16.
Cognitive functioning after repetitive transcranial magnetic stimulation in patients with cerebrovascular disease without dementia: a pilot study of seven patients. Rektorova I, Megova S, Bares M, Rektor I.
First Department of Neurology, Masaryk University, Teaching Hospital sv. Anna, Pekarska 53, 656 91, Brno, Czech Republic.
AIMS: Examine whether one session of high frequency repetitive transcranial magnetic stimulation (rTMS) applied over the left dorsolateral prefrontal cortex (DLPFC) would induce any measurable cognitive changes in patients with cerebrovascular disease and mild cognitive deficits. CONCLUSION: Our pilot study results showed that one session of the high frequency rTMS applied over the left DLPFC was safe in patients with cerebrovascular disease and mild executive deficits, and may induce measurable positive effects on executive functioning.
Clin Neurophysiol. 2005 Mar;116(3):605-13. Epub 2004 Nov 5.
Comparison between short train, monophasic and biphasic repetitive transcranial magnetic stimulation (rTMS) of the human motor cortex. Arai N, Okabe S, Furubayashi T, Terao Y, Yuasa K, Ugawa Y. Department of Neurology, Division of Neuroscience, Graduate School of Medicine University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
OBJECTIVE: To compare motor evoked potentials (MEPs) elicited by short train, monophasic, repetitive transcranial magnetic stimulations (rTMS) with those by short train, biphasic rTMS. RESULTS: 2 or 3Hz stimulation with either monophasic or biphasic pulses evoked MEPs that gradually increased in amplitude with the later MEPs being significantly larger than the earlier ones. Monophasic rTMS showed much more facilitation than biphasic stimulation, particularly at 3Hz. Stimulation at the foramen magnum level at 3Hz elicited fairly constant MEPs. CONCLUSIONS: The enhancement of cortical MEPs with no changes of responses to foramen magnum level stimulation suggests that the facilitation occurred at the motor cortex. We hypothesize that monophasic TMS has a stronger short-term effect during repetitive stimulation than biphasic TMS because monophasic pulses preferentially activate one population of neurons oriented in the same direction so that their effects readily summate. Biphasic pulses in contrast may activate several different populations of neurons (both facilitatory and inhibitory) so that summation of the effects is not so clear as with monophasic pulses. SIGNIFICANCE: This means that when using rTMS as a therapeutic tool or in research fields, the difference in waveforms of magnetic pulses (monophasic or biphasic) may affect the results.
2003 Sep-Oct;72(5):286-8.
Transcranial magnetic stimulation in the reversal of motor conversion disorder.
Schonfeldt-Lecuona C, Connemann BJ, Spitzer M, Herwig U.
Department of Psychiatry, University of Ulm, Germany.
BACKGROUND: We tested the therapeutic potential of high-frequency repetitive transcranial magnetic stimulation (rTMS) in a 20-year-old patient suffering from a conversion paralysis of the right arm. METHOD: rTMS was applied to the contralateral motor cortex. Stimulations were performed on working days at a frequency of 15 Hz. RESULTS: Within 12 weeks, motor function, hyposensibility and muscle bulk were completely restored. CONCLUSIONS: In addition to possible psychological effects, rTMS may have had a causal therapeutic effect by strengthening corticocortical connections and thereby priming voluntary movements. Further controlled studies are needed.
Arq Neuropsiquiatr. 2003 Mar;61(1):146-52. Epub 2003 Apr 16.
[Transcranial magnetic stimulation]
[Article in Portuguese]
Conforto AB, Marie SK, Cohen LG, Scaff M.
Divisao de Clinica Neurologica, Hospital das Clinicas, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brasil.Exp Brain Res. 2003 Jul 17 [Epub ahead of print]. Related Articles, Links
Investigating human motor control by transcranial magnetic stimulation.
Petersen NT, Pyndt HS, Nielsen JB.
Department of Medical Physiology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.
In this review we discuss the contribution of transcranial magnetic stimulation (TMS) to the understanding of human motor control. Compound motor-evoked potentials (MEPs) may provide valuable information about corticospinal transmission, especially in patients with neurological disorders, but generally do not allow conclusions regarding the details of corticospinal function to be made. Techniques such as poststimulus time histograms (PSTHs) of the discharge of single, voluntarily activated motor units and conditioning of H reflexes provide a more optimal way of evaluating transmission in specific excitatory and inhibitory pathways. Through application of such techniques, several important issues have been clarified. TMS has provided the first real evidence that direct monosynaptic connections from the motor cortex to spinal motoneurons exist in man, and it has been revealed that the distribution of these projections roughly follows the same proximal-distal gradient as in other primates. However, pronounced differences also exist. In particular, the tibialis anterior muscle appears to receive as significant a monosynaptic corticospinal drive as muscles in the hand. The reason for this may be the importance of this muscle in controlling the foot trajectory in the swing phase of walking. Conditioning of H reflexes by TMS has provided evidence of changes in cortical excitability prior to and during various movements. These experiments have generally confirmed information obtained from chronic recording of the activity of corticospinal cells in primates, but information about the corticospinal contribution to movements for which information from other primates is sparse or lacking has also been obtained. One example is walking, where TMS experiments have revealed that the corticospinal tract makes an important contribution to the ongoing EMG activity during treadmill walking. TMS experiments have also documented the convergence of descending corticospinal projections and peripheral afferents on spinal interneurons. Current investigations of the functional significance of this convergence also rely on TMS experiments. The general conclusion from this review is that TMS is a powerful technique in the analysis of motor control, but that care is necessary when interpreting the data. Combining TMS with other techniques such as PSTH and H reflex testing amplifies greatly the power of the technique.
PMID: 12879177 [PubMed - as supplied by publisher]------------------------------------------------------------------------
2: CNS Spectr. 2003 Jul;8(7):529-36. Related Articles, Links
Mechanisms and the current state of deep brain stimulation in neuropsychiatry.
Lisanby SH, Morales O, Payne N, Kwon E, Fitzsimons L, Luber B, Nobler MS, Sackeim HA.
Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, New York, USA.
New findings regarding the mechanisms of action of electroconvulsive therapy (ECT) have led to novel developments in treatment technique to further improve this highly effective treatment for major depression. These new approaches include novel electrode placements, optimization of electrical stimulus parameters, and new methods for inducing more targeted seizures (eg, magnetic seizure therapy [MST]). MST is the use of transcranial magnetic stimulation to induce a seizure. Magnetic fields pass through tissue unimpeded, providing more control over the site and extent of stimulation than can be achieved with ECT. This enhanced control represents a means of focusing the treatment on target cortical structures thought to be essential to antidepressant response and reducing spread to medial temporal regions implicated in the cognitive side effects of ECT. MST is at an early stage of development. Preliminary results suggest that MST may have some advantages over ECT in terms of subjective side effects and acute cog
PMID: 12894034 [PubMed - in process]------------------------------------------------------------------------
3: CNS Spectr. 2003 Jul;8(7):522-6. Related Articles, Links
Mechanisms and the current state of deep brain stimulation in neuropsychiatry.
Greenberg BD, Rezai AR.
Department of Psychiatry and Human Behavior, Brown University School of Medicine, Providence, Rhode Island, USA.
Deep brain stimulation (DBS) is established as a therapy for movement disorders, and it is an investigational treatment in other neurologic conditions. DBS precisely targets neuroanatomical targets deep within the brain that are proposed to be centrally involved in the pathophysiology of some neuropsychiatric illnesses. DBS is nonablative, offering the advantages of reversibility and adjustability. This might permit therapeutic effectiveness to be enhanced or side effects to be minimized. Preclinical and clinical studies have shown effects of DBS locally, at the stimulation target, and at a distance, via actions on fibers of passage or across synapses. Although its mechanisms of action are not fully elucidated, several effects have been proposed to underlie the therapeutic effects of DBS in movement disorders, and potentially in other conditions as well. The mechanisms of action of DBS are the focus of active investigation in a number of clinical and preclinical laboratories. As in severe movement disorders,
PMID: 12894033 [PubMed - in process]------------------------------------------------------------------------
4: CNS Spectr. 2003 Jul;8(7):488. Related Articles, Links
Progress in therapeutic brain stimulation in neuropsychiatry.
Schlaepfer TE.
Department of Psychiatry,Johns Hopkins University,Baltimore, USA.
PMID: 12894028 [PubMed - in process]------------------------------------------------------------------------
5: CNS Spectr. 2003 Jul;8(7):496-514. Related Articles, Links
Mechanisms and the current state of transcranial magnetic stimulation.
George MS, Nahas Z, Kozol FA, Li X, Yamanaka K, Mishory A, Bohning DE.
Center for Advanced Imaging Research, Medical University of South Carolina, Charleston, South Carolina, USA.
man is proving to be a most important development for neuroscience in general, and neuropsychiatry in particular.
PMID: 12894031 [PubMed - in process]------------------------------------------------------------------------
6: Cogn Behav Neurol. 2003 Jun;16(2):118-27. Related Articles, Links
Relative effects of repetitive transcranial magnetic stimulation and electroconvulsive therapy on mood and memory: a neurocognitive risk-benefit analysis.
O'Connor M, Brenninkmeyer C, Morgan A, Bloomingdale K, Thall M, Vasile R, Leone AP.
Harvard Medical School, Boston, Massachusetts, USA. mconor@caregroup.harvard.edu
OBJECTIVE: Two procedures for treating major depressive disorder were compared with regard to their respective effects on mood and cognition. BACKGROUND: Fourteen patients underwent treatment with electroconvulsive therapy and 14 underwent treatment with repetitive transcranial magnetic stimulation. Patients were tested on three occasions: before initiation of treatment, at the end of treatment, and 2 weeks after the end of treatment. METHODS: Electroconvulsive therapy was applied unilaterally approximately three times per week for 2 to 4 weeks. Repetitive transcranial magnetic stimulation was applied in sessions of 1600 stimuli at 10 Hertz and 90% of motor threshold intensity to the left dorsolateral prefrontal cortex daily (Monday through Friday) for 2 consecutive weeks. RESULTS: Results indicate that electroconvulsive therapy had a more positive effect on mood than did a 2-week trial of repetitive transcranial magnetic stimulation. With regard to cognitive outcome measures, electroconvulsive therapy exerted a deleterious but transient effect on various components of memory that were no longer detected 2 weeks after the end of treatment; however, there was evidence of persistent retrograde amnesia after treatment with electroconvulsive therapy. As a group, repetitive transcranial magnetic stimulation patients experienced only a modest reduction in depression severity but there was no evidence of anterograde or retrograde memory deficits in the aftermath of treatment with repetitive transcranial magnetic stimulation. CONCLUSIONS: Findings suggest that electroconvulsive therapy is associated with transient negative cognitive side effects, most of which dissipate in the days after treatment. Deficits of this sort are not apparent after treatment with a 2-week course of repetitive transcranial magnetic stimulation.
PMID: 12799598 [PubMed - in process]------------------------------------------------------------------------
7: Cogn Behav Neurol. 2003 Jun;16(2):128-35. Related Articles, Links
Prefrontal cortex transcranial magnetic stimulation does not change local diffusion: a magnetic resonance imaging study in patients with depression.
Li X, Nahas Z, Lomarev M, Denslow S, Shastri A, Bohning DE, George MS.
Brain Stimulation Laboratory, Medical University of South Carolina, Charleston, South Carolina 29425, USA. lixi@musc.edu
OBJECTIVE: To determine whether transcranial magnetic stimulation over the left dorsolateral prefrontal cortex produces pathologic changes or leakage of the blood-brain barrier in patients with depression by using apparent diffusion coefficient magnetic resonance imaging. BACKGROUND: Transcranial magnetic stimulation is a new technology for noninvasively stimulating the brain. It appears to be a relatively safe technique, with some important exceptions. Its neurobiologic mechanisms of action are poorly understood. One theory to explain its apparent antidepressant effects involves a potential change in local blood-brain barrier settings, allowing passage of peripheral substances directly into brain parenchyma. Knowing whether transcranial magnetic stimulation changes local brain diffusion is important as well from a safety perspective. To test whether transcranial magnetic stimulation changes local brain diffusion, we used apparent diffusion coefficient magnetic resonance imaging in depressed patients undergoing interleaved transcranial magnetic stimulation/functional magnetic resonance imaging over the left prefrontal cortex. METHODS: Within a 1.5 Tesla magnetic resonance imaging scanner, 14 depressed patients were stimulated with a figure-eight transcranial magnetic stimulation coil over the left prefrontal cortex. Apparent diffusion coefficient magnetic resonance imaging was acquired before, and immediately after, 1 Hertz transcranial magnetic stimulation (147 stimuli) intermittently delivered at a motor threshold of more than 7.35 minutes. Phase maps of the transcranial magnetic stimulation magnetic fields were used to guide region-of-interest placement. RESULTS: No significant qualitative apparent diffusion coefficient differences were observed before and after 1 Hertz transcranial magnetic stimulation underneath the coil. CONCLUSIONS: One Hertz transcranial magnetic stimulation over the left dorsolateral prefrontal cortex as applied in this study did not result in pathologic changes or leakage of the blood-brain barrier in patients with depression. If prefrontal transcranial magnetic stimulation at these usage parameters changes local diffusion, it is not an obvious or large effect.
PMID: 12799599 [PubMed - in process]------------------------------------------------------------------------
8: Electromyogr Clin Neurophysiol. 2003 Jun;43(4):235-40. Related Articles, Links
Hemiparkinson-hemiatrophy syndrome: a transcranial magnetic stimulation study.
Nardone R, Lochner P, Tezzon F.
Department of Neurology, F. Tappeiner Hospital, Merano, BZ.
We described the clinical and neuroradiological findings together with a transcranial magnetic stimulation study in two patient with hemiparkinson-hemiatrophy syndrome (HP-HA). In both patients the neuroradiological findings (MRI) and the central motor conduction were normal whereas the functional imaging studies (SPECT) showed asymmetrical perfusion in the basal ganglia; the intracortical inhibition at short interstimulus intervals and the silent period duration in the motor cortex contralateral to hemiparkinsonism were significantly increased only in one of the patient which has a poor response to L-Dopa therapy. These studies suggest that intracortical or thalamo-cortical neuronal inhibition may be increased in HP-HA. The etiopathogenetic considerations, the diagnostic criteria and the prognostic value of our finding to evaluate the clinical evolution of parkinsonism are discussed in the context of current models of basal ganglia-thalamo-cortical connectivity. Transcranial magnetic stimulation will provide valuable information for the differential diagnosis of the parkinsonian disorders and may predict the efficacy of L-Dopa therapy.
PMID: 12836589 [PubMed - in process]------------------------------------------------------------------------
9: Eur J Neurosci. 2003 Jun;17(11):2462-8. Related Articles, Links
Metabolic changes after repetitive transcranial magnetic stimulation (rTMS) of the left prefrontal cortex: a sham-controlled proton magnetic resonance spectroscopy (1H MRS) study of healthy brain.
Michael N, Gosling M, Reutemann M, Kersting A, Heindel W, Arolt V, Pfleiderer B.
Department of Psychiatry, University of Munster, FRG, Germany.
Rapid transcranial magnetic stimulation is being increasingly used in the treatment of psychiatric disorders, especially major depression. However, its mechanisms of action are still unclear. The aim of this study was to assess metabolic changes by proton magnetic resonance spectroscopy following high-frequency rapid transcranial magnetic stimulation (20 Hz), both immediately after a single session and 24 h after a series of five consecutive sessions. Twelve healthy volunteers were enrolled in a prospective single-blind, randomized study [sham (n = 5) vs. real (n = 7)]. Three brain regions were investigated (right, left dorsolateral prefrontal cortex, left anterior cingulate cortex). A single as well as a series of consecutive rapid transcranial magnetic stimulations affected cortical glutamate/glutamine levels. These effects were present not only close to the stimulation site (left dorsolateral prefrontal cortex), but also in remote (right dorsolateral prefrontal cortex, left cingulate cortex) brain regions. Remarkably, the observed changes in glutamate/glutamine levels were dependent on the pre-transcranial magnetic stimulation glutamate/glutamine concentration, i.e. the lower the pre-stimulation glutamate/glutamine level, the higher the glutamate/glutamine increase observed after short- or long-term stimulation (5 days). In general, the treatment was well tolerated and no serious side-effects were reported. Neither transient mood changes nor significant differences in the outcome of a series of neuropsychological test batteries after real or sham transcranial magnetic stimulation occurred in our experiment. In summary, these data indicate that rapid transcranial magnetic stimulation may act via stimulation of glutamatergic prefrontal neurons.
PMID: 12814378 [PubMed - in process]------------------------------------------------------------------------
10: Ann N Y Acad Sci. 2003 May;993:1-13; discussion 48-53. Related Articles, Links
Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation.
Andrews RJ.
NASA Ames Research Center, Moffett Field, California, USA. rja@russelljandrews.org
Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.
PMID: 12853290 [PubMed - in process]------------------------------------------------------------------------
11: J Rehabil Med. 2003 May;(41 Suppl):20-6. Related Articles, Links
Transcranial magnetic stimulation to assess cortical plasticity: a critical perspective for stroke rehabilitation.
Butler AJ, Wolf SL.
Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA. ajbutle@emory.edu
Transcranial magnetic stimulation has gained increasing visibility as an evaluative and interventional tool during the past 15 years. Within the context of rehabilitation, transcranial magnetic stimulation has been applied to differentiate excitatory and inhibitory mechanisms and to assess cortical reorganization following specific interventions. This article reviews some of the more salient features of transcranial magnetic stimulation applications relevant to stroke rehabilitation, highlighting the strengths and weaknesses in this approach. Data derived from such studies may be profoundly over-interpreted. Information is provided showing the importance of utilizing fundamental principles of electrode placement and kinesiological electromyography to more accurately reflect and interpret data emerging from transcranial magnetic stimulation mapping studies, particularly as they apply to the interpretation of cortical reorganization following application of neurorehabilitative procedures.
PMID: 12817653 [PubMed - in process]------------------------------------------------------------------------
12: Clin Neurophysiol. 2003 Apr;114(4):600-4. Related Articles, Links
Level of action of cathodal DC polarisation induced inhibition of the human motor cortex.
Nitsche MA, Nitsche MS, Klein CC, Tergau F, Rothwell JC, Paulus W.
Department of Clinical Neurophysiology, University of Goettingen, Robert Koch Str. 40, 37075, Goettingen, Germany. mnitsch1@gwdg.de <mnitsch1@gwdg.de>
OBJECTIVE: To induce prolonged motor cortical excitability reductions by transcranial direct current stimulation in the human. METHODS: Cathodal direct current stimulation was applied transcranially to the hand area of the human primary motor cortex from 5 to 9 min in separate sessions in twelve healthy subjects. Cortico-spinal excitability was tested by single pulse transcranial magnetic stimulation. Transcranial electrical stimulation and H-reflexes were used to learn about the origin of the excitability changes. Neurone specific enolase was measured before and after the stimulation to prove the safety of the stimulation protocol. RESULTS: Five and 7 min direct current stimulation resulted in motor cortical excitability reductions, which lasted for minutes after the end of stimulation, 9 min stimulation induced after-effects for up to an hour after the end of stimulation, as revealed by transcranial magnetic stimulation. Muscle evoked potentials elicited by transcranial electric stimulation and H-reflexes did not change. Neurone specific enolase concentrations remained stable throughout the experiments. CONCLUSIONS: Cathodal transcranial direct current stimulation is capable of inducing prolonged excitability reductions in the human motor cortex non-invasively. These changes are most probably localised intracortically.
PMID: 12686268 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
13: J Physiol. 2003 Mar 1;547(Pt 2):485-96. Epub 2003 Jan 17. Related Articles, Links
Ketamine increases human motor cortex excitability to transcranial magnetic stimulation.
Di Lazzaro V, Oliviero A, Profice P, Pennisi MA, Pilato F, Zito G, Dileone M, Nicoletti R, Pasqualetti P, Tonali PA.
Institute of Neurology, Universita Cattolica, Largo A. Gemelli 8, 00168 Rome, Italy. vdilazzaro@rm.unicatt.it
Subanaesthetic doses of the N-methyl-D-aspartate (NMDA) antagonist ketamine have been shown to determine a dual modulating effect on glutamatergic transmission in experimental animals, blocking NMDA receptor activity and enhancing non-NMDA transmission through an increase in the release of endogenous glutamate. Little is known about the effects of ketamine on the excitability of the human central nervous system. The effects of subanaesthetic, graded incremental doses of ketamine (0.01, 0.02 and 0.04 mg kg-1 min-1, I.V.) on the excitability of cortical networks of the human motor cortex were examined with a range of transcranial magnetic and electric stimulation protocols in seven normal subjects. Administration of ketamine at increasing doses produced a progressive reduction in the mean resting motor threshold (RMT) (F(3, 18) = 22.33, P < 0.001) and active motor threshold (AMT) (F(3, 18) = 12.17, P < 0.001). Before ketamine administration, mean RMT +/- S.D. was 49 +/- 3.3 % of maximum stimulator output and at the highest infusion level it was 42.6 +/- 2.6 % (P < 0.001). Before ketamine administration, AMT +/- S.D. was 38 +/- 3.3 % of maximum stimulator output and at the highest infusion level it was 33 +/- 4.4 % (P < 0.002). Ketamine also led to an increase in the amplitude of EMG responses evoked by magnetic stimulation at rest; this increase was a function of ketamine dosage (F(3, 18) = 5.29, P = 0.009). In contrast to responses evoked by magnetic stimulation, responses evoked by electric stimulation were not modified by ketamine. The differential effect of ketamine on responses evoked by magnetic and electric stimulation demonstrates that subanaesthetic doses of ketamine enhance the recruitment of excitatory cortical networks in motor cortex. Transcranial magnetic stimulation produces a high-frequency repetitive discharge of pyramidal neurones and for this reason probably depends mostly on short-lasting AMPA transmission. An increase in this transmission might facilitate the repetitive discharge of pyramidal cells after transcranial magnetic stimulation which, in turn, results in larger motor responses and lower thresholds. We suggest that the enhancement of human motor cortex excitability to transcranial magnetic stimulation is the effect of an increase in glutamatergic transmission at non-NMDA receptors similar to that described in experimental studies.
PMID: 12562932 [PubMed - in process]------------------------------------------------------------------------
14: J Clin Neurophysiol. 2003 Feb;20(1):59-64. Related Articles, Links
Intracortical inhibition and facilitation of the response of the diaphragm to transcranial magnetic stimulation.
Demoule A, Verin E, Ross E, Moxham J, Derenne JP, Polkey MI, Similowski T.
Laboratoire de Physiopathologie Respiratoire et Unite de Reanimation, Service de Pneumologie, Groupe Hospitalier Pitie-Salpetriere, Assistance Publique-Hopitaux de Paris, France.
Respiratory muscles respond to a subcortical automatic command and to a neocortical voluntary command. In diseases such as stroke or motor neurone disease, an abnormal diaphragmatic response to single transcranial magnetic stimuli can identify a central source for respiratory disorders, but this is not likely to be the case in disorders affecting intracortical inhibitory and facilitatory mechanisms. This study describes the response of the diaphragm to paired transcranial magnetic stimulation. Thirteen normal subjects were studied (age range, 22 to 43 years; 7 men; phrenic conduction, <6.8 msec; latency of diaphragmatic motor evoked potential, <20.5 msec). Motor evoked potentials in response to paired stimulation were obtained in eight subjects only, with the motor threshold in the remaining five subjects too high to absorb the loss of power inherent in the double-stimulation montage. Interstimulus intervals less than 5 msec resulted in a statistically significant inhibition (p < 0.01 for interstimulus intervals of 1 and 3 ms), whereas intervals longer than 6 msec were facilitatory (maximal, 15 msec). The diaphragmatic pattern matched that of the biceps brachii. The authors conclude that it is possible to study intracortical inhibition and facilitation of diaphragmatic control, although not in all subjects. Technical improvement should alleviate current limitations and make paired transcranial magnetic stimulation a tool to study respiratory muscle abnormalities in settings in which intracortical interactions are important, such as movement disorders.
Publication Types:
* Clinical TrialPMID: 12684560 [PubMed - indexed for MEDLINE]
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15: Neuropsychopharmacology. 2003 Feb;28(2):201-5. Related Articles, Links
Efficacy of repetitive transcranial magnetic stimulation (rTMS) in the treatment of affective disorders.
Schlaepfer TE, Kosel M, Nemeroff CB.
Department of Psychiatry, University Hospital, Bern, Switzerland. schlaep@jhmi.edu
Transcranial magnetic stimulation (TMS) is a relatively noninvasive technique to interfere with the function of small cortical areas through currents induced by alternating magnetic fields emanating from a handheld coil placed directly above the targeted area. This technique has clear effects on a whole range of measures of brain function and has become an important research tool in neuropsychiatry. More recently, TMS has been studied in psychiatry mainly to assess its putative therapeutic effects in treatment refractory major depression. Most studies indicate that both low-frequency TMS and higher (20 Hz) frequency repetitive TMS may have some antidepressant properties. However, definite therapeutic effects of clinical significance still remain to be demonstrated.
Publication Types:
* Review
* Review, Tutorial
PMID: 12589372 [PubMed - indexed for MEDLINE]
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16: Neuroreport. 2002 Dec 3;13(17):2229-33. Related Articles, Links
Pulse configuration-dependent effects of repetitive transcranial magnetic stimulation on visual perception.
Antal A, Kincses TZ, Nitsche MA, Bartfai O, Demmer I, Sommer M, Paulus W.
Department of Clinical Neurophysiology, Georg-August University of Gottingen, Robert Koch Strasse 40, 37070 Gottingen, Germany. aantal@gwdg.de
Transcranial magnetic stimulation (TMS) is a noninvasive technique for direct stimulation of the neocortex. In the last two decades it is successfully applied in the study of motor and sensory physiology. TMS uses the indirect induction of electrical fields in the brain generated by intense changes of magnetic fields applied to the scalp. It encompasses two widely used waveform configurations: mono-phasic magnetic pulses induce a single current in the brain while biphasic pulses induce at least two currents of inverse direction. As has been shown for the motor cortex, efficacy of repetitive transcranial magnetic stimulation (rTMS) may depend on pulse configuration. In order to clarify this question with regard to visual perception, static contrast sensitivities (sCS) were evaluated before, during, immediately after and 10 minutes after monophasic and biphasic low frequency (1 Hz) rTMS applied to the occipital cortex of 15 healthy subjects. The intensity of stimulation was the phosphene threshold of each individual subject. Using 4 c/d spatial frequency, significant sCS loss was found during and immediately after 10 min of monophasic stimulation, while biphasic stimulation resulted in no significant effect. Ten minutes after the end of stimulation, the sCS values were at baseline level again. However, reversed current flow direction resulted in an increased efficacy of biphasic and decreased efficacy of monophasic stimulation. Our results are in agreement with previous findings showing that primary visual functions, such as contrast detection, can be transiently altered by low frequency transcranial magnetic stimulation. However the effect of modulation significantly depends on the current waveform and direction.
PMID: 12488802 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
17: Biol Psychiatry. 2002 Dec 1;52(11):1057-65. Related Articles, Links
Chronic psychosocial stress and concomitant repetitive transcranial magnetic stimulation: effects on stress hormone levels and adult hippocampal neurogenesis.
Czeh B, Welt T, Fischer AK, Erhardt A, Schmitt W, Muller MB, Toschi N, Fuchs E, Keck ME.
The German Primate Center, Division of Neurobiology, Gottingen, Germany.
BACKGROUND: Repetitive transcranial magnetic stimulation is increasingly used as a therapeutic tool in psychiatry and has been demonstrated to attenuate the activity of the stress hormone system. Stress-induced structural remodeling in the adult hippocampus may provide a cellular basis for understanding the impairment of neural plasticity in depressive illness. Accordingly, reversal of structural remodeling might be a desirable goal for antidepressant therapy. The present study investigated the effect of chronic psychosocial stress and concomitant repetitive transcranial magnetic stimulation treatment on stress hormone regulation and hippocampal neurogenesis. METHODS: Adult male rats were submitted to daily psychosocial stress and repetitive transcranial magnetic stimulation (20 Hz) for 18 days. Cell proliferation in the dentate gyrus was quantified by using BrdU immunohistochemistry, and both the proliferation rate of progenitors and the survival rate of BrdU-labeled cells were evaluated. To characterize the activity of the hypothalamic-pituitary-adrenocortical system, plasma corticotropin and corticosterone concentrations were measured. RESULTS: Chronic psychosocial stress resulted in a significant increase of stress hormone levels and potently suppressed the proliferation rate and survival of the newly generated hippocampal granule cells. Concomitant repetitive transcranial magnetic stimulation treatment normalized the stress-induced elevation of stress hormones; however, despite the normalized activity of the hypothalamic-pituitary-adrenocortical system, the decrement of hippocampal cell proliferation was only mildly attenuated by repetitive transcranial magnetic stimulation, while the survival rate of BrdU-labeled cells was further suppressed by the treatment. CONCLUSIONS: These results support the notion that attenuation of the hypothalamic-pituitary-adrenocortical system is an important mechanism underlying the clinically observed antidepressant effect of repetitive transcranial magnetic stimulation, whereas this experimental design did not reveal beneficial effects of repetitive transcranial magnetic stimulation on adult hippocampal neurogenesis.
PMID: 12460689 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
18: J ECT. 2002 Dec;18(4):170-81. Related Articles, Links
Mechanisms and state of the art of transcranial magnetic stimulation.
George MS, Nahas Z, Kozel FA, Li X, Denslow S, Yamanaka K, Mishory A, Foust MJ, Bohning DE.
Psychiatry Departmemt, Center for Advanced Imaging Research, Medical University of South Carolina, Charleston, SC 29425, USA. georgem@musc.edu
In 1985, Barker et al. built a transcranial magnetic stimulation (TMS) device with enough power to stimulate dorsal roots in the spine. They quickly realized that this machine could likely also noninvasively stimulate the superficial cortex in humans. They waited a while before using their device over a human head, fearing that the TMS pulse might magnetically "erase the hard-drive" of the human brain. Almost 10 years later, in 1994, an editorial in this journal concerned whether TMS might evolve into a potential antidepressant treatment. In the intervening years, there has been an explosion of basic and clinical research with and about TMS. Studies are now uncovering the mechanisms by which TMS affects the brain. It does not "erase the hard-drive" of the brain, and it has many demonstrated research and clinical uses. This article reviews the major recent advances with this interesting noninvasive technique for stimulating the brain, critically reviewing the data on whether TMS has anticonvulsant effects or modulates cortical-limbic loops.
Publication Types:
* Review
* Review, Tutorial
PMID: 12468991 [PubMed - indexed for MEDLINE]
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19: Brain. 2002 Oct;125(Pt 10):2238-47. Related Articles, Links
Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.
Liebetanz D, Nitsche MA, Tergau F, Paulus W.
Department of Clinical Neurophysiology, Georg-August University Goettingen, Robert-Koch-Strasse 40, 37075 Goettingen, Germany.
Weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex. These plastic excitability changes are selectively controlled by the polarity, duration and current strength of stimulation. To reveal the underlying mechanisms of direct current (DC)-induced neuroplasticity, we combined tDCS of the motor cortex with the application of Na(+)-channel-blocking carbamazepine (CBZ) and the N-methyl-D-aspartate (NMDA)-receptor antagonist dextromethorphan (DMO). Monitored by transcranial magnetic stimulation (TMS), motor cortical excitability changes of up to 40% were achieved in the drug-free condition. Increase of cortical excitability could be selected by anodal stimulation, and decrease by cathodal stimulation. Both types of excitability change lasted several minutes after cessation of current stimulation. DMO suppressed the post-stimulation effects of both anodal and cathodal DC stimulation, strongly suggesting the involvement of NMDA receptors in both types of DC-induced neuroplasticity. In contrast, CBZ selectively eliminated anodal effects. Since CBZ stabilizes the membrane potential voltage-dependently, the results reveal that after-effects of anodal tDCS require a depolarization of membrane potentials. Similar to the induction of established types of short- or long-term neuroplasticity, a combination of glutamatergic and membrane mechanisms is necessary to induce the after-effects of tDCS. On the basis of these results, we suggest that polarity-driven alterations of resting membrane potentials represent the crucial mechanisms of the DC-induced after-effects, leading to both an alteration of spontaneous discharge rates and to a change in NMDA-receptor activation.
Publication Types:
* Clinical Trial
* Controlled Clinical Trial
PMID: 12244081 [PubMed - indexed for MEDLINE]
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20: J Clin Neurophysiol. 2002 Aug;19(4):294-306. Related Articles, Links
Transcranial magnetic stimulation and epilepsy.
Macdonell RA, Curatolo JM, Berkovic SF.
Department of Neurology, Austin & Repatriation Medical Centre, Heidelberg, Victoria, Australia. rmac@austin.unimelb.edu.au
Transcranial magnetic stimulation has been used to study generalized and focal epilepsies for more than a decade. The technique appears safe and has yielded important information about the mechanisms underlying epilepsy. Transcranial magnetic stimulation findings differ depending on the epilepsy syndrome, lending support to the concept that there are distinct pathophysiologies underlying each condition. In most studies of generalized epilepsies, transcranial magnetic stimulation has indicated a state of relative hyperexcitability of excitatory cortical interneurons and possibly inhibitory interneurons as well, which can be reversed through the actions of anticonvulsant medications. Transcranial magnetic stimulation studies in patients with a seizure focus in the motor cortex indicate increased cortical excitability and reduced inhibition, but in patients with seizure foci located elsewhere the findings are similar to those in generalized epilepsies. Transcranial magnetic stimulation has also been used to study the mode of action of anticonvulsants and may prove to be a useful means of testing the potential for new drugs to act as anticonvulsants. Repetitive transcranial magnetic stimulation may prove to have a therapeutic role by producing long-lasting cortical inhibition after a train of impulses.
Publication Types:
* Review
* Review, Tutorial
PMID: 12436086 [PubMed - indexed for MEDLINE]
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21: Neuroreport. 2002 May 7;13(6):809-11. Related Articles, Links
Neuronal tissue polarization induced by repetitive transcranial magnetic stimulation?
Sommer M, Lang N, Tergau F, Paulus W.
Department of Clinical Neurophysiology, University of Gottingen, Robert-Koch-Str. 40, 37075 Gottingen, Germany.
In a blinded cross-over design, 10 healthy controls received 900 monophasic and biphasic repetitive transcranial magnetic stimuli over the primary motor cortex. Stimulation frequency was 1 Hz, and stimulation intensity 90% of the individual resting motor threshold. Suprathreshold stimuli applied at 0.1 Hz before and after repetitive stimulation controlled for changes in corticospinal excitability. We found a lasting corticospinal inhibition that was significantly more pronounced after monophasic than after biphasic repetitive transcranial magnetic stimulation (motor evoked potential amplitude reduced by 35 +/- 20% vs 12 +/- 37%, mean+/- s.d.). We propose that the current flow in the coil plays a significant role in optimising after effects, and asymmetric current flow may be particularly efficient in building up tissue polarization.
PMID: 11997692 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
22: Nervenarzt. 2002 Apr;73(4):332-5. Related Articles, Links
[Modulation of cortical excitability by transcranial direct current stimulation]
[Article in German]
Nitsche MA, Liebetanz D, Tergau F, Paulus W.
Abteilung Klinische Neurophysiolgie, Georg-August-Universitat Gottingen. mnitsch1@gwdg.de
Modulation of cerebral excitability is thought to be one mechanism underlying the pharmacological treatment of neuropsychiatric diseases such as epilepsy, depression, and dystonia. Repetitive transcranial magnetic stimulation (rTMS) has been tested for several years as a nonpharmacological, noninvasive method of directly influencing patients' cortical functions. We present an overview of the more easily performed transcranial direct current stimulation (tDCS) with weak current, which produces distinctly more pronounced changes in excitability than rTMS. The basic underlying mechanism is a shift in the resting membrane potential towards either hyper- or depolarisation, depending on stimulation polarity. This in turn leads to changes in the excitability of cortical neurons. Anodic stimulation increases cortical excitability, while cathodic stimulation decreases it. These changes persist after the end of stimulation if the stimulation lasts long enough, i.e., at least several minutes. The duration of this aftereffect can be controlled through the duration and intensity of the stimulation. Transcranial direct current stimulation essentially allows a focal, selective, reversible, pain-free, and noninvasive induction of changes in cortical excitability, the therapeutic potential of which must be evaluated in clinical studies, once possible risk factors have been assessed.
Publication Types:
* Review
* Review, Tutorial
PMID: 12040980 [PubMed - indexed for MEDLINE]
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23: Percept Mot Skills. 2002 Apr;94(2):575-94. Related Articles, Links
Effects of transcranial magnetic stimulation to the reciprocal Ia inhibitory interneurones in the human wrist.
Kato T, Kasai T, Maehara T.
Graduate School for International Development and Cooperation, Hiroshima University, Higashi-Hiroshima, Japan.
In humans, which neural volleys strongly activate the reciprocal Ia inhibitory interneurones have not been clarified via the corticospinal tract or from the muscle spindles. We examined the inhibition from the corticospinal tract and antagonist group Ia fibres to alpha motoneurone pools using the combined method of transcranial magnetic stimulation (TMS) and the standard H-reflex technique. The test stimulus for the forearm H-reflex and the conditioning stimulus to antagonist muscle afferents were applied to the median and radial nerves, respectively. The transcranial magnetic stimulation was applied noninvasively over the left motor cortex. The radial nerve conditioning strongly suppressed the H-reflex rather than the transcranial magnetic stimulation. Transcranial magnetic stimulation-induced inhibition was disinhibited by the conditioning stimulus applied to the median nerve. To estimate the subliminal inhibition produced by the transcranial magnetic stimulation, we used the following method: the radial nerve conditioning was altered among several different intensities, while transcranial magnetic stimulation intensity was fixed at that for which transcranial magnetic stimulation-induced inhibition was observable. A minor subliminal inhibition was observed. These results suggest that the corticospinal excitatory inputs to reciprocal Ia inhibitory interneurones in the human wrist are very weak relative to those of the originating group I muscle afferents.
PMID: 12027355 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
24: Biol Psychiatry. 2002 Mar 15;51(6):474-9. Related Articles, Links
Effects of different frequencies of transcranial magnetic stimulation (TMS) on the forced swim test model of depression in rats.
Sachdev PS, McBride R, Loo C, Mitchell PM, Malhi GS, Croker V.
School of Psychiatry, University of New South Wales, and Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, Australia.
BACKGROUND: Repetitive transcranial magnetic stimulation has been demonstrated in humans as well as in animal models to have an antidepressant effect, but the optimal frequency of stimulation is not known. We examined this question in a rat model of depression. METHODS: Young male Sprague-Dawley rats were allocated to two placebo (restraint and sham transcranial magnetic stimulation), one active control (imipramine), and four transcranial magnetic stimulation groups at 1, 5, 15 and 25 Hz and 1000 stimuli each. The Porsolt Swim Test was performed on day 1 (experiment 1). In an extension (experiment 2), the treatments were repeated on days 2 through 5, and the Swim Test repeated on days 3, 5, and 7. RESULTS: After one treatment session, all transcranial magnetic stimulation groups had significantly reduced immobility times compared with sham stimulation (p =.000), but the higher frequencies (15 and 25 Hz) did not differ significantly from lower (1 and 5 Hz) frequencies. After three sessions, all transcranial magnetic stimulation groups were different from placebo, and the rapid transcranial magnetic stimulation groups had lower immobility times than the slow transcranial magnetic stimulation groups (p =.035). After five sessions, only 15- and 25-Hz groups were different from control, and on day 7, only the 25-Hz group had reduced immobility. There was an overall difference between fast and slow transcranial magnetic stimulation (p =.010), and 1 Hz was different from the other three transcranial magnetic stimulation conditions (p =.016). CONCLUSIONS: Repetitive transcranial magnetic stimulation reduces immobility time in the Forced Swim Test model of depression, suggesting an antidepressant effect, which is evident at a range (1-25 Hz) of frequencies. With repeated administration, the findings suggest that the antidepressant effect of the higher frequencies, as for imipramine, is likely to be sustained, although the model used for this (i.e., repeating the Swim Test) requires further validation.
PMID: 11922882 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
25: Actas Esp Psiquiatr. 2002 Mar-Apr;30(2):120-8. Related Articles, Links
[Transcranial magnetic stimulation. Clinical trials in psychiatry: therapeutical use]
[Article in Spanish]
Delgado Baquero Y, Crespo Hervas D, Cisneros S, Lopez-Ibor Alino JJ.
INSALUD Area 4, Miraflores de la Sierra, 28792 Madrid, Spain.
Transcranial magnetic stimulation is the noninvasive application of localized pulsed magnetic field to the surface of the skull, to cause a depolarization of neurons in the underlying cerebral cortex (Daryl E., Bohning PH.D.). Based on Reciprocal Induction (Faraday, 1831), and the Ampere Maxwell Law, according to which electric energy is associated with magnetic energy and vice versa, transcranial magnetic stimulation has been used during the last fifteen years in the diagnosis of Central Nervous System dysfunctions, its safeness and good tolerance having been proven.Since 1876, when Darsonval discovered that the use of a similar apparatus caused vertigo, phosphenes and fainting, thousands of transcranial magnetic stimulation studies have been carried out in the fields of Neurology and Psychiatry. The present is a review of clinical studies carried out in Psychiatry, specifically related to Mood Disorders, Obsessive-Compulsive Disorder and Post traumatic-Stress Syndrome.
Publication Types:
* Review
* Review, Academic
PMID: 12028945 [PubMed - indexed for MEDLINE]
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26: Biol Psychiatry. 2002 Mar 1;51(5):417-21. Related Articles, Links
Transcranial magnetic stimulation (TMS) effects on testosterone, prolactin, and corticosterone in adult male rats.
Hedges DW, Salyer DL, Higginbotham BJ, Lund TD, Hellewell JL, Ferguson D, Lephart ED.
Department of Psychology and the Neuroscience Center, Brigham Young University, Provo, Utah 84602, USA.
BACKGROUND: Transcranial magnetic stimulation is a relatively new technique for inducing small, localized, and reversible changes in living brain tissue. Although transcranial magnetic stimulation generally results in no immediate changes in plasma corticosterone, prolactin, and testosterone, it normalizes the dexamethasone suppression test in some depressed subjects and has been shown to attenuate stress-induced increases in adrenocorticotropic hormone in rats. METHODS: In this study, serum corticosterone and testosterone concentrations were assayed in male rats immediately and 3, 6, 9, 12, 24, and 48 hours following a single transcranial magnetic stimulation or sham application. Serum prolactin concentrations were determined immediately and 2 hours following a one-time application of either transcranial magnetic stimulation or sham. RESULTS: Transcranial magnetic stimulation animals displayed significantly lower corticosterone concentrations at 6 and 24 hours following a single application compared with sham-control values. Transcranial magnetic stimulation also resulted in lower corticosterone concentrations numerically but not statistically in transcranial magnetic stimulation animals immediately after application (p =.089). No significant differences were found between groups for serum prolactin or testosterone levels at any given collection time point. CONCLUSIONS: These findings 1) suggest that transcranial magnetic stimulation alters the hypothalamic-pituitary-adrenal stress axis and 2) provide time-course data for the implications of the hormonal mechanism that may be involved in the actions of transcranial magnetic stimulation.
PMID: 11904136 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
27: Eksp Klin Gastroenterol. 2002;(6):68-74, 114. Related Articles, Links
[Intraoperative monitoring of transcranial hemodynamics in gerontological patients under general anesthesia in abdominal surgeries]
[Article in Russian]
Fedorovskii NM, Kosachenko NM, Korsunskii SB.
Moscow I.M. Sechenov Medical Academy, Moscow State Clinical Hospital No. 50.
The efficiency of up-to-date medical technologies is closely related to the development of methods and tools of objective control over the patients' state in the process of treatment. The problem of continuous control over diagnostic information occupies a special place in the medicine of critical states, since the monitoring of the patient's current state can be of vital importance. The development of tools for the monitoring of the patients' state is based on the recording of physiological data and their further evaluation with the purpose of determination of indices characterizing the operation of the most important systems of the organism.
PMID: 12685018 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
28: Semin Clin Neuropsychiatry. 2002 Jan;7(1):42-53. Related Articles, Links
Neuroimaging in neuropsychiatry.
Gordon E.
Brain Dynamics Centre, Westmead Hospital, Westmead, NSW, Australia. egordon@mail.usyd.edu.au
Advances in physics, computing, and signal processing have provided a range of computerized brain imaging technologies that facilitate examination of the brain as a dynamical system. This article provides a review of brain imaging advances and their application in neuropsychiatry. The review encompasses (1) a description of the imaging technologies used in neuropsychiatry; (2) an outline of their temporospatial complementarity; (3) application to clinical applications; and (4) suggested future directions including an "integrative neuroscience" approach to neuropsychiatry (in which theoretical models, data and information concerning mechanisms are integrated). In the absence of a unified theory of the brain, an integrated approach is presented as one means of exploring converging brain-imaging evidence in relation to neuropsychiatric disorders. Copyright 2002 by W.B. Saunders Company
Publication Types:
* Review
* Review, Tutorial
PMID: 11782890 [PubMed - indexed for MEDLINE]
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29: Clin Neurophysiol. 2001 Dec;112(12):2312-9. Related Articles, Links
Motor evoked potentials from masseter muscle induced by transcranial magnetic stimulation of the pyramidal tract: the importance of coil orientation.
Guggisberg AG, Dubach P, Hess CW, Wuthrich C, Mathis J.
Department of Neurology, University Hospital, Inselspital, 3010, Bern, Switzerland.
BACKGROUND: Reliable recording of motor evoked potentials (MEPs) of the masseter muscle by transcranial magnetic stimulation (TMS) has proved more difficult than from facial or intrinsic hand muscles. Up to now it was unclear whether this difficulty was due to methodological and/or anatomical reasons. METHODS: The mechanism of pyramidal cell activation in masseter MEPs was investigated by using magnetic and electric transcranial stimulation. Analysing the effect of magnetic coil positioning and orientation over the scalp, and scrutinizing the masseter recording technique to avoid compound motor action potential (CMAP) contamination from facial muscles, an optimized method of masseter MEPs was developed. RESULTS: In particular, an antero-lateral inducing current orientation in the stimulating coil, approximately paralleling the central sulcus, proved clearly more effective for the masseter muscles than the postero-lateral orientation (P=0.005) found optimal for intrinsic hand muscles. The thus evoked masseter MEPs by transcranial magnetic stimulation (TMS) were found to be identical in shape, amplitude and latency as those evoked by transcranial electric stimulation (TES), evidencing a direct rather than trans-synaptic activation of the pyramidal cells. CONCLUSIONS: We conclude that in TMS evoked MEPs of masseter muscles, the direct stimulation of the pyramidal tract is more easily achieved than the trans-synaptic activation, which is in contrast to the intrinsic hand muscles. We hypothesize that the presynaptic projections to pyramidal cells of the masticatory muscles are less abundant than in hand muscles, and are therefore less accessible to trans-synaptic stimulation.
PMID: 11738204 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
30: J Child Neurol. 2001 Dec;16(12):891-4. Related Articles, Links
Subjective reactions of children to single-pulse transcranial magnetic stimulation.
Garvey MA, Kaczynski KJ, Becker DA, Bartko JJ.
Pediatric Movement Disorders Unit, Pediatrics and Developmental Neuropsychiatry Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1255, USA. garveym@intra.nimh.nih.gov
Single-pulse transcranial magnetic stimulation is a useful tool to investigate cortical function in childhood neuropsychiatric disorders. Magnetic stimulation is associated with a shock-like sensation that is considered painless in adults. Little is known about how children perceive the procedure. We used a self-report questionnaire to assess children's subjective experience with transcranial magnetic stimulation. Normal children and children with attention-deficit hyperactivity disorder (ADHD) underwent transcranial magnetic stimulation in a study of cortical function in ADHD. Subjects were asked to rate transcranial magnetic stimulation on a 1 to 10 scale (most disagreeable = 1, most enjoyable = 10) and to rank it among common childhood events. Thirty-eight subjects completed transcranial magnetic stimulation; 34 said that they would repeat it. The overall rating for transcranial magnetic stimulation was 6.13, and transcranial magnetic stimulation was ranked fourth highest among the common childhood events. These results suggest that although a few children find transcranial magnetic stimulation uncomfortable, most consider transcranial magnetic stimulation painless. Further studies are necessary to confirm these findings.
PMID: 11785502 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
31: Psychiatry Res. 2001 Nov 30;108(2):123-31. Related Articles, Links
The navigation of transcranial magnetic stimulation.
Herwig U, Schonfeldt-Lecuona C, Wunderlich AP, von Tiesenhausen C, Thielscher A, Walter H, Spitzer M.
Department of Psychiatry, University of Ulm, Leimgrubenweg 12, D-89070 Ulm, Germany. uwe.herwig@medizin.uni-ulm.de
Transcranial magnetic stimulation (TMS) is a new method for investigating cortical information processing and for investigating therapeutic applications in psychiatry and neurology. A common problem of most studies in this field regards the localization of the magnetic coil with respect to the cortex. This article reviews the currently used methods and proposes a neuronavigational approach. The method of neuronavigated TMS is described and discussed in detail. It is used to guide the magnetic coil on an individual basis to a structurally or functionally predetermined cortical area while monitoring the location of the coil in relation to the subject's head in real time. Possible applications of TMS in combination with functional neuroimaging in clinical research within a cognitive neuroscience framework are discussed. Future applications of TMS should take individual anatomy into account, and neuronavigation provides the means to do so.
PMID: 11738546 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
32: Clin Neurophysiol. 2001 Nov;112(11):2015-21. Related Articles, Links
The influence of current direction on phosphene thresholds evoked by transcranial magnetic stimulation.
Kammer T, Beck S, Erb M, Grodd W.
Department of Neurobiology, Max-Planck-Institute for Biological Cybernetics, Spemannstrasse 38, D-72076, Tubingen, Germany. thomas.kammer@tuebingen.mpg.de
OBJECTIVES: To quantify phosphene thresholds evoked by transcranial magnetic stimulation (TMS) in the occipital cortex as a function of induced current direction. METHODS: Phosphene thresholds were determined in 6 subjects. We compared two stimulator types (Medtronic-Dantec and Magstim) with monophasic pulses using the standard figure-of-eight coils and systematically varied hemisphere (left and right) and induced current direction (latero-medial and medio-lateral). Each measurement was made 3 times, with a new stimulation site chosen for each repetition. Only those stimulation sites were investigated where phosphenes were restricted to one visual hemifield. Coil positions were stereotactically registered. Functional magnetic resonance imaging (fMRI) of retinotopic areas was performed in 5 subjects to individually characterize the borders of visual areas; TMS stimulation sites were coregistered with respect to visual areas. RESULTS: Despite large interindividual variance we found a consistent pattern of phosphene thresholds. They were significantly lower if the direction of the induced current was oriented from lateral to medial in the occipital lobe rather than vice versa. No difference with respect to the hemisphere was found. Threshold values normalized to the square root of the stored energy in the stimulators were lower with the Medtronic-Dantec device than with the Magstim device. fMRI revealed that stimulation sites generating unilateral phosphenes were situated at V2 and V3. Variability of phosphene thresholds was low within a cortical patch of 2x2cm(2). Stimulation over V1 yields phosphenes in both visual fields. CONCLUSIONS: The excitability of visual cortical areas depends on the direction of the induced current with a preference for latero-medial currents. Although the coil positions used in this study were centered over visual areas V2 and V3, we cannot rule out the possibility that subcortical structures or V1 could actually be the main generator for phosphenes.
PMID: 11682339 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
33: Exp Brain Res. 2001 Nov;141(1):128-32. Related Articles, Links
Transcranial magnetic stimulation. Which part of the current waveform causes the stimulation?
Corthout E, Barker AT, Cowey A.
Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK. erik.corthout@lincoln.ox.ac.uk
To investigate the mechanism of transcranial magnetic stimulation (TMS), we compared the directional effects of two stimulators (Magstim 200 and Magstim Super Rapid). First, stimulating visual cortex and facial nerve with occipital mid-line TMS, we found that, for a particular coil orientation, these two stimulators affected a particular neural structure in opposite hemispheres and that, to affect a particular neural structure in a particular hemisphere, these two stimulators required opposite coil orientations. Second, stimulating a membrane-simulating circuit, we found that, for a particular coil orientation, these two stimulators resulted in a peak induced current of the same polarity but in a peak induced charge accumulation of opposite polarity. We suggest that the critical parameter in TMS is the amplitude of the induced charge accumulation rather than the amplitude of the induced current. Accordingly, TMS would be elicited just before the end of the first (Magstim 200) and second (Magstim Super Rapid) phase of the induced current rather than just after the start of the first phase of the induced current.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 11685417 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
34: Scand J Psychol. 2001 Jul;42(3):297-305. Related Articles, Links
Transcranial magnetic stimulation as a tool for cognitive studies.
Bailey CJ, Karhu J, Ilmoniemi RJ.
BioMag Laboratory, Medical Engineering Centre, Helsinki University Central Hospital, Finland. cjb@biomag.helsinki.fi
Transcranial Magnetic Stimulation (TMS) is a tool for the non-invasive stimulation of the human brain. It allows the activation of arbitrary sites of the superficial cortex and, combined with other brain-imaging techniques such as EEG, PET, and fMRI, it can be used to evaluate cortical excitability and connectivity. This is of major importance in, for example, the study of cognitive processes such as language, learning, memory and self-representation, which are thought to be represented in multiple brain areas. The mechanisms of action of TMS are known on a basic level, but its effect on the activation state of brain tissue is still poorly understood. Clinical applications of TMS have also been proposed and guidelines for its safe use drafted.
Publication Types:
* Review
* Review, Tutorial
PMID: 11501743 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
35: Fukushima J Med Sci. 2001 Jun;47(1):21-32. Related Articles, Links
Spinal evoked potentials following transcranial magnetic stimulation.
Nemoto J, Sasaki T, Kikuchi Y, Konno Y, Sakuma J, Kodama N.
Department of Neurosurgery, Fukushima Medical University School of Medicine, Fukushima City, Japan.
Motor evoked potentials by magnetic stimulation is less invasive and causes no pain as opposed to high current electric stimulation. However, the distribution of the magnetic field generated by the round coil has not been fully studied. In this report, we mapped the extent of the magnetic induction flux density, and then the evoked potentials from the spinal cord were investigated by transcranial magnetic stimulation. We also examined the origin of the evoked potentials obtained by the magnetic stimulation. The following results were obtained. The magnetic induction flux density was at its maximum at the edge of the coil. The potentials consisted of a first negative wave and subsequent multiphasic waves. The first negative wave was similar to a response of the subcorticospinal tract in the lower brain stem, while the subsequent multiphasic waves were similar to those of the pyramidal tract. Although magnetic stimulation has certain advantages over electric stimulation, several problems remain to be solved for the monitoring of motor functions in the clinical settings.
PMID: 11764415 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
36: Biol Psychiatry. 2001 Mar 1;49(5):468-70. Related Articles, Links
Transcranial magnetic stimulation-induced switch into mania: a report of two cases.
Dolberg OT, Schreiber S, Grunhaus L.
Department of Psychiatry C, Division of Psychiatry, Sheba Medical Center, Ramat-Gan, Israel.
BACKGROUND: Transcranial magnetic stimulation is a novel, experimental procedure in the treatment of psychiatric disorders, most notably mood disorders. Transcranial magnetic stimulation is currently being widely studied in other applications, and its efficacies and potential side effects are being investigated. METHODS: Transcranial magnetic stimulation was administered five times a week for 4 weeks. RESULTS: In this report, a manic episode followed treatment with transcranial magnetic stimulation in two patients. CONCLUSIONS: Clinicians should be aware that, like with other antidepressive treatments, a switch into mania might complicate treatment with transcranial magnetic stimulation in bipolar patients.
PMID: 11274660 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
37: Clin Neurophysiol. 2001 Feb;112(2):250-8. Related Articles, Links
Motor thresholds in humans: a transcranial magnetic stimulation study comparing different pulse waveforms, current directions and stimulator types.
Kammer T, Beck S, Thielscher A, Laubis-Herrmann U, Topka H.
Department of Neurobiology, Max-Planck-Institut for Biological Cybernetics, Spemannstrasse 38, D-72076, Tubingen, Germany. thomas.kammer@tuebingen.mpg.de
OBJECTIVES: To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex. METHODS: In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid) and systematically varied current direction (postero-anterior versus antero-posterior, perpendicular to the central sulcus) as well as pulse waveform (monophasic versus biphasic). The coil position was kept constant with a stereotactic positioning device. RESULTS: Motor thresholds varied consistently with changing stimulus parameters, despite substantial interindividual variability. By normalizing the values with respect to the square root of the energy of the capacitors in the different stimulators, we found a homogeneous pattern of threshold variations. The normalized Magstim threshold values were consistently higher than the normalized Dantec thresholds by a factor of 1.3. For both stimulator types the monophasic pulse was more effective if the current passed the motor cortex in a postero-anterior direction rather than antero-posterior. In contrast, the biphasic pulse was weaker with the first upstroke in the postero-anterior direction. We calculated mean factors for transforming the intensity values of a particular configuration into that of another configuration by normalizing the different threshold values of each individual subject to his lowest threshold value. CONCLUSIONS: Our transformation factors allow us to compare stimulation intensities from studies using different devices and pulse forms. The effectiveness of stimulation as a function of waveform and current direction follows the same pattern as in a peripheral nerve preparation (J Physiol (Lond) 513 (1998) 571).
PMID: 11165526 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
38: Neurosci Lett. 2000 Dec 15;296(1):61-3. Related Articles, Links
Diminution of training-induced transient motor cortex plasticity by weak transcranial direct current stimulation in the human.
Rosenkranz K, Nitsche MA, Tergau F, Paulus W.
Department of Clinical Neurophysiology, University of Goettingen, Robert-Koch-Strasse 40, 37075, Gottingen, Germany.
Training of a thumb movement in the opposite direction of a twitch in response to transcranial magnetic stimulation (TMS) induces a transient directional change of post-training TMS-evoked movements towards the trained direction. Functional synaptic mechanisms seem to underlie this rapid training-induced plasticity. Transcranial direct current stimulation (tDCS) induces outlasting changes of cerebral excitability, thus presenting as promising tool for neuroplasticity research. We studied the influence of tDCS, applied over the motorcortex during training, on angular deviation of post-training to pre-training TMS-evoked thumb movements. With tDCS of anodal and cathodal polarity the training-induced directional change of thumb movements was significantly reduced during a 10 min post-training interval, indicating an interference of tDCS with mechanisms of rapid training-induced plasticity.
PMID: 11099834 [PubMed - indexed for MEDLINE]------------------------------------------------------------------------
39: Nat Rev Neurosci. 2000 Oct;1(1):73-9. Related Articles, Links
Transcranial magnetic stimulation and cognitive neuroscience.
Walsh V, Cowey A.
Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, OX1 3UD, UK. vin@psy.ox.ac.uk
Transcranial magnetic stimulation has been used to investigate almost all areas of cognitive neuroscience. This article discusses the most important (and least understood) considerations regarding the use of transcranial magnetic stimulation for cognitive neuroscience and outlines advances in the use of this technique for the replication and extension of findings from neuropsychology. We also take a more speculative look forward to the emerging development of strategies for combining transcranial magnetic stimulation with other brain imaging technologies and methods in the cognitive neurosciences.
Publication Types:
* Review
* Review Literature
PMID: 11252771 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------
40: J Physiol. 2000 Sep 15;527 Pt 3:633-9. Related Articles, Links
Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation.
Nitsche MA, Paulus W.
Department of Clinical Neurophysiology, University of Goettingen, Robert Koch Strasse 40, 37075 Goettingen, Germany. mnitsch1@gwdg.de
In this paper we demonstrate in the intact human the possibility of a non-invasive modulation of motor cortex excitability by the application of weak direct current through the scalp. Excitability changes of up to 40 %, revealed by transcranial magnetic stimulation, were accomplished and lasted for several minutes after the end of current stimulation. Excitation could be achieved selectively by anodal stimulation, and inhibition by cathodal stimulation. By varying the current intensity and duration, the strength and duration of the after-effects could be controlled. The effects were probably induced by modification of membrane polarisation. Functional alterations related to post-tetanic potentiation, short-term potentiation and processes similar to postexcitatory central inhibition are the likely candidates for the excitability changes after the end of stimulation. Transcranial electrical stimulation using weak current may thus be a promising tool to modulate cerebral excitability in a non-invasive, painless, reversible, selective and focal way.
Publication Types:
* Clinical TrialPMID: 10990547 [PubMed - indexed for MEDLINE]
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41: Int J Neuropsychopharmacol. 2000 Se