Magnetic brain stimulation: safety studies

Chokroverty, Sudhansu; Hening, Wayne A.; Wright, David L.; Walczak, Thaddeus S.; Goldberg, Jeffrey I.; Burger, R. Michael; Belsh, Jerry M.; Patel, Bhavana; Flynn, Daniel; Shah, Shruti; Mero, R.

doi:10.1016/0924-980x(94)00250-b

Cited by 62 publications

(27 citation statements)

References 22 publications

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“…Safety studies have shown that single-pulse TMS is safe in normal subjects (13). In patients with epilepsy, Tassinari et al (14) first demonstrated the safety of single TMS, and Reutens et al (15) and Michelucci et al (16) later reported very similar results.…”

Section: Safety Issuessupporting

confidence: 57%

Cortical Excitability in Cryptogenic Localization‐Related Epilepsy: Interictal Transcranial Magnetic Stimulation Studies

Cantello¹,

Civardi²,

Cavalli³

et al. 2000

Epilepsia

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Summary:Purpose: To assess whether single-and pairedpulse transcranial magnetic stimulation (TMS) can measure the interictal brain excitability of medicated patients with cryptogenic localization related epilepsy (CLE). Changes in the balance between excitation and inhibition are the core phenomena in focal epileptogenesis. TMS can assess this balance in the primary motor cortex.Methods: We selected 18 patients with CLE and similar clinical features in whom we located the epileptogenic area reliably, with 11 age-and sex-matched healthy controls. For both motor cortices, we determined the threshold to TMS, the duration of the cortical silent period, and the corticocortical inhibition and facilitation curve.Results: TMS was safe. The more antiepileptic drugs (AEDs) taken by the patients, the higher their threshold to TMS. The silent period duration failed to show significant changes. On paired TMS, a cluster analysis identified a homogeneous subgroup of patients (n = 7) who showed a significantly defective corticocortical inhibition and excess facilitation. With respect to the epileptogenic area, the phenomenon was bilateral in four of these patients, ipsilateral in two, and contralateral in one. The phenomenon was independent of AEDs and many other clinical variables. However, this patient group had a higher seizure frequency and a higher proportion of electroencephalograms (EEGs) showing interictal generalized epileptic discharges than the rest of the patients.Conclusion: Paired TMS provided a valuable pathophysiologic insight into the interictal excitatory state of the cortex in CLE. This method can potentially supply useful prognostic clinical information.

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Section: Safety Issuessupporting

confidence: 57%

Cortical Excitability in Cryptogenic Localization‐Related Epilepsy: Interictal Transcranial Magnetic Stimulation Studies

Cantello¹,

Civardi²,

Cavalli³

et al. 2000

Epilepsia

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“…According to Klass (1977), Kozelka et al (1990), Vaughan et al (1998), Goldman et al (2000) and Kalita et al (2006) the magnitudes of the rhythms of cortical origin, with special consideration given to the value of amplitude and its periodicity, are the basis for proper determination of brain bioelectrical activity, and are also connected with the precise definition of the physiological state of the CNS. This theory is supported by numerous authors (Chokroverty et al 1995, Intriligator et al 1995, Mahla 1997, Liporace et al 1998, Schack et al 1999, Goldman et al 2000, Wolpaw et al 2002, Armitage et al 2003, Ashequr et al 2005, LeVan et al 2006, and there are no studies challenging that theory.…”

Section: Determination Of a Normal Reaction Of The Cerebral Cortex Bimentioning

confidence: 81%

Recording of bioelectrical activity changes in sheep cerebral cortex

Cwynar

Zawadzki

2010

Arch. med. vet.

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RESUMENEl objetivo de este estudio es presentar el uso práctico de la electroencefalografía (EEG), demostrando el aspecto básico de EEG en ovejas, así como su utilidad en el análisis de las alteraciones provenientes del sistema nervioso central. Se examinaron 10 hembras híbridas de Oveja Merino Polaca, seleccionadas especialmente con fines experimentales. Debido a la falta de una fórmula unificada en el método de EEG en animales, se realizó un registro de potenciales provenientes de algunos puntos escogidos tras el experimento en cabezas de animales. Durante los experimentos realizados se demostró que la corteza cerebral de ovejas se caracteriza por una dinámica muy alta, hecho que fue demostrado al examinar las reacciones del sistema nervioso central a los factores tales como: el hambre, la estimulación auditiva o la inyección de xylazyna. La corteza cerebral de ovejas en el estado de reposo muestra una actividad bioeléctrica de una amplitud media de 30 μV y una frecuencia de 25 Hz, con lo cual se confirma la existencia del ritmo beta [β]. La aplicación de un estímulo acústico permite estimular el sistema nervioso central de oveja, lo que queda comprobado por una elevación de la amplitud media (por 23%) y de la frecuencia (por 21%) de la actividad bioeléctrica de la corteza cerebral, como también lo confirma el electroencefalograma conseguido. Los datos obtenidos demuestran que la zona que se caracteriza por tener el tiempo más corto de reacción es la zona del mesencéfalo, con un tiempo medio de reacción de 0,56 segundos (± 0,005 s). Se discute además la aplicabilidad de los experimentos, así como también la posibilidad de unificar el método de EEG.

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“…In Chiuich and Orekhova's study, the subjects were exposed to 10 sessions of ELF-EMF, 16 whereas in other studies, subjects were exposed to only 1 or 2 sessions. [11][12][13]15 In addition, in Chiuich and Orekhova's study, subjects were hypertensive, whereas the subjects were normotensive in other studies. [11][12][13][14][15] In our study, subjects with clinically well-defined hypertension were involved; thus, the status of the subjects seems to be important in eliciting an effect of ELF-EMFs on BP.…”

Section: Discussionmentioning

confidence: 88%

“…[11][12][13]15 In addition, in Chiuich and Orekhova's study, subjects were hypertensive, whereas the subjects were normotensive in other studies. [11][12][13][14][15] In our study, subjects with clinically well-defined hypertension were involved; thus, the status of the subjects seems to be important in eliciting an effect of ELF-EMFs on BP. This argument may be supported by our observation that ELF-EMF exposure seemed to have a greater effect on subjects in the ELF-EMF group at the start of the study (for example, during the first week, there were significant differences between the ELF-EMF and sham groups with respect to change in SBP values preand postexposure session), but had a lesser effect as subjects became normotensive (Table 2 and Figure 1).…”

Section: Discussionmentioning

confidence: 88%

“…8 In several studies, extremely low-frequency (ELF)-EMFs have been shown to have no effect on systolic BP (SBP) or diastolic BP (DBP) in humans. [11][12][13][14][15] However, in a self-controlled study of 60 hypertensive subjects, each of whom was exposed to ten 12-to 15-min sessions of a 50-Hz 30-mT EMF, Chiuich and Orekhova found that the ELF-EMF induced a significant decrease in BP. 16 In that study, posttreatment peripheral vascular resistance was decreased compared with pretreatment, 16 which may have acted to ameliorate hypertension.…”

Section: Introductionmentioning

confidence: 99%

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A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study

et al. 2011

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The effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on blood pressure (BP) are controversial. In this double-blind, randomized, sham-controlled study, we examined the effects of repeated exposure to a 1-lT ELF-EMF on BP in 20 humans with mild-to-moderate hypertension. Subjects were randomly assigned to either the ELF-EMF group or the sham group. Subjects in the ELF-EMF group were exposed to an ELF-EMF (6-and 8 Hz, respectively, peak magnetic field 1 lT, peak electric field 10 V m À1 ) for at least two 10-to 15-min sessions per week, over a period of 4 weeks. In the sham group, the EMF-generating apparatus was not active. We obtained systolic and diastolic BP (SBP and DBP, respectively) measurements at registration and before and after each ELF-EMF exposure session. Subjects in the ELF-EMF and sham groups had mean ages of 52.8 and 55.1 years, and were exposed to a mean of 9.9 and 9.0 sessions, respectively. There was a significant difference between the ELF-EMF and sham groups with respect to change in SBP value between baseline and the end of the exposure regimen (P¼0.02), but not with respect to change in DBP (P¼0.21). There were no adverse events other than mild paresthesia of the hands of two subjects in the ELF-EMF group. Our results suggest that repeated exposure to an ELF-EMF has a BP-lowering effect on humans with mild-to-moderate hypertension.

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Magnetic brain stimulation: safety studies

Cited by 62 publications

References 22 publications

Cortical Excitability in Cryptogenic Localization‐Related Epilepsy: Interictal Transcranial Magnetic Stimulation Studies

Cortical Excitability in Cryptogenic Localization‐Related Epilepsy: Interictal Transcranial Magnetic Stimulation Studies

Recording of bioelectrical activity changes in sheep cerebral cortex

A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study

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