Seizure & Stroke
Seizure

Effect of magnetic fields on the interictal firing rate of epileptic patients
Magnetic stimulation can modulate seizures in epileptic patients
Magnetic field modulates severity of audiogenic seizures in mice
Transcranial magnetic stimulation for the treatment of seizures
Magnetic stimulation in the treatment of partial seizures
Stroke

Magnet therapy in rehabilitation of patients with cerebral ischemia
Treatment-induced cortical reorganization after stroke in humans
Motor hand recovery after stroke - Prognostic yield of early transcranial magnetic stimulation
Protection against focal cerebral ischemia following exposure to a pulsed electromagnetic field


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Seizure

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On the confirmation of an effect of magnetic fields on the interictal firing rate of epileptic patients.

Fuller M, Wilson CL, Velasco AL, Dunn JR, Zoeger J.

HIGP-SOEST, University of Hawaii, 2525 Correa Road, Honolulu, HI 96822, USA. mfuller@soest.hawaii.edu

The effect of magnetic fields on interictal firing rates was investigated in three epileptic patients with depth electrode implantation in the hippocampus for pre-surgical evaluation. The protocol consisted of 10 min test periods, during which magnetic fields were cycled for 1 min on and 1 min off, and intervening 5 min rest periods. Only one patient revealed a 95% significant increase in the 10 s after the fields were switched on compared with the background estimate from the 10s before the fields were applied. This patient was also the only patient to show significant increases in firing rates during field-on compared with field-off periods, and during magnetic field test periods compared with intervening rest periods. This patient had a right hippocampal seizure onset. All patients showed increased firing rates during the 10 min periods of magnetic field testing compared to the 5 min rest periods between tests. This result was significant for the group at the 99% level. Two patients with right temporal lobe onset showed greater activity in the right hippocampus than the left. All patients exhibited a progressive increase in firing rates in rest periods between tests.

Brain Res Bull. 2003 Apr 15;60(1-2):43-52.

 

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Magnetic stimulation can modulate seizures in epileptic patients.

Anninos P, Kotini A, Adamopoulos A, Tsagas N.

Lab of Medical Physics, Medical School, Democritus University of Thrace, Alex/polis, Greece. anninos@med.duth.gr

OBJECTIVE: The aim of this study is to investigate the influence of external magnetic stimulation (EMS) in epileptic patients using magnetoencephalographic (MEG) measurements and non-linear analytic techniques.

METHODS: The examined group consisted of 15 men aged 19-56 years (mean: 39.5 +/- 11.3) and 15 women aged 15-53 years (mean: 36.7 +/- 11.4). For each one the magnetic activity was recorded from 32 points for each temporal lobe. External magnetic stimulation (EMS) with proper field characteristics (intensity: 1-7.5 pT, frequency: the alpha-rhythm of the patient (8-13 Hz)) was applied in the frontal, occipital and temporal lobes for 2 to 6 minutes and the emitted brain magnetic activity was recorded again. In order to investigate if there is any alteration in the MEG complexity underlying the neural dynamics characterizing the pathologic brain before and after the EMS, chaotic analysis approach was applied for the estimation of the dimensional analysis of the existing strange attractors.

RESULTS: The application of EMS resulted in rapid attenuation of the MEG activity of epileptic patients. The obtained results of the dimensionality calculation provide a shift from lower to higher dimensional values. Such a shift is an indication that we are dealing with a chaotic system similar with the one characterizing normal subjects.

CONCLUSIONS: The increased values of the dimensional complexity and the lower activity of the MEG after the application of EMS strongly supports the beneficial effects of EMS in epileptic patients.

Brain Topogr. 2003 Fall;16(1):57-64.


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A static magnetic field modulates severity of audiogenic seizures and anticonvulsant effects of phenytoin in DBA/2 mice.

McLean MJ, Engstrom S, Holcomb RR, Sanchez D.

Department of Neurology, Vanderbilt University Medical Center, 2100 Pierce Avenue, 351 MCS, Nashville, TN 37212, USA. michael.mclean@vanderbilt.edu

RATIONALE: In a search for potential supplements or alternatives to the pharmacological treatment of epilepsy, we examined the effects of static magnetic fields on audiogenic seizures of DBA/2 mice.

METHODS: Two strains of DBA/2 mice were subjected to auditory stimulation that resulted sequentially in wild running, loss of righting, clonus, tonic hindlimb extension, and death in 80-95% of animals in different experiments. The incidence of seizure stages in groups of animals pretreated with a static magnetic field, phenytoin (PHT) or both was compared to the incidence in sham-exposed control mice.

RESULTS: Depending on magnetic flux density and duration of exposure to the field, seizure severity decreased significantly, but not completely, in both strains. However, incidence of five seizure stages was reduced in one strain, with about half of the mice seizure free. Two seizure stages (tonic hindlimb extension and death) were reduced significantly in the other. Magnetic field pretreatment potentiated the effect of PHT. Clonic seizures refractory to PHT or magnetic field pretreatment in DBA/2J mice responded to pretreatment with a combination of PHT and the magnetic field.

CONCLUSIONS: A static magnetic field had some anticonvulsant effects when employed alone. More robust effects were seen in combination with PHT. Further testing of magnetic fields for anticonvulsant effects and elucidation of mechanisms of action seem to be warranted.

Epilepsy Res. 2003 Jun-Jul;55(1-2):105-16.


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Transcranial magnetic stimulation for the treatment of seizures: a controlled study.

Theodore WH, Hunter K, Chen R, Vega-Bermudez F, Boroojerdi B, Reeves-Tyer P, Werhahn K, Kelley KR, Cohen L.

Clinical Epilepsy, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA. theodorw@ninds.nih.gov

OBJECTIVE: To perform a controlled trial of transcranial magnetic stimulation (TMS).

METHODS: Twenty-four patients with localization-related epilepsy were randomized to blinded active or placebo stimulation. Weekly seizure frequency was compared for 8 weeks before and after 1 week of 1-Hz TMS for 15 minutes twice daily.

RESULTS: When the 8-week baseline and post-stimulation periods were compared, active patients had a mean seizure frequency reduction of 0.045 +/- 0.13 and sham-stimulated control subjects -0.004 +/- 0.20. Over 2 weeks, actively treated patients had a mean reduction in weekly seizure frequency of 0.16 +/- 0.18 and sham-stimulated control subjects 0.01 +/- 0.24. Neither difference was significant.

CONCLUSION: The effect of TMS on seizure frequency was mild and short lived.

Neurology. 2002 Aug 27;59(4):560-2.


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Magnetic stimulation in the treatment of partial seizures.

Anninos PA, Tsagas N, Sandyk R, Derpapas K.

Democrition University of Thrace, Department of Medical Physics and Polytechnic School, Alexandroupolis, Greece.

We have recently demonstrated that Magnetoencephalographic (MEG) brain measurements in patients with seizure disorders show significant MEG activity often in the absence of conventional EEG abnormalities. We localized foci of seizure activity using the mapping technique characterized by the ISO-Spectral Amplitude (ISO-SA) on the scalp distribution of specified spectral components or frequency bands of the emitted MEG Fourier power spectrum. In addition, using an electronic device, we utilized the above recorded activity to emit back the same intensity and frequency of magnetic field to the presumed epileptic foci. Using this method we were able, over the past two years, successfully to attenuate seizure activity in a cohort of over 100 patients with various forms of epilepsy. We now present in more detail three randomly selected patients with partial seizures in whom application of an external artificial magnetic field of low intensity produced a substantial attenuation of seizure frequency during an observation period extending from 10 to 14 months. All patients had previously obtained only partial response to conventional anticonvulsant therapy. Attenuation in seizure frequency was associated with normalization of the MEG activity. These cases demonstrate that artificial magnetic treatment may be a valuable adjunctive procedure in the management of partial seizures. The possible mechanisms underlying the anticonvulsant properties of magnetic stimulation at both cellular and systemic levels are discussed. Specifically, since the pineal gland has been shown to be a magnetosensitive organ which forms part of a combined compass-solar clock system, and since it exerts an inhibitory action on seizure activity in both experimental animals and humans, we discuss the potential pivotal role of the pineal gland in the long term anticonvulsant effects of external artificial magnetic stimulation.

Int J Neurosci. 1991 Oct;60(3-4):141-71.

 

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Stroke

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Magnet therapy in rehabilitation of patients with cerabral ischemia.

Provotorov VM, Putilina MV.

Basing on the results of clinical examination and treatment of 420 patients with aftereffects of acute circulatory disturbance, the authors propose a pathogenetically grounded approach to correction of the residual phenomena following stroke. The method proposed includes three courses of impulse electromagnetotherapy used in combination with either standard chemotherapy or massage and therapeutic exercise.

Vopr Kurortol Fizioter Lech Fiz Kult. 2001 Mar-Apr;(2):23-6.


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Treatment-induced cortical reorganization after stroke in humans.

Liepert J, Bauder H, Wolfgang HR, Miltner WH, Taub E, Weiller C.

Department of Neurology, Friedrich-Schiller-University of Jena, Germany. liepert@neuro.uni-jena.de

BACKGROUND AND PURPOSE: Injury-induced cortical reorganization is a widely recognized phenomenon. In contrast, there is almost no information on treatment-induced plastic changes in the human brain. The aim of the present study was to evaluate reorganization in the motor cortex of stroke patients that was induced with an efficacious rehabilitation treatment.

METHODS: We used focal transcranial magnetic stimulation to map the cortical motor output area of a hand muscle on both sides in 13 stroke patients in the chronic stage of their illness before and after a 12-day-period of constraint-induced movement therapy.

RESULTS: Before treatment, the cortical representation area of the affected hand muscle was significantly smaller than the contralateral side. After treatment, the muscle output area size in the affected hemisphere was significantly enlarged, corresponding to a greatly improved motor performance of the paretic limb. Shifts of the center of the output map in the affected hemisphere suggested the recruitment of adjacent brain areas. In follow-up examinations up to 6 months after treatment, motor performance remained at a high level, whereas the cortical area sizes in the 2 hemispheres became almost identical, representing a return of the balance of excitability between the 2 hemispheres toward a normal condition.

CONCLUSIONS: This is the first demonstration in humans of a long-term alteration in brain function associated with a therapy-induced improvement in the rehabilitation of movement after neurological injury.

Stroke. 2000 Jun;31(6):1210-6.


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Motor hand recovery after stroke. Prognostic yield of early transcranial magnetic stimulation.

Cruz Martinez A, Tejada J, Diez Tejedor E.

Unidad de Electromiografia, Hospital La Luz, Madrid, Spain.

Transcranial magnetic stimulation (TMS) was performed in 20 patients within the first days after stroke. Motor evoked potentials (MEPs) were bilaterally recorded over thenar eminence muscles, and central motor conduction time (CMCT), amplitude of the MEPs (A%M) and threshold intensity compared between both sides. Six months later the patients were reexamined. Within the first days after stroke the obtention of MEPs at rest or during voluntary muscle activation have a favorable prognostic value. All patients with early response by TMS reached a good motor function in the following months. The follow-up showed that the electrophysiological improvement was closely related to clinical recovery of the hand function. However, even in cases with a good recovery, the CMCT and, mainly, the A%M, may be significantly different related to those in normal hand. TMS may be an early and valuable prognostic indicator of hand function recovery after stroke, and their prognostic yield is higher than clinical evaluation and CT study. TMS is a quantifiable method of motor disability and may have practical application in the management and rehabilitation therapy in stroke patients.

Electromyogr Clin Neurophysiol. 1999 Oct-Dec;39(7):405-10.

 

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Protection against focal cerebral ischemia following exposure to a pulsed electromagnetic field.

Grant G, Cadossi R, Steinberg G.

Department of Neurosurgery, Stanford University, California 94305.

There is evidence that electromagnetic stimulation may accelerate the healing of tissue damage following ischemia. We undertook this study to investigate the effects of low frequency pulsed electromagnetic field (PEMF) exposure on cerebral injury in a rabbit model of transient focal ischemia (2 h occlusion followed by 4 h of reperfusion). PEMF exposure (280 V, 75 Hz, IGEA Stimulator) was initiated 10 min after the onset of ischemia and continued throughout reperfusion (six exposed, six controls). Magnetic resonance imaging (MRI) and histology were used to measure the degree of ischemic injury. Exposure to pulsed electromagnetic field attenuated cortical ischemia edema on MRI at the most anterior coronal level by 65% (P < 0.001). On histologic examination, PEMF exposure reduced ischemic neuronal damage in this same cortical area by 69% (P < 0.01) and by 43% (P < 0.05) in the striatum. Preliminary data suggest that exposure to a PEMF of short duration may have implications for the treatment of acute stroke.

Bioelectromagnetics. 1994;15(3):205-16.

Stroke
Treatment with sinusoidal modulated currents coupled with Tran cerebral magnetic fields proved more effective than either therapy on its own in the treatment of stroke patients during the period of early rehabilitation.

F.E. Gorbunov, The Effect of Combined Transcerebral Magnetic and Electric Impulse Therapy on the Cerebral and Central Hemodynamic Status of Stroke Patients in the Early Rehabilitation Period.

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