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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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