Document Detail

Reduced excitability of the motor cortex in untreated patients with de novo idiopathic "grand mal" seizures.
MedLine Citation:
PMID:  11723199     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Transcranial magnetic stimulation (TMS) was used to investigate motor cortex excitability, intracortical excitatory, and inhibitory pathways in 18 patients having experienced a first "grand mal" seizure within 48 hours of the electrophysiological test. All had normal brain MRI, and were free of any treatment, drug, or alcohol misuse. Results were compared with those of 35 age matched normal volunteers. METHODS: The following parameters of responses to TMS were measured: motor thresholds at rest and with voluntary contraction, amplitudes of responses, cortical silent periods, and responses to paired pulse stimulation with interstimulus intervals of 1 to 20 ms. RESULTS: In patients, there were significantly increased motor thresholds with normal amplitudes of motor evoked potentials (MEPs), suggesting decreased cortical excitability. Cortical silent periods were not significantly different from those of normal subjects. Paired TMS with short interstimulus intervals (1-5 ms) induced normal inhibition of test MEPs, suggesting preserved function of GABAergic intracortical inhibitory interneurons. On the contrary, the subsequent period of MEP facilitation found in normal subjects (ISIs of 6-20 ms) was markedly reduced in patients. This suggests the existence of abnormally prolonged intracortical inhibition or deficient intracortical excitation. In nine patients retested 2 to 4 weeks after the initial seizure, these abnormalities persisted, although to a lesser extent. CONCLUSION: The present findings together with abnormally high motor thresholds could represent protective mechanisms against the spread or recurrence of seizures.
V Delvaux; G Alagona; P Gérard; V De Pasqua; P J Delwaide; A Maertens de Noordhout
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of neurology, neurosurgery, and psychiatry     Volume:  71     ISSN:  0022-3050     ISO Abbreviation:  J. Neurol. Neurosurg. Psychiatr.     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-11-27     Completed Date:  2001-12-28     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985191R     Medline TA:  J Neurol Neurosurg Psychiatry     Country:  England    
Other Details:
Languages:  eng     Pagination:  772-6     Citation Subset:  IM    
University Department of Neurology, Hôpital de la Citadelle, B-4000 Liège, Belgium.
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MeSH Terms
Case-Control Studies
Epilepsy, Tonic-Clonic / diagnosis*,  etiology,  physiopathology*
Evoked Potentials, Motor*
Magnetics / diagnostic use*
Middle Aged
Motor Cortex / physiopathology*
Multivariate Analysis
Time Factors
gamma-Aminobutyric Acid / physiology
Reg. No./Substance:
56-12-2/gamma-Aminobutyric Acid

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