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The cortical silent period and amyotrophic lateral sclerosis
Author(s) -
Prout Alister J.,
Eisen Andrew A.
Publication year - 1994
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880170213
Subject(s) - amyotrophic lateral sclerosis , silent period , transcranial magnetic stimulation , excitotoxicity , stimulation , motor cortex , medicine , multiple sclerosis , neuroscience , cardiology , glutamate receptor , psychology , disease , receptor , psychiatry
The cortical silent period (C‐SP) was elicited by transcranial magnetic stimulation in 25 normal subjects and 19 patients with amyotrophic lateral sclerosis (ALS). The inhibitory (S‐X) period was highly stimulus intensity (Sl)‐dependent (mean r 2 = 0.89 for both normals and patients with ALS). The range of the C‐SP (difference between maximum and minimum S‐X intervals) was age‐dependent for normals ( r 2 = 0.701, P < 0.001) but not patients with ALS. Means, maximums and ranges for the C‐SP were not significantly different between normal and ALS groups and thresholds to cortical stimulation were also comparable. There was a significant, linear, relation between the maximum C‐SP and disease duration of ALS ( P = 0.002). The maximum C‐SP was shorter early in the disease. It is hypothesized that the reduced inhibition early in the course of ALS might reflect glutamate‐induced corticomotoneuronal excitotoxicity. © 1994 John Wiley & Sons, Inc.