Neurophysiological features of fasciculation potentials evoked by transcranial magnetic stimulation in amyotrophic lateral sclerosis

Citation
M. De Carvalho et al., Neurophysiological features of fasciculation potentials evoked by transcranial magnetic stimulation in amyotrophic lateral sclerosis, J NEUROL, 247(3), 2000, pp. 189-194
Citations number
21
Categorie Soggetti
Neurosciences & Behavoir
Journal title
JOURNAL OF NEUROLOGY
ISSN journal
03405354 → ACNP
Volume
247
Issue
3
Year of publication
2000
Pages
189 - 194
Database
ISI
SICI code
0340-5354(200003)247:3<189:NFOFPE>2.0.ZU;2-9
Abstract
We report 13 patients with amyotrophic lateral sclerosis in whom fasciculat ion potentials (FPs) driven by transcranial magnetic stimulation (TMS) were recorded. ii total of 18 different FPs were analyzed. TMS-driven fascicula tions had a simple morphology and were stable. Complex potentials were neve r cortically driven. Recruitment by a slight voluntary contraction was veri fied in 7 of 13 tested FPs. FPs were driven by threshold stimuli in 7 of 10 patients and by stimuli 5% below threshold in 3 of 6. Mapping demonstrated that FPs were driven in an area close to the center of gravity of the musc le cortical area. In one case FPs were evoked from most of the cortical rep resentation area of a very weak muscle. Three other patients with profuse f asciculations associated with other clinical conditions were also studied. No TMS evoked fasciculation was observed in this group. The results of this systematic study suggest that cortically evoked FPs arise centrally, at sp inal cord or even more proximally, and can represent a marker of increased corticomotor excitability, which is predominant at an earlier phase but can persist as the disease progresses.