Abnormal postexcitatory and interhemispheric motor cortex inhibition in writer's cramp.
J Neurol
; 248(1): 51-6, 2001 Jan.
Article
in En
| MEDLINE
| ID: mdl-11266020
ABSTRACT
Focal transcranial magnetic stimulation (TMS) of the motor cortex was used to study excitatory and inhibitory stimulation effects in 25 patients with writer's cramp and 25 healthy volunteers. We investigated excitatory and inhibitory corticospinally mediated motor effects in muscles contralateral to the stimulation side as well as interhemispheric inhibition of tonic motor activity in muscles ipsilateral to stimulation. Motor evoked potentials (MEPs) were recorded from both first dorsal interosseus muscles. Motor thresholds at rest and amplitudes and latencies of MEPs obtained during maximal contraction were always bilaterally normal. The duration of postexcitatory inhibition was significantly shortened (168+/-55 vs. 198+/-39 ms in normal subjects, P=0.001) and the duration of interhemispheric inhibition prolonged (30.3+/-6.6 vs. 26+/-3.9 ms in normal subjects, P < 0.001). Both observations would be compatible with a decreased inhibition of corticospinal and transcallosal outputs of the motor cortex. The results were not influenced by fatigue effects. Abnormal motor cortex inhibition seems to be a generalized phenomenon in writer's cramp since it was detected in both hemispheres and during a simple isometric motor task which did not evoke dystonic symptoms.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Corpus Callosum
/
Motor Cortex
/
Muscle Cramp
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
J Neurol
Year:
2001
Type:
Article
Affiliation country:
Germany