Motor excitability in a patient with a somatosensory cortex lesion.
OBJECTIVE
We report a patient with an ischemic lesion in right somatosensory cortex who developed dystonic posturing and pseudo-athetotic involuntary left-sided finger movements during voluntary muscle contractions.


METHODS
Motor excitability was assessed using transcranial magnetic stimulation techniques and electrical peripheral nerve stimulation. Results obtained from abductor digiti minimi muscles of both hands were compared.


RESULTS
On the affected side, silent period duration and intracortical inhibition were reduced, indicating a loss of inhibitory properties. Intracortical facilitation was enhanced. Stimulus-response curves showed a smaller increase of motor evoked potential amplitudes when recorded during muscle relaxation, but not during voluntary muscle activation.


CONCLUSIONS
The results suggest that, under normal conditions, somatosensory cortex modifies inhibitory as well as excitatory properties in the motor system.
Liepert
Joachim
J
Department of Neurology, University of Hamburg, University Hospital Eppendorf, Martinistrasse 52, D-20246, Hamburg, Germany. liepert@uke.uni-hamburg.de
Gorsler
A
A
van Eimeren
T
T
Münchau
A
A
Weiller
C
C
D020821:Dystonic Disorders / Q000209:etiology* / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography; D004594:Electrophysiology; D019054:Evoked Potentials, Motor / Q000502:physiology; D005073:Evoked Potentials, Somatosensory; D007839:Functional Laterality; D006225:Hand / Q000294:innervation; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D011930:Reaction Time; D020886:Somatosensory Disorders / Q000150:complications / Q000503:physiopathology*; D014459:Ulnar Nerve / Q000503:physiopathology