To get more insight the pathophysiological basis of periodic limb movement disorder (PLMD), we invastigated wether these patients have changes in the cortical silent period (SP) after transcranial magnetic stimulation (TMS).
TMS studies were performed in 9 patients with severe PLMD receiving no psychoactive drugs and were repeated after administration of a single evening dose of 200/50 mg levodopa/benserazid. These data were compared with the results of the measurment on 9 healthy volunteers as control group receiving no psychoactive drugs. The parameters were recorded in the morning and the evening an the left tibialis anterior muscle (TA) and the left abductor digiti minimi muscle (ADM).
Primary endpoint was the duration of the SP in the TA in the evening. Secundary endpoint was the SP in the TA in the morning, the SP in the ADM in the morning and envening, the excitatory threshold in TA and ADM, the inhibitory threshold in the TA and ADM and the central motor conduction time (CMCT) in the TA and ADM in the morning and evening.
Our data indicate no changes of the central inhibition in PLMD patients. The results of this study give further insight in the pathophysiology of PLMD by showing no deep influence of the central inhibition on PLMD.
