POSTEXCITATORY INHIBITION AFTER TRANSCRANIAL MAGNETIC SINGLE AND DOUBLE BRAIN-STIMULATION IN HUNTINGTONS-DISEASE

Postexcitatory inhibition (pI) was studied in 13 patients with differe nt clinical forms of Huntington's disease (HD), using a transcranial m agnetic single and double stimulation paradigm. We found pathological results of pI in 77% of the HD patients. A significant prolongation of pI could be demonstrated in the group of patients suffering from a cl assical form of HD. In contrast to these patients, those patients suff ering from primary rigid HD variants exhibited a shortening of pI. The se results suggest an altered excitability of the motor cortex in HD a ccording to dysfunctions within the motor cortex-basal ganglia loop, T ranscranial double stimulation was a more sensitive measure in detecti ng changes of cortical excitation levels than single stimulation, The interpretation of pI changes in HD has to Lake the clinical subtype of HD into account.