INTRACORTICAL INHIBITION AND FACILITATION ARE ABNORMAL IN HUNTINGTONS-DISEASE - A PAIRED MAGNETIC STIMULATION STUDY

Transcranial magnetic stimulation with a conditioning-test paradigm wa s used to assess cortico-cortical interactions in the motor cortex of 11 patients with Huntington's disease (HD) as compared to normal contr ols (NC). In the HD patients, threshold and amplitude of motor potenti als evoked in the opponens pollicis muscle at rest were not significan tly different from NC. The cortico-cortical inhibition at interstimulu s intervals of 2-5 ms was significantly reduced and the cortico-cortic al facilitation at longer intervals (10-25 ms) was significantly enhan ced. Changes of intracortical inhibition and facilitation were related to clinical rating of choreic dyskinesias. The data support the hypot hesis of a functional impairment of the motor cortex-basal ganglia loo p in HD patients. (C) 1997 Elsevier Science Ireland Ltd.