Central motor conduction to hand and leg muscles in Huntington's disease.

Using electromagnetic stimulation of motor cortex and cervical or lumbar roots, central conduction times to the thenar and abductor hallucis muscles bilaterally were determined in a population of 32 patients with definite Huntington's disease (HD) and 14 subjects at risk. The HD patients showed a wide variety of different severity of choreatic movements, disease duration, and total disability. None of the stimulation parameters (latency after cortical stimulation, amplitude, threshold, or central conduction time) revealed statistically significant abnormalities compared with a normal control group as well as between patient subgroups. The data indicate that central motor conduction to upper and lower extremity muscles remains normal in Huntington's disease irrespective of the severity of the disorder.