Qualitative H-reflex testing in huntington's disease.

The occurrence of H-reflexes over both the anterior tibial muscle and the thenar muscle on both sides was investigated in 15 patients suffering from Huntington's disease, 8 clinically inconspicuous offspring, and 30 healthy normal controls. The following results were obtained: 1. An obvious H-reflex over the anterior tibial muscle was found in 12 of 15 patients; there was no H-reflex in only 3 patients. 2. After stimulation on the median nerve there was an H-reflex in 12 of 13 patients investigated. 3. In 5 of 8 clinically inconspicuous offspring there was an H-reflex after peroneal [4] or median [5] nerve stimulation. In 30 normal controls, 1 displayed a weak H-reflex over the anterior tibial muscle, 9 showed a weak H-reflex after median nerve stimulation. 5. The possibility is discussed that an abnormal H-reflex might be an early sign of central reflex disinhibition in otherwise asymptomatic offspring.