Quantitative evaluation of functional capacity during isoniazid therapy in Huntington's disease

Eleven patients with Huntington's disease were treated with high doses of isoniazid. In addition to clinical assessment, the functional capacity was evaluated quantitatively. The symptoms of four of the patients showed a marked improvement and their functional capacity increased. The condition of one patient with the rigid form (Westphal's variant) deteriorated, and the remaining six patients showed no change. Patients with prominent mental disturbances appeared to respond best to isoniazid therapy.