Fluctuating dystonia responsive to levodopa.

Four cases of hereditary progressive dystonia with diurnal fluctuation were studied. All were sporadic; three of them mimicked spastic diplegia; and the fourth showed some similarity to torsion dystonia. Emotional or cognitive disturbance, or both, was seen in three. The correct diagnosis was suggested by fluctuating signs and symptoms, which worsened towards evening, but this was reached only after many years of handicap, hospital admissions, and invasive diagnostic procedures. Typically there was a prompt, pronounced, and sustained response to moderate doses of levodopa. Sleep recordings were obtained in three patients and showed increased body movements during rapid eye movement sleep. Several close relatives had periods of increased leg movements during sleep. It is suggested that hereditary dystonia responsive to levodopa should be considered as the diagnosis in children with fluctuating signs of motor disability syndromes, simulating torsion dystonia or spastic diplegia. Polysomnographic studies may be helpful in diagnosis and may also detect early or subclinical cases.