Four cases of hereditary progressive dystonia with diurnal fluctuation were treated at the Sackler School of Medicine, Tel-Aviv University and the Technion-Israel Institute of Technology, Haifa, Israel. All were sporadic, 3 presented as spastic diplegia or were misdiagnosed as spinocerebellar degeneration, two resembled torsion dystonia, and one had been diagnosed previously as Huntington’s chorea and tics. The correct diagnosis was determined by the marked diurnal fluctuation of signs and symptoms, which worsened toward evening, and a prompt, pronounced, and sustained response to levodopa in moderate doses (100-375 mg). Treatment had been continued for 2 to 7 years. Polysomnographic studies were useful in diagnosis and showed increased body movements during REM sleep. Close relatives had increased leg movements in sleep. 
COMMENT: This syndrome was first described by Segawa M et al in Japan (Therapy 1971;24:667) and should correctly be referred to as “Segawa Syndrome”. Diurnal fluctuation of the dystonia is not invariably present and a trial of levodopa is worthwhile in possible variants of this dystonic syndrome. Emotional disturbance is a feature in some cases and may lead to a diagnosis of psychogenic etiology. In fact, in all cases of dystonia musculorum deformans (torsion dystonia) that I have treated, a diagnosis of conversion hysteria had previously been entertained and pyschotherapy prescribed.