[Fluctuating muscular dystonia. Segawa's syndrome. Value of the treatment with L-dopa].

The case of an 8 year-old boy presenting with walking difficulties due to dystonia, peculiar because it was more pronounced during daytime is reported. Improvement with treatment with L-Dopa was dramatic. This diurnal fluctuation and excellent response to L-Dopa suggest the diagnosis of Segawa syndrome. The precise mechanism of the dystonia remains unknown.