Physiological assessment of paroxysmal dystonia secondary to subacute sclerosing panencephalitis.

We report on a 26-year-old woman with subacute sclerosing panencephalitis (SSPE) who presented with frequent paroxysmal dystonic posturing. Electroencephalogram demonstrated generalized 5 to 10-second episodes of high-amplitude (150-300 microV) delta activity alternating with 10 to 20-second periods of theta activity (40-50 microV). The patient experienced episodes of dystonic posturing coinciding with the periods of delta activity. Ictal Tc-99m Ceretec SPECT demonstrated marked increased activity in the bilateral caudate (R>L). The frequency and amplitude of the episodes initially markedly improved after the addition of carbamazepine. We suggest that the movements seen in this case of SSPE may represent basal ganglia ictal activity.