Periodic triphasic waves in levodopa-induced encephalopathy.

Four patients with idiopathic Parkinson's disease developed subacute confusional states, associated with delusions, hallucinations, and myoclonus, following an increase in the dose of levodopa. The EEG revealed periodic generalized triphasic waves. The clinical condition and EEG cleared following levodopa dose reduction or discontinuation. This is the first report of encephalopathy associated with periodic triphasic activity following levodopa treatment.