DYSTONIC TREMOR PRESENTING AS PARKINSONISM: LONG-TERM FOLLOW-UP OF SWEDDs

Of patients entered into several randomized trials of dopaminergic medication for Parkinson disease (PD), 4% to 15% were found to have normal presynaptic nigrostriatal dopaminergic imaging and were termed subjects with scans without evidence of dopaminergic deficits (SWEDDs).1–3 Dopaminergic imaging of these patients, up to 4 years later, is reported to be normal and withdrawal of levodopa had no deleterious effect.2–3 However, several issues remain to be resolved: What conditions do the SWEDDs subjects have, if not PD? What is their long-term prognosis? What lessons can be learned from the original misdiagnoses? ### Case report. A 59-year-old man presented in 1991 with a 6-month history of increasing tremor in the right hand, a slight tremor in the left hand, and feeling generally slowed down. There was no relevant family history. The tremor had not responded to alcohol, trihexyphenidyl 10 mg once a day, or propranolol 80 mg once a day. He had had viral meningitis (age 30), with no neurologic sequelae. Examination showed reduced right arm swing during gait, a rest and postural tremor, positive Froment maneuver in the right arm, and slow repetitive finger movements, worse on the right. A cerebral CT scan and routine blood tests, including copper studies and protein electrophoresis, had normal results. EMG of the right arm demonstrated 6–7 Hz rhythmic activity at rest and on posture with synchronous activity in agonist/antagonist …