Patients with adult‐onset dystonic tremor resembling parkinsonian tremor have scans without evidence of dopaminergic deficit (SWEDDs)

TLDR

The study presents clinical details and dopamine‑transporter SPECT results of 10 patients with arm tremor suspected of Parkinson’s disease, emphasizing that functional imaging should be used to prevent misdiagnosis. The authors assessed dopamine‑transporter SPECT scans in these 10 patients. All 10 patients exhibited dystonic tremor without true akinesia, had normal dopamine‑transporter SPECT scans, and dystonic tremor can cause scans without evidence of dopaminergic deficit (SWEDDs). © 2007 Movement Disorder Society.

Abstract

Abstract We present the clinical details and dopamine transporter SPECT scan results of 10 patients with arm tremor, including a rest component and reduced arm swing on the affected side, in whom the possibility of PD had been raised. All patients had signs of dystonia or components of their arm tremor that were compatible with dystonic tremor, and none had true akinesia with fatiguing or decrement, even after a mean follow‐up period of 5.8 years. All patients had normal dopamine transporter SPECT scans. Clinicians should be aware that primary adult‐onset dystonia can present with an asymmetric resting arm tremor, with impaired arm swing and sometimes also facial hypomimia or a jaw tremor, but without evidence of true akinesia. Given the important consequences of misdiagnosing such patients as PD, in cases with diagnostic uncertainty functional imaging should be considered. Among patients suspected of PD, dystonic tremor may be one cause of SWEDDs (Scans Without Evidence of Dopaminergic Deficit). © 2007 Movement Disorder Society