Patients with scans without evidence of dopaminergic deficit (SWEDD) do not have early Parkinson's disease: Analysis of the PPMI data.

Abstract

BackgroundTo evaluate whether patients with scans without evidence of dopaminergic deficit (SWEDD) have early Parkinson's disease (PD).MethodsThe clinical characteristics, striatal specific binding ratios (SBRs), and the indices of I-123 FP-CIT SPECT images of 50 SWEDD patients, 304 PD patients, and 141 healthy controls were acquired from the Parkinson's Progression Markers Initiative (PPMI) data and evaluated during a 2-year clinical follow-up period.ResultsOf the 50 subjects with SWEDD, PD was confirmed in 13 subjects (the PD-SWEDD group), while the remaining 37 subjects had other diseases (the Other-SWEDD group). Striatal SBR values and striatal asymmetry indices of the PD group were significantly different with those of the PD-SWEDD and Other-SWEDD groups at both baseline and after 2 years (p ConclusionThe different SBR values and asymmetry indices between the PD and PD-SWEDD groups at baseline and after 2 years indicate that SWEDD may not be early PD, but rather a different disease entity.