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Olfaction And Nonmotor Symptoms (NMS) In Subjects With Scans Without Evidence Of Dopaminergic Deficit (SWEDDs)

Fullard, M.E.; Weintraub, D; Duda, J.E.; Morley, J.F.
MDS: San Diego, CA
Download Presentation: FullardSWEDD-Poster-5.4table-MDS-2015.pdf
To compare the characteristics of SWEDDs, de novo Parkinson's disease (PD) subjects, and healthy controls (HC) in the Parkinson's Progression Markers Initiative (PPMI) cohort.

Approximately 10?15% of patients clinically diagnosed with early PD are found to be SWEDDs, the clinical phenotype of which is not well characterized.

Cross?sectional study of de novo PD subjects (N=428), SWEDDs (N=65) and HC (N=200) in the PPMI cohort. Baseline evaluation included olfactory testing with the University of Pennsylvania Smell Identification Test (UPSIT) and motor and NMS assessments. Group differences were examined using Fisher exact or ?2 tests for categorical variables, Mann?Whitney U for continuous variables and partial correlations for associations between continuous variables, controlling for relevant covariates.

The mean(SD) UPSIT score in the SWEDD group (30.9(7.2)) was lower (reflecting worse olfaction) than HCs, 33.9(5.1), (p<0.001) and higher than the PD group at 22.2(8.3) (p<0.001). When controlled for age and gender, 12/66(18.2%) of SWEDDs exhibited severe olfactory impairment (OI, severe microsmia or anosmia), compared to 12/200(6.0%) (p=0.005) of HCs and 268/428(62.6%) (p<0.001) of PD subjects. SWEDDs also had higher rates of other NMS compared to HCs, including REM behavior sleep disorder (RBD) symptoms (SWEDD 32.3%, HC 12.6%, p=0.001), depression (SWEDD 29.2%, HC 6.5%, p<0.001) and apathy (SWEDD 21.2%, HC 5.1%, p<0.001). Rates of RBD (PD 25.5%, p=0.29) and apathy (PD 16.9%, p=0.39) were similar between SWEDDs and PD, while rates of depression (PD 13.8%, p=0.003) were higher in SWEDDs. Within the SWEDD group, OI subjects had higher rates of depression (58.3% vs 23.1%, p=0.03), and RBD (58.3% vs. 26.9%, p=0.048). There was a positive association between UPSIT score and Montreal Cognitive Assessment (MOCA) in SWEDDs (r=0.424, p=0.001). UPDRS motor scores were similar in SWEDDs with or without OI (16.6(10.7) vs 13.8(9.1)), (p=0.39). However, SWEDDs with the combination of RBD and OI had higher bradykinesia scores 11.9(8.1) compared to those without 5.9(5.5), (p=0.02).

SWEDD subjects exhibit NMS more commonly than HCs and often at frequencies similar to PD subjects. The clustering of OI with other NMS in SWEDDs may represent a distinct clinical phenotype that can be further investigated as longitudinal data from the PPMI accumulates.