Silber, Michael

Abstract Introduction Isolated REM sleep behavior disorder (iRBD) is characterized by loss of normal REM sleep atonia and dream enactment behavior. iRBD is strongly associated with α-synucleinopathies and risk for developing Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), yet phenoconversion risk for long-term outcomes of younger women and men remains undefined. We aimed to ascertain longitudinal outcomes and phenoconversion risk in the Mayo Clinic iRBD cohort. Methods Eighty-nine of 165 registry participants with at least one-year follow-up were included. Retrospective chart review attained baseline demographics, age at presentation, baseline Timed Up and Go (TUG) and Montreal Cognitive Assessment (MoCA) scores, and phenoconversion status (iRBD, PD, DLB, mild cognitive impairment [MCI], MSA, or other). Kaplan–Meier survival analysis and Cox proportional hazards modeling were analyzed with alpha at p < 0.05. Results 68 men and 21 women had a mean age of 63 years at polysomnographic diagnosis. At follow-up, 64 (71.9%) remained iRBD; 7 (7.9%) developed PD, 11 (12.4%) developed DLB, 3 (3.4%) developed MCI, 1 (1.1%) developed MSA, and 3 (3.4%) developed another dementia. Abnormal TUG (>12 seconds) occurred in 5.9% and abnormal MoCA (< 24) in 23.3%. Phenoconversion rates were similar in women and men (p = 0.44). Older age at PSG predicted phenoconversion, corresponding to a two-fold increase in risk with each 10-year increase (HR 2.00, 95% CI 1.15–3.52). Neither abnormal TUG nor MoCA predicted conversion. Cumulative phenoconversion was approximately 1% at 1 year, 7% at 3 years, 10% at 5 years, 30% at 10 years, 34% at 12 years, and 49% at 15 years. Mean and median time to phenoconversion was 7 years (range, 1-18 years). Conclusion We found that iRBD phenoconversion rates were lower than historically reported. Only age at presentation predicted phenoconversion, with risk doubling per decade. At 12 years, cumulative phenoconversion rate was approximately 34%. Support (if any)

There has been no comparison of excessive daytime sleepiness (EDS) in patients with Alzheimer’s disease dementia (AD), dementia with Lewy bodies (DLB), and behavioral variant frontotemporal dementia (bvFTD). We identified patients with mild dementia who met criteria for these disorders who also had the Epworth Sleepiness Scale (ESS) completed. The sample included 17 bvFTD, 111 AD, and 31 DLB. An ESS score ≥10 was considered abnormal and consistent with EDS. Analyses with age and sex as covariates revealed higher mean ESS scores for DLB compared to the other groups (DLB 13.9 [5], bvFTD 9.6 [8], AD 8.8 [5], P < .05). An ESS score ≥10 was significantly more likely to occur in DLB compared to bvFTD or AD (DLB 81% vs bvFTD 47% vs AD 45%, P < .01). In patients with mild dementia, EDS is greatest in DLB and comparably lower in bvFTD and AD.