Objective: To study the distribution of chronotypes in Veterans with Parkinson’s disease (PD); and its association with pathological sleepiness.

Background: Excessive daytime sleepiness is a common, disabling, non-motor symptom of Parkinson’s disease. Chronotype reflects the periodicity of biological rhythms including the individual’s natural propensity to sleep, hence could be a contributing factor in the expression of pathological sleepiness in patients with PD. This association has not been fully defined.

Method: Chronotypes of one hundred consecutive subjects with Parkinson’s disease were determined using the Horne and Ostberg’s Morningness and Eveningness scale. Subjective sleepiness was assessed using Epworth Sleepiness Scale. The subjects’ depression, cognitive and motor status was assessed using Zung Self Rating Depression Scale (ZDS), Unified Parkinson’s Disease Rating Scale (UPDRS) and Hoehn and Yahr scale (H&Y), respectively.

Results: 60% (60/100) of the subjects were Morning Type (M) [Definitive (M++) = 12, Moderate (M+) =48], 39% (39/100) were Neither Type (N) and 1% (1/100) was Evening Type (E).

Pathological sleepiness (ESS= or > 10): M++ [50% (6/12)], M+ [58% (28/48)], N [77% (30/39)], E [0% (0/1). ESS > 15: was noted in 8%, 14.6%, 23% and 0% in M++, M+, N and E types respectively.

Depression (ZDS = or > 50): M++ [0% (0/12)] M+ [8.3% (4/48)], N [23% (9/39)], E [0% (0/1)].

Intellectual impairment (UPDRS): M++ [None (25%), Mild (75%) mean = 0.75], M+ [None (16.6%) Mild (64.5%) Moderate (14.6%), Severe (4%) mean = 1.06], N [None (20.5%), Mild (53.8%), Moderate (18%), Severe (7.7%); mean=1.13], E [Mild (100%) = 1]

Mean H&Y scores: 2.3, 2.77, 2.77 and 2.5 for M++, M+, N and E types respectively.

Conclusion: The most common chronotype in this cohort of military veterans with Parkinson’s Disease was Morning Type (M) (60%) followed by the Neither type (N) (39%). Evening type (E) (1%) was rare.  Neither type (N) subjects were pathologically the sleepiest followed by the Moderately Morning type.

Pathological sleepiness, intellectual performance, and depression worsened along the chronotype spectrum from the Definitively Morning (M++) to Moderately Morning (M+) to the Neither (N) types. This observation requires further exploration.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/distribution-of-chronotypes-in-parkinsons-disease-and-its-association-with-pathological-sleepiness/