Objective:

To compare the frequencies of sleep disorders between individuals with early onset parkinsonism (age ≤50 at motor symptom onset) and typical onset parkinsonism (age >50 at motor symptom onset).  

Background:

Sleep disturbances are common in parkinsonian disorders and have been well-studied in individuals with parkinsonism onset after age 50. Whether sleep disorders affect individuals with early onset parkinsonism and whether they differ from individuals with typical onset parkinsonism is unknown. 

Design/Methods:

We used a population-based, 1991 to 2015 incident-cohort study of parkinsonism including 38 patients with early onset and 1001 patients with typical onset parkinsonism. Presence or absence and type of sleep disorder as well as the relationship between motor and sleep symptoms were abstracted. Rates of sleep disorders before and after onset of parkinsonism were compared with logistic regression and Cox proportional hazards models.

Results:

Median (IQR) age of parkinsonism onset was 44.5 (41.0 – 48.7) years for early onset and 75.9 (67.7 – 81.7) years for typical onset patients. Parkinson’s disease (PD) was the most common cause of parkinsonism in each group. The prevalence of sleep disorders prior to the onset of parkinsonism in early vs typical parkinsonism (24% vs 16% p=0.19) and incidence of sleep disorders after parkinsonism onset (5.85 cases per 100 person-years vs 4.11 cases per 100 person-years; HR 1.15 95% CI: 0.74-1.77) were similar between the two groups, with similar latencies of sleep disorders to parkinsonism diagnosis in each group. Early onset parkinsonism had a higher risk for developing insomnia compared with typical onset parkinsonism (HR 1.73, 95% CI: 1.02 – 2.93); the risk for developing all other sleep disorders was similar between groups. 

Conclusions:

Sleep disorders are common in individuals with early onset parkinsonism and occur with similar frequency to those with typical onset parkinsonism, except for insomnia, which was more frequent in the early onset group.