The range and nature of sleep dysfunction in untreated Parkinson's disease (PD). A comparative controlled clinical study using the Parkinson's disease sleep scale and selective polysomnography

Abstract

In this study we have explored the nature and range of sleep dysfunction that occurs in untreated Parkinson's disease (PD) comparing data obtained from the use of the Parkinson's disease sleep scale (PDSS) in an untreated PD patient group compared to advanced PD and healthy controls. 25 untreated (drug-naive, DNPD) PD patients (mean age 66.9 years, range 53–80, 18 males) completed the validated Parkinson's disease sleep scale (PDSS), mean duration of PD was 2.1 years (1–10, up to 4 years in all except one patient with tremulous PD reporting tremor duration of 10 years) and mean Hoehn and Yahr score 1.9 (1–3). Data were compared to 34 advanced PD (mean age 70.2 years, range 51–88, 23 male), mean duration of PD 11 years (range 4–22), mean Hoehn and Yahr score 3.4 (3–5) and PDSS data obtained from 131 healthy controls (mean age 66.6 years, range 50–93, 56 males). Total PDSS scores and PDSS sub-items, except PDSS item 2, were highly significantly different (p < 0.001) between DNPD, advanced PD and controls. Controls reported higher mean PDSS scores than both groups of patients, and advanced cases reported lower (mean ± S.D.) PDSS scores (86.95 ± 20.78) than drug-naive (105.72 ± 21.5) (p < 0.001). Logistic regression analysis showed that items PDSS8 (nocturia), PDSS11 (cramps), PDSS12 (dystonia), PDSS13 (tremor), and PDSS15 (daytime somnolence) were significantly impaired in DNPD compared to controls while PDSS7 (nighttime hallucinations) additionally separated advanced PD from DNPD. In a subgroup of 11 advanced PD cases (mean age 62 years, range = 49–84 years, mean Hoehn and Yahr score 2.5, range = 1–3) with high Epworth Sleepiness Scale (ESS) scores (mean 14.5), low item 15 PDSS score (mean 4.7) and complaints of severe daytime sleepiness, underwent detailed overnight polysomnography (PSG) studies, all showing abnormal sleep patterns.

We conclude that nocturia, nighttime cramps, dystonia, tremor and daytime somnolence seem to be the important nocturnal disabilities in DNPD and some of these symptoms may be reminiscent of “off” period related symptoms even though patients are untreated. Furthermore, polysomnography in “sleepy” PD patients may help diagnose unrecognised conditions such as periodic limb movement of sleep (PLMS), obstructive sleep apnoea (OSA) and REM Sleep Behaviour Disorder.