PSG and MSLT sleep parameters and sleep disorders present in study subjects.

AHI: Apnea-hypopnea index, PLMI: periodic limb movements index, MSL: mean sleep latency, PLMS: periodic limb movements of sleep, OSA: obstructive sleep apnea, RBD: REM sleep behaviour disorder, RLS: restless legs syndrome.Continuous variables are expressed as mean ± SD.aMann-Whitney U test was used to compare continuous variables, and Exact Fisher's test to compare frequenciesbStepwise multiple linear regression was used for continuous variables and forward (Wald) stepwise logistic regression for binary outcomes (presence of each sleep disorder). Multivariate analysis took into account any effects of age and sex (and in the case of OSA and AHI, any effect of BMI and neck circumference).N.B. Overnight PSG reports for 3 PD patients and 1 control, and MSLT reports for 1 PD patient and 2 controls were missing. They were not included in the relevant analyses.