In addition to the genotypes of rs671, the patients were assessed with the PD sleep scale-2nd version (PDSS-2) and the Epworth sleepiness scale (ESS) for symptoms of daytime and nocturnal sleep disturbances.
Each patient completed the Thai version of the Epworth Sleepiness Scale (ESS) questionnaire to evaluate excessive daytime sleepiness (EDS), and the PD Sleep Scale version-2 (PDSS-2) questionnaire to evaluate night-time sleep disturbance.