Validity and reliability of Sleep Quality Scale in subjects with obstructive sleep apnea syndrome

ObjectiveThe present study aimed to evaluate the validity and reliability of Sleep Quality Scale (SQS) in subjects with obstructive sleep apnea syndrome (OSAS).MethodsThe known group technique was used for construct validity. The study sample was composed of 40 persons with OSAS and 37 normal subjects. OSAS was defined as an apnea–hypopnea index (AHI) of ≥5 plus an Epworth Sleepiness Scale (ESS) score of >10. Control group was composed of subjects who had no history of depression and sleep problems as identified by self-report and polysomnography. A Cronbach's alpha coefficient was used for internal consistency.ResultsThe total SQS score of the OSAS subjects was significantly higher than that of the normal subjects. The SQS score homogeneity was high with a Cronbach's alpha coefficient of 0.90 in all subjects, 0.87 in the OSAS subjects, and 0.70 in the normal subjects.ConclusionSQS was confirmed to be an instrument with validity and high reliability for measuring sleep quality in OSAS subjects.