Validity and reliability of the Turkish version of single-item Sleep Quality Scale in healthy adults

Abstract

ObjectiveThe Single Item Sleep Quality Scale (SQS) is a self-reported outcome measure to assess sleep quality. SQS can be used when there is limited time or sleep impairments need to be identified quickly. This study aimed to investigate the validity, including concurrent criterion, convergent, divergent, and known-groups, and test-retest reliability of the SQS in a sample of the Turkish population. MethodsTurkish translation and cross-cultural adaptation of SQS were conducted. Two hundred and thirty-eight healthy adults aged 18–65 years were included in the study. The validity of the SQS was investigated using the Pittsburgh Sleep Quality Index (PSQI). The data were collected online. The retest–retest reliability was investigated in a subsample of 40 people after 7–14 days. ResultsThe SQS significantly correlated with item 6 (sleep quality) on PSQI and PSQI global score (rs = −0.73, −0.61, respectively). Although, it had a small correlation with total sleep time (rs = 0.28), awakenings (rs = −0.21) and habitual sleep efficiency (rs = −0.24). 8 of 11 predetermined hypotheses (73%) for convergent validity and 10 of 12 predetermined hypotheses for divergent validity (83%) were confirmed to test the construct validity. Test-retest reliability was found high (ICC = 0.82 (95%CI: 0.66 to 0.91)). SQS score of the sleep disorders group, which was determined according to the PSQI global score, was significantly lower. ConclusionsThe results revealed that SQS is a valid and reliable instrument and can be used to evaluate sleep quality in healthy Turkish adults.