Validation of the Dutch Occupational Impact of Sleep Questionnaire (OISQ).

Sleep problems are often under-diagnosed, but may have a profound impact on work performance. The purpose of this study was to validate the Dutch version of the Occupational Impact of Sleep Questionnaire (OISQ). A total of 555 adults with a regular daytime job completed the OISQ. In addition, they also completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and the SLEEP-50 questionnaire. 443 surveys were included in the analysis (220 men and 223 women). The Dutch OISQ had high reliability (Chronbach's alpha=0.96). OISQ scores correlated significantly with scores on the SLEEP-50 questionnaire, ESS, and PSQI (p<0.0001). Mean score on the OISQ was 14.0. Poor sleepers (OISQ score around 20) had approximately double the OISQ score as good sleepers (OISQ score around 10), irrespective of this classification was based on self-ratings, PSQI-scores or SLEEP-50 scores. The Dutch OISQ is a suitable tool to examine the occupational impact of sleep.