Validity of a Novel Excessive Daytime Sleepiness’ Screening Stool: the Yaoundé Sleepiness Score

Author(s): Massongo Massongo, Duthoit Louise, Balkissou Adamou Dodo, Ngah Komo Marie Elisabeth, Kuaban Alain, Fry Stéphanie, Pefura Yone Eric Walter, Mallart Anne

Background: The subjective assessment of excessive daytime sleepiness (EDS) using Epworth sleepiness scale (ESS) has shown some limitations. In response to these limitations, we designed the Yaoundé Sleepiness Scale (YSS), a new questionnaire for EDS screening based on 6 items. The content validity was based on sleep physiology. Four sleep specialists approved the initial draft for face validity. The present study aimed to assess criterion and construct validity, as well as define the diagnosis thresholds of YSS.

Methodology: We led a cross-sectional study at Lille University Hospital. Baseline data, full night recording, and sleepiness scales (YSS, ESS) were recorded. The criterion validity was assessed using the Pearson correlation between YSS and ESS and the area under the receiver operator characteristics (AUROC) curve. We used linear regression to seek the association between YSS and EDS predictors for construct validity. We found the EDS diagnosis threshold using a graphical method.

Results: A total of 566 patients (mean age = 53.1 ± 14.6 years, female = 47%) were enrolled. The Pearson correlation was 0.74% (p<0.0001). The AUROC curves for ESS-based EDS and severe EDS predictions were 0.856 and 0.871, respectively. The YSS thresholds for EDS and severe EDS were 9 and 15, respectively. Using ESS as gold standard, the sensitivity of YSS was 92.3 % for EDS and 60.3% for severe EDS; its specificity was 60.6% for EDS and 90.2% for severe EDS. The YSS increased with the use of psychotropic drugs and psychiatric conditions and decreased with age.

Conclusion: We found a good criterion validity and an acceptable construct validity of the YSS. However, these data should be confirmed by studies based on objective sleepiness tests.