0958 Prior Night Self-report and Behaviorally-assessed Sleep Duration Is Associated with the Pupillary Unrest Index

Abstract Introduction Excessive daytime sleepiness is experienced by approximately 5-10% of adults and 20-30% of older adults (Young et al., 2004). However, assessment of sleepiness has posed challenges, specifically lack of agreement between different assessments. While the construct of sleepiness hinges on insufficiently sleep, different assessments of sleepiness may conflate fatigue, mood, or anhedonia. This study tested whether physiological (Pupillary unrest) and subjectively assessed sleepiness were associated with prior night sleep duration. Results may allow subjective reports of sleepiness to be clarified with the potential to intervene more effectively. Methods Participants included 95 never depressed control (M age=38, SD=12) and individuals diagnosed with seasonal depression (M age=39, SD=12). We administrated the pupil sleepiness test, while the EYE-TRAC (R) 6000 tracked pupil diameter at 60Hz. The PUI was quantified as the cumulative change in pupil diameter (mm) over 1 minute. The average PUI over the full 11-minute protocol was calculated. Self-reported sleep duration was calculated as the difference between bedtime and waketime the night prior to the PUI. Self-report sleepiness was assessed via the Epworth Sleepiness Scale the week of the PUI assessment. A subset of participants had actigraphically-assessed sleep (n=47). We used multi-level models to account for repeated measures in winter and summer and included PUI testing time, diagnostic group, season, age, and gender as covariates. PUI was log transformed to account for skewness. Results The PUI was inversely associated with both self-report (b=-0.03, p=0.01) and actigraphy sleep duration (b=-0.00, p=0.02). Conversely, subjective sleepiness was not associated with either self-report sleep duration (b=-0.00, p=0.16) or actigraphy calculated sleep duration (b=-0.02, p=0.31). Conclusion The current findings suggest the PUI is correlated with sleep duration the prior night, but subjective reports of sleepiness is not. This indicates that sleep duration may be a mechanism contributing to excessive physiological daytime sleepiness. Individuals reporting greater sleepiness may be actually experiencing fatigue, anhedonia, or depressed mood; overlapping but distinct constructs with unique etiological considerations. Future work should work to examine how different sleep parameters may be differentially related to sleepiness and fatigue constructs, and to determine if using the PUI to match intervention strategies is clinically advantageous. Support (if any) NIH