0600 Visual Processing Speed After Brief Naps in Hypersomnolent Patients: MSLT and PVT Correlates

• Published in: Sleep (New York, N.Y.) Vol. 42; no. Supplement_1; pp. A238 - A239
• Main Authors: Saini, Prabhjyot, Trotti, Lynn Marie, Rye, David B
• Format: Journal Article
• Language: English
• Published: Westchester Oxford University Press 13.04.2019
• Subjects: Processing speed; Sleep
• DOI: 10.1093/sleep/zsz067.598
• ISSN: 0161-8105

Introduction Previous efforts to quantify sleep inertia effects on alertness using the Psychomotor Vigilance Task (PVT) has revealed worsening vigilance is captured in metrics that are sensitive to variability.Visual processing speed and psychomotor vigilance rely on shared visual pathways that suggest alternative approaches in discriminating between pathological and normal brain states using tools such as the Critical Flicker Fusion (CFF).The CFF threshold is the highest average frequency (Hz) at which an individual can discern a flickering stimulus.We attempt to determine if sleep and napping improve CFF threshold and consistency that is distinct or in concert with the PVT after brief naps. Methods There were 10 healthy non-sleepy controls and 13 patients undergoing overnight PSG/MSLT (Age=29.7±13.8; 65% women),that were diagnosed with Idiopathic hypersomnia (n=4),Myotonic Dystrophy 1 (n=4),Narcolepsy Type 2 (n=4),and Kleine-Leven Syndrome (n=1) were administered PVT before and after daytime MSLT naps 2 and 4 and administered the CFF at bedtime and morning wake time (n=23),before and after naps 2 (n=12),4 (n=12) and 5 (n=21).CFF is the average of 10 pairs of ascending (10Hz,2Hz intervals) and descending trials (60Hz,2Hz intervals),where lower threshold values indicate impairment. CFF threshold consistency was calculated as the coefficient of variation per subject per nap condition.PVT and CFF performance was analyzed using repeated-measures ANOVA with post-hoc t-tests. Results Adjusting for age,gender,and diagnosis,CFF threshold improved with overnight sleep (37.30±3.19 vs 36.37±3.43,p=.06) but,consistency decreased after overnight sleep (3.1±1.6 [bedtime] vs.4.6±2.4 [wake]t=2.61,p=.0183).Sleeping diminished consistency in patients greater than in controls.(2.21±3.1 vs..62±2.7,t=.86,NS).Napping increased impairment in CFF threshold (nap 2: 36.41±3.29 [post] vs 38.79±6.3 [pre],t=-5.65,p=.0013; nap 5: 37.57±3.37 [post] vs 37.9±3.61 [pre],t=-2.19,p=.0446),but improved consistency (nap1: 3.1±1.6 [post] vs.4.6±2.4 [pre],t=-2.66,p=.0326; nap2: 4.0±2.7 [post] vs.10.83±27.12 [pre],t=-28.75,p<.0001; nap5: 4.3±4.75 [post] vs.4.9±4.94 [pre],t=-2.63,p=.0191).There were no significant association between the PVT metrics of variability,length of sleep,or between patients and controls on CFF threshold and consistency. Conclusion Consistency on the CFF may be capturing the subtle improvement in wakefulness provided by napping that is difficult to detect in the PVT. Support (If Any) R01:NS089719