Daytime sleepiness in healthy university students: a multiparametric study

A multiparametric investigation of daytime sleepiness was performed in 18 healthy young university students. After undergoing a standard polysomnographic recording at home the night before, all subjects were evaluated by Multiple sleep latency test (MSLT) at 10.00, 12.00, 14.00, 16.00, 18.00. Subjective sleepiness (by using Visual Analogue Rating Scale) and performance tasks (Cancellation Test, Digit Symbol Substitution, Choice Reaction Time, Critical Flicker Fusion Threshold) were also assessed at the same times. Mean daily sleep latency was found to be about 10 minutes, with several individual values in the borderline range (greater than 5 less than 10 minutes). Subjects did not rate themselves as excessively sleepy and there was no correlation between subjective and objective estimates of sleepiness. No consistent correlation was found between subjective-objective sleepiness and results of performance tests. Anxiety trait (Spielberg State Anxiety Trait) did not correlate with sleepiness, but higher anxiety scores were significantly associated with poor performance. These results confirm the occurrence of fairly marked objective drowsiness in healthy young subjects which, however, was not associated with subjective sleepiness and did not adversely affect performance on a variety of tests of CNS function.