The effect of sleep deprivation on vocal expression of emotion in adolescents and adults.

STUDY OBJECTIVE:Investigate the impact of sleep deprivation on vocal expression of emotion. DESIGN:Within-group repeated measures analysis involving sleep deprivation and rested conditions. SETTING:Experimental laboratory setting. PATIENTS OR PARTICIPANTS:Fifty-five healthy participants (24 females), including 38 adolescents aged 11-15 y and 17 adults aged 30-60 y. INTERVENTIONS:A multimethod approach was used to examine vocal expression of emotion in interviews conducted at 22:30 and 06:30. On that night, participants slept a maximum of 2 h. MEASUREMENTS AND RESULTS:Interviews were analyzed for vocal expression of emotion via computerized text analysis, human rater judgments, and computerized acoustic properties. Computerized text analysis and human rater judgments indicated decreases in positive emotion in all participants at 06:30 relative to 22:30, and adolescents displayed a significantly greater decrease in positive emotion via computerized text analysis relative to adults. Increases in negative emotion were observed among all participants using human rater judgments. Results for the computerized acoustic properties indicated decreases in pitch, bark energy (intensity) in certain high frequency bands, and vocal sharpness (reduction in high frequency bands > 1000 Hz). CONCLUSIONS:These findings support the importance of sleep for healthy emotional functioning in adults, and further suggest that adolescents are differentially vulnerable to the emotional consequences of sleep deprivation.