The Relationship Between Sleep and Language Functioning in Young Adults

It is important to understand the effects of sleep loss in young adulthood as environmental pressures that hinder biologically appropriate sleep patterns increase during this time. While it is well established that sleep loss negatively impacts cognition, the research on sleep and language is limited. This study examined whether sleep influences conversational and expository speech. Sixty-four undergraduate students (age mean(SD)=19.86(1.05); education mean(SD)=13.81(1.19); 52% Male; 70% Caucasian) wore an actigraphic monitoring device for approximately two weeks. Verbal communication was assessed using phonemic and semantic fluency tasks and the Cookie Theft picture description task from the Boston Diagnostic Aphasia Examination. Responses to the picture description task were recorded, and later transcribed using Praat software. A Praat script calculated the speech variables of interest. A series of separate linear regression analyses, controlling for covariates, were conducted to examine the relationships between sleep variables of interest (Average Sleep Efficiency [SE] and Average Sleep Onset Latency [SOL]) and language variables from the verbal fluency tasks and the Cookie Theft picture description task (i.e., Number of Syllables [NS], Number of Pauses [NP], Total Duration [TD], Phonation Time [PT], Speech Rate [SR], Articulation Rate [AR], and Average Syllable Duration [ASD]). Results showed that SE but not SOL predicted NS, after controlling for premorbid intellectual functioning. SE and SOL predicted NP, after controlling accounting for race/ethnicity. Last, SE and SOL predicted TD and PT. SE and SOL did not significantly predict SR, AD, or ASD, nor did they significantly predict phonemic or semantic fluency (all ps ≥ .05). Overall, results were mixed but ultimately provided evidence for a relationship between poor sleep and inferior verbal language functioning. These findings underscore the importance of healthy sleep patterns in young adulthood, as language functioning constitutes a prominent area of intellectual functioning, and is a strong predictor of educational and occupational achievement