Sleep Soundly! Sleep Deprivation Impairs Perception of Spoken Sentences in Challenging Listening Conditions.

Speech perception, a daily task crucial for social interaction, is often performed after sleep deprivation (SD). However, there is only scant research on the effects of SD on real-life speech tasks. Speech-processing models (FUEL, ELU) suggest that challenging listening conditions require a greater allocation of cognitive resources, while ideal listening conditions (speech in quiet) require minimal resources. Therefore, SD, which reduces cognitive reserve, may adversely affect speech perception under challenging, but not ideal, conditions. The goal of this study was to test this, manipulating the extent of available resources (with/without SD) and task difficulty in three conditions: sentences presented in (a) quiet, (b) background noise, and (c) with emotional prosody, where participants identified the emotions conveyed by the speaker. The performance of young adults (n = 41) was assessed twice, after nocturnal sleep and after a 24-hr SD in three tasks: (a) sentence repetition in quiet, and (b) noise, and (c) emotion identification of spoken sentences. Results partially supported our hypotheses. The perception of spoken sentences was impaired by SD, but noise-level did not interact with SD effect. Results suggest that 24-hr SD reduces cognitive resources, which in turn impairs listeners' ability (or motivation) to perform daily functions of speech perception. Theoretically, findings directly relate SD to speech perception, supporting current theoretical speech models. Clinically, we suggest that SD should be considered in daily clinical settings, e.g., hearing tests. Finally, professions that require shift work, such as health care, should consider the negative effects of SD on spoken communication.