Cognitive impacts of circadian misalignment and sleep disruption - shift working and new parenthood

Breese, Emily (2021). Cognitive impacts of circadian misalignment and sleep disruption - shift working and new parenthood. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.00013375

Abstract

Laboratory studies of prolonged sleep deprivation have revealed several negative cognitive impacts. It is uncertain however, how applicable insights derived from these studies are to the various sleep disturbances found in real-world settings. Individuals regularly experiencing forms of sleep disturbance are shift workers (SWs) and new parents (NPs).

Shift work is increasingly common in contemporary society and these individuals often experience circadian misalignment. New parenthood is strongly associated with unpredictable sleep disturbance, though not the prolonged wakefulness applied in laboratory studies.

Improved understanding of cognitive deficits in these groups is of considerable importance, given that SWs, despite potential cognitive compromise, are expected to work as effectively and productively as non-SWs. Similarly, NPs are expected to care for a newborn whilst operating safely in the surrounding world. Therefore, direct cognitive assessment in these groups, as opposed to laboratory-based studies mimicking the patterns of sleep disruption experienced, is valuable.

Here, using online cognitive assessments, four domains that are vital in an occupational and parenting context (attention, response inhibition, working memory and visuomotor control) were evaluated in occupationally heterogeneous and homogenous SW cohorts, to determine the impact of job role, and in a NP cohort including both sexes, to evaluate any sex differences.

All cohorts were assessed in conditions of minimal fatigue to dissociate potential contributions of acute daily fatigue from more chronic lifestyle effects. A frontal EEG analysis of SWs was conducted, using EEG headbands, to screen for physiological correlates.

This study revealed little to no impairment in all four cognitive domains in SWs and NPs, suggesting that the cognitive impairments often reported in these groups are primarily driven by acute fatigue that can be alleviated with sleep. EEG analysis of SWs suggested the presence of some physiological changes, which could indicate compensatory mechanisms engaged to maintain the consistent cognitive performance observed.