Students will examine the relationship between sleep quality and cognitive performance.Students will explore the association between sleep quality and cognitive functioning.

Abstract Sleep is an essential physiological process, which is important for physical health, psychological and cognitive functioning. This review explores the link between sleep quality and cognitive functioning, focusing on memory, attention, working memory and executive functioning. The review is based on 15 relevant studies from the period 2015 to 2023. The literature that was selected covered studies with both subjective (self-report questionnaires) and objective (actigraphy and polysomnography) sleep assessment. The reviewed evidence revealed a relationship between poor sleep and deficits in cognition in a number of domains, with specific focus on sleep fragmentation and sleep deprivation. The results also show significant discrepancies between subjective and objective assessment of sleep quality. Placebo-like (and sometimes nocebo-like) effects of psychological factors such as belief and expectation about sleep on cognitive outcome may occur independently of physiological sleep parameters. Possible mechanisms of sleep–cognition relationship are changes in neural connectivity, neurochemical processes, synaptic plasticity, and sleep-dependent memory consolidation. Methodological differences, self-reported measures, and lack of long-term data in most cases however make it difficult to establish definite causal relations. In conclusion, the review shows that sleep quality is a significant factor in cognitive health and those physical and mental aspects of sleep need to be taken into account when assessing cognitive abilities. Longitudinal and experimental designs with standardized subjective and objective assessment should be implemented in future research to further elucidate these relationships and to create effective interventions.