Sleep-dependent prospective memory consolidation is impaired with aging.

STUDY
OBJECTIVES: Existing literature suggests that sleep-dependent memory consolidation is impaired in older adults but may be preserved for personally relevant information. Prospective memory (PM) involves remembering to execute future intentions in a timely manner and has behavioural importance. As previous work suggests that N3 sleep is important for PM in young adults, we investigated if the role of N3 sleep in PM consolidation would be maintained in older adults.
METHODS: 49 young adults (mean age±SD:21.8±1.61 years) and 49 healthy older adults (mean age±SD:65.7±6.30 years) were randomized into sleep and wake groups. After a semantic categorization task, participants encoded intentions comprising 4 related and 4 unrelated cue-action pairs. They were instructed to remember to perform these actions in response to cue words presented during a second semantic categorization task 12h later that encompassed either daytime wake (09:00-21:00) or overnight sleep with polysomnography (21:00-09:00).
RESULTS: The significant condition x age group x relatedness interaction suggested that the sleep benefit on PM intentions varied according to age group and relatedness (p=0.01). For related intentions, sleep relative to wake benefitted young adults' performance (p<0.001) but not older adults (p = 0.30). For unrelated intentions, sleep did not improve PM for either age group. While post-encoding N3 was significantly associated with related intentions' execution in young adults (r=0.43, p=0.02), this relationship was not found for older adults (r=-0.07, p=0.763).
CONCLUSIONS: The age-related impairment of sleep-dependent memory consolidation extends to PM. Our findings add to an existing body of work suggesting that the link between sleep and memory is functionally weakened in older adulthood. © Sleep Research Society 2021. Published by Oxford University Press on behalf of the Sleep Research Society.

RCT Entities:   Population Interventions Outcomes