Sleep Fragmentation and Cognitive Trajectories After Critical Illness

Area of Science:

• Critical Care Medicine
• Neuroscience
• Sleep Medicine

Background:

• Intensive Care Unit (ICU) survivors frequently experience cognitive dysfunction and sleep disturbances post-hospitalization.
• Sleep disturbances are implicated in cognitive impairment across various patient groups.
• The apolipoprotein E (APOE) genotype has been previously linked to cognitive function and sleep.

Purpose of the Study:

• To investigate the association between sleep patterns, long-term cognitive function, and APOE genotype in individuals who have survived ICU stays.
• To determine if sleep disturbances post-ICU predict persistent cognitive impairment.

Main Methods:

• 102 ICU survivors who required mechanical ventilation for at least 3 days were assessed.
• Actigraphy and cognitive testing were performed at 7 days, 6 months, and 12 months post-ICU discharge.
• APOE single nucleotide polymorphisms were analyzed for each participant.

Main Results:

• Sleep fragmentation at 7 days post-ICU was associated with worse cognitive impairment, but not total sleep time or circadian rhythmicity.
• No sleep variables measured at 7 days predicted cognitive impairment or sleep abnormalities at 6 or 12 months.
• The APOE ε4 allele was not significantly linked to sleep disturbances or modified the risk of sleep-related cognitive impairment.

Conclusions:

• While sleep fragmentation shortly after ICU discharge correlates with cognitive impairment, this link is not sustained at later follow-up intervals.
• APOE genotype does not appear to influence sleep disturbances or cognitive outcomes in this ICU survivor cohort.
• Further research with larger cohorts is necessary to fully understand the long-term relationship between persistent sleep disturbances and cognition in ICU survivors.