Poor sleep is associated with small hippocampal subfields in cognitively normal elderly individuals

Area of Science:

• Neuroscience
• Gerontology
• Sleep Medicine

Background:

• Reduced hippocampal volume is observed in healthy older adults with poor sleep.
• The specific pattern of hippocampal subfield (HS) volume loss related to sleep quality is not well understood.

Purpose of the Study:

• To investigate the association between sleep quality and volume changes in specific hippocampal subfields in cognitively normal elderly individuals.

Main Methods:

• Self-assessed sleep quality using the Pittsburgh Sleep Quality Index (PSQI).
• Hippocampal subfield volumes measured via high-resolution T2-weighted MRI.
• Comparison of 30 normal sleepers (PSQI <5) and 37 poor sleepers (PSQI ≥5) aged 60-83 years.

Main Results:

• Poor sleepers showed significantly lower normalized volumes in the left cornu ammonis field 1 (CA1), dentate gyrus (DG), and subiculum compared to normal sleepers.
• No significant differences in overall grey and white matter volumes were found between groups.
• Global PSQI scores negatively correlated with left CA1, DG, and subiculum volumes; sleep duration correlated with bilateral CA1, DG, left CA2, and subiculum volumes.

Conclusions:

• Poor sleep quality and insufficient sleep duration are associated with volume loss in specific hippocampal subfields crucial for learning and memory.
• The findings suggest that poor sleep may cause hippocampal volume reduction, implying that improving sleep could benefit hippocampal health in the elderly.