Hippocampus Mediates the Effect of Emotional Support on Cognitive Function in Older Adults

Background: Despite strong evidence that emotional support has a protective effect on cognitive decline, the neural basis for how an individual's emotional support is associated with cognition is unknown. We investigated if the hippocampus mediates the relationship between emotional support and cognition in older adults.

Method: Four hundred and ten nondemented Korean older adults were classified into two groups according to their Medical Outcomes Study-Social Support Survey emotional support scores: the poor emotional support (score ≤ 25th percentile of entire sample) and normal emotional support (score > 25th percentile of entire sample) groups. Cognitive function was assessed using the Verbal Memory Score and Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet Neuropsychological Assessment Battery total score (CERAD-TS). Left and right hippocampal volume were obtained using 3T T1-weighted magnetic resonance images. Mediation analyses were conducted.

Results: In the association of emotional support with Verbal Memory Score, left hippocampal volume played a mediating role (indirect effect = 0.40, SE = 0.21, bias-corrected 95% confidence interval = 0.04, 0.86). In the association of emotional support with CERAD-TS, both left (indirect effect = 0.82, SE = 0.45, bias-corrected 95% confidence interval = 0.09, 1.83) and right (indirect effect = 0.51, SE = 0.32, bias-corrected 95% confidence interval = 0.02, 1.24) HPVs played mediating roles.

Conclusions: The hippocampus may mediate the association between emotional support and cognition. Higher levels of emotional support may be associated with better verbal memory and global cognition via larger HPV.