High-Frequency Hearing Loss, Hippocampal Volume, and Motoric Cognitive Risk Syndrome in Older Adults in China: A Population-Based Study.

Background: Little is known about the associations of hearing loss, hippocampal volume, and motoric cognitive risk syndrome (MCR) in older adults.

Objective: We aimed to investigate the associations of hearing loss with MCR and hippocampal volume; and the interaction of hearing loss with hippocampal volume on MCR.

Methods: This population-based cross-sectional study included 2,540 dementia-free participants (age≥60 years; 56.5% women) in the baseline examination of the Multimodal Interventions to Delay Dementia and Disability in rural China. Data were collected through face-to-face interviews, clinical examination, and laboratory tests. Hearing function was assessed using pure tone audiometry test. In the subsample (n = 661), hippocampal volume was assessed on structural magnetic resonance images. Data were analyzed with logistic regression models.

Results: In the total sample, MCR was diagnosed in 246 persons (9.7%). High-frequency hearing loss was significantly associated with an increased likelihood of MCR and slow gait. In the subsample, the restricted cubic spline plots indicated an inverted U-shaped nonlinear relationship between high-frequency hearing performance and hippocampal volume. Moreover, greater hippocampal volume was significantly associated with a deduced likelihood of MCR and subjective cognitive decline (SCD). In addition, there were statistical interactions of high-frequency hearing loss with hippocampal volume on MCR and slow gait (p for interaction < 0.05), such that the associations were statistically significant only among participants free of high-frequency hearing loss.

Conclusions: High-frequency hearing loss was associated with an increased likelihood of MCR in older adults. The hippocampus might play a part in the relationship of high-frequency hearing loss and MCR.