Does social isolation mediate the association between hearing loss and cognition in adults? A systematic review and meta-analysis of longitudinal studies.

Background: There has been extensive research on the relationship between hearing and cognitive impairment in older adults but little examination of the role of mediating factors. Social isolation is a potential mediator, occurring because of hearing loss, and contributing to accelerated cognitive decline. Previous systematic reviews on this topic area have not considered the temporal nature of hearing loss and cognitive impairment exclusively or examined potential mediators within a longitudinal study design. Methods: A systematic review was conducted. Electronic searches were performed in Web of Science, PubMed (Medline), Scopus, EMBASE, PsychInfo, and ProQuest (PsychArticles and ProQuest Dissertation and Theses) based on a search string of keywords relating to hearing loss, social isolation, and cognitive impairment/dementia in June 2023. Papers were critically appraised using the CASP checklists for cohort studies. Risk of bias in the selected studies was assessed using the Item Bank for Assessment of Risk of Bias and Precision for Observational Studies of Interventions or Exposures. Results: Eleven of the 15 included studies provide evidence of a dose-dependent association between hearing threshold (40 dB HL or greater) and later cognitive impairment or incident dementia. Only one study included social isolation as a mediator, which was found to not be a significant contributing factor. The meta-analysis of 5 studies pooled hazard ratio for cognitive impairment due to hearing loss is 1.11 (95% CI: 1.06 to 1.15, p < 0.001). The pooled hazard ratio for incident dementia due to hearing loss was HR 1.21 (95% CI: 1.11 to 1.31, p = 0.002). Conclusion: The analysis of included studies indicate that hearing threshold level affects later cognitive status or dementia diagnosis. There is not enough evidence to determine the role of social isolation as a mediator. Future epidemiology studies need to measure different elements of social isolation and ensure that hearing and cognition are measured at multiple time points.

An ethnography study exploring factors that influence social isolation in care home residents living with dementia and hearing loss.

BACKGROUND: Hearing loss and dementia are highly prevalent conditions amongst older adults living in residential care. The consequences of living with these conditions may include social withdrawal and reduced communication opportunities. We sought to examine patterns of communication and interaction in residential care and explore resident, staff, and relative perspectives within two care homes located in Birmingham, UK. This enabled an understanding of how communication environments contributed to social isolation. METHODS: This work used ethnography methodology to explore mechanisms that created and maintained social isolation in older adults living with dementia and hearing loss. A planning and engagement phase took place in four care homes. This was followed by an environmental audit, observations, and interviews. Data generated were analysed using Grounded Theory methods. RESULTS: There were 33 participants (16 residents, 11 care staff, and six relatives) who took part in the observations and interviews. Residents experienced social isolation through lack of meaningful conversation with others and being misunderstood. Additionally, observations of residents' interactions informed the overall findings. A Grounded Theory model was employed to explain the core phenomenon of social isolation. The main contributors were internal and external barriers to communication, and reduced opportunities for meaningful conversation. CONCLUSIONS: There is a wide range of social isolation that care home residents experience. This was not always associated with the severity of hearing loss but rather communication ability. Simple interventions such as staff dining with residents and focussing on improving communication could reduce social isolation within residential care settings.