How Can Hearing Loss Cause Dementia?

Abstract

Epidemiological studies identify midlife hearing loss as an independent risk factor for dementia, estimated to account for 9% of cases. We evaluate candidate brain bases for this relationship. These bases include a common pathology affecting the ascending auditory pathway and multimodal cortex, depletion of cognitive reserve due to an impoverished listening environment, and the occupation of cognitive resources when listening in difficult conditions. We also put forward an alternate mechanism, drawing on new insights into the role of the medial temporal lobe in auditory cognition. In particular, we consider how aberrant activity in the service of auditory pattern analysis, working memory, and object processing may interact with dementia pathology in people with hearing loss. We highlight how the effect of hearing interventions on dementia depends on the specific mechanism and suggest avenues for work at the molecular, neuronal, and systems levels to pin this down.

Self-reported hearing difficulties are associated with loneliness, depression and cognitive dysfunction during the COVID-19 pandemic

“…Hearing loss (HL) is one of the leading causes of disability in older adults and is commonly associated with increased rates of depression, social isolation, and risk of cognitive decline (Livingston et al 2020;Mick, Kawachi, and Lin 2014;Strawbridge et al 2000). The mechanism of the hearing-cognitive decline relationship has yet to be elucidated, but one theory is an indirect association through the loneliness/social isolation pathway (Griffiths et al 2020). People with HL are more likely to report feelings of loneliness and social isolation (Huang et al 2020;Mick, Kawachi, and Lin 2014;Shukla et al 2020) and these factors have been shown to increase the risk of developing dementia (Fratiglioni et al 2000;Wilson et al 2007).…”

Cortical Responses to the Amplitude Envelopes of Sounds Change with Age

“…Aging is associated with a decline in processing auditory temporal features (Gordon-Salant and Fitzgibbons, 1999) and speech intelligibility, particularly in the presence of background sounds (Gordon-Salant, 2006). In addition to peripheral hearing loss (presbycusis) (Frisina and Frisina, 1997) and cognitive decline (Wayne and Johnsrude, 2015; Griffiths et al, 2020), evidence increasingly suggests that poorer speech intelligibility in older individuals may be related to changes in how the cerebral cortex responds to amplitude envelopes (Millman et al, 2017; Goossens et al, 2018).…”

Association of sudden sensorineural hearing loss with dementia: a nationwide cohort study

“…The potential mechanisms underlying the association between ARHL and cognitive decline, particularly increased risk of dementia [ 19 ], remain unclear. Although Füllgrabe et al suggested that audibility and processing effort can bias the cognitive test performance toward cognitive decline [ 24 ], Griffiths et al proposed a mechanism linking auditory cognitive processing in the medial temporal lobe and dementia pathology [ 25 ]. Previously, Wayne and Johnsrude summarized the four directional hypotheses for the relationship between ARHL and cognitive decline, namely the cognitive load on perception hypothesis, sensory deprivation hypothesis, information degradation hypothesis, and common cause hypothesis [ 26 ].…”