The Prevalence of Peripheral and Central Hearing Impairment and Its Relation to Cognition in Older Adults

Abstract

Age-related hearing loss (ARHL) and dementia are two highly prevalent conditions in the adult population. Recent studies have suggested that hearing loss is independently associated with poorer cognitive functioning. The aim of this study was to evaluate the prevalence of ARHL and cognitive impairment in a large sample of subjects older than 65 years and to correlate hearing function with cognitive function. A total of 488 subjects older than 65 years (mean age 72.8 years) participating in the Great Age Study underwent a complete audiological, neurological and neuropsychological evaluation as part of a multidisciplinary assessment. The prevalence of a hearing loss greater than 25 dB HL was 64.1%, of Central Auditory Processing Disorder (CAPD) was 14.3 and 25.3% of the subjects reported a hearing handicap as reported on the Hearing Handicap Inventory for the Elderly Screening Version questionnaire. Multiple logistic regression analysis corrected for gender, age and education duration showed that mild cognitive impairment (MCI) was significantly associated with hearing impairment (CAPD and hearing threshold; odds ratio 1.6, p = 0.05) and that Alzheimer's disease (AD) was significantly associated with CAPD (odds ratio 4.2, p = 0.05). Given that up to 80% of patients affected by MCI convert to AD, adding auditory tests to a screening cognitive battery might have value in the early diagnosis of cognitive decline.

Age-Related Trajectories of Memory Function in Middle-Aged and Older Adults with and without Hearing Impairment

“…The potential confounders that we considered were significantly associated with lower memory scores but did not cause much confounding of the relationship of hearing impairment with cognitive trajectory. These findings support studies [10,20,26] that have reported that vascular risk factors might be crucial, either as common pathological processes or as shared etiological pathways underlying both age-related hearing impairment and cognitive disorders in late life, and might be part of important prevention strategies in this field.…”

“…Fourth, some important factors such as medication, depression, cognitive stimulation, social engagement, frailty syndrome, hypercholesterolemia, and other vascular risk factors were not examined in this study. These factors are encouraged to be incorporated in future research because they might constitute possible confounders or shared etiological pathways underlying both age-related hearing impairment and cognitive disorders in late life [10,20,26] . Fifth, in this study, selection bias because of a nonrandom loss to follow-up might have occurred.…”

Hearing Loss and Risk of Mild Cognitive Impairment and Dementia: Findings from the Singapore Longitudinal Ageing Study

“…There is little previous literature investigating the association of HL with MCI, a prodromal stage of dementia that confers a high risk of developing dementia. A few studies have demonstrated that elevated hearing thresholds and worse performance in central auditory processing tests are evident in patients with MCI [9,21,22]. While it may not be surprising that such highly cognitively demanding tests for central auditory dysfunction (CAD) are abnormal in subjects with cognitive impairment, more convincing electrophysiological evidence of the presence of CAD in MCI is seen in increased amplitudes of auditory cortical potentials [23].…”

“…HL is consistently shown to be associated with increased risk of developing dementia in older persons of Western populations [5,6,7,8]. There has been little work investigating the relationship between HL and the risk of mild cognitive impairment (MCI), representing a transitional stage between normal healthy ageing and the development of dementia [9]. …”

Role of the Ubiquitin C-Terminal Hydrolase L1-Modulated Ubiquitin Proteasome System in Auditory Cortex Senescence

“…According to recent cohort studies, the effects of hearing loss on communication and recognition are severe and are strongly associated with Alzheimer disease and Parkinson disease [6,7,8]. Central auditory processing disorder was much more closely associated with Alzheimer disease in another study [9]. However, until now the mechanism of central auditory disorder has remained unclear.…”