Table 1.
Principal systematic reviews and meta-analyses of peripheral ARHL and age-related CAPD in relation to late-life cognitive decline, MCI, dementia, and AD.
| Reference | Studies/patient age | Type of auditory function | Cognitive-related outcomes | Principal findings |
|---|---|---|---|---|
| Taljaard and colleagues61 | 33 studies 5735 participants. Mean age 57.7 years | Treated or untreated peripheral ARHL | General cognitive function, attention and processing speed, semantic processing and word knowledge, short-term and working memory, long-term memory, and executive functioning | Cognition was significantly poorer in individuals with untreated ARHL and remains poorer in treated ARHL compared with normal hearers. Hearing intervention significantly improves cognition. Better hearing is associated with better performance across all cognitive domains examined, including attention and processing speed, short-term/working, and long-term memory, executive functioning, and semantic processing and word knowledge, although the effects were all small |
| Thomson and colleagues62 | 17 studies (12 prospective studies). Systematic review only | Peripheral ARHL and age-related CAPD | Dementia and cognitive decline | ARHL was associated with higher incidence of dementia or cognitive decline |
| Zheng and colleagues63 | 4 prospective studies 7461 participants. Mean age 76.8 years | Peripheral ARHL and age-related CAPD | Incident AD and incident cognitive decline | The overall combined RR of people with hearing impairment to develop AD was 4.87 (95% CI: 0.90–26.35), compared with the control group, while the overall combined RR of AD and incident cognitive decline was 2.82 (95% CI: 1.47–5.42) |
| Livingston and colleagues7 | 3 prospective studies 3585 participants. Mean age 67.7 years | Peripheral ARHL | Incident dementia | Peripheral ARHL was a significant risk factor for incident dementia, calculating a pooled risk ratio of 1.94 (95% CI: 1.38–2.73) |
| Wei and colleagues64 | 10 prospective studies 15,521 participants. Mean age ranged from 56.1 to 77.4 years | Peripheral ARHL and age-related CAPD | Incident dementia and MCI | ARHL was associated with a greater risk of MCI (RR = 1.30; 95% CI: 1.12–1.51) and dementia (RR = 2.39; 95% CI: 1.58–3.61) |
| Loughrey and colleagues65 | 36 studies 20,264 participants. Mean age ranged from 51.4 to 85.0 years | Peripheral ARHL (pure tone audiometry) | Cognitive impairment and decline, dementia, AD, and vascular dementia | Among cross-sectional studies, a significant association was found for cognitive impairment (OR = 2.00; 95% CI: 1.39–2.89) and dementia (OR = 2.42; 95% CI: 1.24–4.72). Among prospective cohort studies, a significant association was found for cognitive impairment (OR = 1.22; 95% CI: 1.09–1.36) and dementia (OR = 1.28; 95% CI: 1.02–1.59) but not for AD (OR = 1.69; 95% CI: 0.72–4.00) |
| Yuan and colleagues66 | 11 prospective studies 176,893 participants. Mean age ranged from 63.6 to 79.6 years | Peripheral ARHL and age-related CAPD | Incident cognitive impairment | Peripheral ARHL and age-related CAPD had a higher risk of cognitive impairment (for moderate/severe peripheral ARHL: RR = 1.29; 95% CI: 1.04–1.59 during a follow up ⩽ 6 years. RR = 1.57; 95% CI: 1.13–2.20 during a follow up > 6 years; for severe age-related CAPD, RR = 3.21; 95% CI: 1.19–8.69) compared with those with normal hearing function |
| Ford and colleagues33 | 14 prospective studies 72,831 participants. Mean age ranged from 56.1 to 79.6 years | Peripheral ARHL and age-related CAPD | Incident dementia | A pooled HR of 1.49 (95% CI: 1.30–1.67) was found for all-cause dementia |
AD, Alzheimer’s disease; ARHL, age-related hearing loss; CAPD, central auditory processing dysfunction; CI, confidence interval; HR, hazard ratio; MCI, mild cognitive impairment; OR, odds ratio; RR, relative risk.