Improvement of Working Memory and Processing Speed in Patients over 70 with Bilateral Hearing Impairment Following Unilateral Cochlear Implantation

Abstract

Several studies demonstrated the association of hearing disorders with neurocognitive deficits and dementia disorders, but little is known about the effects of auditory rehabilitation on the cognitive performance of the elderly. Therefore, the research question of the present study was whether cochlear implantation, performed in 21 patients over 70 with bilateral severe hearing impairment, could influence their cognitive skills. The measuring points were before implantation and 12 months after the first cochlear implant (CI) fitting. Evaluation of the working memory (WMI) and processing speed (PSI) was performed using the Wechsler Adult Intelligence Scale 4th edition (WAIS-IV). The audiological assessment included speech perception (SP) in quiet (Freiburg monosyllabic test; FMT), noise (Oldenburg sentence test; OLSA), and self-assessment inventory (Oldenburg Inventory; OI). Twelve months after the first CI fitting, not only the auditory parameters (SP and OI), but also the WMI and PSI, improved significantly (p < 0.05) in the cohort. The presented results imply that cochlear implantation of bilaterally hearing-impaired patients over 70 positively influences their cognitive skills.

Pure Tone Audiometry and Hearing Loss in Alzheimer's Disease: A Meta-Analysis

“…Of these, all but one demonstrated findings of subjects with dementia having increased hearing thresholds (i.e., hearing impairment) compared to controls; however, the findings of Haggstrom et al (2018) could not be used in our analysis as they reported threshold hearing loss as median-values and not mean-values. Overall, the trend of increased hearing loss in subjects with dementia compared to controls was present in both included and excluded studies, supporting both the findings of this meta-analysis and current literature (Loughrey et al, 2018;Panza et al, 2018;Ray et al, 2018;Chern and Golub, 2019;Jafari et al, 2019;Ralli et al, 2019;Mertens et al, 2020;Utoomprurkporn et al, 2020;Knopke et al, 2021). The shortcomings outlined above illustrate the importance of better characterizing peripheral hearing ability in subjects with AD compared to healthy-aging controls.…”

“…Due to the known positive correlation between age and hearing-loss (Loughrey et al, 2018;Panza et al, 2018;Ray et al, 2018;Chern and Golub, 2019;Jafari et al, 2019;Ralli et al, 2019;Mertens et al, 2020;Utoomprurkporn et al, 2020;Knopke et al, 2021), a pooled, standardized mean age difference was calculated. Using a random-effects model, a DerSimonian-Laird meta-analysis for mean age difference across all studies was conducted.…”

“…The link between age-related hearing loss (ARHL) and the subsequent development AD is increasingly well-documented; however, the nature of this relationship remains unclear (Gurgel et al, 2014;Loughrey et al, 2018;Panza et al, 2018;Ray et al, 2018;Chern and Golub, 2019;Jafari et al, 2019;Ralli et al, 2019;Mertens et al, 2020;Utoomprurkporn et al, 2020;Knopke et al, 2021). Current hypotheses postulate that hearing loss increases cognitive demand and therefore predisposes individuals to AD neurodegeneration; that hearing loss results in social isolation which is a risk factor for AD; or that ARHL is an early clinical feature of AD pathology (Loughrey et al, 2018;Chern and Golub, 2019;Jafari et al, 2019;Ralli et al, 2019;Mertens et al, 2020;Utoomprurkporn et al, 2020;Knopke et al, 2021). Regardless of etiology, diagnosis of ARHL in AD may be useful since its treatment shows potential for being a modifiable risk factor to delay disease onset or slow rate of cognitive impairment (Hubbard et al, 2018;Jafari et al, 2019;Gregory et al, 2020;Mertens et al, 2020;Utoomprurkporn et al, 2020).…”

“…As AD remains incurable, promotion of healthy lifestyle and reduction of modifiable risk factors remain the most practical and cost-effective methods of addressing the disease (Khalsa, 2015;Hubbard et al, 2018;Jongsiriyanyong and Limpawattana, 2018;Mattson and Arumugam, 2018;Bhatti et al, 2020;Gregory et al, 2020). To reduce the negative impacts of ARHL on AD, determination of whether treatment of peripheral auditory processing, central auditory processing, or some combination of both, is necessary (Ralli et al, 2019;Xu et al, 2019;Jayakody et al, 2020;Johnson et al, 2021;Knopke et al, 2021). Characterization of peripheral and central hearing ability in patients with AD using a variety of assessment modalities is crucial for understanding the relationship between ARHL and AD (Xu et al, 2019;Jayakody et al, 2020).…”

Reported Hearing Loss in Alzheimer’s Disease Is Associated With Loss of Brainstem and Cerebellar Volume

“…Currently less than 20% of individuals that could benefit from hearing aids use them (Popelka et al, 1998;Chien and Lin, 2012), suggesting that there is a large potential pool of individuals that could benefit from early intervention to limit the impact of ARHL, and therefore potentially lower the incidence of AD. Consistent with the potential benefits of early and aggressive intervention to treat ARHL is the finding that cochlear implantation may enhance overall cognitive function in elderly patients with hearing loss (Utoomprurkporn et al, 2020;Knopke et al, 2021;Mertens et al, 2021). The animal literature is generally supportive of the finding that induction of HL can cause more global cognitive dysfunction, but does not generally lead to a progressive degenerative phenotype (reviewed by Nadhimi and Llano, 2020).…”