AUTHOR=Völter Christiane , Götze Lisa , Bajewski Marcel , Dazert Stefan , Thomas Jan Peter 

TITLE=Cognition and Cognitive Reserve in Cochlear Implant Recipients

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 14 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.838214

DOI=10.3389/fnagi.2022.838214

ISSN=1663-4365

ABSTRACT=Dementia is a hot topic nowadays. Hearing loss is considered to be one modifiable risk factor for cognitive decline. The underlying mechanism remains unclear and might be mediated by socioeconomic and psychosocial factors. Cochlear implantation has been shown to restore auditory abilities, but also to decrease mental distress and improve cognitive functions in people with severe hearing impairment. However, the promising results need to be confirmed. 
In a prospective single center study, we tested neurocognitive abilities in a large group of 71 subjects with bilateral severe hearing impairment with a mean age of 66.03 (SD 9.15) preoperatively and 6, 12, and 24 months after cochlear implantation using a comprehensive non-auditory computer-based test battery and we also assessed cognitive reserve (Cognitive Reserve Index Questionnaire), health-related quality of life (Nijmegen Cochlear Implant Questionnaire), and depression (Geriatric Depression Scale-15). 
Cognitive functions significantly increased after 6 months in attention (p=0.00004), working memory (Operation Span Task p=0.002), and inhibition (p=0.0002); and after 12 months in recall (p=0.003) and verbal fluency (p=0.0048), and remained stable up to 24 months (p≥0.06). Cognitive reserve positively correlated with cognitive functions pre- and postoperatively (both p<0.005), but postoperative improvement in cognition was better in subjects with poor cognitive reserve (p=0.003). Depression only had a slight influence on one subtest. No correlation was found between cognitive skills, quality of life, and speech perception (each p≥0.05). 
Cochlear implantation creates an enriched environment stimulating the plasticity of the brain with a global positive impact also on neurocognitive functions, especially in subjects with poor preoperative cognitive performance and low cognitive reserve.