Benefits of Cochlear Implantation in Middle-Aged and Older Adults

INTRODUCTION: Nowadays cochlear implantation (CI) is the treatment of choice in adults in case conventional hearing devices fail. Besides speech perception, an improvement in quality of life and in cognitive performance has been reported. Thereby, the study focused on the impact of age. PARTICIPANTS AND METHODS: Thirty middle-aged (MA) between 50 and 64 years and 41 older subjects (OA) aged 65 and older with bilateral severe hearing loss performed a comprehensive computer-based neurocognitive test battery (ALAcog) pre- and 12 months post-implantation. Besides, monosyllabic speech perception in quiet (Freiburg monosyllabic speech test), health-related quality of life (HR-QoL, Nijmegen Cochlear Implant Questionnaire) and depressive symptoms (GDS-15) have been assessed. RESULTS: Both age groups significantly improved in all three categories after 12 months. No differences were evaluated between MA and OA regarding speech perception and HR-QoL pre- and post-operatively. In contrast, cognitive performance differed between the age groups: pre-operatively OA performed worse in most neurocognitive subdomains like working memory (p=0.04), inhibition (p=0.004), processing speed (p=0.003) and mental flexibility (p=0.01), post-operatively MA outperformed OA only in inhibition (p=0.01). Age only slightly influenced cognitive performance in MA, whereas in OA age per se tremendously impacted on working memory (p=0.04), inhibition (p=0.02), memory (p=0.04) and mental flexibility (p=0.01). Educational level also affected processing speed, mental flexibility (p=0.01) and working memory (p=0.01). This was more pronounced in OA. In both age groups, hearing status had a strong effect on attentional tasks (p=0.01). In MA, depressive symptoms were more influential on cognitive functioning and on HR-QoL than in OA. Improvement in quality of life (p=0.0002) and working memory (p=0.001) was greater for those with a higher pre-operative depression score. CONCLUSION: Speech perception and HR-QoL improved in hearing impaired, independently of age. Pre-operative differences in cognitive performance between OA and MA clearly attenuated 12 months after CI. Impact of comorbidities differed between age groups.