Can Cochlear Implantation in Older Adults Reverse Cognitive Decline Due to Hearing Loss?

Introduction: Older adults with late-onset hearing loss are at risk for cognitive decline. Our study addresses the question of whether cochlear implantation (CI) can counteract this potential influence. We investigated whether cognitive performance in older adults with severe and profound hearing loss improves 12 months after CI to a level comparable to controls with normal hearing, matched for age, sex, and education level. Design: This cohort study was performed at two tertiary referral centers. The study included 29 patients, of age between 60 and 80 years, with adult-onset, severe to profound bilateral sensorineural hearing loss and indication for CI (study group), as well as 29 volunteers with age-adjusted hearing abilities, according to the norm curves of ISO-702 9:2000-01, (control group). Before CI and 12 months after CI, participants completed a neurocognitive test battery including tests of global cognition, verbal and figural episodic memory, and executive functions (attentional control, inhibition, and cognitive flexibility). Results: Twelve months after CI, the performance of the study group improved significantly in global cognition, compared to the situation before CI. Differences in verbal episodic memory, figural episodic memory, and executive function were not significant. Moreover, the improvement of the study group was significantly larger only in global cognition compared to the control group. Noninferiority tests on the cognitive performances of the study group after CI revealed that comparable levels to normal hearing controls were reached only in global cognition, figural episodic memory (immediate recall), and attentional control. The improvement in global cognition was significantly associated with speech recognition 3 months after CI, but not with speech recognition 12 months after CI. Conclusion: One year after CI, cognitive deficits in older individuals with adult-onset hearing loss, compared to normal-hearing peers, could only improve some cognitive skills.