New Australian research suggests cochlear implants may improve cognitive function and slow dementia symptoms in older adults.
Lead author, audiologist Professor Julia Sarant, who leads the Hearing Loss & Cognition Program in the Department of Audiology and Speech Pathology at The University of Melbourne, said she was excited to share the latest results of the COCHLEA (Cochlear Implant Outcomes & Cognitive Health – Longitudinal Evaluation of Adults) study.
“The results of our study suggest that cochlear implant use may actually improve cognitive performance and/or delay cognitive decline in older adults with severe-profound hearing loss for several years, promoting wellbeing and healthy ageing,” she said on the university’s Pursuit platform.
The results suggested cochlear implantation may increase cognitive resilience/function, providing proof-of-concept evidence of the effects of hearing intervention with CIs on cognitive function, the researchers said when reporting findings in Brain Sciences.
The prospective longitudinal observational study followed the cognitive performance of 101 adults aged 60 and over with severe to profound hearing loss and cochlear implants (CI) (mean age 74) over four and a half years.
Their outcomes were compared with outcomes for 100 participants aged 60 and over with untreated hearing loss or normal hearing without hearing aids or cochlear implants.
Computerised card games were used to assess cognitive performance before cochlear implantation and in both groups at each follow-up interval of 18-months.
“Cochlear implant users demonstrated significantly improved performance in executive function and working memory, as well as stability in attention, psychomotor function, and visual learning at 4.5-year follow-up,” the researchers said.
Untreated participants showed significantly greater worsening performance per year in attention and psychomotor function, and stability in working memory and visual learning at three-year follow-up.
“Our research found that both executive function and working memory performance improved and other cognitive functions remained stable for the cochlear implant group,” Prof Sarant explained.
Unusual for cognitive performance to improve
The other participants declined significantly on two of four cognitive functions assessed, despite having much better hearing.
Executive function was defined as higher-level cognitive skills including decision-making, planning, problem-solving and managing emotions. Working memory, information retained in the brain for seconds or minutes, helps with performing complex tasks such as reasoning, comprehension or learning.
“It’s highly unusual to see cognitive performance improving significantly in ageing adults, and for this to be sustained over several years,” Prof Sarant said, in Pursuit. “Even older adults with normal hearing are expected to decline cognitivtely over time as part of the natural process of ageing.”
The study began in 2016, led by Prof Sarant in collaboration with researchers from The Royal Victorian Eye and Ear Hospital, Queensland’s Mater Hospital, and the AIBL study at the Florey Institute of Neuroscience and Mental Health.
Screening hearing aid recipients
“Cochlear implantation could help to delay the onset of dementia, extending quality of life, promoting healthy aging, and facilitating significant economic benefits,” the researchers said.
“Ongoing screening of auditory status and function in older adults who use hearing aids but may be candidates for CIs is important, as this will enable proactive and effective hearing intervention to support continued social engagement, maintenance of function, and aging well.”
They said promotion of cochlear implants could be an important strategy for reducing or delaying dementia in adults with severe to profound HL.
“Given the current very low take-up rates, improved knowledge of CIs (particularly eligibility criteria) in the medical profession and significantly increased referrals would be required to implement this intervention as a successful public health strategy,” they said.
Only about 10% of adults who would benefit from cochlear implantation receive the implants.
The study, which Prof Sarant said was one of the longest running in this field in the world, receives ongoing funding from Cochlear Ltd.
It is still recruiting and adults aged 60 years and over who are eligible and would like to receive a cochlear implant to participate in the COCHLEA study can contact the research teams in Melbourne or Brisbane.
More reading
Hearing loss, cognitive decline and dementia: the experts explain
Hearing loss can stabilise cognitive function in elderly: University of Melbourne study
Brain scans show hearing aids help slow brain aging in mild cognitive impairment
