Hearing loss in older people is associated with cognitive decline and dementia, according to research by scientists at Trinity College Dublin.
Researchers from Trinity College Institute of Neuroscience and Global Brain Health Institute made the findings following a review of 36 studies from 12 countries involving 20,264 participants.
Previous studies reported an association between cognitive decline and hearing loss; others say there is little or no connection.
As a result, the review only included observational studies that used standard cognitive tests and pure-tone audiometry, the clinical standard for testing peripheral hearing loss.
The research concluded people with age-related hearing loss had an increased risk for cognitive decline including executive function (mental processes that enable people to plan, focus attention and juggle tasks), processing speed and episodic memory (recollection of specific events). They also had a higher risk for cognitive impairment and dementia.
The researchers did not know if there was “a casual relationship” or what the reasons for the connection were and said further research was needed.
Lead author David Loughrey said: “We need intervention trials that look at the benefits of hearing loss treatment over a long follow-up period to see if it decreases the risk of someone getting dementia.”
Possible connections could include a person’s diversion of mental resources to make up for hearing loss, leaving fewer resources for other processes such as memory.
Research suggests factors such as depression or loneliness may be associated with a higher risk of dementia.
Dementia affects some 45 million people worldwide, and this is estimated to grow to 131 million by 2050. About one-third of adults older than 65 experience a disabling hearing loss - in many cases untreated.
The research was published in the medical journal JAMA Otolaryngology - Head & Neck Surgery.
