11 February 2013

Untreated hearing loss has a negative impact on cognition

Cognitive abilities decline faster in people with untreated hearing loss than in those with normal hearing. Use of hearing aids may forestall or reduce cognitive decline.

Older adults with untreated hearing loss are more likely to develop problems thinking and remembering than older adults whose hearing is normal, according to a study by hearing experts at Johns Hopkins University School of Medicine in the US.

In the study, volunteers with hearing loss, who underwent repeated cognition tests over six years, had cognitive abilities that declined some 30% to 40% faster than in those whose hearing was normal. Levels of declining brain function were directly related to the amount of hearing loss, the researchers say. On average, older adults with untreated hearing loss developed a significant impairment in their cognitive abilities 3.2 years earlier than those with normal hearing.

Frank Lin, assistant professor at the Johns Hopkins University School of Medicine, tells that the possible explanations for the cognitive slide include the ties between hearing loss and social isolation, with loneliness being well-established in previous research as a risk factor for cognitive decline. Degraded hearing may also force the brain to devote too much of its energy to processing sound at the expense of energy which otherwise would be spent on memory and thinking. He adds that there may also be some common, underlying damage that leads to both hearing and cognitive problems.

Use of hearing aids

The research team plans to launch a much larger study to determine if the use of hearing aids or other devices to treat hearing loss in older adults might forestall or delay cognitive decline.

An earlier study, conducted for the National Council of Ageing in the US, found that hearing aid users were perceived as having better cognitive functioning than non-users and to be less introverted. In general, hearing aid users had a greater overall health status than non-owners, including higher self-confidence, better social life and better mental and physical health.

“Our results show that hearing loss should not be considered an inconsequential part of aging, because it may come with some serious long-term consequences to healthy brain functioning," says Lin.

"Our findings emphasise just how important it is for physicians to discuss hearing with their patients and to be proactive in addressing any hearing declines over time."

He also says that only 15% of those who need a hearing aid in the US get one, leaving much of the problem and its consequences untreated.

Sources: www.sciencedaily.com and The Hearing Review 7, 2000

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