Speech-in-noise hearing impairment an early sign of dementia
Research has found that older adults who have difficulties hearing speech over noisy backgrounds – a condition referred to as “speech-in-noise hearing impairment” – have up to 91% increased risk of developing dementia in later years. Many people with dementia will experience difficultly following speech in a noisy environment i.e. the “cocktail party problem”; these hearing changes are a risk factor that could potentially be treated, said Dr. Katy Stubbs from Alzheimer’s Research UK.
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“Difficulty hearing speech in background noise is one of the most common problems for people with age-related hearing impairment,” agreed Dr. Jonathan Stevenson, from the University of Oxford’s Nuffield Department of Population Health (NDPH), UK.
In a new study that confirms how this type of hearing impairment is associated with developing dementia, Dr. Stevenson and colleagues followed 82,000 men and women aged 60 years or older over the course of 11 years. Participants were made to identify certain spoken words against a background of white noise; and were divided into three distinct groups: normal, insufficient, and poor speech-in-noise hearing, based on their scores.
When the researchers modeled hearing loss scores against participants who developed or were in the course of developing dementia, they were surprised to find insufficient and poor speech-in-noise hearing were associated with a 61% and 91% increased risk of developing dementia, compared to normal speech-in-noise hearing, respectively.
According to the World Health Organization (WHO), up to 1.5 billion individuals suffer from some form of hearing impairment – a sizeable fraction of which consists of older adults. Hearing impairment may contribute to the risk of dementia. In a 2015 study, researchers at Johns Hopkins University found that mild hearing loss doubled dementia risk; moderate loss tripled the risk, while people with a severe hearing loss were five times more likely to develop dementia.
“Brain scans show us that hearing loss may contribute to a faster rate of atrophy in the brain,” said Frank Lin, the director of the Cochlear Center for Hearing and Public Health at Johns Hopkins. “Hearing loss also contributes to social isolation. You may not want to be with people as much, and when you are you may not engage in conversation as much. These factors may contribute to dementia.”
Emerging research even suggests that poor hearing may impact memory care drastically later in life.
“Developing dementia is not inevitable and that the risk could be reduced by treating pre-existing conditions. Whilst preliminary, these results suggest speech-in-noise hearing impairment could represent a promising target for dementia prevention,” surmised Dr. Thomas Littlejohns, senior epidemiologist at NDPH.
