Older adults suffering from hearing loss could have an increased risk of developing dementia, or more specifically, Alzheimer's disease. This risk could increase as hearing loss worsens, according to a recent study.
The study, led by Frank R. Lin, M.D., Ph.D. at John Hopkins Medical Institutions, aims to address possible solutions to the rising problem of dementia, which estimates say will affect 100 million people globally by 2050.
Researchers claim that preventative interventions that delay the onset of dementia by just one year could cause a 10 percent decrease in dementia's prevalence over the next 40 years. Nonetheless, scientists still need to conduct intensive research to identify potentially helpful interventions.
Scientists have focused on identifying risk factors of dementia, under the assumption that the condition is easier to prevent than to reverse. These potential factors include low involvement in leisure activities and social interactions, sedentary lifestyles, diabetes mellitus and hypertension.
Since hearing loss leads to low involvement in leisure and social activities as well as a sedentary state, researchers have identified hearing damage as a possible risk factor as well.
Lin's long term study, published in the February 2011 edition of Archives of Neurology, consisted of 639 people between the ages of 36 and 90 who did not have dementia when the research project started in 1990. Researchers first tested the participants' cognitive and hearing abilities between 1990 and 1994. They followed up by testing for the development of dementia, including Alzheimer's disease, on May 31, 2008.
Of the study's 639 subjects, 125 had mild hearing loss, 53 moderate and six severe. When tested in 2008, 58 participants were diagnosed with dementia, including 37 with Alzheimer's.
According to researchers, the risk of dementia increased among those with at least a mild 25 decibel (dB) hearing loss and increased further as hearing damage worsened. Those with the most severe hearing loss were the most likely to be diagnosed with Alzheimer's or other forms of dementia.
Among subjects 60 or older, 36.4 percent of the risk of dementia was linked to hearing loss. For every 10 dB of hearing loss, the risk of developing Alzheimer's increased by 20 percent.
Researchers also found no correlation between the use of hearing aids and a reduction in the risk of Alzheimer's or dementia in general, indicating that prevention of hearing loss, rather than treatment, could reduce the risk of dementia.
The study's researchers speculate that either dementia could potentially be overdiagnosed in people with hearing loss or that hearing loss could be overdiagnosed in those with cognitive impairment.
Charting the Correlations
Although hearing loss and dementia might be misdiagnosed in some cases, the conditions could share a common, underlying cause, according to researchers. Both hearing loss and dementia could be caused by the exhaustion of cognitive reserve, social isolation or various other factors.
Researchers also comment that if these findings are confirmed by further research, the study could have significant implications for public health and individuals with these conditions.
Hearing loss in older adults can be prevented and treated with modern technologies like digital hearing aids and cochlear implants. Researchers also claim that rehabilitative interventions could develop down the road that focus on improving social and environmental conditions for hearing, to diminish hearing loss and the onset of dementia.
If you or someone you know would like to learn more about hearing loss treatments or hearing aids in general, please feel free to schedule a consultation or contact one of our representatives today.