Several pieces of interesting research were released in the world of audiology this month and we want to tell you about them. One study has found that smoking increases hearing loss. Other bodies of research have found new connections between hearing loss, cognitive impairment, dementia and memory loss.
As physicians come to know more about hearing loss they can develop better treatments that may lead to improved patient outcomes. Ongoing research provides the information that clinicians need to understand the broader implications of hearing loss and its impact on physical and cognitive health. Here are some of the research findings that were announced recently.
Smoking increases hearing loss
A new study1 in Japan shows that hearing loss may occur at a rate that is directly proportionate to the amount that an individual smokes. In other words, hearing risk increased with the number of cigarettes that a person smoked each day.
Researchers studied information from more than 50,000 Japanese workers who were between the ages of 20 and 64 and who had no hearing loss at the beginning of the study. The study followed them for up to eight years. The results of the study showed that there was a “20 to 60 percent increased risk for hearing loss among current smokers versus non-smokers”. More than 3500 people who smoked developed high-frequency hearing loss and more than 1500 participants developed low-frequency hearing loss, as compared to non-smokers.
Study links hearing loss to dementia
Over the years research published by hospitals2 and in clinical journals3 has repeatedly pointed out that hearing loss can increase the risk for dementia. A recent study in Singapore confirms these findings and found that seniors who have hearing impairment are two times “more likely to develop mild cognitive impairment or dementia.”
The National University of Singapore and Ng Teng Fong General Hospital conducted the study of more than 1,500 people over the age of 55. When the study began, participants showed no signs of memory loss or cognitive impairment. Two separate rounds of cognitive and clinical assessments were conducted over the course of three years. Researchers found that “Although hearing loss does not cause mental decline or dementia on its own, the results of the study show an association between untreated hearing loss and more rapid cognitive decline.”
The study’s principal otolaryngology researcher, Dr. Rebecca Heywood, a consultant at the ENT, Head and Neck Surgery Department at Ng Teng Fong General Hospital, said these findings are important because it is the first study of its kind in Singapore and Asia “…that supports emerging evidence around the world that hearing loss is a risk factor for dementia.”
Study shows that central age-related hearing loss may be associated with memory loss and mild cognitive impairment
It’s important to note that age-related memory loss is different from dementia. It is the result of the normal aging of the brain, not a disease, which dementia is. A recent study4 shows that age-related central hearing loss may be associated with age-related memory loss as well as mild cognitive impairment.
The study took place in Italy and reviewed data from more than 1600 participants that were an average of 75 years old. Each had some type of age-related hearing loss. Researchers tested the participants’ hearing, thinking and memory skills.
The study found that of the 192 participants who had hearing loss, 75 percent of them (144) had mild cognitive impairment. Of the 609 participants with no hearing loss, only 60 percent (365) had mild cognitive impairment.
The study shed new light on the nature of central hearing loss, saying that it may actually be caused by a progressive loss of functioning brain cells, just as occurs with cognitive decline. Researchers say that for those aged over 65 and who have some cognitive impairment, hearing perception tests, as opposed to sensory tests, may be a good idea.
These research studies shed light on many new aspects of hearing and the wide-ranging implications of hearing loss. Their findings advance the science of audiology and physicians’ ability to protect the well-being of their patients. The more we know the more we can protect our hearing and improve our health in later years.