Purdue Research Team Examines Correlation Between Postural Sway and Balance

The relationship between human hearing loss and balance is an important health correlation that continues to be investigated by researchers in the Purdue University Department of Speech, Language, and Hearing Sciences.

One of the newest, ongoing studies added the variable of postural sway into the research equation. Postural sway is a natural phenomenon that helps humans retain balance when upright. The slight, small movements around our centers of gravity help us from toppling when standing for periods of time.

For those with hearing loss, postural sway is more pronounced, according to new work by Purdue University audiology professor Alexander Francis and colleagues. Hearing aids seem to reduce the sway but not eliminate it, which is good because having some sway is important, especially in older adults.

“When we think about stability of anything physiological, traditionally we think of things being immobile but in fact, the best way to be prepared for change is to be a little bit fluid,” Francis explained. “If you’re too rigid, it’s really easy to fall over.”

Funded by a $25,000 grant from Purdue’s Kinley Trust, Francis first tested the hearing of 38 adults aged 62-85. After being coded into three groups — hearing impaired (10), hearing impaired but wearing a hearing aid (15) and no hearing impairment (13) — participants were asked to stand still for one minute to observe their sway under different listening conditions. With hearing loss’ connection to more falls in older adults, Francis’ work looks at how their bodies behave under stable conditions by monitoring postural sway.

Francis pushed his participants a bit further by blinding them during the one-minute standing test. A face shield was spray-painted black, which took away their sense of vision. A few participants who had hearing loss could not make it through the 60 seconds and were excluded from the study. Others had to grasp onto a safety railing, which was consistent with the loss of sight greatly affects balance in older adults.

“For an older person, a fall could mean a permanent loss of independence. That’s really terrifying. We’d like to be able to find things that can predict whether someone is likely to fall in the future even without them falling already,” Francis said. “We would like to be able to match up some laboratory measures that compliment more accurate daily diary-type measures.”

‘Dear diary … ’

Simply asking people how many times they’ve fallen in a year is not good enough for research, even though that’s how many medical doctors still evaluate older patients, according to Francis. Once the participants left his lab, they filled out a daily diary for four months via text message, email or written in a provided booklet. If not done daily, participants may forget little slips or off-balance moments that did not result in a painful fall. To Francis’ study, those small moments are just as important as a fall that would require a bandage.

While the findings are still being written, Francis found that the group wearing hearing aids were more stable, had less sway and fell less than the hearing-impaired individuals without hearing aids. This adds to the belief that hearing is a significant factor in older adults’ balance.

More questions

Francis found four months of data worked well for this study, but a year’s worth would offer more insight. He is left with more questions as he combs the data:

• Are people who invested in hearing aids more cautious about their balance in general?

• Just how much does hearing loss reflect problems in an older adult’s vestibular function or inner ear?

• Do hearing aids conclusively help with balance in older adults?

The body has a complex collection of functions that help us maintain balance — hearing, sight and spatial orientation, postural sway, vestibular function and proprioception, which is the awareness of the body in space. If one starts to fall, the body can usually compensate to keep from falling. However, most hearing researchers like Francis would agree that if two or more functions are damaged, falls will increase.

“The epidemiological data suggests if you have hearing loss, you’re almost twice as likely to fall as someone matched to you that doesn’t have hearing loss. But we don’t have a really well-documented study showing that wearing hearing aids makes you fall less,” Francis said. “People with poor hearing could also have poor vestibular function, so hearing aids aren’t going to change that, but wearing a hearing aid reduces the cognitive demands of listening. There’s not really good evidence that hearing aids help balance, but it makes sense that they ought to based on the theories of why hearing loss increases fall risk.”

Article originally appeared on Purdue University