Hearing Loss Associated with Balance Issues

Hearing loss, even if only on one side, increases the risks for postural instability in older adults, according to study results published in JAMA Otolaryngology-Head & Neck Surgery. The researchers suggest that this was particularly pronounced in older women with hearing loss.

“Hearing loss affects 6.1% of the world’s population and is one of the most frequently occurring sensory disabilities. Hearing loss results from the accumulation of sensory cell damage in the inner ear and is the most common chronic disorder in the aging population,” wrote these researchers, led by Seung-Hwan Bang, MD, of the Korea University Guro Hospital, Korea University Medicine, Seoul, Korea.

“Auditory and vestibular systems function together although their exact mechanism of interaction is not clear. To date, there is a lack of studies analyzing the association between hearing loss and postural instability in the general population,” they added.

To this end, Bang and colleagues conducted a cross-sectional, population-based study, for which they used data from the 5th Korea National Health and Nutrition Examination Survey to identify 3,864 subjects (mean age: 57.8 years; 55.2% women) with hearing loss data. Participants were tested with pure tone audiometry on both sides and were classified into categories according to the hearing grade of each side as follows: normal hearing, mild hearing loss (threshold: 26-40 dB), or moderate hearing loss or worse (threshold: > 40 dB).

Participants were also categorized into the following hearing loss subcategories:

• Bilateral normal.
• Unilateral mild.
• Bilateral mild.
• Unilateral moderate.
• Bilateral moderate.
• Unilateral mild.
• Contralateral moderate.

Researchers defined age-related hearing loss as a threshold of 26 dB or more, and postural instability as the inability to remain standing on a foam pad surface while the feet were 10 cm apart, arms folded, hands cupping elbows, and eyes closed. Using a binomial logistic regression model, they determined the association between hearing loss and postural instability.

In the overall study population, the mean hearing threshold was 22.21 dB on the right side, and 23.16 on the left. There were no statistically significant differences in mean hearing thresholds between men and women. Some form of hearing loss was found in 38.7% of participants, with mild hearing loss being the most common (10.4%).

Researchers identified postural instability in 3.3% of the study population, and this was higher in women than in men (3.7% vs 2.7%, respectively). Thus, compared with male gender, female gender was associated with greater odds of postural instability (OR: 1.65; 95% CI: 1.12-2.42). Further, Bang and colleagues found that the odds of postural instability increased with each 1-year increase in age (OR: 1.13; 95% CI: 1.10-1.16). Both analyses were adjusted for age and hearing status.

They also found that neither bilateral nor unilateral mild hearing losses were associated with an increased risk of postural instability. Moderate hearing loss on at least one side, however, was associated in an increased risk as follows:

• Unilateral, moderate hearing loss (25 of 383 [6.5%]; OR: 2.71; 95% CI: 1.12-6.10).
• One side mild and the other moderate hearing loss (23 of 261 [8.8%]; OR: 2.18; 95% CI: 1.16-4.09).
• Bilateral moderate hearing loss (33 of 280 [11.8%]; OR: 2.18; 95% CI: 1.16-4.09); all adjusted for age and sex.

In the 156 participants with severe hearing loss (threshold: 71 to 90 dB unilaterally or bilaterally) the incidence of postural instability was 12.2%, and in the 67 with profound hearing loss (threshold: > 91 dB), 11.9%.

Study limitations include the failure to exclude temporary dizziness while testing, as well as the lack of available data on participants’ physical ability and vestibular function.

“In this study, being female, and having moderate hearing loss were associated with postural instability among participants 40 years and older. It may be helpful to consider these findings when making recommendations or research on hearing rehabilitation to prevent postural instability,” concluded Bang and fellow researchers.

In agreement, Anat V. Lubetzky, PhD, of New York University, New York City, explored the possible need for clinicians to change their approach to postural control in an accompanying editorial.

“Is it time for a paradigm shift in the inquiry of postural control? Vision, somatosensory, and vestibular information are known to be crucial sensory inputs for balance. Should auditory input be added to this model?” he queried.

“New evidence suggests that balance is impaired and often overlooked in patients with hearing loss. Clinically, a paradigm shift calls for individuals with hearing loss to be screened for balance performance and fall risk…Scientifically, a paradigm shift calls for the inclusion of auditory cues in postural control studies to better understand the mechanism explaining the observed association. Overall, as Bang et al suggest, hearing loss should be considered beyond its auditory implications and taking into consideration its broader association with the individual’s quality of life and fall risk,” Lubetzky concluded.

1. Compared with normal hearing, moderate or worse hearing loss in adults over 40 years old is associated with increased odds of postural instability.

2. Korean researchers found that postural instability was associated with hearing loss (even unilateral), with increased age, and female gender.

E.C. Meszaros, Contributing Writer, BreakingMED™

Cat ID: 494

Topic ID: 398,494,282,494,730,192,925