The Relationship between Chronic Unilateral Hearing Loss, Balance Function, and Falls Is Not Informed by Vestibular Status

Abstract

Objectives: Recent studies suggest that hearing loss is associated with balance dysfunction and an increased risk of falls. The purpose of this study was to investigate whether adults with unilateral hearing loss (UHL) have an underlying vestibular dysfunction and whether vestibular testing explains balance function and fall risk.

Study design: Cross-sectional.

Setting: Urban otology practice and a human motion laboratory.

Patients: We recruited 41 healthy controls (mean age, 52 years; range, 22-78 years) and 29 adults with stable UHL (mean age, 53 years; range, 18-80 years) who denied symptoms of dizziness (Dizziness Handicap Inventory average, 1.86; range, 0-14). UHL occurred an average of 4 years (range from sudden loss, 4 months to 27.5 years) prior to testing.

Interventions: We conducted the caloric portion of the videonystagmography test, video head impulse test (vHIT), and a battery of balance tests: standing on foam with eyes closed, timed up and go test, four square step test, 10-meter walk, and a virtual reality (VR) assessment of postural control.

Main outcome measures: Hearing was quantified by four-frequency pure-tone average (PTA). Caloric weakness was defined as asymmetry greater than 25%. Participants self-reported falls over the past 12 months and history of vertigo. Performance on balance tests was quantified by time to completion or duration of hold. Performance on the VR assessment was quantified by root-mean-square velocity of head sway.

Results: Proportion of unilateral caloric weakness was significantly higher in the UHL group (25%) than the control group (12%). Five participants with UHL refused caloric testing. vHIT gains of lateral canals were normal in both groups. The majority of participants in the UHL group experienced vertigo at the onset of hearing loss (72%). There were five fallers in the UHL group (17%) and three in the control group (7%). Participants with caloric weakness or vertigo at onset did not differ from those without in age or in any of the balance tests. Participants with history of falls differed in head sway and duration of hold standing on foam with eyes closed.

Conclusions: Individuals with UHL are more likely to have caloric weakness than healthy controls; however, these findings are not correlated with functional outcomes or history of falls. Postural control testing using virtual reality or standing on foam with eyes closed may help detect those at a risk for falls.

Figure 1.

Head Root Mean Square Velocity in the AP direction (top) and ML direction (bottom) during the static scenes (left-hand side) and dynamic scenes (right-hand side) comparing 8 fallers (5 in the UHL group, 3 in the control group) to non-fallers.