Head Impulse Test Abnormalities and Influence on Gait Speed and Falls in Older Individuals

Abstract

Objective: To assess the prevalence of vestibular dysfunction in older adults using the head impulse test (HIT) and to assess the independent influence of HIT abnormalities on gait speed and fall risk in older individuals. Study Design: Cross-sectional study. Setting: Tertiary care academic medical center. Patients: Fifty community-dwelling individuals age 70 and older. Interventions: HIT (abnormal HIT defined as right or left HIT abnormality), visual acuity, monofilament testing, and grip strength. Main Outcome Measures: Gait speed on a 4-meter walk and a history of falls (including number of falls) in the last 1 and 5 years. Results: The participants' mean age was 77 years (range, 70Y95 yr); 52% were female subjects. Fifty percent of participants had an abnormal HIT. An abnormal HIT was significantly associated with a 0.23 m/s reduction in gait speed (p = 0.042), 0.44 more falls in the last 1 year (p = 0.047), and a 5-fold increase in the odds of falling in the last 5 years (p = 0.024) in multivariate analyses adjusted for age, sex, and other balance and fall risk factors. Conclusion: We observed that half of the community-dwelling older individuals in our study had evidence of vestibular dysfunction, which was significantly associated with gait speed and fall risk in adjusted analyses. Screening for vestibular impairment using the simple HIT and directing targeted vestibular therapy may be important to reduce gait impairment and fall risk in older individuals.The vestibular system is integral to balance control and locomotion. A recent epidemiologic analysis using data from the National Health and Nutrition Examination Survey (NHANES) found that vestibular dysfunction is highly prevalent among older individuals and significantly increases fall risk (1). In this study, vestibular dysfunction was defined as a subject's inability to stand with their eyes closed on a foam pad, whereby somatosensory and visual cues are eliminated and the subject is relying exclusively on vestibular information to maintain standing balance. A limitation of such postural tests is their lack of specificity in measuring peripheral vestibular function, given that they may reflect central processing and efferent motor output function as well. As such, the specific prevalence of peripheral vestibular dysfunction in older individuals and their influence on clinically significant outcomes remain unclear.In this report, we evaluated the prevalence of vestibular dysfunction in a cohort of ''normative'' older adults using the head impulse test (HIT), a clinical test that specifically measures vestibulo-ocular reflex (VOR) function. The HIT has been well validated in younger populations, and its use has been expanded to older individuals (2Y4). We also consider the influence of vestibular dysfunction on clinically significant outcomes in older individuals including gait speed and fall risk, using multivariate analyses adjusted for other balance and fall risk factors. We anticipate that a greater understanding of the frequency and clinical impli...

Association Between Saccular Function and Gait Speed

“…While previous studies have collected VEMP data in aging populations(22), these data have not been linked to gait function. Studies that have evaluated the influence of vestibular function on gait have largely focused on tests of semicircular function such as head-impulse testing(24) or head-shake tests(8). Our analysis suggests that age-related changes in otolith function influence gait speed, and that these associations differ between men and women.…”

“…Previous studies have shown that head impulse testing, when used to screen for semi-circular canal function in older individuals, predicted slower gait speeds and increased fall risk(24). Yet the impact of the otolith organs in age-related vestibular loss and functional gait parameters has not been fully investigated.…”

Epidemiology of Vestibulo-Ocular Reflex Function

“…A recent pilot study administered the HIT in a cohort of 50 healthy older adults to evaluate the prevalence of age-related vestibular loss in the community. The study observed a 50% prevalence of HIT abnormality, which was significantly associated with slow gait speed and fall risk (3). …”

Age-Related Imbalance Is Associated With Slower Walking Speed: An Analysis From the National Health and Nutrition Examination Survey

“…Indeed, we observed in prior work that older adults with impaired semicircular canal function had slower gait relative to adults with intact function. 23 We also previously reported an association between saccular dysfunction and slower walking speed among older women, but not older men. 24 The peripheral vestibular system senses head movements and responds to high-frequency head oscillations that occur during walking.…”