Kowalewski V.1, Thibodeau L.2, Patterson R.3, Fox J.1, Kinzler B.1, Bugnariu N.1
1University of North Texas Health Science Center, Physical Therapy, Fort Worth, United States, 2University of Texas at Dallas - Callier Center for Communication Disorders, Audiology, Dallas, United States, 3University of North Texas Health Science Center, Osteopathic Manipulative Medicine, Fort Worth, United States
Background: One in three adults 65 years or older fall annually, leading to $34 billion in direct medical costs due to fractures, emergency procedures, and hospitalization. Traditionally, three sensory inputs - visual, vestibular, and somatosensory - are associated with the control of balance and have been investigated for their potential contribution to increased risk of falls. Recent evidence suggests additional sensory input, such as auditory input, may also contribute to balance control. Epidemiological studies have shown hearing loss is associated with balance deficits and increased risk of falls in older adults. Although current evidence reveals an association between hearing loss and balance difficulty, the mechanisms behind how and why hearing loss affects balance are unknown. It is possible that hearing loss taxes cognitive resources in complex environments, causes perceptual problems, leads to social isolation and decreased physical activity, or shares a physiological pathology with the vestibular systems, thus explaining balance impairments.
Purpose: We investigated the contribution of auditory inputs to balance control in healthy young and older adults by simulating hearing loss.
Methods: Participants were tested for balance, gait and functional activities, under control and simulated hearing loss condition. Hearing loss was achieved using a pair of Bose QuietComfort 35 wireless noise-cancelling headphones and Adobe Audition software that manipulated volume and frequencies to simulate moderate hearing loss. Participants completed standing balance, walking, and responding to perturbations while completing a standardized audiology test (BKB-SIN). Outcome measures included: standing center of pressure sway, Center of Pressure Center of Mass (COP-COM), performance of dual-task, and self-selected gait speed. Clinical tests of 6-Minute Walk Test, Functional Gait Assessment, and Short Physical Performance Battery were also administered. ANOVA was conducted for each of the dependent variables with respect to group and condition of auditory task.
Results: Preliminary results showed that in response to perturbations simulating a fall, the COP-COM distance was an average of 25 cm and 15 cm in young and older adults, respectively. Center of pressure sway variability increased significantly in participants under simulated hearing loss condition as compared to normal hearing.
Conclusion(s): Simulated hearing loss negatively impacts postural control particularly in dual-task conditions when individuals simultaneously attend to auditory and postural tasks. The effect is stronger in older adults who have fewer resources to compensate for poor sensory input.
Implications: Age-related hearing loss affects a large percentage of the older adult population. Individuals with hearing loss may be at greater risk of falling than individuals without hearing loss. One possible explanation includes reduced or conflicting auditory information increases the cognitive load and thus, attentional resources may be taxed particularly in older adults. Majority of current PT clinical outcome measures are not designed to evaluate the impact of hearing loss on measures of postural control, however most of the therapist patient interaction is mediated through speech recognition, therefore further studies are necessary.
Funding acknowledgements: Supported by Neurobiology of Aging Training Program (National Institute of Health training grant - T32 AG 020494)
Topic: Older people
Ethics approval: UNT Health Science Center IRB committee approved the Research Project #2016-099 titled, The Effect of Hearing Loss on Balance.
All authors, affiliations and abstracts have been published as submitted.
