The Laryngoscope C 2014 The American Laryngological, V
Rhinological and Otological Society, Inc.
The Effect of Hearing Aids on Postural Stability Kavelin Rumalla; Adham M. Karim, BS; Timothy E. Hullar, MD Objectives/Hypothesis: In the United States, falls are the leading cause of accidental deaths in adults aged over 65 years. Epidemiologic studies indicate that there is a correlation between hearing loss and the risk of falling among older people. The vestibular, proprioceptive, and visual systems are known to contribute to postural stability, but the contribution of audition to maintaining balance has not yet been determined. Study Design: Cross-sectional study to measure postural stability in bilateral hearing-aid users aged over 65 years in aided and unaided conditions. Methods: Balance was assessed using the Romberg on foam test and the tandem stance test. Tests were administered in the presence of a point-source broadband white-noise sound (0–4 kHz) source in both unaided and aided conditions in the dark. Subjective measures of balance were made using the Activities-specific Balance Confidence Scale. Results: Performance was significantly better in the aided than the unaided condition (P 5 0.005 for both tests). No statistically significant relationship between improvement in balance, and hearing was identified. Participants did not report that they perceived a difference in balance between the two conditions. Conclusion: These results indicate that hearing aids are a novel treatment modality for imbalance in older adults with hearing loss and suggest that wearing hearing aids may offer a significant public-health benefit for avoiding falls in this population. Key Words: Fall, elderly, hearing, aid, audition, Romberg, auditory, landmark, posture, stability, balance. Level of Evidence: 4. Laryngoscope, 125:720–723, 2015
INTRODUCTION Vestibular, visual, and proprioceptive inputs provide sensory information required to maintain stability.1 Aging causes decreased function of these sensory systems and is associated with an increased risk of falls in the elderly.2–4 Hearing acuity also decreases with aging. Like other age-related sensory losses, presbycusis is associated with an increased risk of falls.5–9 This association might be explained by a global age-related loss of labyrinthine function in which auditory loss is simply a marker for vestibular losses leading to imbalance. Alternatively, audition may represent an independent sensory input providing spatial sound cues that are important for maintaining balance. If auditory input is important for maintaining balance, interventions such as hearing aids might serve to improve balance as well as auditory performance. Showing this improvement would significantly impact clinical
From the Department of Otolaryngology–Head and Neck Surgery, Washington University in St. Louis, St. Louis, Missouri, U.S.A. Editor’s Note: This Manuscript was accepted for publication September 23, 2014. This study was supported by Washington University Institute of Clinical and Translational Sciences and the National Center for Advancing Translational Sciences through grants UL1 TR000448 and TL1 TR000449. The authors have no other funding, financial relationships, or conflicts of interest to disclose. KR ad AMK contributed to authorship equally. Send correspondence to Timothy E. Hullar, MD, Department of Otolaryngology–Head and Neck Surgery, Washington University in St. Louis, 660 South Euclid Avenue #8115, St. Louis, MO 63130. E-mail: [email protected] DOI: 10.1002/lary.24974
Laryngoscope 125: March 2015
720
care by introducing hearing aids as a novel and effective treatment for imbalance in people with hearing loss. It would also shed light on the basic mechanism of maintaining stability by showing that hearing cues rank alongside vestibular, visual, and proprioceptive inputs as significant contributors to maintaining balance. Here, we evaluated balance function in older, experienced users of hearing aids in unaided and aided conditions using two balance tests: Romberg on foam and tandem stance.
MATERIALS AND METHODS This study was carried out with the approval of the Washington University Institutional Review Board. Potentially eligible subjects were drawn from consecutive patients treated at the Washington University Department of Otolaryngology, Division of Audiology. Inclusion criteria were adults greater than 65 years old who wore bilateral hearing aids for 3 months or more, had aided thresholds of 25 dB or worse in each ear, could understand English-spoken directions, and could ambulate without assistive devices. Exclusion criteria were a history of degenerative neurologic disease, stroke, spinal stenosis, joint replacement, or balance-altering medication or surgery. Subjects were paid for their participation. We collected data from each participant’s most recent audiologic evaluation, including the improvement (“gain”) currently provided by their hearing aids. Gain is defined in this context as the decibel sound pressure level (dB SPL) that sound must be amplified to in order to be perceived by the wearer as a comfortable conversational sound at a given frequency.10 We calculated each participant’s overall improvement by averaging gain at 0.5, 1.0, 2.0, and 4.0 kHz. Participants also completed the Activitiesspecific Balance Confidence Scale (ABC) test to assess their overall level of physical functionality.11 Prior to testing, the
Rumalla et al.: Hearing Aids and Balance
your hearing aids on, hearing aids off, or no difference?” All participants were blinded to the purpose of the experiment.
RESULTS
Fig. 1. Effect of wearing hearing aids when performing the Romberg on foam test. Length of time over which 14 participants could stand in unaided and aided conditions (maximum of 30 seconds). Dashed line represents the four participants who scored perfectly on the test. participants were asked: “Do you feel that your hearing aids make your balance better, worse, or is there no difference?” We measured postural stability using two methods: the Romberg on foam test and the tandem stance test. For the foam test, participants were instructed to stand with their feet together on a foam pad (Balance-pad; Airex, Sins, Switzerland) with their arms crossed above their shoulders. The goal was to maintain balance for 30 seconds. In the tandem test, the participants were instructed to place their dominant foot in front of the other in a heel to toe fashion with no angle allowed and remain in that posture for a maximum of 30 seconds while standing on a firm substrate.12 In all conditions, participants were instructed to take off their shoes and wear a spotter’s belt to prevent falls. Test results were measured in seconds. A trial was terminated and time recorded if a participant moved their arms or feet to maintain stability, opened their eyes, required a spotter to maintain balance, or took a step. Broadband white noise (0–4 kHz, 65 dB) was presented for the duration of the experiment. This frequency band was chosen because some hearing aids apply frequency compression above 4 kHz, which could otherwise cause a confounding effect when comparing sound thresholds with hearing aids on versus aids off. The white noise was played by a speaker with a frequency response of 0.1 to 22.0 kHz (Model R1; YC Cable, Ontario, CA) placed 1 meter directly in front of the participants and adjusted to be at ear level. Visual cues were eliminated with a blindfold. Each participant stood for a maximum of 30 seconds with hearing aids on (aided condition) and hearing aids off (unaided condition) in each experimental condition. Each condition was repeated in three trials, with conditions and trials pseudorandomized. The participants’ median score on three trials was counted as the final score for the test condition. After testing, participants were asked two questions, “Do you feel that the sound made your balance better, worse, or no difference?” and “Do you feel that you performed better with
Laryngoscope 125: March 2015
A total of 14 participants were enrolled (7 female; mean age 5 77; age range 5 65–91). No participant had a history of falls in the past year. The mean audiometric gain among all participants was 12.75 dB SPL. Prior to testing, none of the 14 participants reported a perceived difference in balance or performance due to wearing hearing aids. For the Activities-specific Balance Confidence Scale test, 13 of the 14 participants scored as having a high level of physical functioning, and one participant scored at a moderate level of physical functioning. Results for the Romberg on foam test are shown in Figure 1. Ten of the 14 participants scored better in the aided than in the unaided condition, whereas the other four scored a maximum of 30 seconds in both conditions. The mean score in the unaided condition was 17.0 6 10.2 seconds (median 5 14.3 seconds) and in the aided condition was 25.6 6 7.8 seconds (median 5 30.0 seconds). A two-tailed, nonparametric, Wilcoxon sign-ranked test indicated a statistically significant difference between balance performance in the aided versus the unaided condition on foam (P 5 0.0051). When considering the mean rather than the median of the three trials, the significance level improved to P 5 0.0033. Results of the ABC test showed no correlation to performance. Results for the tandem test showed improvement in the aided compared to unaided condition (Fig. 2). In the
Fig. 2. Effect of wearing hearing aids when performing the tandem stance test. Length of time over which participants could stand during unaided and aided conditions (maximum of 30 seconds). Dashed lines correspond to the four participants who scored perfectly on the Romberg on foam test.
Rumalla et al.: Hearing Aids and Balance
721
unaided condition, participants were able to stand for a mean of 4.5 6 3.3 seconds (median 5 3.2 seconds). In the aided condition, participants were able to stand for a mean of 9.8 6 7.4 seconds (median 5 9.6 seconds). A twotailed, nonparametric, Wilcoxon sign-ranked test comparing median trial performances for each participant indicated a statistically significant effect of wearing hearing aids while performing the tandem stance test (P 5 0.0052). When considering the mean of three trials rather than the median, the significance level improved to P 5 0.0035. The four participants who had reached the ceiling of 30 seconds in both the unaided and aided conditions on the foam test showed improvement with amplification in the more difficult tandem test. The ABC test results did not show any correlation to the participants’ overall performance on this test. The mean improvement on the foam test for the 14 participants was 8.5 seconds. However, the mean improvement for the 10 participants who did not have a ceiling effect was 11.6 seconds (mean audiometric gain5 13.9 dB SPL). The mean improvement on the tandem test for all 14 participants was 5.3 seconds. For the four participants who reached a ceiling effect on the foam, mean improvement on the tandem test was 8.7 seconds (mean audiometric gain 5 9.8 dB SPL). There was no detectable correlation between gain while wearing hearing aids and mean improvement in balance for the 10 participants who improved on the foam test (Spearman’s rho 5 20.115; P 5 0.751). The correlation for the relationship between hearing gain and mean improvement on the tandem test was also not significant (Spearman’s rho 5 0.400; P 5 0.600).
DISCUSSION The results presented here show that wearing hearing aids will provide a significant improvement in balance and a decreased risk of falling among older adults with hearing loss. This suggests that hearing aids offer a novel treatment modality for imbalance and allow auditory inputs to be considered, along with vestibular, proprioceptive, and visual cues as important contributors to maintaining balance. A limited number of studies have previously examined the relationship between audition and balance but did not investigate the ability of hearing aids to improve balance, as done here. A study of postural sway in a group of sighted (blindfolded) subjects and congenitally blind patients found that a pair of fixed, external auditory sources located immediately adjacent (5 cm lateral) to each ear reduced movement of the center of pressure compared to when standing in silence.13 A more recent study measuring center of pressure while standing on a Nintendo Wii (Kyoto, Japan) platform reported a small improvement in sway in a group of normal subjects in the presence of external sound, but results were inconsistent across conditions.14 However, not all studies have shown an improvement in balance with external auditory cues. In one example, an external sound source providing either a pure tone or a recorded conversation Laryngoscope 125: March 2015
722
reported that participants had increased postural sway in the presence of auditory cues compared to silence.15 Many studies have used the Romberg test on foam to quantify balance in a variety of clinical situations.12,16 We found the test to be a useful measure for most of our participants, but observed that four of the participants performed at a maximum score of 30 seconds in both the aided and unaided conditions. The tandem stance test served as a more difficult measure of stability, likely because it limits the test participant to a narrower base of support and therefore accentuate evidence for losses in static balance.17 Using this test, we were able to detect an improvement with sound even in those participants in whom a ceiling effect obscured this improvement on the foam test. We hypothesize that the mechanism of the improvement that we observed is likely due to the increased salience of external auditory inputs, in particular the presence of an artificial point sound source that resulted from wearing hearing aids. These inputs acted as effective spatial orienting landmarks, just as visible objects serve as landmarks to improve stability with sight. In this interpretation, the brain relies on the sound localization ability of the ears to create a three-dimensional map of the sound sources around an individual and keeps the body steady by maintaining its relationship to these external landmarks constant. We cannot rule out that wearing the hearing aids acted simply as an alerting mechanism rather than truly offering spatial auditory landmarks to improve balance, but this seems unlikely because the participants were never isolated from the surrounding auditory environment. A study using the National Health and Nutrition Examination Survey (2001–2004) database showed that for each 10 dB of hearing loss, individuals had a 1.4 times increased risk of falling.6 Applying this relationship to the 12.75 dB average gain in performance seen in our participants, we could estimate an increase in risk of falling per annum by a factor of 1.68. The same database has been used to correlate performance on the Romberg on foam test to the risk of falling.18,19 According to that relationship, the mean difference in performance of 8.5 seconds that we saw on the Romberg on foam test corresponds to an increased risk of falling in the unaided condition of 1.67 times the risk of falling in the aided condition. These remarkably similar results suggest a good correlation between balance improvement and auditory gain, even if we were not able to observe that in the small sample here. Although applying the predictions of a large epidemiologic study to our small group of participants is obviously speculative, the large difference that we observed between the aided and unaided conditions suggests that wearing hearing aids may indeed be shown to reduce the incidence of falls among a larger group of individuals. Despite quantitative improvements in balance, none of our participants reported a subjective improvement when wearing their hearing aids either before or after our testing session. This is consistent with previous work showing a poor correlation between subjective and objective measures of balance and postural stability.19–22 This finding may be particularly important because it Rumalla et al.: Hearing Aids and Balance
suggests that identifying patients whose balance might improve with hearing aids should not rely on the patient’s own estimate of the effectiveness of amplification on balance. In our case, this concern might be accentuated because almost all of the participants (13 out of 14) rated themselves as having a high level of physical functioning according to their score on the ABC. Thus, it is possible that they may have underestimated the amount of balance function that could be improved with amplification.
CONCLUSION Our results may have implications for people using other forms of hearing rehabilitation, including cochlear implantation. One study indicated a slight improvement in balance in adult subjects with unilateral cochlear implants when the implants were on versus when they were off.23 A published abstract consisting of a case study of a patient with single-sided deafness reported that postural sway was reduced when the implant was turned on.24 Although these studies are suggestive of a benefit due to cochlear implantation, it is important to recognize that balance may actually worsen, at least temporarily, presumably from labyrinthine trauma during to the surgical implantation procedure itself.19,25
Acknowledgments Thanks to Nicholas Chang, Madelyn Stevens, and Rosalie Uchanski for assistance in data analysis, and the audiologic staff of the Department of Otolaryngology at Washington University in St. Louis for patient recruitment.
BIBLIOGRAPHY 1. Shumway-Cook A, Horak FB. Assessing the influence of sensory interaction of balance. Suggestion from the field. Phys Ther 1986;66:1548–1550. 2. Reed-Jones RJ, Solis GR, Lawson KA, Loya AM, Cude-Islas D, Berger CS. Vision and falls: a multidisciplinary review of the contributions of visual impairment to falls among older adults. Maturitas 2013;75:22–28. 3. de Mettelinge TR, Calders P, Palmans T, Vanden Bossche L, Van Den Noortgate N, Cambier D. Vibration perception threshold in relation to postural control and fall risk assessment in elderly. Disabil Rehabil 2013;35:1712–1717.
Laryngoscope 125: March 2015
4. Honaker JA, Shepard NT. Use of the Dynamic Visual Acuity Test as a screener for community-dwelling older adults who fall. J Vestib Res 2011;21:267–276. 5. Viljanen A, Kaprio J, Pyykko I, et al. Hearing as a predictor of falls and postural balance in older female twins. J Gerontol A Biol Sci Med Sci 2009;64:312–317. 6. Lin FR, Ferrucci L. Hearing loss and falls among older adults in the United States. Arch Intern Med 2012;172:369–371. 7. Tromp AM, Pluijm SM, Smit JH, Deeg DJ, Bouter LM, Lips P. Fall-risk screening test: a prospective study on predictors for falls in communitydwelling elderly. J Clin Epidemiol 2001;54:837–844. 8. Tinetti ME, Williams TF, Mayewski R. Fall risk index for elderly patients based on number of chronic disabilities. Am J Med 1986;80:429–434. 9. Crews JE, Campbell VA. Vision impairment and hearing loss among community-dwelling older Americans: implications for health and functioning. Am J Public Health 2004;94:823–829. 10. Mueller H, Hawkins D, Northern J. Probe Microphone Measurements: Hearing Aid Selection and Assessment. San Diego, CA: Singular Publishing Group; 1992. 11. Powell LE, Myers AM. The Activities-specific Balance Confidence (ABC) Scale. J Gerontol 1995;50:M28–M34. 12. Black FO, Shupert CL, Peterka RJ, Nashner LM. Effects of unilateral loss of vestibular function on the vestibulo-ocular reflex and postural control. Ann Otol Rhinol Laryngol 1989;98:884–889. 13. Easton RD, Greene AJ, DiZio P, Lackner JR. Auditory cues for orientation and postural control in sighted and congenitally blind people. Exp Brain Res 1998;118:541–550. 14. Kanegaonkar RG, Amin K, Clarke M. The contribution of hearing to normal balance. J Laryngol Otol 2012;126:984–988. 15. Raper SA, Soames RW. The influence of stationary auditory fields on postural sway behaviour in man. Eur J Appl Physiol Occup Physiol 1991; 63:363–367. 16. Fitzgerald DC. Persistent dizziness following head trauma and perilymphatic fistula. Arch Phys Med Rehabil 1995;76:1017–1020. 17. Maranhao-Filho PA, Maranhao ET, Silva MM, Lima MA. Rethinking the neurological examination I: static balance assessment. Arq Neuropsiquiatr 2011;69:954–958. 18. Agrawal Y, Carey JP, Hoffman HJ, Sklare DA, Schubert MC. The modified Romberg Balance Test: normative data in U.S. adults. Otol Neurotol 2011;32:1309–1311. 19. Stevens M, Chang NY, Hullar TE. Short-term imbalance after cochlear implantation. Audiol Neurootol 2014. 20. Basta D, Todt I, Goepel F, Ernst A. Loss of saccular function after cochlear implantation: the diagnostic impact of intracochlear electrically elicited vestibular evoked myogenic potentials. Audiol Neurootol 2008;13:187– 192. 21. Krause E, Louza JP, Wechtenbruch J, Gurkov R. Influence of cochlear implantation on peripheral vestibular receptor function. Otolaryngol Head Neck Surg 2010;142:809–813. 22. Mbongo F, Tran Ba Huy P, Vidal PP, de Waele C. Relationship between dynamic balance and self-reported handicap in patients who have unilateral peripheral vestibular loss. Otol Neurotol 2007;28:905–910. 23. Buchman CA, Joy J, Hodges A, Telischi FF, Balkany TJ. Vestibular effects of cochlear implantation. Laryngoscope 2004;114:1–22. 24. Jacob R, Stelzig Y. The Koblenz experience in treating single-sided deafness with cochlear implants. Audiol Neurootol 2011;16:6–8. 25. Kluenter HD, Lang-Roth R, Guntinas-Lichius O. Static and dynamic postural control before and after cochlear implantation in adult patients. Eur Arch Otorhinolaryngol 2009;266:1521–1525.
Rumalla et al.: Hearing Aids and Balance
723
Rhinological and Otological Society, Inc.
The Effect of Hearing Aids on Postural Stability Kavelin Rumalla; Adham M. Karim, BS; Timothy E. Hullar, MD Objectives/Hypothesis: In the United States, falls are the leading cause of accidental deaths in adults aged over 65 years. Epidemiologic studies indicate that there is a correlation between hearing loss and the risk of falling among older people. The vestibular, proprioceptive, and visual systems are known to contribute to postural stability, but the contribution of audition to maintaining balance has not yet been determined. Study Design: Cross-sectional study to measure postural stability in bilateral hearing-aid users aged over 65 years in aided and unaided conditions. Methods: Balance was assessed using the Romberg on foam test and the tandem stance test. Tests were administered in the presence of a point-source broadband white-noise sound (0–4 kHz) source in both unaided and aided conditions in the dark. Subjective measures of balance were made using the Activities-specific Balance Confidence Scale. Results: Performance was significantly better in the aided than the unaided condition (P 5 0.005 for both tests). No statistically significant relationship between improvement in balance, and hearing was identified. Participants did not report that they perceived a difference in balance between the two conditions. Conclusion: These results indicate that hearing aids are a novel treatment modality for imbalance in older adults with hearing loss and suggest that wearing hearing aids may offer a significant public-health benefit for avoiding falls in this population. Key Words: Fall, elderly, hearing, aid, audition, Romberg, auditory, landmark, posture, stability, balance. Level of Evidence: 4. Laryngoscope, 125:720–723, 2015
INTRODUCTION Vestibular, visual, and proprioceptive inputs provide sensory information required to maintain stability.1 Aging causes decreased function of these sensory systems and is associated with an increased risk of falls in the elderly.2–4 Hearing acuity also decreases with aging. Like other age-related sensory losses, presbycusis is associated with an increased risk of falls.5–9 This association might be explained by a global age-related loss of labyrinthine function in which auditory loss is simply a marker for vestibular losses leading to imbalance. Alternatively, audition may represent an independent sensory input providing spatial sound cues that are important for maintaining balance. If auditory input is important for maintaining balance, interventions such as hearing aids might serve to improve balance as well as auditory performance. Showing this improvement would significantly impact clinical
From the Department of Otolaryngology–Head and Neck Surgery, Washington University in St. Louis, St. Louis, Missouri, U.S.A. Editor’s Note: This Manuscript was accepted for publication September 23, 2014. This study was supported by Washington University Institute of Clinical and Translational Sciences and the National Center for Advancing Translational Sciences through grants UL1 TR000448 and TL1 TR000449. The authors have no other funding, financial relationships, or conflicts of interest to disclose. KR ad AMK contributed to authorship equally. Send correspondence to Timothy E. Hullar, MD, Department of Otolaryngology–Head and Neck Surgery, Washington University in St. Louis, 660 South Euclid Avenue #8115, St. Louis, MO 63130. E-mail: [email protected] DOI: 10.1002/lary.24974
Laryngoscope 125: March 2015
720
care by introducing hearing aids as a novel and effective treatment for imbalance in people with hearing loss. It would also shed light on the basic mechanism of maintaining stability by showing that hearing cues rank alongside vestibular, visual, and proprioceptive inputs as significant contributors to maintaining balance. Here, we evaluated balance function in older, experienced users of hearing aids in unaided and aided conditions using two balance tests: Romberg on foam and tandem stance.
MATERIALS AND METHODS This study was carried out with the approval of the Washington University Institutional Review Board. Potentially eligible subjects were drawn from consecutive patients treated at the Washington University Department of Otolaryngology, Division of Audiology. Inclusion criteria were adults greater than 65 years old who wore bilateral hearing aids for 3 months or more, had aided thresholds of 25 dB or worse in each ear, could understand English-spoken directions, and could ambulate without assistive devices. Exclusion criteria were a history of degenerative neurologic disease, stroke, spinal stenosis, joint replacement, or balance-altering medication or surgery. Subjects were paid for their participation. We collected data from each participant’s most recent audiologic evaluation, including the improvement (“gain”) currently provided by their hearing aids. Gain is defined in this context as the decibel sound pressure level (dB SPL) that sound must be amplified to in order to be perceived by the wearer as a comfortable conversational sound at a given frequency.10 We calculated each participant’s overall improvement by averaging gain at 0.5, 1.0, 2.0, and 4.0 kHz. Participants also completed the Activitiesspecific Balance Confidence Scale (ABC) test to assess their overall level of physical functionality.11 Prior to testing, the
Rumalla et al.: Hearing Aids and Balance
your hearing aids on, hearing aids off, or no difference?” All participants were blinded to the purpose of the experiment.
RESULTS
Fig. 1. Effect of wearing hearing aids when performing the Romberg on foam test. Length of time over which 14 participants could stand in unaided and aided conditions (maximum of 30 seconds). Dashed line represents the four participants who scored perfectly on the test. participants were asked: “Do you feel that your hearing aids make your balance better, worse, or is there no difference?” We measured postural stability using two methods: the Romberg on foam test and the tandem stance test. For the foam test, participants were instructed to stand with their feet together on a foam pad (Balance-pad; Airex, Sins, Switzerland) with their arms crossed above their shoulders. The goal was to maintain balance for 30 seconds. In the tandem test, the participants were instructed to place their dominant foot in front of the other in a heel to toe fashion with no angle allowed and remain in that posture for a maximum of 30 seconds while standing on a firm substrate.12 In all conditions, participants were instructed to take off their shoes and wear a spotter’s belt to prevent falls. Test results were measured in seconds. A trial was terminated and time recorded if a participant moved their arms or feet to maintain stability, opened their eyes, required a spotter to maintain balance, or took a step. Broadband white noise (0–4 kHz, 65 dB) was presented for the duration of the experiment. This frequency band was chosen because some hearing aids apply frequency compression above 4 kHz, which could otherwise cause a confounding effect when comparing sound thresholds with hearing aids on versus aids off. The white noise was played by a speaker with a frequency response of 0.1 to 22.0 kHz (Model R1; YC Cable, Ontario, CA) placed 1 meter directly in front of the participants and adjusted to be at ear level. Visual cues were eliminated with a blindfold. Each participant stood for a maximum of 30 seconds with hearing aids on (aided condition) and hearing aids off (unaided condition) in each experimental condition. Each condition was repeated in three trials, with conditions and trials pseudorandomized. The participants’ median score on three trials was counted as the final score for the test condition. After testing, participants were asked two questions, “Do you feel that the sound made your balance better, worse, or no difference?” and “Do you feel that you performed better with
Laryngoscope 125: March 2015
A total of 14 participants were enrolled (7 female; mean age 5 77; age range 5 65–91). No participant had a history of falls in the past year. The mean audiometric gain among all participants was 12.75 dB SPL. Prior to testing, none of the 14 participants reported a perceived difference in balance or performance due to wearing hearing aids. For the Activities-specific Balance Confidence Scale test, 13 of the 14 participants scored as having a high level of physical functioning, and one participant scored at a moderate level of physical functioning. Results for the Romberg on foam test are shown in Figure 1. Ten of the 14 participants scored better in the aided than in the unaided condition, whereas the other four scored a maximum of 30 seconds in both conditions. The mean score in the unaided condition was 17.0 6 10.2 seconds (median 5 14.3 seconds) and in the aided condition was 25.6 6 7.8 seconds (median 5 30.0 seconds). A two-tailed, nonparametric, Wilcoxon sign-ranked test indicated a statistically significant difference between balance performance in the aided versus the unaided condition on foam (P 5 0.0051). When considering the mean rather than the median of the three trials, the significance level improved to P 5 0.0033. Results of the ABC test showed no correlation to performance. Results for the tandem test showed improvement in the aided compared to unaided condition (Fig. 2). In the
Fig. 2. Effect of wearing hearing aids when performing the tandem stance test. Length of time over which participants could stand during unaided and aided conditions (maximum of 30 seconds). Dashed lines correspond to the four participants who scored perfectly on the Romberg on foam test.
Rumalla et al.: Hearing Aids and Balance
721
unaided condition, participants were able to stand for a mean of 4.5 6 3.3 seconds (median 5 3.2 seconds). In the aided condition, participants were able to stand for a mean of 9.8 6 7.4 seconds (median 5 9.6 seconds). A twotailed, nonparametric, Wilcoxon sign-ranked test comparing median trial performances for each participant indicated a statistically significant effect of wearing hearing aids while performing the tandem stance test (P 5 0.0052). When considering the mean of three trials rather than the median, the significance level improved to P 5 0.0035. The four participants who had reached the ceiling of 30 seconds in both the unaided and aided conditions on the foam test showed improvement with amplification in the more difficult tandem test. The ABC test results did not show any correlation to the participants’ overall performance on this test. The mean improvement on the foam test for the 14 participants was 8.5 seconds. However, the mean improvement for the 10 participants who did not have a ceiling effect was 11.6 seconds (mean audiometric gain5 13.9 dB SPL). The mean improvement on the tandem test for all 14 participants was 5.3 seconds. For the four participants who reached a ceiling effect on the foam, mean improvement on the tandem test was 8.7 seconds (mean audiometric gain 5 9.8 dB SPL). There was no detectable correlation between gain while wearing hearing aids and mean improvement in balance for the 10 participants who improved on the foam test (Spearman’s rho 5 20.115; P 5 0.751). The correlation for the relationship between hearing gain and mean improvement on the tandem test was also not significant (Spearman’s rho 5 0.400; P 5 0.600).
DISCUSSION The results presented here show that wearing hearing aids will provide a significant improvement in balance and a decreased risk of falling among older adults with hearing loss. This suggests that hearing aids offer a novel treatment modality for imbalance and allow auditory inputs to be considered, along with vestibular, proprioceptive, and visual cues as important contributors to maintaining balance. A limited number of studies have previously examined the relationship between audition and balance but did not investigate the ability of hearing aids to improve balance, as done here. A study of postural sway in a group of sighted (blindfolded) subjects and congenitally blind patients found that a pair of fixed, external auditory sources located immediately adjacent (5 cm lateral) to each ear reduced movement of the center of pressure compared to when standing in silence.13 A more recent study measuring center of pressure while standing on a Nintendo Wii (Kyoto, Japan) platform reported a small improvement in sway in a group of normal subjects in the presence of external sound, but results were inconsistent across conditions.14 However, not all studies have shown an improvement in balance with external auditory cues. In one example, an external sound source providing either a pure tone or a recorded conversation Laryngoscope 125: March 2015
722
reported that participants had increased postural sway in the presence of auditory cues compared to silence.15 Many studies have used the Romberg test on foam to quantify balance in a variety of clinical situations.12,16 We found the test to be a useful measure for most of our participants, but observed that four of the participants performed at a maximum score of 30 seconds in both the aided and unaided conditions. The tandem stance test served as a more difficult measure of stability, likely because it limits the test participant to a narrower base of support and therefore accentuate evidence for losses in static balance.17 Using this test, we were able to detect an improvement with sound even in those participants in whom a ceiling effect obscured this improvement on the foam test. We hypothesize that the mechanism of the improvement that we observed is likely due to the increased salience of external auditory inputs, in particular the presence of an artificial point sound source that resulted from wearing hearing aids. These inputs acted as effective spatial orienting landmarks, just as visible objects serve as landmarks to improve stability with sight. In this interpretation, the brain relies on the sound localization ability of the ears to create a three-dimensional map of the sound sources around an individual and keeps the body steady by maintaining its relationship to these external landmarks constant. We cannot rule out that wearing the hearing aids acted simply as an alerting mechanism rather than truly offering spatial auditory landmarks to improve balance, but this seems unlikely because the participants were never isolated from the surrounding auditory environment. A study using the National Health and Nutrition Examination Survey (2001–2004) database showed that for each 10 dB of hearing loss, individuals had a 1.4 times increased risk of falling.6 Applying this relationship to the 12.75 dB average gain in performance seen in our participants, we could estimate an increase in risk of falling per annum by a factor of 1.68. The same database has been used to correlate performance on the Romberg on foam test to the risk of falling.18,19 According to that relationship, the mean difference in performance of 8.5 seconds that we saw on the Romberg on foam test corresponds to an increased risk of falling in the unaided condition of 1.67 times the risk of falling in the aided condition. These remarkably similar results suggest a good correlation between balance improvement and auditory gain, even if we were not able to observe that in the small sample here. Although applying the predictions of a large epidemiologic study to our small group of participants is obviously speculative, the large difference that we observed between the aided and unaided conditions suggests that wearing hearing aids may indeed be shown to reduce the incidence of falls among a larger group of individuals. Despite quantitative improvements in balance, none of our participants reported a subjective improvement when wearing their hearing aids either before or after our testing session. This is consistent with previous work showing a poor correlation between subjective and objective measures of balance and postural stability.19–22 This finding may be particularly important because it Rumalla et al.: Hearing Aids and Balance
suggests that identifying patients whose balance might improve with hearing aids should not rely on the patient’s own estimate of the effectiveness of amplification on balance. In our case, this concern might be accentuated because almost all of the participants (13 out of 14) rated themselves as having a high level of physical functioning according to their score on the ABC. Thus, it is possible that they may have underestimated the amount of balance function that could be improved with amplification.
CONCLUSION Our results may have implications for people using other forms of hearing rehabilitation, including cochlear implantation. One study indicated a slight improvement in balance in adult subjects with unilateral cochlear implants when the implants were on versus when they were off.23 A published abstract consisting of a case study of a patient with single-sided deafness reported that postural sway was reduced when the implant was turned on.24 Although these studies are suggestive of a benefit due to cochlear implantation, it is important to recognize that balance may actually worsen, at least temporarily, presumably from labyrinthine trauma during to the surgical implantation procedure itself.19,25
Acknowledgments Thanks to Nicholas Chang, Madelyn Stevens, and Rosalie Uchanski for assistance in data analysis, and the audiologic staff of the Department of Otolaryngology at Washington University in St. Louis for patient recruitment.
BIBLIOGRAPHY 1. Shumway-Cook A, Horak FB. Assessing the influence of sensory interaction of balance. Suggestion from the field. Phys Ther 1986;66:1548–1550. 2. Reed-Jones RJ, Solis GR, Lawson KA, Loya AM, Cude-Islas D, Berger CS. Vision and falls: a multidisciplinary review of the contributions of visual impairment to falls among older adults. Maturitas 2013;75:22–28. 3. de Mettelinge TR, Calders P, Palmans T, Vanden Bossche L, Van Den Noortgate N, Cambier D. Vibration perception threshold in relation to postural control and fall risk assessment in elderly. Disabil Rehabil 2013;35:1712–1717.
Laryngoscope 125: March 2015
4. Honaker JA, Shepard NT. Use of the Dynamic Visual Acuity Test as a screener for community-dwelling older adults who fall. J Vestib Res 2011;21:267–276. 5. Viljanen A, Kaprio J, Pyykko I, et al. Hearing as a predictor of falls and postural balance in older female twins. J Gerontol A Biol Sci Med Sci 2009;64:312–317. 6. Lin FR, Ferrucci L. Hearing loss and falls among older adults in the United States. Arch Intern Med 2012;172:369–371. 7. Tromp AM, Pluijm SM, Smit JH, Deeg DJ, Bouter LM, Lips P. Fall-risk screening test: a prospective study on predictors for falls in communitydwelling elderly. J Clin Epidemiol 2001;54:837–844. 8. Tinetti ME, Williams TF, Mayewski R. Fall risk index for elderly patients based on number of chronic disabilities. Am J Med 1986;80:429–434. 9. Crews JE, Campbell VA. Vision impairment and hearing loss among community-dwelling older Americans: implications for health and functioning. Am J Public Health 2004;94:823–829. 10. Mueller H, Hawkins D, Northern J. Probe Microphone Measurements: Hearing Aid Selection and Assessment. San Diego, CA: Singular Publishing Group; 1992. 11. Powell LE, Myers AM. The Activities-specific Balance Confidence (ABC) Scale. J Gerontol 1995;50:M28–M34. 12. Black FO, Shupert CL, Peterka RJ, Nashner LM. Effects of unilateral loss of vestibular function on the vestibulo-ocular reflex and postural control. Ann Otol Rhinol Laryngol 1989;98:884–889. 13. Easton RD, Greene AJ, DiZio P, Lackner JR. Auditory cues for orientation and postural control in sighted and congenitally blind people. Exp Brain Res 1998;118:541–550. 14. Kanegaonkar RG, Amin K, Clarke M. The contribution of hearing to normal balance. J Laryngol Otol 2012;126:984–988. 15. Raper SA, Soames RW. The influence of stationary auditory fields on postural sway behaviour in man. Eur J Appl Physiol Occup Physiol 1991; 63:363–367. 16. Fitzgerald DC. Persistent dizziness following head trauma and perilymphatic fistula. Arch Phys Med Rehabil 1995;76:1017–1020. 17. Maranhao-Filho PA, Maranhao ET, Silva MM, Lima MA. Rethinking the neurological examination I: static balance assessment. Arq Neuropsiquiatr 2011;69:954–958. 18. Agrawal Y, Carey JP, Hoffman HJ, Sklare DA, Schubert MC. The modified Romberg Balance Test: normative data in U.S. adults. Otol Neurotol 2011;32:1309–1311. 19. Stevens M, Chang NY, Hullar TE. Short-term imbalance after cochlear implantation. Audiol Neurootol 2014. 20. Basta D, Todt I, Goepel F, Ernst A. Loss of saccular function after cochlear implantation: the diagnostic impact of intracochlear electrically elicited vestibular evoked myogenic potentials. Audiol Neurootol 2008;13:187– 192. 21. Krause E, Louza JP, Wechtenbruch J, Gurkov R. Influence of cochlear implantation on peripheral vestibular receptor function. Otolaryngol Head Neck Surg 2010;142:809–813. 22. Mbongo F, Tran Ba Huy P, Vidal PP, de Waele C. Relationship between dynamic balance and self-reported handicap in patients who have unilateral peripheral vestibular loss. Otol Neurotol 2007;28:905–910. 23. Buchman CA, Joy J, Hodges A, Telischi FF, Balkany TJ. Vestibular effects of cochlear implantation. Laryngoscope 2004;114:1–22. 24. Jacob R, Stelzig Y. The Koblenz experience in treating single-sided deafness with cochlear implants. Audiol Neurootol 2011;16:6–8. 25. Kluenter HD, Lang-Roth R, Guntinas-Lichius O. Static and dynamic postural control before and after cochlear implantation in adult patients. Eur Arch Otorhinolaryngol 2009;266:1521–1525.
Rumalla et al.: Hearing Aids and Balance
723
