Presbycusis, or hearing loss associated with the aging process, is one of the most common chronic conditions afflicting the older adult population today. Almost half the population over 65 years exhibits some degree of hearing impairment.1–4
The major consequence of presbycusis is difficulty in communication, particularly in noisy and/or reverberant listening situations.5–7 Due to these communicative difficulties, reduced psychosocial functioning in this population has often been reported. In particular, declines in social interaction, intimate relations, self-concept, psychological status, and cognition have been noted.3,8–13
For example, Mulrow et al. evaluated the effect of hearing loss on quality of life in older men.3 Results revealed that the presence of hearing loss was highly associated with decline in emotional, social, and communication performance. Additionally, Sherer and Frisina evaluated the effects of minimal hearing impairment on quality of life.14 This investigation found that the subjects with hearing impairment reported greater communicative, social, and emotional handicap, as well as lower self-esteem and social satisfaction, than did individuals without measurable hearing loss.
In addition to psychosocial effects, hearing loss has also been shown to compromise physical health status.8,15,16 Carabellese et al. reported that elderly persons with hearing deficit were at an increased risk for difficulties in accomplishing activities of daily living.8 Additionally, Bess et al. reported that presbycusis was associated with an increased incidence of health-related diseases, such as hypertension, ischemic heart disease, arrhythmias, and osteoarthritis.15 Moreover, this study indicated that the greater the hearing impairment, the greater the prevalence of these health-related dysfunctions.
One possible solution to the aforementioned declines in psychosocial and functional health status is the use of amplification. Past studies have revealed that persons using amplification reported fewer depressive feelings, richer social relationships, and higher quality of life than those who did not.17,18
For example, Mulrow et al. evaluated elderly veterans with hearing impairment after the provision of hearing aids.18 They noted improvements in social, emotional, and communication areas.
Crandell found that the use of amplification could also positively affect functional health status.19 In his study, 20 elderly individuals with mild to severe sensorineural hearing loss were evaluated via the Sickness Impact Profile (SIP),20 the Short Form-36 Health Survey (SF-36),21 and the Abbreviated Profile of Hearing Aid Benefit (APHAB).22 The forms were administered before the fitting of hearing aids and at 3 and 6 months afterward. APHAB scores indicated improved communicative function with the use of amplification. After 3 months of hearing aid use, statistically significant improvements in physical and psychosocial functioning, as measured by the SIP, were noted. This positive trend remained stable for 6 months after the initial fitting. Although not statistically significant, slight improvements in the SF-36 were also noted.
Although prior studies have evaluated the psychosocial and functional health benefits of hearing aids, none have examined the benefits of frequency modulation (FM) systems. When a personal FM system is employed, the speaker's voice is picked up via an FM wireless microphone located near his/her mouth where the detrimental effects of reverberation and noise are minimal. The acoustic signal is then converted to an electrical waveform and transmitted via an FM signal to a receiver tuned to the same frequency. The electrical signal is then amplified, converted back to an acoustical waveform, and conveyed to the listener.
We are currently conducting research on the possible psychosocial and physical health benefits of hearing aids that incorporate recent FM technologies.
Twenty subjects, 10 at the University of Florida and 10 at Washington University School of Medicine, are participating in this investigation. Subjects range in age from 65 to 84 years, with a mean age of 74 years. Prior to the study, pure-tone air-conduction thresholds and bone-conduction thresholds were obtained bilaterally on all subjects. The results revealed mean pure-tone thresholds suggestive of a mild sloping to severe sensorineural hearing loss (presbycusis) bilaterally.
Word-recognition scores were also obtained bilaterally, using recorded test materials. Results for the subjects at the University of Florida showed mean word-recognition scores (WRS) of 79% and 78% for the right and left ears, respectively. The subjects at Washington University had mean WRS of 71% for the right ear and 77% for the left ear.
All subjects have been fitted with digital Phonak Claro 311 dAZ BTE hearing aids bilaterally. In addition to the hearing aids, these subjects were given Phonak Microlink ML8 FM receivers bilaterally. These FM receivers attach to the bottom of a BTE hearing aid, but, unlike traditional FM systems, they do not use cords or a body-worn device (see Figure 1). The FM receivers may be used in either the FM-only mode, which attenuates the hearing aid microphone by 20 dB, or in the FM-plus-HA mode, which allows for FM input and input of environmental sounds via the hearing aid microphones simultaneously at equal loudness levels.
All subjects used a Phonak TX3 HandyMic FM transmitter. These devices were fitted as recommended via the Desired Sensation Level (DSL) prescriptive fitting formula23 on the Phonak Fitting Guideline (PFG) Version 7.3 software. All fittings were verified via probe-microphone measures. Subjects were encouraged to use their hearing aids and FM systems consistently throughout the day. Questionnaire data indicated that all subjects used their hearing aid plus FM systems 6 to 8 hours each day.
Quality of life (psychosocial and function health status) among the subjects is being assessed via the Medical Outcomes Short-Form 36 (SF-36). The SF-36 is a 35-item questionnaire that assesses physical and mental heath function across eight domains: physical functioning, role limitation due to physical problems, bodily pain, general health, energy/vitality, social functioning, role limitation due to emotional problems, and mental health. A 36th item asks the subject to rate his/her current health status compared to 1 year ago. All subjects completed the SF-36 prior to being fitted with the devices. They then completed the forms again at 1 month post-fitting.
Total SF-36 scores, from the pre-fitting and after 1 month of using hearing aids plus FM, are presented in Figure 2. As is evident from this figure, SF-36 scores showed an increase after 1 month of amplification use. Higher SF-36 scores suggest improved physical and psychosocial health status. Interestingly, both research sites reported an identical improvement in SF-36 scores. Analyses of variance procedures indicated that these reductions were statistically significant (dF=1, 19; F=16.78; p<.001). An examination of individual data indicated that 17 of the 20 subjects (85%) exhibited higher SF-36 scores after 1-month use of the hearing aid/FM systems.
Preliminary results from this investigation demonstrate that the use of hearing-aid-plus-FM amplification significantly improved the quality of life of individuals with SNHL after just 1 month of use. Hence, just as hearing loss has been associated with declines in quality of life, amplification systems, such as the ones in the study, appear to have the potential to improve the user's quality of life.
We are currently continuing this investigation. As part of this project, we will be examining the sustainability of these benefits over time. To do so, we will take measures with the SF-36 every month for up to 6 months. Furthermore, we will make assessments also in the hearing-aid-alone condition to determine if the reported improvement in quality of life is a result of the hearing aids, the FM systems, or both.
It should be noted, as previously discussed, that a similar study involving hearing aids alone did not show a significant change in SF-36 scores.19 However, the results from the present investigation, as well as those of some prior investigations, suggest that audiologists should counsel their patients on these potential benefits of FM technologies as well as incorporating measures of psychosocial and physical health function, such as the SF-36, into their hearing aid fitting protocol.
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