Journal of Speech and Hearing Research, Volume 35, 1402-1405, December 1992
Sustained Benefits of Hearing Aids Cynthia D. Mulrow Michael R. Tuley Christine Aguilar University of Texas Health Science Center and Audie L. Murphy Memorial VA Hospital San Antonio
This study was designed to evaluate long-term benefits of hearing aids in elderly individuals with hearing loss. A primary care cohort of 192 elderly, hearing-impaired veterans (mean age 72 ± 6, 97% White, 94% retired) were assessed at baseline and at 4, 8, and 12 months after hearing aid fitting. Drop-out rates at 4, 8, and 12 months were 5%, 13%, and 16%, respectively. Outcome assessments included several quality-of-life scales: Hearing Handicap Inventory in the Elderly (HHIE), Quantified Denver Scale of Communication Function (QDS), Geriatric Depression Scale (GDS), and the Short Portable Mental Status Questionnaire (SPMSQ). All qualityof-life areas improved significantly from baseline to 4-month post-hearing aid fittings (p < 0.05). Social and emotional (HHIE), communication (QDS), and depression (GDS) benefits were sustained at 8 and 12 months, whereas cognitive changes (SPMSQ) reverted to baseline at 12 months. We conclude that hearing aids provide sustained benefits for at least a year in these elderly individuals with hearing impairment. KEY WORDS: hearing aids, elderly, efficacy, hearing loss
Several "before and after" and case-control studies of older adults with hearing impairment have demonstrated improved psychosocial functioning after hearing aid fitting (Alberti, Corbin, Pichora-Fuller, & Riko, 1984; Birk-Nielson & Ewertsen, 1974; Dempsey, 1986; Dye & Peak, 1983; Harless & McConnell, 1982; Hosford-Dunn & Baxter, 1985; Hutton, 1980; Malinoff & Weinstein, 1989; Tannahil, 1979; Ventry & Weinstein, 1982; Ward, Tudor, & Gowers, 1978). In a recent randomized controlled trial in which older veterans with impaired hearing were either assigned to a waiting list or given a hearing aid immediately, marked improvements were seen in the hearing aid group compared with the waiting-list group at 4-month follow-up (Mulrow et al., 1990). This paper describes the long-term follow-up of both groups of individuals and whether the initial psychosocial benefits seen with hearing aids were sustainable for a 1-year period.
Method Subjects Details of the study methods have been described previously (Mulrow et al., 1990). Most study subjects were recruited from the General Medicine Clinic at the Audie L. Murphy Memorial Veterans Hospital in San Antonio. The following sequential selection process was used. Medical records of all 711 subjects over 64 years of age who attended the General Medicine Clinic between June 1987 and June 1988 were reviewed. To maximize the ability to measure dysfunction secondary to hearing loss, 72 subjects with severely disabling comorbid diseases (terminal cancer, hepatic encephalopathy, end-stage pulmonary disease requiring home oxygen therapy) and 53 subjects who were currently hearing aid users were excluded. Because of planned follow-up visits, 59 subjects living more than 100 miles from the clinic were excluded. The remaining 587 patients attending the clinic were asked to participate in this study; © 1992, American Speech-Language-Hearing Association
Mulrow et al.: Sustained Benefits 72 (12%) refused. (The most common reasons for refusal were insufficient time on the part of the patient [72%] and lack of interest [28%]. Persons refusing to participate were less likely to be married [61% compared with 80%, p = 0.003, chi-square test] and were older [75 ± 8 compared with 72 ± 6 years of age, p = 0.001, t test] than participants.) Of the 515 clinic patients who agreed to be screened for hearing impairment, 393 were identified as nonhearing impaired and 122 as hearing impaired (see definition below). In addition to these 122 hearing-impaired patients, 70 patients referred from other primary care clinics (including walk-in and nurse practitioners' clinics) participated in the trial, for a total study sample of 192. The 70 referred subjects were patients with hearing impairment who were specifically referred by their healthcare providers to be considered for participation in the trial. Their demographic and clinical characteristics, including degree of hearing loss, were not statistically different from those of the 122 patients recruited from the medicine clinic.
Materials and Procedures Hearing impairment was initially screened using the Welch Allyn audioscope (Welch Allyn, Inc., Skaneateles Falls, New York); it is a hand-held otoscope with a built-in audiometer that delivers tones at a 40-dB hearing level (ANSI, 1989) at frequencies of 500, 1000, 2000, and 4000 Hz (Bienvenue, Michael, & Chaffinich, 1984; Frank & Petersen, 1987; Lichtenstein, Bess, & Logan, 1988). For the screening examination, hearing impairment was defined as a hearing level of 40 dB or greater at 2000 Hz. This definition excludes patients with slight degrees of hearing loss and was chosen to ensure that persons who failed screening would be candidates for hearing aids. All persons failing the screening criterion had their hearing loss confirmed within 1 week using formal audiologic testing. All persons were confirmed by the audiologist to be candidates for hearing aid use. At this examination, a highfrequency pure-tone average (HFPTA) was determined by averaging hearing threshold levels at 1000, 2000, and 4000 Hz. Within 2 weeks of the formal audiologic examination described above, subjects received one follow-up evaluation consisting of a 45-min hearing aid fitting and orientation session; no further aural rehabilitation sessions were given. Hearing aids and batteries were provided at no cost. Quality of life was defined as a multidimensional concept encompassing social, affective, cognitive, and physical domains. Quality of life at baseline and follow-up was assessed using a battery of disease-specific and generic instruments. The disease-specific measures were the Hearing Handicap Inventory for the Elderly (HHIE), a 25-item questionnaire (scored from 0-100) that assesses emotional and social effects of hearing loss (Newman & Weinstein, 1988; Ventry & Weinstein, 1982; Weinstein, Spitzer, & Ventry, 1986), and the Quantified Denver Scale of Communication Function (QDS), a 25-item questionnaire (scored from 0-100) that assesses perceived communication difficulties because of hearing loss (Alpiner, 1982; Tuley, Mulrow, Aguilar, & Velez, 1990). Generic measures included the Short Portable Mental Status Questionnaire (SPMSQ), a 10-item scale (scored
TABLE 1. Baseline characteristics of elderly hearlng-lmpalred subjects. Demographic characteristics Men 99% Age (years) 72 + 6^ White 97% Married 80% Retirees 94% Education 9.5 ± 5' Clinical characteristics 1.3 Comorbid conditionsb Medicationsc 3.2 Hearing lossd 52 dB Notes. Plus-minus values are means + SD. bAverage number of diagnosed medical conditions for patients. CAverage number of prescribed medicines for patients. dMean thresholds in dB HL at 1000, 2000, and 4000 KHz. from 0-10) that assesses cognitive function (Pfeiffer, 1975), and the Geriatric Depression Scale (GDS), a 15-item scale (scored from 0-15) that assesses affect (Koenig, Meador, Cohen, & Blazer, 1988; Yesavage et al., 1983). For all the scales, higher scores indicate greater dysfunction. All of the scales were self-administered, except the SPMSQ, which was administered by a trained interviewer. All were given at baseline and at 4-, 8-, and 12-month follow-up visits. Statistical analyses were done using SAS (SAS/STAT, 1987). Repeated-measures analysis of variance, which allowed incorporation of all data points including early information from dropouts, was used to assess the statistical significance of changes inquality-of-life measures from baseline to 4-month follow-up, and whether changes were sustainable from 4 to 12 months (Armitage, 1971). Analysis of variance was used because it is a robust statistical procedure not affected by minor deviations from normality, particularly when sample sizes are greater than 60 (Kirk, 1982).
Results Baseline demographic and clinical characteristics of the 192 elderly individuals fitted with hearing aids are given in Table 1. Most subjects were men who were married and retired. Their degree of hearing loss (classified by the average hearing level in the better ear at three frequencies) was mild (0-40 dB HL) in 70% of the subjects, moderate (41-55 dB HL) in 27%, and moderately severe (56-70 dB HL) in 3% (Goodman, 1965). All subjects had either sensorineural defects (97%) or mixed hearing losses (3%). Most of the hearing aids were in-the-ear type fitted monaurally (97%) because of financial constraints. In general, the ear with the worse pure-tone thresholds was fitted. The average decibel gain in hearing for the fitted ear was 16.3 + 2.4 decibels. This represented a 28% improvement [t (92) = 23.88, p < 0.0001, 95% Cl, 26% to 30%]. This gain was calculated by averaging each individual's threshold hearing level of improvement from pre- to post-hearing aid fitting at 1000, 2000, and 4000 Hz. Dropouts and Compliance Drop-out rates at 4, 8, and 12 months were 5%, 13%, and 16%, respectively. Moreover, 183 subjects completed the first
1404 Journalof Speech and Hearing Research so;
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0 4 Months 8 Months 12 Months FIGURE 1. Self-reported daily hours of hearing aid use at 4, 8, and 12 months. follow-up, 167 completed the second, and 162 completed the third. Most dropouts were caused by deaths or by patients moving from the study site area. Baseline demographic and clinical characteristics were not different between persons who completed follow-up and those who did not. Self-reported daily hours of hearing aid use are shown in Figure 1. At 4-month follow-up, 90% of subjects reported using their aids more than 4 hours daily. At 8- and 12-month follow-up, this had decreased significantly to 83% and 76%, respectively [) 2 for trend (8, N = 183, 167, 162 at time 1,2,3) = 18.2, p = 0.02]. Patients were asked if they were very satisfied, satisfied, uncertain, unsatisfied, or very unsatisfied with their aids. Seventy-one percent, 80%, and 70% of subjects stated that they were "very satisfied" with their aids at 4, 8, and 12 months, respectively. Five percent said they were not satisfied; this proportion did not vary during the follow-up period [X2 for trend (4, N = 183, 167, 162 at time 1,2,3) = 5.52, p = 0.24]. No one said they were uncertain or very unsatisfied with their aids.
Quality-of-Life Outcomes Baseline quality-of-life scores are shown in Table 2. Sixtythree percent of subjects reported severe social and emotional handicap from hearing impairment (HHIE score > 42), and 20% reported mild to moderate handicap (HHIE score 16 to 42). Moderate communication difficulties were reported by 85% of subjects (QDS score > 30). Depression (GDS score
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> 5) was identified in 23% of subjects, and only 1% were significantly cognitively impaired (SPMSQ > 2). Changes in quality-of-life measures also are shown in Table 2. Statistically significant improvements (p < 0.05) were seen in all measures from baseline to 4 months post-hearing aid fitting. The social, emotional, and communication benefits assessed by the two disease-specific scales, the HHIE [t (186) = 9.9, p < 0.0001] and QDS [t(186) = 6.7, p < 0.0001], and the generic (GDS) [t (186) = 2.2, p = 0.03] were the most marked. These changes remained stable at 4, 8, and 12 months (p > 0.10). Although the improvements in cognition assessed by the SPMSQ from baseline to 4-month follow-up were statistically significant, they were not great, and these improvements changed or reverted to baseline at the 8- and 12-month follow-up visits (p < 0.05).
Discussion To our knowledge, this is one of the first relatively large studies to evaluate comprehensively whether quality-of-life outcomes seen with hearing aids are sustainable over a 1-year period. Many previous studies either have involved few subjects (Dempsey, 1986; Newman & Weinstein, 1988; Tannahil, 1979), had large numbers of dropouts (Alberti, Corbin, PichoraFuller, & Riko, 1984; Birk-Nielson & Ewertsen, 1974), or used limited outcome measures (Alberti, Corbin, Pichora-Fuller, & Riko, 1984). Moreover, the strengths of this study are that multiple, validated quality-of-life measures were the primary outcome variables. Self-reported hours of use of hearing aids, which is dependent upon an individual person's needs for communication (i.e., being alone most of the time vs. working in an environment that requires frequent communication), was used only as a secondary outcome variable. Also, relatively few dropouts (5%, 13%, and 16% at months 4, 8, and 12 respectively) were seen. The primary findings were encouraging. Most persons were satisfied with their hearing aids throughout the 1-year follow-up period, and wore them at least 4 hours daily. Improved psychosocial function was sustained over a 1-year time. Benefits in the areas of social, emotional, and communication function were the most marked. Changes in cognition were minimal, had questionable clinical significance, and were not sustained after 4 months. Finally, benefits were best detected with the disease-specific quality-of-life or handicap measures, the HHIE and the QDS.
TABLE 2. Quality-of-lfe questionnaire mean scores and standard deviations at baseline, 4, 8, and 12 months. Baseline Scale
4 Months SD
12 Months SD
23.3 20.5 20.6 20.4 20.1 27.9 21.3 50.6 HHIE 24.9 39.9 24.4 40.3 23.9 41.9 24.6 60.8 ODS 3.1 2.7 3.0 2.8 3.0 2.8 3.2 3.5 GDS 0.7 0.4 0.3 0.7 0.3 0.6 0.7 0.4 SPMSQ Note. HHIE = Hearing Handicap Inventory for the Elderly; QDS = Quantified Denver Scale of Communication Function; GDS = Geriatric Depression Scale; SPMSQ = Short Portable Mental Status Questionnaire.
Mulrow et al.: Sustained Benefits
Several limitations to the present study are worth noting. First, all subjects were veterans. It is possible that findings are not generalizable to other populations of hearing aid users. Second, some areas of quality of life improved more than others with hearing aid use. These differential effects are probably due to hearing impairment affecting certain dimensions of function (for example, social and communication) more than others (for example, cognition and affect). In addition, differing specificity and responsiveness characteristics of the instruments that were used to assess quality of life could explain some of the variation in effects. In particular, the instruments used to assess cognition (SPMSQ) and affect (GDS) are commonly used, simple screening tools that were not originally developed to detect changes in function. Use of more specific and detailed instruments to assess cognition and affect could have resulted in greater changes being seen in these areas. Third, as the primary outcome measures were subjective self-assessments and the study could not be blinded, positive quality-of-life changes could have been potentiated by placebo and Hawthorne effects (Buck & Donner, 1982). However, the very large magnitude of changes in quality-of-life scale scores that were sustained throughout the 12-month follow-up and the relative specificity of the large quality of life changes in the areas of communication and social function are unlikely to be due solely to placebo and Hawthorne effects. Fourth, only one hearing aid counseling session was offered. Additional sessions could have increased satisfaction with and benefits of hearing aids. Finally, the hearing aids were provided free of charge, which could have inflated rates of satisfaction with aids. In conclusion, this study confirms that hearing aids are beneficial in many ways for this sample of elderly persons with hearing impairment. These benefits are sustainable for a 1-year period, and are best demonstrated with diseasespecific handicap scales such as the HHIE and the QDS.
Acknowledgments Grant support for this study came from the Robert Wood Johnson Foundation, a Milbank Scholar Program Award, and an American College of Physicians' Teaching and Research Scholar Award. This paper was presented at The Society of General Internal Medicine Meeting, Seattle, May 1991.
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