Despite sufficient hearing gains, many patients with hearing loss have difficulty using hearing aids due to poor word recognition ability. This study was performed to introduce our hearing rehabilitation therapy (HRT) program for hearing aid users and to evaluate its effect on hearing improvement.
In this prospective randomized case-control study, 37 participants with moderate or moderate-severe sensorineural hearing loss who had used bilateral hearing aids for more than 3 months with sufficient functional hearing gain were enrolled in this study. Nineteen participants were randomly assigned to the control group (CG) and 18 patients were assigned to participate in our HRT program once a week for 8 consecutive weeks (hearing rehabilitation therapy group [HRTG]). Their hearing results and questionnaire scores for hearing handicap and hearing aid outcomes were prospectively collected and compared between the two groups.
After completing 8 weeks of the HRT program, the HRTG showed a significantly greater improvement in scores for consonant-only and consonant-vowel sound perception than the CG (
Even after short-term HRT, patients had subjectively better hearing outcomes and improved phoneme perception ability; this provides scientific evidence regarding a possible positive role for HRT programs in hearing aid users. Further validation in a larger population through a long-term follow-up study is needed.
Hearing loss is a major issue in healthcare. Around 466 million people worldwide were estimated to suffer from hearing loss in 2018, and this number has steeply risen concomitantly with growth in the elderly population [
The use of hearing aids (HAs) is a major approach for hearing rehabilitation in the elderly, and its effectiveness for health-related quality of life has been shown in a systematic review [
Worldwide, several web-based hearing rehabilitation programs, such as Listening and Communication Enhancement (LACE) [
Moreover, clinical studies on hearing rehabilitation or auditory training in HA users in Korea remain in the early stages. To our knowledge, most reports describing Korean-based auditory training were case reports, and only one case-control study with a small number of enrolled subjects has been published [
This prospective study was approved by the Ethics Committee of Seoul St. Mary’s Hospital (No. KC18EESI0403) and followed the tenets of the Declaration of Helsinki. The patient records and information were anonymized and de-identified before analysis. All participants provided written informed consent prior to commencement of the study and voluntarily participated in this clinical trial.
We included 40 participants with sensorineural hearing loss (SNHL) who had been wearing bilateral HAs and were recruited from the department of otorhinolaryngology-head and neck surgery at a tertiary referral center between November 2018 and January 2020. Study eligibility criteria specified adults aged more than 20 years with moderate to severe SNHL in both ears. Moderate to severe hearing loss was diagnosed when the average value of pure tone audiometry (PTA) measured at 500, 1,000, 2,000, and 4,000 Hz was 41 to 80 dB [
Our 8-week HRT program consists of two components: (1) professionals’ face-to-face interview and training sessions: three sessions of doctor’s interview and eight sessions of audiologist’s 30-min face-to-face HRT and (2) daily homework for self-hearing rehabilitation. HRTG participants received our HRT program once a week for 8 consecutive weeks. During the first 4 weeks, consonant discrimination retraining was conducted, followed by retraining in consonant identification and understanding for the next 5 to 8 weeks.
Consonant discrimination retraining consisted of three steps. The first step was to choose whether two sounds with the same consonants were the same or not; for example, if the sounds were M-Ah and M-Eu, the answer is “No.” The second step was similar to the first step but was tested with three sounds with the same consonants. The third step was to listen to three words, two that were the same and one that was different, and to choose the word that was different.
Retraining in consonant identification and understanding was conducted in two steps. The first step was to listen to three words and tell what the other one was, and the second step was to listen to three words and write down what the other one was. All steps were performed under audio-visual conditions and were then carried out under audio-only conditions if the participants had done well in the previous step.
The sound level used in HRT was adjusted to the most comfortable level, and the 10 most frequently used Korean consonants (m, n, r, g, b, h, tɕh, j, s, and s*; from low-frequency to high-frequency consonants) were selected according to Korean National Institute of Special Education-Developmental Assessment of Speech Perception (KNISE-DASP) for training [
A self-training handout was provided to the HRTG participants so that they could perform daily HRT at home. The handout consisted of three sessions: first session, words starting with one consonant; second session, words with the same consonant in the middle; and third session, words with a final consonant. Of the 10 consonants selected by KNISE-DASP, low- to high-frequency consonants were used in sequence. The participants were asked to read the words out loud to hear the differences, and a checklist to record the completion of their own training was provided to confirm their compliance of HRT. The average time for self-training as a homework was about 30 to 40 minutes per day, which was similar to face-to-face HRT session in the hospital. The process of the HRT program is described in
All participants completed hearing tests and questionnaires at the 0-, 4-, and 8-week visits. PTA without HAs and sound field threshold audiometry testing with HAs were conducted to exclude changes in hearing level and inappropriate function of HAs. Audiological outcomes were evaluated with word recognition score (WRS), Korean consonant perception test (KCPT) [
In order for statistical significance at 0.05 confidence level with 80% power, the sample size required for the two groups was estimated as 18 patients per each group. Allowing for a 10% dropout rate, 42 patients were estimated to be required in total. However, 40 patients finished the study protocol and were finally enrolled in this study, which were the sufficient patient number for statistical analysis.
Statistical analysis was conducted using SAS ver. 9.4 (SAS Institute, Cary, NC, USA). The Shapiro-Wilk test was used to examine the normality of the measured variables. Data was expressed as mean, standard deviation, and percentage.
We statistically analyzed data from a total of 38 participants, consisting of 37 participants who had completed the assessment and one CG participant who performed only the first evaluation. The ages ranged from 55 and 86 years, with a mean of 72.7 years, and the male-to-female ratio was 13:25. There was no statistically significant difference in age (
In the initial PTA results, there was no significant difference in the average hearing threshold level between the two groups at all frequencies, regardless of unaided/aided conditions or the better/worse ear (
Data from one participant who was lost to follow-up after the first visit were excluded from the assessment. There were no significant improvements in the WRS and KSPIN test results in either group (
The K-IOI-HA scores were 25.6±4.5 in the HRTG and 26.1± 4.2 in the CG at the first visit (
The K-HHIE scores showed similar results. The initial mean total score was 36.6±28.1 in the HRTG and 33.5±26.3 in the CG (
In addition, 12 out of 18 participants (66.67%) in the HRTG and 5 out of 19 participants (26.32%) in the CG showed a decrease of more than 36% in their social/situational K-HHIE scores, indicating significant changes in the K-HHIE scores in both groups [
Compliance is an important factor for better outcomes in HRT, but one study reported that the compliance rate in a cohort of home-based HRT trainees was less than 30% [
In our study, only two out of 20 participants in the HRTG had trouble completing our HR program; one was unable to implement the self-home training program due to illiteracy and the other found it difficult to concentrate on the program itself. Eighteen participants who were able to follow our HRT program completed the 8-week schedule, resulting in a high compliance rate (90%).
No consensus has been established regarding the factors or methods that promote better compliance in HRT. However, our 30-minute face-to-face HRT sessions by an audiologist, as well as three separate interviews and reinforcement by an ENT doctor during the 8-week program, seemed to increase patients’ compliance; these components of our program are noteworthy insofar as they differ from the protocols of other studies. It is assumed that reinforcing patients’ motivation by both a trainer (therapist) and a doctor in a face-to-face manner was an important factor contributing to the higher compliance rate during HRT.
The short but intensive method in which our HRT program was conducted, requiring the completion of daily self-home training checklists, might have been another reason for the observation of higher compliance than has been reported for HRT methods involving longer sessions. Shorter training sessions have been proposed to be more effective for auditory perceptual learning as a way to increase compliance [
The WRS, KCPT, and KSPIN tests were conducted to evaluate audiologic outcomes in our study, but significant improvements were observed only in the KCPT results. There is disagreement regarding whether audiologic outcomes can be enhanced by HRT in HA users. Sweetow and Sabes [
In this study, possible reasons why we did not observe significant improvements in the WRS and KSPIN test results are that our 8-week HRT period may have been too short to show significant results or that our program did not include hearing training in a noisy environment. Further studies with a longer training period and a training protocol including hearing training in a noisy environment will be required to support these hypotheses. In addition, the KCPT scores in the CG also improved at 4 and 8 weeks of follow-up, even though the magnitude of improvement was smaller than in the HRTG. Repeated exposure to the same test or the hearing rehabilitation effects caused by everyday HA use in CG might explain why we observed improvements in KCPT scores in both groups.
As the final goal of HRT in HA users is to improve communication skills in everyday life, self-reported measures might be more appropriate than laboratory speech recognition tests [
The IOI-HA questionnaire has been developed to quantify the satisfaction of HA users and consists of a total of seven questions on daily use, benefit, residual activity, satisfaction, residual participation restrictions, impact on others, and quality of life [
However, our study and previous studies have reported that HRT or auditory training programs improved subjective satisfaction with HAs, which might be related to the different methods applied. Humes et al. [
It can be assumed that hearing training with personal communication rather than a solely computer-based process can be more effective for HA users. The good compliance and therapeutic effect of our HRT program, as evidenced by a prospective randomized case-control study, reveals the value of HRT programs for HA users. The limitations of this study are the relatively short duration of our 8-week HRT program and the small number of participants in this subject-control experiment, which might have been insufficient to show significant improvements in the WRS and KSPIN tests.
This prospective randomized controlled study was conducted to evaluate the effectiveness of our HRT program consisting of specialists’ face-to-face instruction with 30-minute HRT sessions and daily self-administered HRT for HA users. Our HRT program yielded significant improvements in the consonant perception test and self-reporting measures (K-HHIE and K-IOI-HA) and a higher compliance rate than other programs. This HRT program strategy could prove beneficial to many HA users.
▪ The effects of a hearing rehabilitation therapy (HRT) program for hearing aid users were evaluated.
▪The program consisted of 30-minute training sessions by an expert and daily self-HRT.
▪The higher compliance rate suggests that short-time/face-toface HRT is effective.
▪Consonant perception tests and questionnaires scores significantly improved.
This study was partially funded by GN ReSound. No other potential conflicts of interest relevant to this article were reported.
Conceptualization: JMP, SYP, SNP. Data curation: JSH, JMP, YK. Formal analysis: JSH. Funding acquisition: SNP. Methodology: JSH, JMP, YK, SNP. Project administration: JSH, JMP, YK, SNP. Visualization: JSH. Writing–original draft: JSH, SNP. Writing–review & editing: JMP, YK, JHS, DKK, SYP, SNP.
This study was partially funded by GN ReSound.
Statistical consultation was supported by the Department of Biostatistics of the Catholic Research Coordinating Center.
Flow diagram for the hearing rehabilitation therapy clinical trial.
A schematic presentation of the hearing rehabilitation training (HRT) protocol. The HRT program consisted of face-to-face training and self-home training with three interviews with an ENT doctor. A 30-minute face-to-face training was conducted once a week for 8 weeks, with the first 4-week period involving constant discrimination retraining and weeks 5–8 focusing on identification and understanding training. At the same time, patients were taught to perform self-home training every day at home. In the training process, the 10 most commonly used Korean consonants were used for training, starting with low-frequency consonants and gradually progressing to high-frequency consonants. The doctor’s role during our HRT program was to interview the patient three times (HRT prescription, reinforcement, and final motivation for self-HRT). AV, auditory-visua; AO, auditory-only.
Baseline results of pure tone audiometry (PTA; A) and word recognition score (B) show no significant differences between the auditory training group and the control group (
Changes in scores of the Korean consonant perception tests. Significantly higher mean changes in scores were observed in the HRTG under both consonant-only and consonant+vowel conditions (*
Changes in hearing questionnaire scores. (A) The Korean version of the International Outcome Inventory for Hearing Aids (K-IOI-HA) score gradually increased in the hearing rehabilitation therapy group (HRTG), but no significant change was observed in the control group (CG), indicating that the HRTG had higher satisfaction than the CG with hearing aid use. Total (B), situational (C), and emotional (D) scores on the Korean version of the Hearing Handicap Inventory (K-HHIE) questionnaire significantly decreased in the HRTG, while no changes were observed in the CG, indicating that the level of discomfort regarding hearing loss significantly decreased after HRT. ***
Clinical characteristics of the participants
Variable | HRTG (n=18) | CG (n=20) | |
---|---|---|---|
Age (yr) | 73.9±8.8 | 71.6±8.8 | 0.419 |
Sex (male:female) | 5:13 | 8:12 | 0.428 |
Hearing aid type (CIC:RIC, ears) | 28:8 | 35:5 | 0.261 |
Hearing aid usage (mo) | 45.8±33.2 | 39.0±34.1 | 0.463 |
Better hearing side (right:left) | 12:6 | 11:9 | 0.392 |
Values are presented as mean±standard deviation.
HRTG, hearing rehabilitation therapy group; CG, control group; CIC, complete in the canal; RIC, receiver in the canal.
Mann-Whitney test.
Fisher exact test.
Evaluation of the therapeutic effectiveness of the hearing rehabilitation therapy program
Variable | 1st visit | 2nd visit | 3rd visit | |
---|---|---|---|---|
Word recognition score | ||||
HRTG | 73.8±8.1 | 74.4±7.9 | 74.9±8.3 | 0.230 |
CG | 73.5±17.8 | 74.0±19.3 | 74.1±20.1 | 0.591 |
|
0.310 |
0.344 |
0.454 |
|
KCPT | ||||
Consonant only | ||||
HRTG | 12.6±7.3 | 17.7±7.0 | 21.4±6.4 | <0.001 |
CG | 12.3±8.2 | 15.3±7.6 | 17.6±7.1 | <0.001 |
|
0.920 |
0.336 |
0.100 |
|
Consonant+vowel “–a” | ||||
HRTG | 14.9±6.5 | 18.5±6.1 | 21.3±6.5 | <0.001 |
CG | 14.1±6.9 | 15.5±7.3 | 17.8±7.8 | <0.001 |
|
0.720 |
0.182 |
0.203 |
|
KSPIN test | ||||
SNR 5 | ||||
HRTG | 15.4±17.0 | 16.1±18.1 | 16.3±16.6 | 0.507 |
CG | 9.6±13.5 | 11.7±15.3 | 11.5±14.6 | 0.399 |
|
0.378 |
0.462 |
0.306 |
|
SNR 0 | ||||
HRTG | 8.1±15.1 | 11.2±17.0 | 10.6±16.2 | 0.176 |
CG | 4.5±11.6 | 7.2±12.1 | 7.7±13.7 | 0.093 |
|
0.570 |
0.789 |
0.586 |
Values are presented as mean±standard deviation.
HRTG, hearing rehabilitation therapy group; CG, control group; KCPT, Korean consonant perception test; KSPIN, Korean speech perception in noise; SNR, signal-to-noise ratio.
Summary of randomized controlled trials for auditory training in hearing aid users
Study | Participant | Placebo | Compliance (completed/ enrolled) | Age (yr) | Training method | Intervention | Duration | Measure | Positive result |
---|---|---|---|---|---|---|---|---|---|
This study | Bilateral HA users (at least 3 months) | No | 18/18 (100%) | 55–86 | Individual | Consonant training (perception, discrimination, comprehension) | 4 Hours over an 8-week period | WRS, CPT, SPIN, HHIE, IOI-HA | CPT, HHIE, IOI-HA |
Hickson et al. [ |
Some HA users (approximately half) | Yes (social program) | 82/178 (46%) | 53–94 | Group | Active communication education | 10 Hours over a 5-week period | HHQ, SAC, QDS, Ryff, SF-36 PCS, COSI, IOI-HA | HHQ, SAC, QDS, Ryff, COSI, IOI-AI |
Preminger and Ziegler [ |
HA users (at least 3 months) | No | 31/34 (91%) | 55–75 | Group | Speech perception training | 5–6 Hours over a 6-week period | Analytic and synthetic speech perception, HHIE, WHODAS II | HHIE |
Humes et al. [ |
HA users | Yes (audiobooks) | 12/15 (80%) | 54–80 | Tablet computer-based | At-home auditory training program | 5-Week period | CST, CID, PHAP, HHIE, and HASS, ANL | CID |
Stecker et al. [ |
HA users | No | 31 |
50–80 | Personal computer-based | Perceptual training | 8-Week training period | NST | NST |
Sweetow and Sabes [ |
HA users (56)+non-HA users (9) | No (cross-over) | 49/65 (75%) | 28–85 | Web-based | LACE | 4-Week period | QuickSIN, HINT, HHIE, CSOA, | QuickSIN, HHIE, CSOA |
Yu et al. [ |
HA users | Yes (traditional training) | 10 |
68–84 | Mobile-based | Consonant training (perception, discrimination, comprehension) | 16 Hours over a 4-week period | Speech recognition scores | Consonant and sentence tests |
HA, hearing aid; WRS, word recognition score; CPT, consonant perception test; SPIN, speech perception in noise; HHIE, Hearing Handicap Inventory for the Elderly; IOI-HA, International Outcome Inventory for Hearing Aids; HHQ, Hearing Handicap Questionnaire; SAC, Self-Assessment of Communication; QDS, Quantified Denver Scale of Communicative Function; Ryff, Ryff Psychological Well-Being Scale; SF-36 PCS, short-form 36 physical component score; COSI, Client Oriented Scale of Improvement; WHODAS II, World Health Organization Disability Assessment Schedule II; CST, Connected Speech Test; CID, Central Institute for the Deaf Sentence Materials; PHAP, Profile of Hearing Aid Performance; HASS, Hearing Aid Satisfaction Survey; ANL, acceptable noise level; NST, Nonsense Syllable Test; LACE, Listening and Communication Enhancement; QuickSIN, Quick Speech In Noise; HINT, Hearing in Noise Test; CSOA, Communication Scale for Older Adults.
No information on participants who completed the training.