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Department of Otorhinolaryngology, Aichi Medical University, Nagakute, Aichi, JapanDepartment of Otorhinolaryngology, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan
Department of Otorhinolaryngology, Aichi Medical University, Nagakute, Aichi, JapanDepartment of Otorhinolaryngology, Middle Ear Surgical Center, Meitetsu Hospital, Nagoya, Aichi, Japan
Department of Otolaryngology-Head and Neck Surgery, Nagoya City University, Graduate School of Medical Sciences and Medical SchoolDepartment of Otorhinolaryngology-Head and Neck Surgery, Aichi Gakuin University School of Dentistry, Nagoya, Aichi, Japan
Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
Department of Otolaryngology-Head and Neck Surgery, Nagoya City University, Graduate School of Medical Sciences and Medical SchoolEast Medical Center, Nagoya, Aichi, Japan
To obtain new insights into research questions on how executive function and social interaction would be observed to change after the introduction of hearing aids (HAs) in older people with hearing impairment.
Outpatients with complaints of hearing difficulty who visited HA clinics between October 18, 2017, and June 30, 2019, in 7 different university hospitals in Japan.
Methods
The inclusion criteria of the study named Hearing-Aid Introduction for Hearing-Impaired Seniors to Realize a Productive Aging Society—A Study Focusing on Executive Function and Social Activities Study (HA-ProA study) were age ≥60 years and no history of HA use. A series of multi-institution common evaluations including audiometric measurements, the digit symbol substitution test to assess executive functions, convoy model as an index of social relations, and hearing handicap inventory for the elderly (HHIE) were performed before (pre-HA) and after 6 months of the HA introduction (post-HA).
Results
Out of 127 enrollments, 94 participants completed a 6-month follow-up, with a mean age of 76.9 years. The digit symbol substitution test score improved significantly from 44.7 at baseline to 46.1 at 6 months (P = .0106). In the convoy model, the social network size indicated by the number of persons in each and whole circles were not significantly different between pre- and post-HA; however, the total count for kin was significantly increased (P = .0344). In the analyses of HHIE, the items regarding the family and relatives showed significant improvement.
Conclusions and Implications
HA use could benefit older individuals beginning to use HAs in executive function and social interaction, though the results should be interpreted cautiously given methodological limitations such as a single-arm short 6 months observation. Reduction in daily hearing impairment would have a favorable effect on relationships with the family.
A nation with a high population aging rate is required to assess a society that makes good use of the abilities and activities of the older people. The idea of “productive aging,” advocated by American geriatrician Robert Butler in 1975, has been refocused in the recent era of global aging. It is an approach that emphasizes on the positive aspects of aging and means through which individuals can make important contributions to their communities and society.
Age-related hearing impairment (ARHI) is a common chronic health concern among older adults. It is prevalent in 1 among 3 adults age >65 years, according to several large epidemiologic studies.
Unaddressed hearing impairment has been associated with various adverse consequences such as declined interpersonal communication, psychiatric disturbances including depression and cognitive decline, social isolation, and reduced quality of life.
However, whether a hearing aid (HA), the first countermeasure for ARHI, is effective in reducing these adverse consequences has not yet been ascertained.
ARHI is likely to remain undertreated. The use of HAs among people with a hearing impairment remains low, particularly in Japan. Only about 1 in 7 people with a hearing impairment use HAs in Japan.
Previously, we estimated the size of the Japanese population >65 years of age with a hearing impairment as 16,553,000, using a population-based cohort survey of approximately 2200 adults and national demographic statistics in 2010.
Estimates of the size of the hearing-impaired elderly population in Japan and 10-year incidence of hearing loss by age, based on data from the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA).
The cohort survey is the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA), which is a comprehensive and interdisciplinary study of community-dwellers to observe age-related changes.
From the analyses of NILS-LSA, we also reported the impact of baseline hearing status on the degree of cognitive change during a 12-year follow-up assessed with the Japanese Wechsler Adult Intelligence Scale-Revised Short Forms, including the digit symbol substitution test (DSST), which is a neuropsychological test most frequently used to evaluate executive functions.
The DSST scores of the individuals with a hearing impairment declined faster compared with those of the individuals without hearing impairment. Several abilities are necessary for performing DSST adequately.
The DSST scores in our previous study were extremely sensitive to the interactive effects of aging and hearing impairment. We were then interested in finding whether there would be any impact on DSST when hearing is compensated in people with hearing impairments.
In addition, we recently reported from the NILS-LSA that the social network size in older individuals with a hearing impairment was significantly smaller than those in individuals without hearing impairment by a cross-sectional analysis of the convoy model, which is an index of social relations.
The relationships are influenced by personal characteristics, such as age and situational status, and have been reported to have significant implications on health and well-being.
An older person's social contacts are influenced by conditions over the life course and recent events. Although our previous analyses of the NILS-LSA were cross-sectional, in the present project, we conducted a 6-month follow-up study on help-seeking outpatients with hearing impairment to assess the effect of HA-use on executive function and social interaction by comparing characteristics before and after HA introduction.
Social participation, a source of social relations, in formal and informal group activities, is associated with better mental and physical health
Self-reported hearing loss in older adults is associated with future decline in instrumental activities of daily living but not in social participation.
In the present study, we investigated whether hearing compensation could have an impact on older people who have relatively maintained activities of daily living and physical functions other than hearing loss because there have not been many prospective studies to evaluate the changes observed in older individuals beginning to use HAs. The executive function, social activities, and hearing loss in older people who do not have dementia were assessed using assessments including DSST and convoy model.
Methods
Study Design and Participants
The participants were outpatients with complaints of hearing difficulty. Between October 18, 2017, and June 30, 2019, 127 individuals were prospectively enrolled into a multi-institutional research project named Hearing-Aid Introduction for Hearing-Impaired Seniors to Realize a Productive Aging Society—A Study Focusing on Executive Function and Social Activities study (HA-ProA study) at 7 different university hospitals in Japan, namely, 1)Aichi Medical University, 2)Teikyo University School of Medicine, Mizonokuchi Hospital, 3)Keio University School of Medicine, 4)Nagoya City University, 5)Shinshu University School of Medicine, 6)Okayama University Graduate School of Medicine, and 7)Kyushu University.
Patients were evaluated using audiometric tests. Hearing level was assessed by pure tone audiometry, and the tested frequencies were between 0.125 kHz and 8 kHz at 1-octave intervals after inspection of the eardrum. Speech intelligibility was measured using 67-S monosyllable lists, which is approved by the Japan Audiological Society, and maximum discrimination scores of the left and right ears were obtained.
After hearing function was assessed, the patients visited an HA clinic. During their first visit, the purpose of the study was explained to the patients who met the following criteria: age >60 years and no history of HA use. If there was a left-right difference in hearing, they were excluded (left-right difference was defined as a difference of >20 dB in air conduction hearing at 2 or more of the frequencies of 0.5, 1, 2, and 4 kHz). Patients with dementia or cognitive decline were also excluded. All participating patients provided written informed consent by the Declaration of Helsinki. The study was approved by the institutional review boards of all participating institutions and the primary institution (2017-H228). This study has been registered to the University Hospital Medical Information Network-Clinical Trials Registry.
Before the trial use of HAs, baseline data of participants were acquired. Patients borrowed and used trial HAs daily for 1 to 3 months and visited the hospital several times a month for HA adjustment and guidance from physicians, speech-language-hearing therapists, and HA technicians during the trial. Following this, the patients who were satisfied with the effects, purchased HA products. The patients who were not satisfied with the use of or did not need the HAs, returned the trial HAs and research tracking ended there. Prescribed measurements were performed in patients who continued to use the HAs for 6 months, including the trial period.
Measurements at the Baseline (Pre-HA)
The participants completed a series of questionnaires before the examination, which was common for all institutes, and enquired about demographic characteristics such as working and marital status, family living together, educational history, social participation activities of last year, and comorbidities. For the level of education in Japan, >9 years indicated elementary school or junior high school equivalent, 10–12 years indicated high school or junior high school equivalent under the former Japanese educational system, 13–14 years was comparable to higher vocational school or junior college, and >15 years was comparable to college or graduate college. The number of social activities was determined by the following question: “Have you participated in any of the following voluntary activities with individuals or friends or with groups or organizations during the past year? If there is more than one that applies, please mark for all.” Here are some of the choices: health/sports (gymnastics, walking sessions, and gateball), hobbies (Japanese poems, ceramic art, etc), local events (local festivals), improvement of living environment (environmental beautification, greening promotion, town development), and education and culture (learning sessions, fostering children's associations, and folk entertainment).
In DSST, participants were asked to write down as many symbols as possible that correspond to a given number within 90s (possible score range: 0–93). This test measured processing speed, visual-motor coordination, visuospatial attention, executive cognitive function, and working memory.
Association between lower digit symbol substitution test score and slower gait and greater risk of mortality and of developing incident disability in well-functioning older adults.
The number of correct responses was used as the score. To ensure uniformity among institutes, an instruction video by a clinical psychologist was distributed. At the time of implementation, we adopted a method of using both oral and visual explanations together with a teaching sheet to facilitate appropriate test procedure teaching for participants with a hearing impairment.
As an index of social relationships, the convoy model was adopted. The procedure has been reported in detail elsewhere.
Briefly, respondents were shown a series of 3 concentric circles, with the word “you” at the center, and were then asked to imagine themselves at the center of the circles and list the names of important people in their lives according to how close they felt to them. The inner circle represented “people to whom you feel so close that it is hard to imagine life without them.” The middle circle represented “people to whom you may not feel quite that close but who are still important to you.” Finally, the outer circle represented “people whom you have not already mentioned but who are close and important enough in your life that they should be placed in your personal network.” Altogether, the 3 circles represented the overall convoy of the individual. The number of people with whom respondents had interpersonal relationships was counted for the present analysis with the type based on whether they were kin. The number of people included in each circle or the sum of the number of network members nominated by the participants across the 3 circles (inner, middle, and outer) was used as indicators in the analysis.
The hearing handicap inventory for the elderly (HHIE) developed in 1982
was one of the first hearing-related patient-reported outcome measures intended for clinical use and was designed to assess self-perceived hearing impairment in older adults. The HHIE has 25 questions, with 2 subscales: emotional consequence and social/situational effects because of hearing loss. It can be used as a supplement to audiometry in the evaluation of HA effectiveness.
During an assessment of the social activity in older people, whether activities of daily living are maintained should be established. The Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) was taken as an evaluation scale of IADL,
in: Kent D. Kastenbaum R. Sherwood S. Research Planning and Action for the Elderly: The Power and Potential of Social Science. Human Sciences Press,
New York1972
The TMIG-IC is a multidimensional 13-item index, as shown in Table 1, where items are classified into 3 subscales. The response to each item was scored 1 for “yes” (able to do) and 0 for “no” (unable), and the total score was the sum total of 13 items.
Table 1The TMIG-IC to Assess Higher-Level Functional Capacity in Older Adults
Subscales
Item no.
Question
Respose
Instrumental activities of daily living
1
Can you use public transportation (bus or train) by yourself?
1. Yes
0. No
2
Are you able to shop for daily necessities?
1. Yes
0. No
3
Are you able to prepare meals by yourself?
1. Yes
0. No
4
Are you able to pay bills?
1. Yes
0. No
5
Can you handle your own banking?
1. Yes
0. No
Effectance
6
Are you able to fill out forms for your pension?
1. Yes
0. No
7
Do you read newspapers?
1. Yes
0. No
8
Do you read books or magazines?
1. Yes
0. No
9
Are you interested in news stories or programs dealing with health?
1. Yes
0. No
10
Do you visit the homes of friends?
1. Yes
0. No
Social Role
11
Are you sometimes called on for advice?
1. Yes
0. No
12
Are you able to visit sick friends?
1. Yes
0. No
13
Do you sometimes initiate conversations with young people?
Measurements 6 Months after the Use of HAs (Post-HA)
Multi-institution common post-HA questionnaires, including social participation activities, HAs usage status, and usage time were used. The convoy model, DSST, HHIE, and TMIG-IC scores were also obtained. As audiometric measures, the aided and unaided sound field thresholds with warble tones and speech intelligibility of monosyllables were evaluated.
Statistical Analyses
Statistical analyses were conducted using SAS software v 9.3 (SAS Institute, Inc, Cary, NC, USA). Comparisons of the continuous variables from the convoy model, DSST, and TMIG-IC scores between pre-HA and post-HA were performed using a paired t-test. In the HHIE, those who answered “yes” and “sometimes” to each question were treated as respondents with a disability, and the percentage of respondents with a disability between pre-HA and post-HA were compared using a McNemar test. Statistical significance was set at P < .05.
The following audiometric values were calculated for analyses: the average hearing threshold for frequencies 0.5, 1, 2, and 4 kHz of the ear with the better hearing (AHTBE) and the average hearing threshold for frequencies 0.5, 1, 2, and 4 kHz in the sound field (AHT).
A scatter plot was added to visually identify the difference between pre-HA and post-HA in the DSST score.
Results
Ninety-four out of 127 individuals at 7 facilities completed a 6-month follow-up. After the trial period, 98 patients purchased HAs; however, 4 patients discontinued hospital visits because of admission in nursing homes and/or health-related reasons.
The characteristics of the participants who completed the 6-month survey are given in Table 2. The mean age of participants was 76.9 years ± 6.6 [standard deviation (SD)], 41.5% were male and 24.5% were working. Regarding audiometric measures, the mean AHTBE was 46.7 ± 9.4 dB, and the mean speech intelligibility of the better between the 2 ears was 80.1 ± 15.0%. The mean years of education were 13.1. ± 2.7 years, among the 92 persons who responded to the query.
Table 2Demographic Characteristics of the Study Participants
The results of an analysis comparing the data between baseline (pre-HA) and 6 months (post-HA) are presented in Table 3. The DSST score improved from 44.7 at baseline to 46.1 at 6 months, and the difference was statistically significant (P = .0106). The number of social activities was 1.9 at baseline and 2.2 at 6 months, with a marginally significant difference (P = .0837). In the convoy model, no significant difference was found in comparing a number of persons in each circle and in whole circles between pre- and post-HA. However, the total count for kin was 8.1 persons at baseline and 9.2 persons at 6 months, which was significantly different (P = .0344).
Table 3Comparison of Measured Variables Between Baseline (Pre-HA) and 6 Months (Post-HA)
HA use showed a significant benefit on self-reported hearing impairment. The total HHIE score decreased from 30.8 at baseline to 18.0 at 6 months (P < .0001), and improvement was found in all the emotional and social/situational subscales. Table 4 shows the results of the comparison of the percentage of respondents with a disability between pre-HA and post-HA for each item on the HHIE. Among items related to a relationship with family and relatives, the following showed significant improvement: E-5, S-10, S-13, E-14, S-19, and S-21.
Table 4The Results of the Comparison in the Percentage of Respondents with Impairment Between Pre-HA and Post-HA for Each Item on the HHIE
Item no.
Question
With Impairment (%)
McNemar Test
Pre-HA
Post-HA
P Value
S-1
Does a hearing problem cause you to use the phone less often than you would like?
33.0
20.2
.029
E-2
Does a hearing problem cause you to feel embarrassed when meeting new people?
38.3
26.6
.061
S-3
Does a hearing problem cause you to avoid groups of people?
25.5
20.2
.405
E-4
Does a hearing problem make you irritable?
53.2
29.8
<.001
E-5
Does a hearing problem cause you to feel frustrated when talking to members of your family?
56.4
25.5
<.001
S-6
Does a hearing problem cause you difficulty when attending a party?
78.5
54.8
<.001
E-7
Does a hearing problem cause you to feel “stupid” or “dumb”?
22.3
16.0
.2379
S-8
Do you have difficulty hearing when someone speaks in a whisper?
96.8
84.0
.004
E-9
Do you feel you have a disability by a hearing problem?
53.2
36.2
.009
S-10
Does a hearing problem cause you difficulty when visiting a friend, relative, or neighbors?
72.3
47.9
<.001
S-11
Does a hearing problem cause you to attend religious services less often than you would like?
→Does a hearing problem cause you to attend a meeting you want to attend less often than you would like?
39.4
19.2
.001
E-12
Does a hearing problem cause you to be nervous?
44.1
29.0
.020
S-13
Does a hearing problem cause you to visit friends, relatives, or neighbors less often than you would like?
22.3
10.6
.019
E-14
Does a hearing problem cause you to have arguments with family members?
42.6
25.5
<.001
S-15
Does a hearing problem cause you difficulty when listening to TV or radio?
86.2
46.8
<.001
S-16
Does a hearing problem cause you to go shopping less often than you would like?
4.3
2.1
.688
E-17
Does any problem or difficulty with your hearing upset you?
37.2
30.9
.345
E-18
Does a hearing problem cause you to want to be by yourself?
20.2
13.8
.286
S-19
Does a hearing problem cause you to talk to family members less often than you would like?
30.9
11.7
<.001
E-20
Do you feel that any difficulty with your hearing limits or hampers your personal or social life?
54.3
35.1
.002
S-21
Does a hearing problem cause you difficulty when in a restaurant with relatives or friends?
69.2
42.6
<.001
E-22
Does a hearing problem cause you to feel depressed?
26.6
19.2
.167
S-23
Does a hearing problem cause you to listen to television or radio less often than you would like?
37.2
17.0
.001
E-24
Does a hearing problem cause you to feel uncomfortable when talking to friends?
42.6
18.1
<.001
E-25
Does a hearing problem cause you to feel left out when you are with a group of people?
47.9
33.0
.013
Items that show significant changes are shown in bold.
TMIG-IC, an index of IADL, was maintained without change.
The scatter diagram of the DSST scores is shown with pre-HA and post-HA on each axis in Figure 1 showing the relationship between them. Although there were 2 participants whose DSST score decreased 10 points or more, there were 7 participants whose DSST score increased10 points or more.
Fig. 1Scatter plots showing the differences of DSST scores between pre-HA and post-HA. Samples in the gray area show that the post-HA scored worse than the pre-HA.
In this prospective multi-institutional joint research, there was a small but statistically significant change in DSST scores observed in older individuals beginning to use HAs during the first 6 months. There were also modest changes in the convoy model and the number of social activities.
High performance of the DSST needs different interrelated abilities, such as perceptual speed,
The DSST has been adopted in many large epidemiologic studies dealing with hearing and cognitive function, including the National Health and Nutrition Examination Study,
Hearing treatment for reducing cognitive decline: Design and methods of the aging and cognitive health evaluation in elders randomized controlled trial.
and hearing impairment was significantly associated with cognitive deterioration cross-sectionally and accelerated cognitive decline longitudinally.
All cognitive abilities are not equally affected by aging to the same degree, and some cognitive abilities appear more vulnerable to the aging effect than others. In our previous report, the model-predicting 12-year change indicated that older people with a hearing impairment showed a more rapid decline in DSST scores than their counterparts without hearing loss.
Because the mean number of repeated visits was 4.6 in the previous study, we added indicators of prior exposure to the neuropsychological tests in the analytical model to control for practice effects. The DSST scores declined significantly over time in individuals with hearing impairments regardless of whether the practice effects were considered or not. The DSST scores in individuals with a hearing impairment (mean age: 71.2 years at baseline) declined by 0.5120/year in the analytical model with consideration of the practice effects. Cognitive function measured by DSST is vulnerable to age and hearing loss; however, the current participants (mean age: 76.9 years at baseline) demonstrated a favorable change after one-half a year of HA use. The fact that a small but statistically significant improvement was found in the DSST, which is a nonverbal task, was noteworthy, even though the observations for one-half a year were not sufficient and further study with a control group is required in order to know the impact of auditory compensation.
Social networking and maintaining social activities are major elements for productive aging and maintaining well-being in aging societies.
In the current analysis, the number of social activities increased slightly compared with baseline after one-half-year HA usage. Regarding the convoy model, a significant difference between pre- and post-HA was observed only in the total count of whole circles for kin. This result of the convoy model was inconsistent with our previous analysis of age community-dwellers.
Our previous analysis investigated whether the social network size indicated by the convoy model is associated with the presence or absence of hearing impairment in Japanese community-dwellers age >60 years. The previous results showed that the social network size, expressed as the sum of the number in whole circles, was significantly smaller in the group with hearing impairment compared with that in the group without hearing impairment. Moreover, individuals with a hearing impairment were more likely to report fewer non-kin members compared with their counterparts who do not have hearing impairments, and that the number of kin in each circle was not significantly related to participants’ hearing status. The decisive difference between the participants of the present study is related to the degree of hearing loss. In the previous study on community-dwellers, only 18.8% of the group with a hearing impairment had disabling hearing impairment (AHTBE >40 dB HL),
whereas disabling hearing impairment was observed in 74.5% of the current study participants who completed a 6-month follow-up (70 out of 94 participants).
In the present results, from the answers to HHIE, it was observed that the difficulty in hearing hinders communication with family and relatives. Participants in this study felt they had a disability even in relationships with family members and relatives who were psychologically closer compared with non-kin or who were likely to understand the hearing difficulties of people with a hearing impairment. However, after the use of HAs, several inquiries about the relationship with family and relatives showed significant improvement. In the E-14, “Does a hearing problem cause you to have arguments with family members?,” the rate of respondents with an impairment significantly reduced from 42.6% to 25.5% (P < .001), and in the S-19; “Does a hearing problem cause you to talk to family members less often than you would like?,”’ the rate of respondents with an impairment significantly reduced from 30.9% to 11.7% (P < .001). The change observed in the response to these HHIE inquiries seems to reflect in the present result of the convoy model in which a significant increase between pre- and post-HA was found in the total count of whole circles for kin. It will probably take more than 6 months until the changes after HA use in the relationship between the those with a hearing impairment and nonrelatives may be appreciated.
In designing this research plan, the distribution situation of HAs in Japan should be explained. HAs are available at department stores, optical shops including hard discount glasses stores, home appliance retailers, and even online shops.
Although the system for regulation of HA distribution is being developed, there is no strictly official qualification and no national examination for HA technicians in Japan, contrary to other industrialized countries. Because the distinction between HAs and sound collection devices is not sufficiently enlightened as a social recognition, many products on the Internet are on sale, and do not include fitting by professional HA technicians. Therefore, for assessment of the effect of HAs on individuals with a hearing impairment by comparing before and after HA introduction, it was important to ascertain that the participants used appropriate products and were properly fitted by the medical professionals. We believe this is one of the strengths of the current research project.
Some limitations of this study should be acknowledged. Because of the features of the study facilities, which were all university hospitals, there may be a selection bias of participant characteristics. It was likely that a health-conscious person who understood the importance of research purpose had completed it to the end. In the process of consent to participate in the study after receiving an explanation of the purpose and meaning of the research, it is undeniable that those who were more interested in maintaining cognitive function might provide consent and might have completed a 6-month follow-up. The fact that the average years of education in the present study was as long as 13 years suggests that university hospital patients are generally more educated. Although this was a prospective cohort study, the cohort was not large and had a single-arm observation. The results should be interpreted cautiously in view of methodological limitations inherent in the study design. Because the gold standard for clinical trials is a well-organized randomized controlled trial with blinding throughout the study period, it cannot be determined whether the favorable outcome in the present study without a control group was really derived from the effect of improved hearing itself.
Even considering the above limitations, it is worthwhile that the modest but certain impact of hearing compensation on executive function and social interaction was found in individuals beginning to use HAs.
Conclusions and Implications
In the present study following 94 outpatients with a hearing impairment over 60 years of age in 7 university hospitals for 6 months since the fitting of HAs, we found that HA use could benefit older individuals in executive function and social interaction, though the results should be interpreted cautiously given methodological limitations such as a single-arm short period observation. Reduction in daily hearing impairment could bring a favorable effect on relationships with family and relatives.
Acknowledgments
We thank the participants of the Hearing-Aid Introduction for Hearing-Impaired Seniors to Realize a Productive Aging Society—A Study Focusing on Executive Function and Social Activities Study (HA-ProA study) and health professionals and researchers from the 7 participating study institutions, who were involved in the data collection and analyses. We thank Editage (www.editage.com) for English language editing.
References
Goman A.M.
Lin F.R.
Prevalence of hearing loss by severity in the United States.
Estimates of the size of the hearing-impaired elderly population in Japan and 10-year incidence of hearing loss by age, based on data from the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA).
Self-reported hearing loss in older adults is associated with future decline in instrumental activities of daily living but not in social participation.
Association between lower digit symbol substitution test score and slower gait and greater risk of mortality and of developing incident disability in well-functioning older adults.
in: Kent D. Kastenbaum R. Sherwood S. Research Planning and Action for the Elderly: The Power and Potential of Social Science. Human Sciences Press,
New York1972
Hearing treatment for reducing cognitive decline: Design and methods of the aging and cognitive health evaluation in elders randomized controlled trial.
The funding sources had no role in the study design or conduct of the study; in the collection, management, analysis, or interpretation of the data; in the writing of the manuscript; or the decision to submit.
This work was primarily supported by the Japan Agency for Medical Research and Development (AMED, Grant 19dk0310085h0003) and partly by the Japan Society for the Promotion of Science KAKENHI (Grant 26502016) and AMED (Grant 19dk0207041h0002).
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