During the last 30 years several hearing disability and handicap questionnaires have been designed and used for clinical purposes. The present study includes a review of the most frequently used scales. The aim of the present study was to evaluate the reliability and validity of the Hearing Disability and Handicap Scale (HDHS), which is a shortened and modified version of the Hearing Measurement Scale. Correlations between the Hearing Handicap and Support Scale, the Communication Strategy Scale from the Communication Profile of the Hearing Impaired, pure tone audiometry and speech recognition scores in noise were analysed. Data from 168 men with noise induced hearing loss of different degrees was obtained. Also a test-retest was conducted. The disability section of the HDHS seemed accurate but offered no improvement of prediction compared to previous scales. Even though the reliability of the handicap section was sufficient, its validity and clinical use is discussed and suggestions about improvements given. Since standardised scales are necessary if results are to be compared worldwide, guidelines regarding the clinical use and benefit of hearing disability and handicap scales are required.
Keywords: Handicap, disability, hearing loss, measurements
|How to cite this article:|
Barrenas ML, Holgers KM. A clinical evaluation of the hearing disability and handicap scale in men with noise induced hearing loss. Noise Health 2000;2:67-78
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Barrenas ML, Holgers KM. A clinical evaluation of the hearing disability and handicap scale in men with noise induced hearing loss. Noise Health [serial online] 2000 [cited 2013 May 22];2:67-78. Available from: http://www.noiseandhealth.org/text.asp?2000/2/6/67/31733
| Introduction|| |
Noise-induced hearing loss (NIHL) is still a major occupational health problem. In Sweden, approximately 13% of the male population experience great problems following a conversation between two or more persons, aided or unaided (National Statistics Office, 1992). Hearing loss not only includes damage to the sensory hair cells or an audiometric high frequency dip, but has also consequences in everyday life. In our work, we have adopted the definitions by Stephens & Hetu (1991), i.e. that hearing disability refers to the difficulties in hearing in a real environment such as hearing in noisy environments, while hearing handicap reflects to the effect of the hearing loss on the individuals life, such as social isolation, irritation and reduced self-esteem. To quantify these psychosocial consequences, a number of hearing disability and handicap questionnaires have been designed see [Table - 1]; for example the Hearing Handicap Scale (High et al.,1964), the Hearing Performance Inventory (Giolas, 1979) and the Social Hearing Handicap Index ( Ewertsen & Birk-Nielsen, 1973 ). Comparisons to clinical ratings have not been reported previously.
There is a demand in clinical practice for psychometrically reliable and valid scales as a complement to audiometry. Such scales, which must be easy to use for the professionals, are needed not only for screening but also for evaluation of different rehabilitative efforts. Even though several questionnaires have been introduced to the clinicians over the last 30 years [Table - 1], their validity are uncertain. One reason for the demand for psychometrically reliable and valid scales is that disability and handicap do not correlate well to pure tone audiometry, nor to speech recognition scores see [Table - 1]. A further reason why many of the questionnaires were abandoned is that they took so long and that they were clinically impractical. Moreover, few patients were prepared to have them repeated. With time some scales were shortened and modified, because scales including many items and many response alternatives did not show stronger correlations with pure tone audiometry than scales with few items or few response alternatives. Nor did self-assessed scales show weaker correlations with the hearing thresholds than face-to-face interviews [Table - 1]. For example the Hearing Disability and Handicap Scale (HDHS) (Hetu et al.,1994) was designed as a short version of the Hearing Measurement Scale (HMS) (Noble & Atherley, 1970), which was originally developed to assess auditory disability and handicap in persons with NIHL. Recently, the Swedish version of the HDHS was evaluated and the author requested further investigations to assess the clinical use of this questionnaire (Hallberg, 1998).
If questionnaires are to be used as tools for screening and evaluation of audiological rehabilitation programs, their reliability and validity is essential. Usually reliability is estimated by internal consistency, by factor analyses or by test-retests. Validity is estimated by evaluating agreement of clinical experience versus the outcome of the questionnaire or by analysing correlations between different questionnaires, or the disability/handicap scores as assessed by the questionnaire and impairment measures, usually pure-tone audiometry. Even though hearing impairment, hearing disability and hearing handicap all occur as a result of NIHL, only weak to moderate correlations are found between hearing thresholds and self assessed hearing handicap as reviewed in [Table - 1]. Speech recognition scores with or without noise were used to improve the correlations, but speech audiometry was no better at predicting the disability and handicap scores than pure tone audiometry [Table - 1].
One major explanation for the low correlations, is that individuals with identical hearing impairment as measured by audiometry differ substantially in perceived disability and handicap. There are also other individual and environmental handicap predictors than hearing loss, such as ineffective coping strategies, acceptance of the hearing problems and poor education (Hallberg & Carlsson, 1991; Hallberg et al.,1993). Moreover, not only the individual himself/herself but also family members, friends and colleagues may be both creators of as well as sufferers from the communication problems. Finally, the compliance of the patient must also be taken into consideration.
The aim of the present study was to evaluate the reliability and validity of the HDHS by analysing correlations between the disability and handicap scores versus clinical ratings of the hearing problems, pure tone hearing thresholds, speech audiometry in noise, the Hearing Handicap and Support Scale (HHSS) and the Communication Strategy Scale from the Communication Profile of the Hearing Impaired (CSS/CPHI).
| Material and methods|| |
This material comprised 168 males with NIHL (mean age=54 years; s.d. 11; range: 17-73 years), consecutively selected from a waiting list of patients attending an audiological clinic for hearing examination. After the subjects had filled in the self-administered HDHS and CSS/CPHI questionnaires pure tone audiometry and speech audiometry in noise was assessed. All subjects were then interviewed by a physician specialising on Occupational Audiology, who made an overall rating of the severity of the hearing problems. This rating was based on both history and audiometry and subjects were categorised as having either slight, moderate or severe hearing problems. Fifty-four of the 168 subjects who had a more severe hearing impairment answered the HHSS also. The ethical considerations were in line with previous and present studies at our clinic, which are approved by the local ethics committee. For the test-retest, thirty other workers with a varying degree of NIHL were asked to fill in the HDHS twice, two months apart.
Pure tone audiometry
All hearing tests were carried out in a soundproof test room with background sound pressure levels below those recommended by ISO 8253-1 (1989). The audiometers (Interacoustics AC-30, Madsen OB-822) were regularly calibrated in accordance with ISO 389 (1991). The pure tone average at 0.5, 1, and 2 kHz (PTAmid), at 3, 4, and 6 kHz (PTAhigh), and also the pure tone average 0.5, 1, 2, 3, 4, and 6 kHz (PTA0.5-6)for both ears were used as summery statistics.
Speech recognition scores in noise
The percentage of correct answers out of 50 monosyllabic phonetically balanced words was determined in the presence of a speech weighted noise, low-pass filtered from 1 kHz with a slope of 12dB/octave and with a constants spectrum level from 125 to 1000 Hz (Magnusson, 1995; 1996). This noise is a frequency-weighted unmodulated random noise according to IEC 645-2, clause 13.1. The speech-to-noise ratio, as calculated from measurements of the speech and noise levels, was +4 dB. The speech signal was presented at a comfortable level, chosen by the subject, 30-40dB above the speech reception threshold. Both lists used were taken from the ordinary test material commonly used in Swedish speech audiometry practice (Liden, 1954).
The Hearing Disability and Handicap Scale (HDHS) (Hetu et al., 1994) consists of 20 items specifically focusing on hearing problems and 7 complementary items concerning occupation, duration of hearing problems and hearing aid usage (see Appendix). The HDHS measures the occurrence of problems, the four alternatives on the response scale being "never" (1 point), "sometimes", "often", and "always" (4 points). However, the wording of items 2, 6, 10, 14 and 18 was in the opposite direction and therefore these responses were reversed before the analysis, i.e. high scores on any item on the HDHS indicate potential problems related to the hearing loss. According to Hetu et al., (1994) the HDHS has a high reliability, as the three factors, speech perception, non-speech sound perception and hearing handicaps explained 58.4% of the total variance. Furthermore, the coefficient alphas for these three factors were 0.81 (speech perception), 0.84 (non-speech sounds) and 0.80 (handicaps).
The handicap section of the Hearing Handicap and Support Scale (HHSS) (Erlandsson et al., 1992) comprises eight items or statements. While the HDHS measures handicap by occurrence, the HHSS estimates perceived handicap by degree on a 5-point response format ranging from "strongly disagree" (1 point) to "strongly agree" (5 points). Two items from HHS are "Nearly everything I do is influenced by my hearing disability" and "I'm left out of certain activities".
The Communication Strategies Scale of the Communication Profile for the Hearing Impaired (CSS/CPHI) (Demorest & Erdman, 1987; Hallberg et al., 1992) consists of 25 items, assessing how often the subject uses "maladaptive behaviour" (alpha = 0.77), "verbal strategies" (alpha = 0.77) and "nonverbal strategies " (alpha = 0.82) to deal with demanding auditory situations. The five-point response scale ranges between "rarely/almost never" (1 point), "sometimes/every now and then", "every other time", "often", and "usually/almost always" (5 points), indicating how frequently the situation or behaviour occurs.
The statistical analyses were performed by using the statistical package of SPSS for Macintosh. For the multivariate analyses the statistical package of GLIM was used (Aitkin et al,1988). Multivariate analysis is related to multiple regression and estimates how changes of the independent explanatory variables (not necessarily independent from each other) alter the dependent, response variable. The result of a multivariate analysis is presented as an equation, which describes how an alteration by 1 unit of the pure tone average, age or the communication strategies change the disability or handicap variable. Moreover, any combination of values for the explanatory variables can be put into the equation to calculate the outcome of the response variable. GLIM uses the maximum likelihood estimate when fitting the data.
| Results|| |
According to the clinical rating 11% of the subjects had slight, 59% moderate and 30% of the subjects severe hearing problems [Table - 2]. Age, PTAmid and PTAhigh increased with severity, while SRS-N decreased. In all groups, disability (i.e. hearing difficulties in everyday life) was experienced more often than hearing handicap (i.e. the communicative, social and emotional effects of a hearing impairment). Disability was seldom experienced by males with slight hearing problems (mean disability score=1.7) but often by males with severe hearing problems (mean disability score=2.9). Handicap, as measured by the HDHS, was sometimes a problem for males with severe hearing problems (mean handicap score=2.0), even though disability was often reported (mean disability score=2.9) and subjects suffered from severe hearing problems (mean PTAhigh=66 dBHL). Subjects with severe hearing problems used the different communication strategies somewhat more frequently than subjects with slight hearing problems. The non-verbal communication strategies were used more often than verbal strategies, while the maladaptive strategies (i.e. avoiding auditory demanding situations, guessing or pretending that you have heard were used more seldom than the other two. As the hearing problems became worse the use of the maladaptive strategies increased from "a seldom use" to "use every now and then", the verbal strategies from "use every now and then" to "use every other time" and the non-verbal strategies from "use every now and then" to "often used".
Reliability: factor analysis and test-retest
A principal component analysis followed by a varimax rotation was performed on the 20 items in the HDHS. The results of the data reduction are summarised in [Table - 3]. Four factors emerged from the analysis and an eigenvalue above 1 was used as a criterion for extraction of the factors. This solution accounted for 61% of the total variance and the major components (factor 1: speech, and factor 2: non-speech) explained 48,2 % of the total variance. It was notable that question 11 (Does it bother or upset you if you are unable to follow a conversation?) loads onto factor 1 (speech) as well as to the handicap component (factor 4). The components of the factors in the present study are in accordance with earlier reports (Hetu et al, 1994; Hallberg, 1997). In the test-retest (n=30), the mean point for the ten disability and the ten handicap items [Table - 3] were calculated. The Pearson correlation coefficients between these test and retest means for disability and handicap were 0.35 and 0.71, respectively.
Correlations between audiometry, HDHS, HHSS and CSS/PHI
The linear correlations relating the different audiometric descriptors to the individual questions as well as the three components of the HDHS are presented in [Table - 4]. Most correlations are significant, but relationships are weak or moderate. The strongest correlations with the audiometric descriptors are for speech disability. Perceived handicap correlates less well to audiometry. Pure tone audiometry is here found to be a better predictor than SRS-N for most components of the HDHS. Disability in comprehend speech is more correlated to high than to mid frequency HTs, while no such difference is seen in disability to recognise nonspeech sounds, nor for perceived handicap. The strongest correlations with the audiometric descriptors are for speech disability. Moderate correlations are found for all five speech items, the group conversation item 13 correlating the strongest. The two non-speech items, "focusing the door bell" and "the telephone signal" show moderate correlations, the other three items only weak relationships. All handicap items correlate weakly with the audiometric variables. Items 3, 12, 15 and 20 do not correlate with any audiometric predictor, indicating that males with NIHL do not seem to worry about others finding out about their hearing loss. They also neither believe that their NIHL has had any impact on the relations within the family, nor that their NIHL caused tension and tiredness or that other people are avoiding them.
When analysing correlations between the questionnaires HDHS and HHSS, strong correlations were found (handicap/HHSS versus handicap/HDHS: r=0.731, p<0.001; disability/HDHS versus handicap/HDHS: r=0.567, p<0.001; disability/HDHS versus handicap/HHSS: r=0.538, p<0.001). There is a systematic difference between the questionnaires, because the HHSS estimates handicap higher than the HDHS due to the difference in the alternative of the answers. Also a strong correlation was seen between PTA and SRS-N (r=-0.61, p<0.001).
The HDHS in relation to CSS/CPHI, hearing loss and age
Multivariate statistics (GLIM packages) were used to describe disability and perceived handicap as a function of the three communication strategies, hearing loss and age, all variables being defined as continuous ones. For simplicity reasons, the scores for disability to recognise speech and non-speech sounds were averaged to measure disability only, because the speech disability model showed an equal pattern as the model for non-speech disability did.
According to these models, the more severe the hearing loss is and the more frequently the maladaptive and nonverbal communication strategies are used, the more often the person is disabled and perceives himself/herself as handicapped. The maladaptive avoiding coping strategies correlate three times more strongly to handicap and twice as strongly to disability compared to nonverbal coping strategies. Verbal strategies, speech recognition scores in noise and age affected neither disability nor handicap.
| Discussion|| |
This clinical evaluation of the HDHS showed high reliability. Moreover, stronger correlations were found between audiometry and disability than between audiometry and handicap. Furthermore, HDHS had a stronger correlation to pure tone audiometry than to speech audiometry in noise, and a stronger correlation to high frequency hearing than to mid frequency hearing. Finally, HDHS correlated strongly both to the HHSS handicap section and to CPHI/CSS. These results are in accordance with previous studies [Table - 1]. Still, validity for the handicap section has to be questioned, since men with severe NIHL reported that hearing handicap only occurred sometimes. This is contradictory to the clinical rating, to previous reports (Hallberg and Barrenas, 1993;1995) and also to our clinical experience.
Other difficulties in quantifying handicap may be due to poor compliance, because men with NIHL are known to be reluctant to acknowledge their hearing difficulties (Hetu et al.,1990). This behaviour was also described among Swedish hearing impaired workers (Hallberg & Barrenas, 1995), and is in agreement with the present study, clinical experience and with interviews with the men's spouses, who often experienced severe communication problems within the family (Hallberg & Barrenas, 1993). Accordingly, we believe that the HDHS might have underestimated the perceived hearing handicap, rather than that hearing handicap was a minor problem for males with NIHL.
Another assessment problem is that the definition of hearing handicap has been altered in order to elucidate different creators to handicap. Hearing handicap was first defined as the communicative, social and emotional consequences for a hearing-impaired person, such as social isolation, irritation and reduced self-esteem (Stephens & Hetu, 1991). Then as attributed to a deficient environment, including both the social surroundings and the physical milieu (Soder, 1988). Noble and Hetu (1994) defined perceived handicap as the non-auditory consequences of a hearing disability, e.g. the emotional outcome of coping with a demanding auditory situation. From a rehabilitation point of view the change in perspective from focusing on the individual alone to also including the family, the environment and coping is preferable, because the obstacles are more frequently set by the surrounding than by the person himself /herself. Moreover, coping may be improved by auditory rehabilitation programmes.
Communication strategies should be assessed for at least two reasons. Firstly, it has been described that a frequent use of maladaptive strategies, e.g. avoiding interactions or guessing and pretending to understand what is being said, increases perceived handicap. Secondly, to measure the outcome of audiological rehabilitation aimed at increasing use of adaptive strategies. The present data revealed that patients with NIHL used active adaptive strategies more often than the passive maladaptive ones [Table - 2]. In clinical interviews, men with NIHL usually describe that they begin by using adaptive verbal strategies but alter towards more maladaptive behaviours when the verbal strategies are no longer sufficient. They stop asking for repeats, because other people get irritated if one person is interrupting all the time. Even though surrounding people are asked to speak up, colleagues and family members forget to adjust almost immediately. The use of non-verbal and maladaptive strategies allows the person to remain within the group but at the cost of increased handicap, as verified by the present study. It is obvious that hearing disability and perceived hearing handicap is determined by others and by factors outside the control of the hearing impaired person.
When adapting the milieu-related definition of Soder (1988), handicap arises from the interaction between the impaired person and surroundings which are not adjusted to the impairment. Therefore, the significant others are always encouraged to join our audiological rehabilitation programme for men with NIHL (Barrenas, 1998) and be taught how to improve communication and speech intelligibility to reduce handicap, and also what they should not do. Since frequent use of maladaptive and nonverbal strategies correlate with increased hearing handicap, audiological rehabilitation programmes should be aimed at altering such behaviours towards active strategies and also to increase the self-esteem.
The results of the present factor analyses were in accordance with previous results, the factors in this study explaining 61% of the total variance, in Hetu et al. (1994) explaining 58% and in Hallberg (1997) 65%. All studies indicate high reliability for the HDHS, and so does the testretest. In audiological rehabilitation it is necessary to distinguish disability to recognise speech from that of non-speech sounds, since many persons with hearing loss need only technical devices and not hearing aids. For the handicap items, we agree with Hetu et al.,(1994) to use hearing handicap as the overall variable. Accordingly, we see no point in dividing hearing handicap into different factors as suggested by Hallberg (1998), especially not since its informative value is arguable.
The HDHS and HHSS handicap sections correlated strongly, even though the HDHS uses a 4-point response format and not a 5-point or that the HDHS measures handicap by occurrence and not degree. Both occurrence and degree are important aspects from a clinical point of view. However, these differences did not seem to matter, because the HDHS did not correlate more strongly with hearing function than other scales [Table - 1]. It was expected that the SRS-N would influence the HDHS significantly, since the linear correlations were moderate [Table - 4]. However, this relationship disappeared when multivariate statistics were used. Possibly, this was due to the way the SRS-N test was performed. The speech signal was given at the comfort level and not at a fixed level corresponding to every day speech, which could give a more accurate picture of the perceived hearing handicap and also less variability for SRS-N.
The increasing number of questionnaires has not fully clarified the issue of how to estimate hearing disability and handicap. Therefore, the necessity for guidelines of the overall experiences is obvious if the informative value of questionnaires is to be optimised. It is also desired that disability/handicap scales are standardised so that results may be compared. There are good possibilities of making a proper selection of disability items because those items across questionnaires are all very similar, asking how often the person fails to notice the telephone signal, the door bell or speech when talking to several persons in a noisy environment. For selfreports, we recommend the HMS disability items and the CSS/CPHI, because these are the most widely used scales (Noble and Atherley, 1970; Demorest & Erdman, 1987). We also recommend the four handicap items from Luthman et al.,(1987), which address the individual in a more indirect way. Handicap items focusing deep emotions as the HDHS are to be used as a tool for structural interviews and by physicians only. We would like to stress that interviewers should be able to take care of reactions from the patients such as reluctance or personal distress, which may occur when the psychological defences relating to the hearing impairment are elucidated. Otherwise, the information given from the patients may not be accurate. A possibility not discussed previously is that correctly designed questionnaires may be used as tools to increase awareness of the hearing problems and also the use of adaptive behaviour.
| Conclusions|| |
There is a need for questionnaires both for screening and for clinical use, to provide good and valid information about the perceived problems of persons with hearing impairment. While the disability scales are in agreement with clinical experience, most questionnaires have problems with assessing the perceived hearing handicap accurately. This is also the case for the HDHS. To improve the clinical value of the HDHS we recommend that the handicap items are used for structural interviews. It is also important that results from different studies and audiological rehabilitation programmes can be compared. Therefore, we require a consensus concerning the use of hearing disability and handicap scales.
| Acknowledgements|| |
For financial support we are grateful to the Swedish National Board of Health and Welfare and also the regional Health Authority in West Sweden.
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Department of Audiology, Sahlgren's University Hospital, Gröna Stråket 11, S-413 45 Göteborg
[Table - 1], [Table - 2], [Table - 3], [Table - 4]