Hearing impairment is most accurately measured by a clinical pure-tone audiogram. This method is not suitable for large-scale, population-based epidemiological studies as it requires that study participants visit a clinic with trained personnel. An alternative approach to measuring hearing ability is self-estimation through questionnaires, but the correlation to clinical audiometric tests varies.
To evaluate an Internet-based hearing test pilot compared to a question about self-estimated hearing and the feasibility of using an Internet-based hearing test and an Internet-based questionnaire in a population of 560 members of the Swedish Hunters’ Association in the age group 20-60 years.
An invitation was mailed to the participants in March 2007 together with the URL to the study Web site, a personal username, and a password. The Web site included the questionnaire, the hearing test, and instructions for participating in the study. The hearing test resembles a clinical audiogram presenting 6 tones between 500 and 8000 Hz. Tones are presented between 0 and 60 dB, and the participant responds to the tones by pressing the space bar. The hearing test requires headphones and is based on JAVA programming. Before the participant can start the hearing test, it has to be calibrated against a reference person with good hearing between 15 and 35 years of age.
After 5 months, 162 out of 560 (29%) had answered the questionnaire, out of which 88 (16%) had completed the hearing test. Those who actively declined participation numbered 230 out of 560 (41%). After removing duplicates and hearing tests calibrated by unreliable reference data, 61 hearing tests remained for analysis. The prevalence of hearing impairment from the Internet-based hearing test was 20% (12 out of 61), compared to 52% (32 out of 61) from the self-estimated question. Those who completed the hearing test were older than the non-participants, and more had headphones (
Though an Internet-based hearing test cannot replace a clinical pure-tone audiogram conducted by a trained audiologist, it is a valid and useful screening tool for hearing ability in a large population carried out at a low cost.
Hearing loss is one of the most common physical impairments in the western world and is an increasing problem among younger age groups [
Digital technologies provide the possibility of developing computer-based programs for measurement of physical impairment. A number of commercial programs resembling clinical audiograms for measuring hearing are available online [
We have developed an Internet-based hearing test resembling a clinical pure-tone audiogram. The hearing test aims at measuring real-time hearing ability in large-scale epidemiological and clinical studies in the participant’s home environment, using headphones and a home computer. The Internet-based hearing test has been validated against a pure-tone audiogram at the Karolinska University Hospital [
This paper evaluates the pilot study testing the feasibility of collecting epidemiological data on hearing ability using an Internet-based hearing test together with an extensive questionnaire including questions about self-estimated hearing prior to the test. The study is also evaluated in terms of willingness to participate and possible reasons for non-participation, including technical obstacles.
A pilot study was designed to test the feasibility of conducting a large-scale cohort study among more than 200,000 hunters and marksmen from the Swedish population. The larger study aims at studying the relationship between noise-induced hearing loss, exposure to heavy gun shots, and the use of hearing protection.
The participants enter the study through a Web site that includes a Web-based questionnaire and an Internet-based hearing test. To enter the Web page, the participant enters a personal username and password. The participants cannot access the hearing test before filling in the questionnaire. The questionnaire includes 12 sections with, in total, approximately 100 questions regarding background, hunting, self-estimated hearing, occupation, military service, problems with hearing, medications, and recreational activities. The question about self-estimated hearing was stated as, “How is your hearing?”, and the optional answers were “good”, “minor hearing loss”, “moderate hearing loss”, or “severe hearing loss”.
The hearing test is based on JAVA 5.0, and before the participants can start the hearing test, they are instructed to verify whether or not the computer has the correct version of the JAVA program. If not, the JAVA program can be downloaded free of charge. Before the participants can start the hearing test, the sound levels are calibrated against a reference person to compensate for variations in different headphones and noise interference from the computer and surroundings. Prior to the calibration test, the participant and the reference person are instructed to follow guidelines on how to set correct volume settings on the computer as well as using the headphones. In the following calibration phase, the reference person enters age (preferably between 14 and 35 years) and gender. The reference person is presented with a volume slider having a fine-tuned scale ranging over 30 dB. The reference person is instructed to move the slide head to a barely audible position, which is the reference hearing level (RefHL) for the frequency, and then request the program to present the next tone. The tone is a frequency-modulated sinus tone—a slightly vibrating tone which can be heard on headphones having “dead points” at certain pure frequencies. This tone is presented to both ears to get the lowest hearing threshold for each ear. The procedure starts from 500 Hz and is repeated for 1000 Hz, 2000 Hz, 4000 Hz, 6000 Hz, and 8000 Hz.
Quality check of the calibration of the RefHL data is performed on the finalized data. It is limited to a maximum check of a 15 dB difference over the frequencies, along with a check of whether the reference person has moved the volume slider for each frequency.
During the hearing test, intensity levels are presented between 0 (from reference calibration) and 60 dB sound pressure level (dBSPL). The hearing test starts by presenting the 500 Hz tone to the left ear for 1 second at 30 dBRefHL, which is 30 dB higher than the hearing threshold set by the reference person for that frequency. The tone is followed by a shorter pause of random length to discourage the participant from guessing. The participant presses the space bar on the computer keyboard to register that a tone is heard. The key press is accepted as registering a threshold if the key is pressed within the presented tone timeframe, adjusted for the human reaction time. If the space bar is pressed half a second after the accepted timeframe, it is registered as too late and considered “imagined”. This is not accepted as a threshold measure. When a tone is registered as heard, the test presents the same frequency at a 6 dB lower intensity level. When a tone is not heard, the test instead presents a tone at a 6 dB higher intensity level. The test proceeds for both left and right ears to settle the hearing levels for each frequency. This test procedure is a Web adaptation of established clinical audiometric testing and follows the guidelines for clinical audiometric testing [
After completing the test, the participant is shown an audiogram presenting the hearing levels for both ears at each measured frequency.
In March 2007, an invitation letter was sent to 560 members of the Swedish Hunters’ Association. Subjects were selected proportionally to the distribution among the members in terms of gender (men = 500, women = 60) and age (in the age group 20-60). The mailed invitation included a description of the study and a personal username and password. The invitation also included a prepaid return letter which the participants could use to decline participation. This letter included a voluntary question about their reason for non-participation. The data collection was closed in August 2007. During the study, 2 paper reminders were sent, followed by a telephone reminder. The first reminder was sent 3 weeks after the initial invitation, followed by a second reminder after an additional 3 weeks and a telephone reminder 3 weeks after the second paper reminder. During the telephone reminder, those who declined participation were asked about the reason for their non-participation. Reminders were sent to subjects who had not yet completed the questionnaire and hearing test without declining participation, and to those who had answered the questionnaire but not completed the hearing test.
The audiometric data from the hearing test was classified according to the definition by WHO for normal hearing, minor hearing loss, moderate hearing loss, and severe hearing loss [
The study procedure is described with respect to the compliance and dropout at different checkpoints throughout the study (
After 3 reminders, 162 out of 560 (29%) had completed the questionnaire (questionnaire respondents), of which 88 (16%) had completed the hearing test (full respondents). After reminders 1 and 2, 146 had actively declined participation, and an additional 84 declined participation during the telephone reminder (total 230, 41% of the total sample). There were 154 individuals who could not be reached or did not contact the study center for non-participation, and 14 participants entered the password without completing the study. A flowchart of the participation scheme is presented in
Flowchart of participation in the pilot study for evaluating an Internet-based hearing test among 560 members of the Swedish Hunters’ Association
In total, 126 hearing tests were carried out by 88 unique participants. Among the duplicates, the test with the best (eg, smallest degree of hearing loss) result was used in the analysis. After removal of those hearing tests with an incorrect reference, 61 hearing tests remained for which the mean age was 45 years. Results of the hearing test in comparison to the self-estimated hearing question are shown in
On the self-estimated hearing question, 32 out of 61 (52%) reported hearing loss; 12 of those 61 (20%) showed hearing loss on the Internet-based hearing test. The Chi-Square test shows this difference to be statistically significant (
Correlation of hearing test to the self-estimated hearing question (61 individuals)
Self-estimated hearing loss, 1 question | |||||||
No | Minor | Moderate | Severe | ||||
Hearing test | |||||||
No | 27 (55%) |
21 (43%) |
1 (2%) |
- | 49 (80%) | ||
Minor | 2 (29%) |
3 (43%) |
2 (29%) |
- | 7 (11%) | ||
Moderate | - | 1 (25%) |
3 (75%) |
- | 4 (7%) | ||
Severe | - | - | 1 (100%) |
- | 1 (2%) | ||
29 (48%) | 25 (41%) | 7 (11%) | - | 61 |
The distribution of gender was similar in all groups of respondents, the original sample, declined participants, and non-respondents (
Common reasons for declining participation were lack of time (17%), lack of interest in the study (35%), lack of headphones (13%) (which reflects a difference between questionnaire respondents and full respondents), having no experience of gunshots or hunting, or already experiencing hearing loss and therefore considering themselves to be inappropriate for the study (
Distribution of age and gender among all participants in the pilot study for evaluating an Internet-based hearing test among 560 members of the Swedish Hunters’ Association
Non- |
Declined |
Drop outs/ |
Answered |
Hearing test and questionnaire |
Total |
|
|
||||||
Men | 138 (90%) | 200 (87%) | 13 (93%) | 68 (92%) | 81 (92%) | 500 (89%) |
Women | 16 (10%) | 30 (13%) | 1 (7%) | 6 (8%) | 7 (8%) | 60 (11%) |
|
||||||
20-34 | 51 (33%) | 57 (25%) | 3 (21%) | 17 (23%) | 17 (19%) | 145 (26%) |
35-49 | 63 (41%) | 110 (48%) | 7 (50%) | 35 (47%) | 39 (44%) | 254 (45%) |
50-60 | 40 (26%) | 63 (27%) | 4 (29%) | 22 (30%) | 32 (36%) | 161 (29%) |
Sociodemographic characteristics among questionnaire respondents and full respondents for evaluating an Internet-based hearing test among questionnaire and full responders
Answered questionnaire only |
Hearing test and questionnaire |
Pearson’s Chi-Square |
|
|
|
||||
Men | 68 (92%) | 81 (92%) | 0.001 | 0.97 |
Women | 6 (8%) | 7 (8%) | ||
|
||||
20-34 | 17 (23%) | 17 (19%) | 0.86 | 0.65 |
35-49 | 35 (47%) | 39 (44%) | ||
50-60 | 22 (30%) | 32 (36%) | ||
|
||||
1 | 12 (16%) | 6 (7%) | 5.20 | 0.16 |
2 | 26 (35%) | 27 (31%) | ||
3-4 | 31 (42%) | 43 (54%) | ||
5-6 | 5 (7%) | 11 (69%) | ||
Missing | 1 (1%) | |||
|
||||
Preschool | 9 (12%) | 9 (10%) | 1.03 | 0.80 |
High School | 30 (41%) | 34 (39%) | ||
College/ |
35 (47%) | 43 (49%) | ||
Missing | 2 (2%) | |||
|
||||
Large city | 10 (13%) | 8 (10%) | 2.50 | 0.64 |
Suburb | 11 (15%) | 9 (10%) | ||
Medium-sized city | 10 (14%) | 14 (16%) | ||
Small town | 14 (19%) | 23 (26%) | ||
Countryside | 29 (39%) | 33 (38%) | ||
Missing | 1 (1%) | |||
|
||||
Yes | 23 (31%) | 44 (50%) | 7.31 | 0.007 |
No | 51 (69%) | 40 (45%) | ||
Missing | 4 (5%) | |||
|
||||
Yes | 73 (99%) | 86 (98%) | 0.19 | 0.66 |
No | 1 (1%) | 2 (3%) | ||
|
||||
Yes | 48 (39%) | 74 (60%) | 8.88 | 0.003 |
No | 26 (61%) | 13 (30%) | ||
Missing | 1 (1%) | |||
|
||||
No loss | 44 (59%) | 39 (44%) | 7.35 | 0.06 |
Minor loss | 18 (24%) | 35 (40%) | ||
Moderate loss | 8 (24%) | 12 (14%) | ||
Severe loss | 4 (5%) | 1 (1%) | ||
Missing | 1 (1%) |
Reasons for declining participation in the pilot study for evaluating an Internet-based hearing test among 560 members of the Swedish Hunters’ Association
Non-participation Reason | After paper reminders 1 and 2 |
After telephone reminder |
Total |
Have hearing loss prior study | 5 (3%) | 1 (1%) | 6 (3%) |
Have no computer | 7 (5%) | 10 (12%) | 17 (7%) |
Have no headphones | 27 (18%) | 4 (5%) | 31 (13%) |
Have no reference | 3 (2%) | 1 (1%) | 4 (2%) |
Don’t trust technique | 3 (2%) | - | 3 (1%) |
Not interested | 62 (42%) | 19 (23%) | 81 (35%) |
Have no time | 13 (9%) | 26 (31%) | 39 (17%) |
No experience of hunting | 17 (12%) | 15 (18%) | 32 (14%) |
Computer problem | 5 (3%) | 8 (10%) | 13 (7%) |
Other | 4 (3%) | - | 4 (2%) |
This study evaluates an Internet-based hearing test in terms of its agreement to self-estimated hearing assessed by a question in a questionnaire and willingness to participate. Statistically, the results from the hearing test and the self-estimated hearing were significantly different (
The study also aims at evaluating the willingness to take part in a study including a Web-based questionnaire and an Internet-based hearing test. Our study had a response rate of 29% to the questionnaire and 16% to the hearing test, which is low for an epidemiological study. Full respondents were slightly older than the average non-participant, which might indicate that the older age group had a keener interest in the study. This was expected, as hearing decreases with age.
There were no differences between questionnaire respondents and full respondents in terms of sociodemographic characteristics and self-estimated hearing, where the full respondents were a representative sample of the total respondents. The full respondents had, however, greater access to headphones and already possessed the correct version of JAVA prior to the test more often than did the questionnaire respondents. The low response rate might therefore be due to the technique and the many steps prior to the test (including the need for acquiring headphones, JAVA, and a reference person), rather than personal characteristics. One concern prior to the study was computer and Internet knowledge among the study participants, but Internet use in Sweden is among the highest in the world. In Sweden, 96% of the population can access the Internet from their homes [
One of the major problems of this study was the calibration and especially the quality of the reference data, as many of the respondents seemed to use a reference person with unreliable hearing. The ability to test the hearing of the reference person is limited. Other Internet-based hearing tests have used a reference tone or a specific program for calibrating the zero level [
For the large-scale study, the calibration technique will be redesigned to measure the reference threshold twice in order to get more reliable values and to better judge that a reference is suitable (hearing loss estimated to be less than 15 dB). Also, the reference person will be asked to answer a couple of questions regarding hunting experience and perceived hearing in order to detect potential bias.
Hearing impairment is a growing problem and can occur at all ages. Causes include repetitive exposure to loud sounds, or other external noises [
Though the Internet-based hearing test cannot replace an audiogram from a clinical pure-tone audiometer conducted by a trained audiologist, it is a more useful and objective tool for screening hearing in a large population than a self-estimated hearing questionnaire.
The study was supported by a grant from the Swedish Research Council.
None declared.
Java technology was created as a computer programming tool at Sun Microsystems in 1991
decibel
dB reference hearing level
dB sound pressure level
Hertz
Uniform Resource Locator
World Health Organization