Swedish hunters get online hearing test

Doctors from the Swedish university Karolinska Institute have developed a new internet-based hearing test that has been trialled on Swedish hunters.

The benefits of the online tool, which can be used on a home PC, have been proven in an initial pilot study, and is now being tested in a study of 20,000 Swedish hunters and gun enthusiasts.

“We have developed an internet based hearing test resembling a clinical pure tone audiogram”, says lead researcher Christin Bexelius who has just published the results of the study in the current issue of the Journal of Medical Internet Research. “The hearing test aims at measuring real time hearing ability in the home environment, using headphones and a home computer.”

In a validation study, Bexelius and colleagues showed that the internet based test correlates reasonably well with the gold standard in diagnosing hearing loss, the pure tone audiogram in the controlled environment of a test laboratory.

The new test reached a specificity of 96% compared to the clinical audiogram. This means that only one out of 25 patients with a suspected hearing loss in the internet based test did not have a pathological pure tone audiogram in a controlled environment.

The current pilot study now aims to analyse whether the internet based test was suitable for screening programmes, for example in the context of epidemiological studies. “The study was designed to test the feasibility of conducting a large scale cohort study among more than 20,0000 hunters and marksmen from the Swedish population”, said Bexelius.

This large study will look at the relationship between noise-induced hearing loss, exposure to gun shots, and use of hearing protection devices.

The initial pilot study was conducted among 560 members of the Swedish Hunter’s Association. They were invited to visit the website with the hearing test. The site contained a standard questionnaire for self estimated evaluation of possible hearing problems, and the online audiogram as a second screening tool.

After up to three reminders, a total of 162 hunters answered the questionnaire. Eighty-eight of them also finished the hearing test. In the end, 61 audiograms were available for analysis, because some audiograms were not adequately calibrated and some were duplicates.

The researchers found that the results of the self estimated hearing questionnaire and the results of the online audiogram diverged considerably. In the self estimated hearing questionnaire, 32 out of 61 patients (52%) showed a pathological result indicating possible hearing loss.

In the online audiogram, in contrary, “only” twelve hunters (or 20%) performed pathologically. “These results could indicate an underestimation of hearing ability and display the difficulty of evaluating a self estimated hearing impairment”, says Bexelius.

Apart from reducing over diagnosis, the online test also managed to identify a remarkably high number of hunters with hearing loss who did not show any abnormalities in the questionnaire at all. “Among those who had a hearing impairment according to the internet-based hearing test, six out of twelve or fifty per cent, had classified their hearing differently in the self estimated question”, Bexelius stresses.

The researchers conclude that an online audiogram is suitable for screening purposes within clinical or epidemiological studies like the large hunter study planned in Sweden. Among the difficulties is calibration, though. For the larger study, the calibration technique will be redesigned in order to reduce errors.

Link

JMIR

Bexelius C, Honeth L, Ekman A, Eriksson M, Sandin S, Bagger-Sjöbäck D, Litton J Evaluation of an Internet-Based Hearing Test—Comparison with Established Methods for Detection of Hearing Loss J Med Internet Res 2008;10(4):e32