Analysis of data from the International Outcome Inventory for Hearing Aids (IOI-HA) using Bayesian Item Response Theory.

OBJECTIVE: IOI-HA response data are conventionally analysed assuming that the ordinal responses have interval-scale properties. This study critically considers this assumption and compares the conventional approach with a method using Item Response Theory (IRT). DESIGN: A Bayesian IRT analysis model was implemented and applied to several IOI-HA data sets. STUDY SAMPLE: Anonymised IOI-HA responses from 13273 adult users of one or two hearing aids in 11 data sets using the Australian English, Dutch, German and Swedish versions of the IOI-HA. RESULTS: The raw ordinal responses to IOI-HA items do not represent values on interval scales. Using the conventional rating sum as an overall score introduces a scale error corresponding to about 10 - 15% of the true standard deviation in the population. Some interesting and statistically credible differences were demonstrated among the included data sets. CONCLUSIONS: It is questionable to apply conventional statistical measures like mean, variance, t-tests, etc., on the raw IOI-HA ratings. It is recommended to apply only nonparametric statistical test methods for comparisons of IOI-HA results between groups. The scale error can sometimes cause incorrect conclusions when individual results are compared. The IRT approach is recommended for analysis of individual results.

International Outcome Inventory for Hearing Aids: Data From a Large Swedish Quality Register Database.

PURPOSE: The purpose of this study was to analyze a database of completed International Outcome Inventory for Hearing Aids (IOI-HA) questionnaires obtained from over 100,000 clients fitted with new hearing aids in Sweden during the period of 2012-2016. Mean IOI-HA total scores were correlated with degree of hearing loss, unilateral versus bilateral fitting, first-time versus return clients, gender, and variation among dispensing clinics. The correlations with expectations, service quality, and technical functioning of the hearing aids were also analyzed. METHOD: Questionnaires containing the 7 IOI-HA items as well as questions concerning some additional issues were mailed to clients 3-6 months after fitting of new hearing aids. The questionnaires were returned to and analyzed by an independent research institute. RESULTS: More than 100 dispensing clinics nationwide take part in this project. A response rate of 52.6% resulted in 106,631 data sets after excluding incomplete questionnaires. Forty-six percent of the responders were women, and 54% were men. The largest difference in mean score (0.66) was found for the IOI-HA item "use" between return clients and first-time users. Women reported significantly higher (better) scores for the item "impact on others" compared with men. The bilaterally fitted subgroup reported significantly higher scores for all 7 items compared with the unilaterally fitted subgroup. Experienced users produced higher scores on benefit and satisfaction items, whereas first-time users gave higher scores for residual problems. No correlation was found between mean IOI-HA total score and average hearing threshold level (pure-tone average [PTA]). Mean IOI-HA total scores were found to correlate significantly with perceived service quality of the dispensing center and with the technical functionality of the hearing aids. CONCLUSIONS: When comparing mean IOI-HA total scores from different studies or between groups, differences with regard to hearing aid experience, gender, and unilateral versus bilateral fitting have to be considered. No correlation was found between mean IOI-HA total score and degree of hearing loss in terms of PTA. Thus, PTA is not a reliable predictor of benefit and satisfaction of hearing aid provision as represented by the IOI-HA items. Identification of a specific lower fence in PTA for hearing aid candidacy is therefore to be avoided. Large differences were found in mean IOI-HA total scores related to different dispensing centers.

Bridging the Gap Between Hearing Screening and Successful Rehabilitation: Research Protocol of a Randomized Controlled Trial of Motivational Interviewing via Internet.

PURPOSE: Studies point to low help-seeking after a failed hearing screening. This research forum article presents the research protocol for a randomized controlled trial of motivational interviewing via the Internet to promote help-seeking in people who have failed an online hearing screening. METHOD: Adults who fail a Swedish online hearing screening, including a speech-in-noise recognition test, will be randomized to either an intervention group (participating in motivational interviewing) or an active control group (reading a book on history of hearing aids). Both of the conditions will be delivered via the Internet. The primary outcome is experience with seeking health care and using hearing aids 9 months after the intervention. Secondary outcomes are changes in before and after measures of self-reported hearing difficulties, anxiety, depression, and quality of life. Stages of change and self-efficacy in hearing help-seeking are measured immediately after intervention and at a 9-month follow-up for the purpose of mediation analysis. RESULTS: The results of this randomized controlled trial may help bridge the gap between hearing screening and successful hearing rehabilitation. CONCLUSION: Although no large instantaneous benefits are expected, a slow change toward healthy behaviors­seeking health care and using hearing aids­would shed light on how to use the Internet to assist people with hearing impairment.

Internet-based hearing screening using speech-in-noise: validation and comparisons of self-reported hearing problems, quality of life and phonological representation.

OBJECTIVES: For the last decade a host of different projects have been launched to allow persons who are concerned about their hearing status to quickly and at a low cost test their hearing ability. Most often, this is carried out without collecting complementary information that could be correlated with hearing impairment. In this two-part study we first, present the development and validation of a novel Internet-based hearing test, and second, report on the associations between this test and phonological representation, quality of life and self-reported hearing difficulties. DESIGN: Cross-sectional study. SETTING: An opportunity sample of participants was recruited at the Stockholm central station for the first study. All parts of the second study were conducted via the Internet, with testing and self-report forms adapted for online use. PARTICIPANTS: The first part of the study was carried out in direct contact with the participants, and participants from the second study were recruited by means of advertisements in newspapers and on webpages. The only exclusion criterion was that participants had to be over 18 years old. Most participants were between 60 and 69 years old. There were almost an equal number of men and women (total n=316). OUTCOME MEASURES: 48 participants failed the Internet-based hearing screening test. The group failing the test reported more problems on the Amsterdam Inventory of Auditory Disability. In addition, they were found to have diminished phonological representational skills. However, no difference in quality of life was found. CONCLUSIONS: Almost one in five participants was in need of contacting their local hearing clinic. This group had more complaints regarding tinnitus and hyperacusis, rated their own hearing as worse than those who passed, and had a poorer capability of generating accurate phonological representations. This study suggests that it is feasible to screen for hearing status online, and obtain valid data.

Hearing-aid automatic gain control adapting to two sound sources in the environment, using three time constants.

A hearing aid AGC algorithm is presented that uses a richer representation of the sound environment than previous algorithms. The proposed algorithm is designed to (1) adapt slowly (in approximately 10 s) between different listening environments, e.g., when the user leaves a single talker lecture for a multi-babble coffee-break; (2) switch rapidly (about 100 ms) between different dominant sound sources within one listening situation, such as the change from the user's own voice to a distant speaker's voice in a quiet conference room; (3) instantly reduce gain for strong transient sounds and then quickly return to the previous gain setting; and (4) not change the gain in silent pauses but instead keep the gain setting of the previous sound source. An acoustic evaluation showed that the algorithm worked as intended. The algorithm was evaluated together with a reference algorithm in a pilot field test. When evaluated by nine users in a set of speech recognition tests, the algorithm showed similar results to the reference algorithm.

An efficient robust sound classification algorithm for hearing aids.

An efficient robust sound classification algorithm based on hidden Markov models is presented. The system would enable a hearing aid to automatically change its behavior for differing listening environments according to the user's preferences. This work attempts to distinguish between three listening environment categories: speech in traffic noise, speech in babble, and clean speech, regardless of the signal-to-noise ratio. The classifier uses only the modulation characteristics of the signal. The classifier ignores the absolute sound pressure level and the absolute spectrum shape, resulting in an algorithm that is robust against irrelevant acoustic variations. The measured classification hit rate was 96.7%-99.5% when the classifier was tested with sounds representing one of the three environment categories included in the classifier. False-alarm rates were 0.2%-1.7% in these tests. The algorithm is robust and efficient and consumes a small amount of instructions and memory. It is fully possible to implement the classifier in a DSP-based hearing instrument.