Background South Korea has one of the world’s fastest aging populations and is witnessing increased age-related hearing impairment cases as well as an increase in the number of hearing aid users. The aim of this study was to analyze complications caused by hearing aid mold materials. In addition, we hope to raise awareness of the harm and danger that inexperienced hearing aid providers can cause to patients. Methods We retrospectively reviewed the medical records of 11 patients who were diagnosed with hearing aid mold material as a foreign body in the ear at a tertiary center between 2016 and 2020. The following data were analyzed: symptoms, endoscopic findings, audiometry, temporal bone CT images, treatment methods, and complications after removal. The currently available literature was also reviewed to develop clinical guidelines, to identify the systematic weaknesses in the South Korean hearing aid market, and to identify policies that warrant better quality control. Results Among the 11 cases, 9 were restricted to the external auditory canal, all of which were successfully removed under endoscopy with minor complications. Two cases with middle ear involvement resulted in infection and thus required surgical removal with mastoidectomy. The average age of these patients was 76.4, and all patients received their molding procedure at private hearing aid shops without an otolaryngologist’s examination. Conclusion Thorough patient history-taking and otologic examination must be performed to identify patients at higher risk of complications. Such patients should be referred to an otolaryngologist. If a patient exhibits alarming symptoms, early referral is critical since prompt surgery can minimize complications. A CT scan is highly recommended to determine an optimal approach for foreign body removal. Systematic and regulatory changes in hearing aid dispensers, such as requiring apprenticeship, raising the required level of education, and legally mandating referrals, can help reduce these complications.

Spatial hearing, which largely relies on binaural time/level cues, is a challenge for patients with asymmetric hearing. The degree of the deficit is largely variable, and better sound localization performance is frequently reported. Studies on the compensatory mechanism revealed that monaural level cues and monoaural spectral cues contribute to variable behavior in those patients who lack binaural spatial cues. However, changes in the monaural level cues have not yet been separately investigated. In this study, the use of the level cue in sound localization was measured using stimuli of 1 kHz at a fixed level in patients with single-sided deafness (SSD), the most severe form of asymmetric hearing. The mean absolute error (MAE) was calculated and related to the duration/age onset of SSD. To elucidate the biological correlate of this variable behavior, sound localization ability was compared with the cortical volume of the parcellated auditory cortex. In both SSD patients (n = 26) and normal controls with one ear acutely plugged (n = 23), localization performance was best on the intact ear side; otherwise, there was wide interindividual variability. In the SSD group, the MAE on the intact ear side was worse than that of the acutely plugged controls, and it deteriorated with longer duration/younger age at SSD onset. On the impaired ear side, MAE improved with longer duration/younger age at SSD onset. Performance asymmetry across lateral hemifields decreased in the SSD group, and the maximum decrease was observed with the most extended duration/youngest age at SSD onset. The decreased functional asymmetry in patients with right SSD was related to greater cortical volumes in the right posterior superior temporal gyrus and the left planum temporale, which are typically involved in auditory spatial processing. The study results suggest that structural plasticity in the auditory cortex is related to behavioral changes in sound localization when utilizing monaural level cues in patients with SSD.

Objectives: To train participants to localize sound using virtual reality (VR) technology, appropriate auditory stimuli that contain accurate spatial cues are essential. The generic head-related transfer function (HRTF) that grounds the programmed spatial audio in VR does not reflect individual variation in monaural spatial cues, which is critical for auditory spatial perception in patients with single-sided deafness (SSD). As binaural difference cues are unavailable, auditory spatial perception is a typical problem in the SSD population that warrants intervention. This study assessed the applicability of binaurally recorded auditory stimuli in VR-based training for sound localization in SSD patients. Methods: Sixteen subjects with SSD and thirty-eight normal-hearing controls (NHs) underwent VR-based training for sound localization and were assessed three weeks after completing training. The VR program incorporated prerecorded auditory stimuli created individually in the SSD group and over an anthropometric model in the NH group. Results: Sound localization performance revealed significant improvement in both groups after training, with retained benefits lasting for an additional three weeks. Subjective improvements in spatial hearing were confirmed in the SSD group. Conclusion: By examining individuals with SSD and NH, VR-based training for sound localization that used binaurally recorded stimuli, measured individually was presented as effective and beneficial. Furthermore, VR-based training does not require sophisticated instruments or setups. These results suggest that this technique represents a new therapeutic treatment for impaired sound localization.

This paper examines the response of 10 typical and 10 autism spectrum participants in their reaction to a set of uniand multisensory warning signals designed to indicate different levels of urgency. The warnings were composed of auditory, visual and tactile signals that were presented alone or in combination. Two experiments were conducted, a first that examined perceived urgency and annoyance with the warnings and a second that used a driving simulator scenario to explore recognition of the level of urgency and the speed of response. Results of Experiment 1 showed that there was no difference between groups in the perceived urgency of the warning signals, though the autism spectrum group reported less annoyance with the signals. Results of Experiment 2 showed that while both groups showed high accuracy in correctly reporting urgency level, the autism spectrum group performed better. Moreover, the fastest overall reaction times obtained were by the autism spectrum group when the warning included a visual component, with vision alone producing the quickest response. These results provide novel empirical insights on behaviour of drivers with autism when exposed to multimodal driver displays. They also highlight how consideration of characteristics of individual differences can contribute to the design of effective warning signals.