Objectives Abnormal hearing tests have been noted in HIV-infected patients in several studies, but the nature of the hearing deficit has not been clearly defined. We performed a cross-sectional study of both HIV+ and HIV− individuals in Tanzania using an audiological test battery. We hypothesized that HIV+ adults would have a higher prevalence of abnormal central and peripheral hearing test results compared to HIV− controls. Additionally, we anticipated that the prevalence of abnormal hearing assessments would increase with anti-retroviral therapy (ART) use, and treatment for tuberculosis (TB). Design Pure-tone thresholds, distortion product otoacoustic emissions (DPOAEs), tympanometry, and a gap detection test were performed using a laptop-based hearing testing system on 751 subjects (100 HIV− in the U.S., plus 651 in Dar es Salaam Tanzania including 449 HIV+ [130 ART− and 319 ART+], and 202 HIV−, subjects. No U.S. subjects had a history of TB treatment. In Tanzania, 204 of the HIV+, and 23 of the HIV−, subjects had a history of TB treatment. Subjects completed a video and audio questionnaire about their hearing as well as a health history questionnaire. Results HIV+ subjects had reduced DPOAE levels compared to HIV− subjects, but their hearing thresholds, tympanometry results, and gap detection thresholds were similar. Within the HIV+ group, those on ART reported significantly greater difficulties understanding speech-in-noise, and were significantly more likely to report that they had difficulty understanding speech than the ART− group. The ART+ group had a significantly higher mean gap detection threshold compared to the ART− group. No effects of TB treatment were seen. Conclusions The fact that the ART+/ART− groups did not differ in measures of peripheral hearing ability (DPOAEs, thresholds), or middle ear measures (tympanometry), but that the ART+ group had significantly more trouble understanding speech and higher gap detection thresholds, indicates a central processing deficit. These data suggest that: (a) hearing deficits in HIV+ individuals could be a central nervous system (CNS) side effect of HIV infection, (b) certain ART regimens might produce CNS side effects that manifest themselves as hearing difficulties, and/or (c) some ART regimens may treat CNS HIV inadequately, perhaps due to insufficient CNS drug levels, which is reflected as a central hearing deficit. Monitoring of central hearing parameters could be used to track central effects of either HIV or ART.

Objective To assess the test-retest variability of hearing thresholds obtained with an innovative, mobile wireless automated hearing-test system (WAHTS) with enhanced sound attenuation to test industrial workers at a worksite as compared to standardized automated hearing thresholds obtained in a mobile trailer sound booth. Design A within-subject repeated-measures design was used to compare air-conducted threshold tests (500 to 8000 Hz) measured with the WAHTS in six workplace locations, and a third test using computer-controlled audiometry obtained in a mobile trailer sound booth. Ambient noise levels were measured in all test environments. Study sample Twenty workers served as listeners and 20 workers served as operators. Results On average, the WAHTS resulted in equivalent thresholds as the mobile trailer audiometry at 1000, 2000, 3000 and 8000 Hz and thresholds were within ±5 dB at 500, 4000, and 6000 Hz. Conclusion Comparable performance may be obtained with the WAHTS in occupational audiometry and valid thresholds may be obtained in diverse test locations without the use of sound-attenuating enclosures.

Objectives In our cross-sectional study of human immunodeficiency virus (HIV)-infected adults, we showed lower distortion product otoacoustic emissions (DPOAEs) in HIV+ individuals compared to controls as well as findings consistent with a central auditory processing deficit in HIV+ adults on anti-retroviral therapy. We hypothesized that HIV+ children would also have a higher prevalence of abnormal central and peripheral hearing test results compared to HIV− controls. Design Pure-tone thresholds, DPOAEs, and tympanometry were performed on 244 subjects (131 HIV+, and 113 HIV−, subjects). Thirty-five of the HIV+, and 3 of the HIV−, subjects had a history of tuberculosis treatment. Gap detection results were available for 18 HIV− and 44 HIV+ children. Auditory brainstem response (ABR) results were available for 72 HIV− and 72 HIV+ children. Data from ears with abnormal tympanograms were excluded. Results HIV+ subjects were significantly more likely to have abnormal tympanograms, histories of ear drainage, tuberculosis, or dizziness. All audiometric results were compared between groups using a two-way ANOVA with HIV status and ear drainage history as grouping variables. Mean audiometric thresholds, gap detection thresholds, and ABR latencies did not differ between groups, although the HIV+ group had a higher proportion of individuals with a hearing loss >25 dB HL in the better ear. The HIV+ group had reduced DPOAE levels (p<0.05) at multiple frequencies compared to HIV− subjects. No relationships were found between treatment regimens or delay in starting treatment and audiological parameters. Conclusions As expected, children with HIV+ were more likely to have a history of ear drainage, and to have abnormal tympanograms. Similar to the adult findings, the HIV+ group did not show significantly reduced audiometric thresholds, but did have significantly lower DPOAE magnitudes. These data suggest that: (a) HIV+ children often have middle ear damage which complicates understanding the direct effects of HIV on the hearing system, and (b) even when corrected for confounders DPOAEs were lower in the HIV+ group. Previous studies suggest ototoxicity from anti-retroviral drugs is an unlikely cause of the reduced DPOAE magnitudes. Other possibilities include effects on efferent pathways connecting to outer hair cells or a direct effect of HIV on the cochlea.

Speech communication often takes place in noisy environments; this is an urgent issue for military personnel who must communicate in high-noise environments. The effects of noise on speech recognition vary significantly according to the sources of noise, the number and types of talkers, and the listener's hearing ability. In this review, speech communication is first described as it relates to current standards of hearing assessment for military and civilian populations. The next section categorizes types of noise (also called maskers) according to their temporal characteristics (steady or fluctuating) and perceptive effects (energetic or informational masking). Next, speech recognition difficulties experienced by listeners with hearing loss and by older listeners are summarized, and questions on the possible causes of speech-in-noise difficulty are discussed, including recent suggestions of "hidden hearing loss". The final section describes tests used by military and civilian researchers, audiologists, and hearing technicians to assess performance of an individual in recognizing speech in background noise, as well as metrics that predict performance based on a listener and background noise profile. This article provides readers with an overview of the challenges associated with speech communication in noisy backgrounds, as well as its assessment and potential impact on functional performance, and provides guidance for important new research directions relevant not only to military personnel, but also to employees who work in high noise environments.

Objective: Evidence suggests damage to brain auditory pathways, rather than inner ear damage, underlies the hearing difficulties HIV+ individuals report. But, anti-retroviral therapy (ART) may affect the hearing system and also lead to hearing complaints.Design: Longitudinal study of HIV+ and HIV-individuals in Dar es Salaam Tanzania. A subset of this cohort started ART while in the study allowing the effects of ART to be studied directly. Methods:The ability to hear quiet sounds (pure-tone audiometry), cochlear outer hair cell function (distortion-product otoacoustic emissions (DPOAEs), and gaps-in-noise detection thresholds (a central auditory processing test) were assessed at each visit. Visits were scheduled for 6-month intervals, but the number and spacing of visits varied. In the group that started ART while in the study, 107 HIV+ individuals had audiometric thresholds, 98 had DPOAEs, and 98 had gap measurements suitable for analysis. Data were analyzed using a linear mixed model with time and starting ART as fixed effects and individual subject repeated measures as random effects.Results: Starting ART did not affect audiometric or gap detection thresholds. The slope of the DPOAE amplitude vs. time relationship was more negative after starting ART but did not differ from the HIV-group. Gap thresholds were higher in the HIV+ group.

Understanding speech in noise measured both objectively with the HINT and subjectively with the AIAH was inversely related to cognitive abilities despite a normal ability to hear soft sounds determined by audiometry. Although age was also an important independent factor affecting speech perception, the age relationship within the speech findings in this study may represent more than just age-related declines in speech in noise understanding. Although reliable data on disease duration are not available, the older members of this cohort likely had HIV longer and probably had more severe symptoms at presentation than the younger members because early detection and treatment of HIV in Shanghai has improved over time. Therefore, the age relationship may also include elements of disease duration and severity. Speech perception, especially in challenging listening conditions, involves cortical and subcortical centers and is a demanding neurological task. The problems interpreting speech in noise HIV+ individuals have may reflect HIV-related or HIV treatment-related, central nervous damage, suggesting that CNS complications in HIV+ individuals could potentially be diagnosed and monitored using central auditory tests.

New mobile technology has the potential to influence the development and implementation of OMPs and lower barriers to patient access by providing time efficient, portable and self-administered testing options for use in the clinic and in the patient's home.

Objective: The recent emphasis on outcomes-based medical research has motivated a need for technology that allows researchers and clinicians to reach a larger and more diverse subject population for recruitment and testing. Design: This article reports on open-source mobile software (TabSINT) that enables researchers to administer customised hearing tests and questionnaires on tablets located across multiple sites. Researchers create and modify test protocols using text-based templates and deploy it to the tablets via a cloud-based repository or USB-computer connection. Results are exported locally to the tablet SD card and can also be automatically posted to a cloud-based database. Results: Between 2014 and 2019, TabSINT collected 25,000þ test results using more than 200þ unique test protocols for researchers located worldwide. Conclusions: TabSINT is a powerful software system with the potential to greatly enhance research across multiple disciplines by enabling access to subject cohorts in remote and disparate locations. Released open-source, this software is available to researchers across the world to use and adapt to their specific needs. Researchers with engineering resources can contribute to the repository to extend the capability and robustness of this software.