The Effects of Signal to Noise Ratio, T60 , Wide-Dynamic Range Compression Speed, and Digital Noise Reduction in a Virtual Restaurant Setting.

OBJECTIVES: Hearing aid processing in realistic listening environments is difficult to study effectively. Often the environment is unpredictable or unknown, such as in wearable aid trials with subjective report by the wearer. Some laboratory experiments create listening environments to exert tight experimental control, but those environments are often limited by physical space, a small number of sound sources, or room absorptive properties. Simulation techniques bridge this gap by providing greater experimental control over listening environments, effectively bringing aspects of the real-world into the laboratory. This project used simulation to study the effects of wide-dynamic range compression (WDRC) and digital noise reduction (DNR) on speech intelligibility in a reverberant environment with six spatialized competing talkers. The primary objective of this study was to determine the efficacy of WDRC and DNR in a complex listening environment using virtual auditory space techniques. DESIGN: Participants of greatest interest were listeners with hearing impairment. A group of listeners with clinically normal hearing was included to assess the effects of the simulation absent the complex effects of hearing loss. Virtual auditory space techniques were used to simulate a small restaurant listening environment with two different reverberation times (0.8 and 1.8 sec) in a range of signal to noise ratios (SNRs) (-8.5 to 11.5 dB SNR). Six spatialized competing talkers were included to further enhance realism. A hearing aid simulation was used to examine the degree to which speech intelligibility was affected by slow and fast WDRC in conjunction with the presence or absence of DNR. The WDRC and DNR settings were chosen to be reasonable estimates of hearing aids currently available to consumers. RESULTS: A WDRC × DNR × Hearing Status interaction was observed, such that DNR was beneficial for speech intelligibility when combined with fast WDRC speeds, but DNR was detrimental to speech intelligibility when WDRC speeds were slow. The pattern of the WDRC × DNR interaction was observed for both listener groups. Significant main effects of reverberation time and SNR were observed, indicating better performance with lower reverberation times and more positive SNR. CONCLUSIONS: DNR reduced low-amplitude noise before WDRC-amplified the low-intensity portions of the signal, negating one potential downside of fast WDRC and leading to an improvement in speech intelligibility in this simulation. These data suggest that, in some real-world environments that include both reverberation and noise, older listeners with hearing impairment may find speech to be more intelligible if DNR is activated when the hearing aid has fast compression time constants. Additional research is needed to determine the appropriate DNR strength and to confirm results in wearable hearing aids and a wider range of listening environments.

From skillful to empathic: evaluating shifts in medical students' perceptions of surgeons through a combined patient as teacher and arts-based reflection program.

Introduction: The purpose of this study was to identify whether the incorporation of a combined Patient as teacher (PAT) and arts-based reflection (ABR) program during a surgical clerkship rotation could influence more humanistic perceptions of surgeons, using an innovative evaluation approach. Methods: A novel, single question evaluation tool was created. Third year medical-students were asked to "list the top 5 attributes of a surgeon, in order of perceived importance" both before and after their surgical clerkship rotations and participation in the PAT/ABR program. Attributes identified by students were coded as either "humanistic" or "non-humanistic," which were then analyzed using generalized linear regression models under a Bayesian framework. Results: After participation in the PAT/ABR program, the predicted probability of students ranking a humanistic characteristic as the most important attribute of a surgeon had increased by 17%, and the predicted probability of students ranking a humanistic characteristic amongst their top three attributes for a surgeon had increased by 21%. Conclusion: This innovative evaluative method suggested the success of a combined PAT/ABR program in encouraging a humanistic perspective of surgery and this approach could potentially be explored to evaluate other humanistic education initiatives.

Introduction: L'objectif de cette étude était de déterminer si l'introduction d'une nouvelle approche d'évaluation associant la participation de Patients comme enseignants (PCE) à une Réflexion basée sur les arts (RBA) dans un stage d'externat en chirurgie permettait de mieux percevoir les qualités humanistes chez les chirurgiens. Méthodes: Un nouvel outil d'évaluation à question unique a été créé. Des étudiants en troisième année de médecine ont été invités à ''énumérer les cinq principaux attributs d'un chirurgien, par ordre d'importance perçue'', avant et après leur stage d'externat en chirurgie et le programme PCE/RBA. Les attributs identifiés par les étudiants ont été codés comme « humanistes ¼ ou « non humanistes ¼, puis analysés à l'aide de modèles de régression linéaire généralisée dans un cadre bayésien. Résultats: Après leur participation au programme PCE/RBA, la probabilité prédite moyenne que les étudiants classent un trait humaniste comme l'attribut le plus important d'un chirurgien a augmenté de 17 %, et la probabilité prédite que les étudiants classent un trait humaniste parmi les trois premiers attributs d'un chirurgien a augmenté de 21 %. Conclusion: Cette méthode d'évaluation innovante porte à croire que le programme PCE/RBA réussit en effet à favoriser une vision humaniste de la chirurgie. Cette approche peut être explorée pour évaluer d'autres activités de formation axées sur l'humanisme.

Effectiveness of Life Goal Framing to Motivate Medical Students During Online Learning: A Randomized Controlled Trial.

Introduction: Educators need design strategies to support medical students' motivation in online environments. Prompting students to frame a learning activity as preparing them to attain their life goals (e.g., helping others) via their clinical practice, a strategy called 'life goal framing', may enhance their autonomous motivation, learning strategy use, and knowledge retention. However, for students with low perceived competence for learning (PCL), life goal framing may have an adverse effect. A randomized controlled trial was conducted to test the effectiveness of life goal framing and the moderating effect of students' PCL. Methods: First- and second-year medical students across four Canadian universities (n = 128) were randomized to receive a version of an online module with an embedded prompt for life goal framing, or one without. Students' motivation, learning strategy use, and knowledge retention were assessed. Differences between conditions on each outcome were estimated using Bayesian regression. Results: Students' PCL was a moderator for autonomous motivation but no other outcomes. The prompt did not have a statistically significant effect on any outcome, even for learners with high PCL, except for a small effect on link-clicking behaviour. Discussion: The results of this study suggest that learners' autonomous motivation is influenced by how they make meaning of instruction in terms of their future life goals and their present confidence. We cannot recommend life goal framing as an effective design strategy at this point, but we point to future work to increase the benefit of life goal framing for learners with high confidence.

Motivational Design for Web-Based Instruction in Health Professions Education: Protocol for a Systematic Review and Directed Content Analysis.

BACKGROUND: Web-based instruction plays an essential role in health professions education (HPE) by facilitating learners' interactions with educational content, teachers, peers, and patients when they would not be feasible in person. Within the unsupervised settings where web-based instruction is often delivered, learners must effectively self-regulate their learning to be successful. Effective self-regulation places heavy demands on learners' motivation, so effective web-based instruction must be designed to instigate and maintain learners' motivation to learn. Models of motivational design integrate theories of motivation with design strategies intended to create the conditions for motivated engagement. Teachers can use such models to develop their procedural and conceptual knowledge in ways that help them design motivating instruction in messy real-world contexts. Studies such as randomized controlled trials (RCTs) and other quasi-experimental designs that compare different motivational design strategies play a critical role in advancing models of motivational design. Synthesizing the evidence from those studies can identify effective strategies and help teachers and researchers understand the mechanisms governing why strategies work, for whom, and under what circumstances. OBJECTIVE: The planned review aims to analyze how studies comparing motivational design strategies for web-based instruction in HPE support and advance models of motivational design by (1) controlling for established risks to internal validity, (2) leveraging authentic educational contexts to afford ecological validity, (3) drawing on established theories of motivation, (4) investigating a wide breadth of motivational constructs, and (5) analyzing mediators and moderators of strategy effects. METHODS: The planned review will use database searching, registry searching, and hand searching to identify studies comparing motivational design strategies for web-based instruction, delivered to learners in HPE. Studies will be considered from 1990 onward. Two team members will independently screen studies and extract data from the included studies. During extraction, we will record information on the design characteristics of the studies, the theories of motivation they are informed by, the motivational constructs they target, and the mediators and moderators they consider. RESULTS: We have executed our database and registry searches and have begun screening titles and abstracts. CONCLUSIONS: By appraising the characteristics of studies that have focused on the motivational design of web-based instruction in HPE, the planned review will produce recommendations that will ensure impactful programs of future research in this crucial educational space. TRIAL REGISTRATION: PROSPERO CRD42022359521; https://tinyurl.com/57chuzf6. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/42681.

Toward 'seeing' critically: a Bayesian analysis of the impacts of a critical pedagogy.

Critical reflection supports enactment of the social roles of care, like collaboration and advocacy. We require evidence that links critical teaching approaches to future critically reflective practice. We thus asked: does a theory-informed approach to teaching critical reflection influence what learners talk about (i.e. topics of discussion) and how they talk (i.e. whether they talk in critically reflective ways) during subsequent learning experiences? Pre-clinical students (n = 75) were randomized into control and intervention conditions (8 groups each, of up to 5 interprofessional students). Participants completed an online Social Determinants of Health (SDoH) module, followed by either: a SDoH discussion (control) or critically reflective dialogue (intervention). Participants then experienced a common learning session (homecare curriculum and debrief) as outcome assessment, and another similar session one-week later. Blinded coders coded transcripts for what (topics) was said and how (critically reflective or not). We constructed Bayesian regression models for the probability of meaning units (unique utterances) being coded as particular what codes and as critically reflective or not (how). Groups exposed to the intervention were more likely, in a subsequent learning experience, to talk in a critically reflective manner (how) (0.096 [0.04, 0.15]) about similar content (no meaningful differences in what was said). This difference waned at one-week follow up. We showed experimentally that a particular critical pedagogical approach can make learners' subsequent talk, ways of seeing, more critically reflective even when talking about similar topics. This study offers the field important new options for studying historically challenging-to-evaluate impacts and supports theoretical assertions about the potential of critical pedagogies.

Using Smartphone-Based Ecological Momentary Assessment in Audiology Research: The Participants' Perspective.

Purpose The article's purpose was to examine participants' impressions and experiences with smartphone-based ecological momentary assessment (EMA) to inform future EMA study design. Method Adults with hearing impairment (HI, n = 9) and with normal hearing (NH, n = 10) participated in a study using a smartphone-based EMA system to measure their auditory lifestyles. A 14-item survey was scheduled to deliver every 45 min by an EMA app. After a 1-week trial, participants were interviewed regarding their study experiences. The app log files were analyzed to understand how the participants interacted with the app. Results Across the two groups, 1,295 surveys were completed (compliance rate 74.4%). On average, HI participants completed 10.0 and NH participants completed 9.1 surveys per day. The mean survey completion time for HI and NH groups were 72 s and 51 s, respectively. For both groups, about 90% of the participants reported the app as easy to use; about 60% of the participants reported that repetitive surveys interrupted or somewhat interrupted their activities. Participants reported surveys disrupting situations, for example, working, driving, and social events, and that they were more likely to skip surveys in these situations. Additionally, 50% of NH and 30% of HI participants indicated that the survey was not delivered too frequently and none indicated that the survey was too long. Conclusion Overall, the app and EMA design seem to be appropriate. Insights from this study can help researchers design their studies to adequately assess listeners' experience in the field with optimal compliance and data quality.

Preliminary Examination of the Accuracy of a Fall Detection Device Embedded into Hearing Instruments.

BACKGROUND: Accidental falls are a significant health risk to older adults and patients seen in audiology clinics. Personal emergency response systems are effective in preventing long lies (defined as remaining on the floor or ground for greater than one hour after a fall), but some individuals would prefer to wear less-conspicuous devices than a traditional neck-worn pendant. No previous investigation has compared the accuracy of head-worn fall detection devices with those worn on other parts of the body. In this study, we compared the accuracy of one commonly used fall detection pendant with two variants of a new hearing instrument-based fall detection system. PURPOSE: The purpose of the study was to evaluate the accuracy of detecting falls by using inertial sensors embedded in hearing instruments. RESEARCH DESIGN: A study with repeated measures for one group. STUDY SAMPLE: Ten young adults served as participants. All participants had normal or corrected-to-normal vision during testing. Individuals were excluded if they had self-reported cardiac disorders, recent concussions, or musculoskeletal conditions. DATA COLLECTION AND ANALYSIS: Data were collected from inertial measurement unit (IMU) sensors, embedded into a binaural set of hearing instruments, during laboratory-based simulations of falls, near-falls, and activities of daily living (ADLs). The detection state of a fall detection pendant was simultaneously recorded during performance of each trial and compared with the outputs of offline hearing instrument firmware emulators. RESULTS: One hearing instrument-based fall detection system was more accurate than the fall detection pendant. A second hearing instrument-based fall detection system performed similar to the fall detection pendant. Each of the three fall detection systems investigated were robust against false-positive detections during ADLs. CONCLUSIONS: Preliminary findings demonstrate that hearing instruments embedded with a fall detection device (FDD) may be a suitable alternative to more traditional forms of FDDs (e.g., pendant, wrist-worn device, etc.) for detecting falls and potentially preventing long lies.

The Effects of Varying Directional Bandwidth in Hearing Aid Users' Preference and Speech-in-Noise Performance.

PURPOSE: Directional microphone systems are typically used to improve hearing aid users' understanding of speech in noise. However, directional microphones also increase internal hearing aid noise. The purpose of this study was to investigate how varying directional microphone bandwidth affected listening preference and speech-in-noise performance. METHOD: Ten participants with normal hearing and 10 participants with hearing impairment compared internal noise levels between hearing aid memories with 4 different microphone modes: omnidirectional, full directional, high-frequency directionality with directional processing above 900 Hz, and high-frequency directionality with directional processing above 2000 Hz. Speech-in-noise performance was measured with each memory for the participants with hearing impairment. RESULTS: Participants with normal hearing preferred memories with less directional bandwidth. Participants with hearing impairment also tended to prefer the memories with less directional bandwidth. However, the majority of participants with hearing impairment did not indicate a preference between omnidirectional and directional above 2000 Hz memories. Average hearing-in-noise performance improved with increasing directional bandwidth. CONCLUSIONS: Most participants preferred memories with less directional bandwidth in quiet. Participants with hearing impairment indicated no difference in preference between directional above 2000 Hz and the omnidirectional memories. Speech recognition in noise performance improved with increasing directional bandwidth.

Fitting Noise Management Signal Processing Applying the American Academy of Audiology Pediatric Amplification Guideline: Verification Protocols.

BACKGROUND: Although guidelines for fitting hearing aids for children are well developed and have strong basis in evidence, specific protocols for fitting and verifying some technologies are not always available. One such technology is noise management in children's hearing aids. Children are frequently in high-level and/or noisy environments, and many options for noise management exist in modern hearing aids. Verification protocols are needed to define specific test signals and levels for use in clinical practice. PURPOSE: This work aims to (1) describe the variation in different brands of noise reduction processors in hearing aids and the verification of these processors and (2) determine whether these differences are perceived by 13 children who have hearing loss. Finally, we aimed to develop a verification protocol for use in pediatric clinical practice. STUDY SAMPLE: A set of hearing aids was tested using both clinically available test systems and a reference system, so that the impacts of noise reduction signal processing in hearing aids could be characterized for speech in a variety of background noises. A second set of hearing aids was tested across a range of audiograms and across two clinical verification systems to characterize the variance in clinical verification measurements. Finally, a set of hearing aid recordings that varied by type of noise reduction was rated for sound quality by children with hearing loss. RESULTS: Significant variation across makes and models of hearing aids was observed in both the speed of noise reduction activation and the magnitude of noise reduction. Reference measures indicate that noise-only testing may overestimate noise reduction magnitude compared to speech-in-noise testing. Variation across clinical test signals was also observed, indicating that some test signals may be more successful than others for characterization of hearing aid noise reduction. Children provided different sound quality ratings across hearing aids, and for one hearing aid rated the sound quality as higher with the noise reduction system activated. CONCLUSIONS: Implications for clinical verification systems may be that greater standardization and the use of speech-in-noise test signals may improve the quality and consistency of noise reduction verification cross clinics. A suggested clinical protocol for verification of noise management in children's hearing aids is suggested.

Accuracy and reliability of a real-ear-to-coupler difference measurement procedure implemented within a behind-the-ear hearing aid.

BACKGROUND: Measurement of the real ear response of a fitted hearing aid allows matching of the frequency response to prescriptive targets, as well as comparison of the response to both threshold and loudness discomfort level (LDL). These processes are recommended procedures for hearing aid fittings. The real ear aided response (REAR) is often predicted based on the coupler response of the device, the real-ear-to-coupler difference (RECD), and the microphone location effect (MLE). Individualized measurement of the RECD tends to increase the accuracy of this prediction. A commercial hearing aid has been developed that measures the individual RECD and incorporates the data into the software-assisted fitting process. PURPOSE: This study evaluated the test-retest reliability and predictive validity of this particular method for measuring the RECD. RESEARCH DESIGN: A repeated measures design was used to evaluate differences between subsequent measures of the RECD in the same ear, and prediction differences associated with using the RECD (and other information) to predict the REAR. STUDY SAMPLE: Fifteen ears, on a convenience sample of ten adults (45-86 yr) and five children (6-15 yr) were tested. All participants were hearing aid users. DATA COLLECTION AND ANALYSIS: Predicted and measured REARs were collected using normal clinical procedures, on an Audioscan Verifit VF-1 for two test signals/levels. Reliability, mean differences between predicted and measured REARs, and 95% confidence intervals of the prediction accuracy are reported. RESULTS: The RECD procedure had test-retest reliability within 2.5 dB for 14 out of 15 ears between 500 and 4000 Hz, and had predictive accuracy within 5 dB between 500 and 4000 Hz for 14 out of 15 ears. However, errors associated with earhook misalignment were discovered. Also, the RECD values measured using this hearing-aid-specific procedure differ somewhat from the normative data available from insert earphone RECDs. CONCLUSIONS: This procedure, when measured according to recommendations, provides a reasonably accurate prediction of the REAR. Functionally, this procedure does not replace the range of measures offered by modern real ear measurement systems. However, given the inaccuracy of software-assisted fittings without a measure of individual ear canal acoustics, use of this procedure may have the potential to improve the accuracy of fittings versus fittings completed without real ear measurement.

Antioxidant protection from HIV-1 gp120-induced neuroglial toxicity.

BACKGROUND: The pathogenesis of HIV-1 glycoprotein 120 (gp120) associated neuroglial toxicity remains unresolved, but oxidative injury has been widely implicated as a contributing factor. In previous studies, exposure of primary human central nervous system tissue cultures to gp120 led to a simplification of neuronal dendritic elements as well as astrocytic hypertrophy and hyperplasia; neuropathological features of HIV-1-associated dementia. Gp120 and proinflammatory cytokines upregulate inducible nitric oxide synthase (iNOS), an important source of nitric oxide (NO) and nitrosative stress. Because ascorbate scavenges reactive nitrogen and oxygen species, we studied the effect of ascorbate supplementation on iNOS expression as well as the neuronal and glial structural changes associated with gp120 exposure. METHODS: Human CNS cultures were derived from 16-18 week gestation post-mortem fetal brain. Cultures were incubated with 400 microM ascorbate-2-O-phosphate (Asc-p) or vehicle for 18 hours then exposed to 1 nM gp120 for 24 hours. The expression of iNOS and neuronal (MAP2) and astrocytic (GFAP) structural proteins was examined by immunohistochemistry and immunofluorescence using confocal scanning laser microscopy (CSLM). RESULTS: Following gp120 exposure iNOS was markedly upregulated from undetectable levels at baseline. Double label CSLM studies revealed astrocytes to be the prime source of iNOS with rare neurons expressing iNOS. This upregulation was attenuated by the preincubation with Asc-p, which raised the intracellular concentration of ascorbate. Astrocytic hypertrophy and neuronal injury caused by gp120 were also prevented by preincubation with ascorbate. CONCLUSIONS: Ascorbate supplementation prevents the deleterious upregulation of iNOS and associated neuronal and astrocytic protein expression and structural changes caused by gp120 in human brain cell cultures.

AZT myopathy and HIV-1 polymyositis: one disease or two?

PURPOSE: This paper discusses the association between inflammatory and mitochondrial pathologies in patients with HIV-1/AIDS treated with zidovudine (AZT). METHODS: We present the clinical and pathological details of a 52-year-old HIV-1 positive male who presented with progressive muscle weakness. We also review the current literature and address the debated pathogenesis of the inflammatory pathology. RESULTS: Muscle biopsy revealed evidence of both HIV-1 polymyositis and AZT myopathy. Six months after initiation of corticosteroid therapy and discontinuation of AZT, the patient's symptoms had greatly improved. The biopsy was repeated to show that both pathologies had resolved. CONCLUSIONS: The perceived overlap in the pathological spectra of HIV-1 polymyositis and AZT myopathy has produced some debate on causation and treatment. Unfortunately, there have been very few reports where a repeat biopsy following a drug washout period confirmed resolution of the pathology. Furthermore, affected patients have not been treated in a uniform fashion. Whether this represents one disease or two remains uncertain. The clinical relevance of this issue lies in the potential for harm from the unnecessary use of corticosteroids. This question may be best addressed by a randomized clinical trial.