Auditory Environments and Hearing Aid Feature Activation Among Younger and Older Listeners in an Urban and Rural Area.

OBJECTIVES: The purpose of this study was to investigate differences in auditory environments and hearing aid feature activation between younger listeners with normal hearing and older listeners with hearing loss in an urban and rural location. We hypothesized that (1) urban dwellers and younger listeners would encounter more diverse and demanding auditory environments than rural dwellers and older listeners, respectively; (2) the advanced hearing aid features (noise reduction and directional microphone) of urban dwellers and younger listeners would be activated more frequently than rural dwellers and older listeners, respectively. DESIGN: The design of this study was cross-sectional with repeated measures. A total of 12 older adults with hearing loss (OHL-U) and 11 younger adults with normal hearing (YNH-U) were recruited from an urban area (Berkeley, California) and 13 older adults with hearing loss (OHL-R) and 10 YNH-U were recruited from a rural area (Iowa City, Iowa). Participants wore hearing aids that recorded data about their listening environments and completed ecological momentary assessments for 1 week. RESULTS: The YNH-U group experienced higher sound pressure levels and hearing aid features were activated more frequently than in the OHL groups. The OHL-R group experienced significantly less diverse sound pressure levels than the YNH-U group. The YNH-R group had sound levels between the YNH-U group and the OHL groups but without significant differences from any other group. The YNH groups showed a greater likelihood of hearing aid feature activation than the OHL-R group. CONCLUSIONS: Demographics affect auditory environments and the activation of hearing aid features. Younger urban dwellers have the most diverse or demanding auditory environments and hearing aid feature activation, and older, rural dwellers with hearing loss have the least diverse or demanding auditory environments and hearing aid feature activation. Future studies of real-world auditory environments and audiology intervention effectiveness should consider location in recruitment and interpretation of results.

The Influence of Forced Social Isolation on the Auditory Ecology and Psychosocial Functions of Listeners With Cochlear Implants During COVID-19 Mitigation Efforts.

OBJECTIVES: The impact of social distancing on communication and psychosocial variables among individuals with hearing impairment during COVID-19 pandemic. It was our concern that patients who already found themselves socially isolated (Wie et al. 2010) as a result of their hearing loss would be perhaps more susceptible to changes in their communication habits resulting in further social isolation, anxiety, and depression. We wanted to better understand how forced social isolation (as part of COVID-19 mitigation) effected a group of individuals with hearing impairment from an auditory ecology and psychosocial perspective. We hypothesized that the listening environments would be different as a result of social isolation when comparing subject's responses regarding activities and participation before COVID-19 and during the COVID-19 pandemic. This change would lead to an increase in experienced and perceived social isolation, anxiety, and depression. DESIGN: A total of 48 adults with at least 12 months of cochlear implant (CI) experience reported their listening contexts and experiences pre-COVID and during-COVID using Ecological Momentary Assessment (EMA; methodology collecting a respondent's self-reports in their natural environments) through a smartphone-based app, and six paper and pencil questionnaires. The Smartphone app and paper-pencil questionnaires address topics related to their listening environment, social isolation, depression, anxiety, lifestyle and demand, loneliness, and satisfaction with amplification. Data from these two-time points were compared to better understand the effects of social distancing on the CI recipients' communication abilities. RESULTS: EMA demonstrated that during-COVID CI recipients were more likely to stay home or be outdoors. CI recipients reported that they were less likely to stay indoors outside of their home relative to the pre-COVID condition. Social distancing also had a significant effect on the overall signal-to-noise ratio of the environments indicating that the listening environments had better signal-to-noise ratios. CI recipients also reported better speech understanding, less listening effort, less activity limitation due to hearing loss, less social isolation due to hearing loss, and less anxiety due to hearing loss. Retrospective questionnaires indicated that social distancing had a significant effect on the social network size, participant's personal image of themselves, and overall loneliness. CONCLUSIONS: Overall, EMA provided us with a glimpse of the effect that forced social isolation has had on the listening environments and psychosocial perspectives of a select number of CI listeners. CI participants in this study reported that they were spending more time at home in a quieter environments during-COVID. Contrary to our hypothesis, CI recipients overall felt less socially isolated and reported less anxiety resulting from their hearing difficulties during-COVID in comparison to pre-COVID. This, perhaps, implies that having a more controlled environment with fewer speakers provided a more relaxing listening experience.

GPS predicts stability of listening environment characteristics in one location over time among older hearing aid users.

OBJECTIVE: Hearing aid technology can allow users to "geo-tag" hearing aid preferences using the Global Positioning System (GPS). This technology assumes that listening environment characteristics that affect hearing aid benefit change little in a location over time. The purpose of this study was to investigate whether certain characteristics (reverberation, signal type, listening activity, noise location, noisiness, talker familiarity, talker location, and visual cues) changed in a location over time. Design: Participants completed GPS-tagged surveys on smartphones to report on characteristics of their listening environments. Coordinates were used to create indices that described how much listening environment characteristics changed in a location over time. Indices computed in one location were compared to indices computed across all locations for each participant. Study sample: 54 adults with hearing loss participated in this study (26 males and 38 females; 30 experienced hearing aid users and 24 new users). Results: A location dependency was observed for all characteristics. Characteristics were significantly different from one another in their stability over time. Conclusions: Listening environment characteristics changed less over time in a given location than in participants' lives generally. The effectiveness of GPS-dependent hearing aid settings likely depends on the accuracy and location definition of the GPS feature.

Efficacy and Effectiveness of Advanced Hearing Aid Directional and Noise Reduction Technologies for Older Adults With Mild to Moderate Hearing Loss.

OBJECTIVES: The purpose of the present study was to investigate the laboratory efficacy and real-world effectiveness of advanced directional microphones (DM) and digital noise reduction (NR) algorithms (i.e., premium DM/NR features) relative to basic-level DM/NR features of contemporary hearing aids (HAs). The study also examined the effect of premium HAs relative to basic HAs and the effect of DM/NR features relative to no features. DESIGN: Fifty-four older adults with mild-to-moderate hearing loss completed a single-blinded crossover trial. Two HA models, one a less-expensive, basic-level device (basic HA) and the other a more-expensive, advanced-level device (premium HA), were used. The DM/NR features of the basic HAs (i.e., basic features) were adaptive DMs and gain-reduction NR with fewer channels. In contrast, the DM/NR features of the premium HAs (i.e., premium features) included adaptive DMs and gain-reduction NR with more channels, bilateral beamformers, speech-seeking DMs, pinna-simulation directivity, reverberation reduction, impulse NR, wind NR, and spatial NR. The trial consisted of four conditions, which were factorial combinations of HA model (premium versus basic) and DM/NR feature status (on versus off). To blind participants regarding the HA technology, no technology details were disclosed and minimal training on how to use the features was provided. In each condition, participants wore bilateral HAs for 5 weeks. Outcomes regarding speech understanding, listening effort, sound quality, localization, and HA satisfaction were measured using laboratory tests, retrospective self-reports (i.e., standardized questionnaires), and in-situ self-reports (i.e., self-reports completed in the real world in real time). A smartphone-based ecological momentary assessment system was used to collect in-situ self-reports. RESULTS: Laboratory efficacy data generally supported the benefit of premium DM/NR features relative to basic DM/NR, premium HAs relative to basic HAs, and DM/NR features relative to no DM/NR in improving speech understanding and localization performance. Laboratory data also indicated that DM/NR features could improve listening effort and sound quality compared with no features for both basic- and premium-level HAs. For real-world effectiveness, in-situ self-reports first indicated that noisy or very noisy situations did not occur very often in participants' daily lives (10.9% of the time). Although both retrospective and in-situ self-reports indicated that participants were more satisfied with HAs equipped with DM/NR features than without, there was no strong evidence to support the benefit of premium DM/NR features and premium HAs over basic DM/NR features and basic HAs, respectively. CONCLUSIONS: Although premium DM/NR features and premium HAs outperformed their basic-level counterparts in well-controlled laboratory test conditions, the benefits were not observed in the real world. In contrast, the effect of DM/NR features relative to no features was robust both in the laboratory and in the real world. Therefore, the present study suggests that although both premium and basic DM/NR technologies evaluated in the study have the potential to improve HA outcomes, older adults with mild-to-moderate hearing loss are unlikely to perceive the additional benefits provided by the premium DM/NR features in their daily lives. Limitations concerning the study's generalizability (e.g., participant's lifestyle) are discussed.

Characteristics of Real-World Signal to Noise Ratios and Speech Listening Situations of Older Adults With Mild to Moderate Hearing Loss.

OBJECTIVES: The first objective was to determine the relationship between speech level, noise level, and signal to noise ratio (SNR), as well as the distribution of SNR, in real-world situations wherein older adults with hearing loss are listening to speech. The second objective was to develop a set of prototype listening situations (PLSs) that describe the speech level, noise level, SNR, availability of visual cues, and locations of speech and noise sources of typical speech listening situations experienced by these individuals. DESIGN: Twenty older adults with mild to moderate hearing loss carried digital recorders for 5 to 6 weeks to record sounds for 10 hours per day. They also repeatedly completed in situ surveys on smartphones several times per day to report the characteristics of their current environments, including the locations of the primary talker (if they were listening to speech) and noise source (if it was noisy) and the availability of visual cues. For surveys where speech listening was indicated, the corresponding audio recording was examined. Speech-plus-noise and noise-only segments were extracted, and the SNR was estimated using a power subtraction technique. SNRs and the associated survey data were subjected to cluster analysis to develop PLSs. RESULTS: The speech level, noise level, and SNR of 894 listening situations were analyzed to address the first objective. Results suggested that as noise levels increased from 40 to 74 dBA, speech levels systematically increased from 60 to 74 dBA, and SNR decreased from 20 to 0 dB. Most SNRs (62.9%) of the collected recordings were between 2 and 14 dB. Very noisy situations that had SNRs below 0 dB comprised 7.5% of the listening situations. To address the second objective, recordings and survey data from 718 observations were analyzed. Cluster analysis suggested that the participants' daily listening situations could be grouped into 12 clusters (i.e., 12 PLSs). The most frequently occurring PLSs were characterized as having the talker in front of the listener with visual cues available, either in quiet or in diffuse noise. The mean speech level of the PLSs that described quiet situations was 62.8 dBA, and the mean SNR of the PLSs that represented noisy environments was 7.4 dB (speech = 67.9 dBA). A subset of observations (n = 280), which was obtained by excluding the data collected from quiet environments, was further used to develop PLSs that represent noisier situations. From this subset, two PLSs were identified. These two PLSs had lower SNRs (mean = 4.2 dB), but the most frequent situations still involved speech from in front of the listener in diffuse noise with visual cues available. CONCLUSIONS: The present study indicated that visual cues and diffuse noise were exceedingly common in real-world speech listening situations, while environments with negative SNRs were relatively rare. The characteristics of speech level, noise level, and SNR, together with the PLS information reported by the present study, can be useful for researchers aiming to design ecologically valid assessment procedures to estimate real-world speech communicative functions for older adults with hearing loss.

Predicting three-month and 12-month post-fitting real-world hearing-aid outcome using pre-fitting acceptable noise level (ANL).

OBJECTIVE: Determine the extent to which pre-fitting acceptable noise level (ANL), with or without other predictors such as hearing-aid experience, can predict real-world hearing-aid outcomes at three and 12 months post-fitting. DESIGN: ANLs were measured before hearing-aid fitting. Post-fitting outcome was assessed using the international outcome inventory for hearing aids (IOI-HA) and a hearing-aid use questionnaire. Models that predicted outcomes (successful vs. unsuccessful) were built using logistic regression and several machine learning algorithms, and were evaluated using the cross-validation technique. STUDY SAMPLE: A total of 132 adults with hearing impairment. RESULTS: The prediction accuracy of the models ranged from 61% to 68% (IOI-HA) and from 55% to 61% (hearing-aid use questionnaire). The models performed more poorly in predicting 12-month than three-month outcomes. The ANL cutoff between successful and unsuccessful users was higher for experienced (∼18 dB) than first-time hearing-aid users (∼10 dB), indicating that most experienced users will be predicted as successful users regardless of their ANLs. CONCLUSIONS: Pre-fitting ANL is more useful in predicting short-term (three months) hearing-aid outcomes for first-time users, as measured by the IOI-HA. The prediction accuracy was lower than the accuracy reported by some previous research that used a cross-sectional design.

Secure scalable disaster electronic medical record and tracking system.

INTRODUCTION: Electronic medical records (EMRs) are considered superior in documentation of care for medical practice. Current disaster medical response involves paper tracking systems and radio communication for mass-casualty incidents (MCIs). These systems are prone to errors, may be compromised by local conditions, and are labor intensive. Communication infrastructure may be impacted, overwhelmed by call volume, or destroyed by the disaster, making self-contained and secure EMR response a critical capability. Report As the prehospital disaster EMR allows for more robust content including protected health information (PHI), security measures must be instituted to safeguard these data. The Wireless Internet Information System for medicAl Response in Disasters (WIISARD) Research Group developed a handheld, linked, wireless EMR system utilizing current technology platforms. Smart phones connected to radio frequency identification (RFID) readers may be utilized to efficiently track casualties resulting from the incident. Medical information may be transmitted on an encrypted network to fellow prehospital team members, medical dispatch, and receiving medical centers. This system has been field tested in a number of exercises with excellent results, and future iterations will incorporate robust security measures. CONCLUSION: A secure prehospital triage EMR improves documentation quality during disaster drills.

Auditory environment diversity quantified using entropy from real-world hearing aid data.

Introduction: Using data collected from hearing aid users' own hearing aids could improve the customization of hearing aid processing for different users based on the auditory environments they encounter in daily life. Prior studies characterizing hearing aid users' auditory environments have focused on mean sound pressure levels and proportions of environments based on classifications. In this study, we extend these approaches by introducing entropy to quantify the diversity of auditory environments hearing aid users encounter. Materials and Methods: Participants from 4 groups (younger listeners with normal hearing and older listeners with hearing loss from an urban or rural area) wore research hearing aids and completed ecological momentary assessments on a smartphone for 1 week. The smartphone was programmed to sample the processing state (input sound pressure level and environment classification) of the hearing aids every 10 min and deliver an ecological momentary assessment every 40 min. Entropy values for sound pressure levels, environment classifications, and ecological momentary assessment responses were calculated for each participant to quantify the diversity of auditory environments encountered over the course of the week. Entropy values between groups were compared. Group differences in entropy were compared to prior work reporting differences in mean sound pressure levels and proportions of environment classifications. Group differences in entropy measured objectively from the hearing aid data were also compared to differences in entropy measured from the self-report ecological momentary assessment data. Results: Auditory environment diversity, quantified using entropy from the hearing aid data, was significantly higher for younger listeners than older listeners. Entropy measured using ecological momentary assessment was also significantly higher for younger listeners than older listeners. Discussion: Using entropy, we show that younger listeners experience a greater diversity of auditory environments than older listeners. Alignment of group entropy differences with differences in sound pressure levels and hearing aid feature activation previously reported, along with alignment with ecological momentary response entropy, suggests that entropy is a valid and useful metric. We conclude that entropy is a simple and intuitive way to measure auditory environment diversity using hearing aid data.

Personalizing over-the-counter hearing aids using pairwise comparisons.

Over-the-counter hearing aids enable more affordable and accessible hearing health care by shifting the burden of configuring the device from trained audiologists to end-users. A critical challenge is to provide users with an easy-to-use method for personalizing the many parameters which control sound amplification based on their preferences. This paper presents a novel approach to fitting hearing aids that provides a higher degree of personalization than existing methods by using user feedback more efficiently. Our approach divides the fitting problem into two parts. First, we discretize an initial 24-dimensional space of possible configurations into a small number of presets. Presets are constructed to ensure that they can meet the hearing needs of a large fraction of Americans with mild-to-moderate hearing loss. Then, an online agent learns the best preset by asking a sequence of pairwise comparisons. This learning problem is an instance of the multi-armed bandit problem. We performed a 35-user study to understand the factors that affect user preferences and evaluate the efficacy of multi-armed bandit algorithms. Most notably, we identified a new relationship between a user's preference and presets: a user's preference can be represented as one or more preference points in the initial configuration space with stronger preferences expressed for nearby presets (as measured by the Euclidean distance). Based on this observation, we have developed a Two-Phase Personalizing algorithm that significantly reduces the number of comparisons required to identify a user's preferred preset. Simulation results indicate that the proposed algorithm can find the best configuration with a median of 25 comparisons, reducing by half the comparisons required by the best baseline. These results indicate that it is feasible to configure over-the-counter hearing aids using a small number of pairwise comparisons without the help of professionals.

Why Ecological Momentary Assessment Surveys Go Incomplete: When It Happens and How It Impacts Data.

BACKGROUND: Ecological momentary assessment (EMA) often requires respondents to complete surveys in the moment to report real-time experiences. Because EMA may seem disruptive or intrusive, respondents may not complete surveys as directed in certain circumstances. PURPOSE: This article aims to determine the effect of environmental characteristics on the likelihood of instances where respondents do not complete EMA surveys (referred to as survey incompletion), and to estimate the impact of survey incompletion on EMA self-report data. RESEARCH DESIGN: An observational study. STUDY SAMPLE: Ten adults hearing aid (HA) users. DATA COLLECTION AND ANALYSIS: Experienced, bilateral HA users were recruited and fit with study HAs. The study HAs were equipped with real-time data loggers, an algorithm that logged the data generated by HAs (e.g., overall sound level, environment classification, and feature status including microphone mode and amount of gain reduction). The study HAs were also connected via Bluetooth to a smartphone app, which collected the real-time data logging data as well as presented the participants with EMA surveys about their listening environments and experiences. The participants were sent out to wear the HAs and complete surveys for 1 week. Real-time data logging was triggered when participants completed surveys and when participants ignored or snoozed surveys. Data logging data were used to estimate the effect of environmental characteristics on the likelihood of survey incompletion, and to predict participants' responses to survey questions in the instances of survey incompletion. RESULTS: Across the 10 participants, 715 surveys were completed and survey incompletion occurred 228 times. Mixed effects logistic regression models indicated that survey incompletion was more likely to happen in the environments that were less quiet and contained more speech, noise, and machine sounds, and in the environments wherein directional microphones and noise reduction algorithms were enabled. The results of survey response prediction further indicated that the participants could have reported more challenging environments and more listening difficulty in the instances of survey incompletion. However, the difference in the distribution of survey responses between the observed responses and the combined observed and predicted responses was small. CONCLUSION: The present study indicates that EMA survey incompletion occurs systematically. Although survey incompletion could bias EMA self-report data, the impact is likely to be small.

Test-Retest Reliability of Ecological Momentary Assessment in Audiology Research.

BACKGROUND: Ecological momentary assessment (EMA) is a methodology involving repeated surveys to collect in situ data that describe respondents' current or recent experiences and related contexts in their natural environments. Audiology literature investigating the test-retest reliability of EMA is scarce. PURPOSE: This article examines the test-retest reliability of EMA in measuring the characteristics of listening contexts and listening experiences. RESEARCH DESIGN: An observational study. STUDY SAMPLE: Fifty-one older adults with hearing loss. DATA COLLECTION AND ANALYSIS: The study was part of a larger study that examined the effect of hearing aid technologies. The larger study had four trial conditions and outcome was measured using a smartphone-based EMA system. After completing the four trial conditions, participants repeated one of the conditions to examine the EMA test-retest reliability. The EMA surveys contained questions that assessed listening context characteristics including talker familiarity, talker location, and noise location, as well as listening experiences including speech understanding, listening effort, loudness satisfaction, and hearing aid satisfaction. The data from multiple EMA surveys collected by each participant were aggregated in each of the test and retest conditions. Test-retest correlation on the aggregated data was then calculated for each EMA survey question to determine the reliability of EMA. RESULTS: At the group level, listening context characteristics and listening experience did not change between the test and retest conditions. The test-retest correlation varied across the EMA questions, with the highest being the questions that assessed talker location (median r = 1.0), reverberation (r = 0.89), and speech understanding (r = 0.85), and the lowest being the items that quantified noise location (median r = 0.63), talker familiarity (r = 0.46), listening effort (r = 0.61), loudness satisfaction (r = 0.60), and hearing aid satisfaction (r = 0.61). CONCLUSION: Several EMA questions yielded appropriate test-retest reliability results. The lower test-retest correlations for some EMA survey questions were likely due to fewer surveys completed by participants and poorly designed questions. Therefore, the present study stresses the importance of using validated questions in EMA. With sufficient numbers of surveys completed by respondents and with appropriately designed survey questions, EMA could have reasonable test-retest reliability in audiology research.

Common Configurations of Real-Ear Aided Response Targets Prescribed by NAL-NL2 for Older Adults With Mild-to-Moderate Hearing Loss.

Purpose This study investigates common real-ear aided response (REAR) configurations prescribed by the NAL-NL2 algorithm for older adults with hearing loss. Method A data set that is representative of the older adult U.S. population with mild-to-moderate sensorineural hearing loss was constructed from the audiometric data of 934 adults (aged 55-85 years) from the National Health and Nutrition Examination Survey years 1999-2012. Two clustering approaches were implemented to generate common REAR configurations for eight frequencies (0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz) at three input levels (55, 65, and 75 dB SPL). (a) In the REAR-based clustering approach, the National Health and Nutrition Examination Survey audiograms were first converted to REAR targets and then clustered to generate common REAR configurations. (b) In the audiogram-based clustering approach, the audiograms were first clustered into common hearing loss profiles and then converted to REAR configurations. The trade-off between the number of available REAR configurations and the percentage of the U.S. population whose hearing loss could be fit by at least one of them (i.e., percent coverage) was evaluated. Hearing loss fit was defined as less than ± 5-dB difference between an individual's REAR targets and those of the clustered REAR configuration. Results Percent coverage increases with the number of available REAR configurations, with four configurations resulting in 75% population coverage. Overall, REAR-based clustering yielded 5 percentage points better coverage on average compared to audiogram-based clustering. Conclusions The common REAR configurations can be used for programming the gain frequency responses in preconfigured over-the-counter hearing aids and provide clinically appropriate amplification settings for older adults with mild-to-moderate hearing loss.

Comparison of In-Situ and Retrospective Self-Reports on Assessing Hearing Aid Outcomes.

BACKGROUND: Ecological momentary assessment (EMA) is a methodology involving repeated surveys to collect in-situ self-reports that describe respondents' current or recent experiences. Audiology literature comparing in-situ and retrospective self-reports is scarce. PURPOSE: To compare the sensitivity of in-situ and retrospective self-reports in detecting the outcome difference between hearing aid technologies, and to determine the association between in-situ and retrospective self-reports. RESEARCH DESIGN: An observational study. STUDY SAMPLE: Thirty-nine older adults with hearing loss. DATA COLLECTION AND ANALYSIS: The study was part of a larger clinical trial that compared the outcomes of a prototype hearing aid (denoted as HA1) and a commercially available device (HA2). In each trial condition, participants wore hearing aids for 4 weeks. Outcomes were measured using EMA and retrospective questionnaires. To ensure that the outcome data could be directly compared, the Glasgow Hearing Aid Benefit Profile was administered as an in-situ self-report (denoted as EMA-GHABP) and as a retrospective questionnaire (retro-GHABP). Linear mixed models were used to determine if the EMA- and retro-GHABP could detect the outcome difference between HA1 and HA2. Correlation analyses were used to examine the association between EMA- and retro-GHABP. RESULTS: For the EMA-GHABP, HA2 had significantly higher (better) scores than HA1 in the GHABP subscales of benefit, residual disability, and satisfaction (p = 0.029-0.0015). In contrast, the difference in the retro-GHABP score between HA1 and HA2 was significant only in the satisfaction subscale (p = 0.0004). The correlations between the EMA- and retro-GHABP were significant in all subscales (p = 0.0004 to <0.0001). The strength of the association ranged from weak to moderate (r = 0.28-0.58). Finally, the exit interview indicated that 29 participants (74.4%) preferred HA2 over HA1. CONCLUSION: The study suggests that in-situ self-reports collected using EMA could have a higher sensitivity than retrospective questionnaires. Therefore, EMA is worth considering in clinical trials that aim to compare the outcomes of different hearing aid technologies. The weak to moderate association between in-situ and retrospective self-reports suggests that these two types of measures assess different aspects of hearing aid outcomes.

Continuous in-home PM2.5 concentrations of smokers with and without a history of respiratory exacerbations in Iowa, during and after an air purifier intervention.

BACKGROUND: Americans spend most of their time indoors. Indoor particulate matter (PM) 2.5 µm and smaller (PM2.5) concentrations often exceed ambient concentrations. Therefore, we tested whether the use of an air purifying device (electrostatic precipitator, ESP) could reduce PM2.5 in homes of smokers with and without respiratory exacerbations, compared with baseline. METHODS: We assessed PM2.5 concentrations in homes of subjects with and without a recent (≤3 years) history of respiratory exacerbation. We compared PM2.5 concentrations during 1 month of ESP use with those during 1 month without ESP use. RESULTS: Our study included 19 subjects (53-80 years old), nine with a history of respiratory exacerbation. Geometric mean (GM) PM2.5 and median GM daily peak PM2.5 were significantly lower during ESP deployment compared with the equivalent time-period without the ESP (GSD = 0.50 and 0.37 µg/m3, respectively, p < 0.001). PM2.5 in homes of respiratory exacerbators tended (p < 0.14) to be higher than PM2.5 in homes of those without a history of respiratory exacerbation. CONCLUSIONS: Subjects with a history of respiratory exacerbation tended to have higher mean, median, and mean peak PM2.5 concentrations compared with homes of subjects without a history of exacerbations. The ESP intervention reduced in-home PM2.5 concentrations, demonstrating its utility in reducing indoor exposures. NOVELTY OF STUDY: Our work characterizes PM air pollution concentrations in homes of study subjects with and without respiratory exacerbations. We demonstrate that PM concentrations tend to be higher in homes of participants with respiratory exacerbations, and that the use of an inexpensive air purifier resulted in significantly lower daily average PM concentrations than when the purifier was not present. Our results provide a helpful intervention strategy for purifying indoor air and may be useful for susceptible populations.

Indoor Particulate Matter From Smoker Homes Induces Bacterial Growth, Biofilm Formation, and Impairs Airway Antimicrobial Activity. A Pilot Study.

Background: Particulate matter (PM) air pollution causes deleterious health effects; however, less is known about health effects of indoor air particulate matter (IAP). Objective: To understand whether IAP influences distinct mechanisms in the development of respiratory tract infections, including bacterial growth, biofilm formation, and innate immunity. Additionally, we tested whether IAP from Iowa houses of subjects with and without recent respiratory exacerbations recapitulated the National Institute of Standards and Technology (NIST) IAP findings. Methods: To test the effect of NIST and Iowa IAP on bacterial growth and biofilm formation, we assessed Staphylococcus aureus growth and Pseudomonas aeruginosa biofilm formation with and without the presence of IAP. To assess the effect of IAP on innate immunity, we exposed primary human airway surface liquid (ASL) to NIST, and Iowa IAP. Lastly, we tested whether specific metals may be responsible for effects on airway innate immunity. Results: NIST and Iowa IAP significantly enhanced bacterial growth and biofilm formation. NIST IAP (whole particle and the soluble portion) impaired ASL antimicrobial activity. IAP from one Iowa home significantly impaired ASL antimicrobial activity (p < 0.05), and five other homes demonstrated a trend (p ≤ 0.18) of impaired ASL antimicrobial activity. IAP from homes of subjects with a recent history of respiratory exacerbation tended (p = 0.09) to impair ASL antimicrobial activity more than IAP from homes of those without a history respiratory exacerbation. Aluminum and Magnesium impaired ASL antimicrobial activity, while copper was bactericidal. Combining metals varied their effect on ASL antimicrobial activity. Conclusions: NIST IAP and Iowa IAP enhanced bacterial growth and biofilm formation. ASL antimicrobial activity was impaired by NIST IAP, and Iowa house IAP from subjects with recent respiratory exacerbation tended to impair ASL antimicrobial activity. Individual metals may explain impaired ASL antimicrobial activity; however, antimicrobial activity in the presence of multiple metals warrants further study.

AudioSense: Enabling Real-time Evaluation of Hearing Aid Technology In-Situ.

AudioSense integrates mobile phones and web technology to measure hearing aid performance in real-time and in-situ. Measuring the performance of hearing aids in the real world poses significant challenges as it depends on the patient's listening context. AudioSense uses Ecological Momentary Assessment methods to evaluate both the perceived hearing aid performance as well as to characterize the listening environment using electronic surveys. AudioSense further characterizes a patient's listening context by recording their GPS location and sound samples. By creating a time-synchronized record of listening performance and listening contexts, AudioSense will allow researchers to understand the relationship between listening context and hearing aid performance. Performance evaluation shows that AudioSense is reliable, energy-efficient, and can estimate Signal-to-Noise Ratio (SNR) levels from captured audio samples.

Achieving reliable communication in dynamic emergency responses.

Emergency responses require the coordination of first responders to assess the condition of victims, stabilize their condition, and transport them to hospitals based on the severity of their injuries. WIISARD is a system designed to facilitate the collection of medical information and its reliable dissemination during emergency responses. A key challenge in WIISARD is to deliver data with high reliability as first responders move and operate in a dynamic radio environment fraught with frequent network disconnections. The initial WIISARD system employed a client-server architecture and an ad-hoc routing protocol was used to exchange data. The system had low reliability when deployed during emergency drills. In this paper, we identify the underlying causes of unreliability and propose a novel peer-to-peer architecture that in combination with a gossip-based communication protocol achieves high reliability. Empirical studies show that compared to the initial WIISARD system, the redesigned system improves reliability by as much as 37% while reducing the number of transmitted packets by 23%.

Toward a two-tier clinical warning system for hospitalized patients.

Clinical study has found early detection and intervention to be essential for preventing clinical deterioration in patients at general hospital units. In this paper, we envision a two-tiered early warning system designed to identify the signs of clinical deterioration and provide early warning of serious clinical events. The first tier of the system automatically identifies patients at risk of clinical deterioration from existing electronic medical record databases. The second tier performs real-time clinical event detection based on real-time vital sign data collected from on-body wireless sensors attached to those high-risk patients. We employ machine-learning techniques to analyze data from both tiers, assigning scores to patients in real time. The assigned scores can then be used to trigger early-intervention alerts. Preliminary study of an early warning system component and a wireless clinical monitoring system component demonstrate the feasibility of this two-tiered approach.

Reliable real-time clinical monitoring using sensor network technology.

We propose wireless sensor networks composed of nodes using low-power 802.15.4 radios as an enabling technology for patient monitoring in general hospital wards. A key challenge for such applications is to reliably deliver sensor data from mobile patients. We propose a monitoring system with two types of nodes: patient nodes equipped with wireless pulse oximeters and relays nodes used to route data to a base station. A reliability analysis of data collection from mobile users shows that mobility leads to packet losses exceeding 30%. The majority of packet losses occur between the mobile subjects and the first-hop relays. Based on this insight we developed the Dynamic Relay Association Protocol (DRAP), an effective mechanism for discovering the right relays for patient nodes. DRAP enables highly reliable data collection from mobile subjects. Empirical evaluation showed that DRAP delivered at least 96% of data from multiple users. Our results demonstrate the feasibility of wireless sensor networks for real-time clinical monitoring.