Effect of Signal-to-Noise Ratio on Directional Microphone Benefit and Preference

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Automatic directionality algorithms currently implemented in hearing aids assume that hearing-impaired persons with similar hearing losses will prefer the same microphone processing mode in a specific everyday listening environment. The purpose of this study was to evaluate the robustness of microphone preferences in everyday listening. Two hearing-impaired persons made microphone preference judgments (omnidirectional preferred, directional preferred, no preference) in a variety of everyday listening situations. Simultaneously, these acoustic environments were recorded through the omnidirectional and directional microphone processing modes. The acoustic recordings were later presented in a laboratory setting for microphone preferences to the original two listeners and other listeners who differed in hearing ability and experience with directional microphone processing. The original two listeners were able to replicate their live microphone preferences in the laboratory with a high degree of accuracy. This suggests that the basis of the original live microphone preferences were largely represented in the acoustic recordings. Other hearing-impaired and normal-hearing participants who listened to the environmental recordings also accurately replicated the original live omnidirectional preferences; however, directional preferences were not as robust across the listeners. When the laboratory rating did not replicate the live directional microphone preference, listeners almost always expressed no preference for either microphone mode. Hence, a preference for omnidirectional processing was rarely expressed by any of the participants to recorded sites where directional processing had been preferred as a live judgment and vice versa. These results are interpreted to provide little basis for customizing automatic directionality algorithms for individual patients. The implications of these findings for hearing aid design are discussed.

Section: DI Is Sc Cu Us Ss Si Io On Nsupporting

confidence: 84%

Section: Sumariomentioning

confidence: 99%

The Robustness of Hearing Aid Microphone Preferences in Everyday Listening Environments

Walden¹,

Surr²,

Cord³

et al. 2007

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“…If the listening context described in a questionnaire is not specific enough, the questionnaire might not be able to determine if a given technology is beneficial. For example, laboratory data have shown that, compared to omnidirectional microphones, the effect of directional microphone hearing aids on speech understanding could be positive, neutral, or even negative, depending on the locations of the talker and noises (Lee et al, 1998; Wu et al, 2013), signal-to-noise ratio (SNR) (Walden et al, 2005), reverberation level (Ricketts and Hornsby, 2003), and availability of visual cues (Wu and Bentler, 2010a, b). Because such detailed contextual information is not available in the questionnaire Abbreviated Profile of Hearing Aid Benefit (Cox and Alexander, 1995) (e.g., “When I am in a crowded grocery store talking with the cashier, I can follow the conversation.”), it is unlikely that this inventory can detect the effect of directional technology in the real world (Ricketts et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Construct Validity of the Ecological Momentary Assessment in Audiology Research

Wu¹,

Stangl²,

Zhang³

et al. 2015

Background Ecological momentary assessment (EMA) is a methodology involving repeated assessments/surveys to collect data describing respondents’ current or very recent experiences and related contexts in their natural environments. The use of EMA in audiology research is growing. Purpose This study examined the construct validity (i.e., the degree to which a measurement reflects what it is intended to measure) of EMA in terms of measuring speech understanding and related listening context. Experiment 1 investigated the extent to which individuals can accurately report their speech recognition performance and characterize the listening context in controlled environments. Experiment 2 investigated whether the data aggregated across multiple EMA surveys conducted in uncontrolled, real-world environments would reveal a valid pattern that was consistent with the established relationships between speech understanding, hearing aid use, listening context, and lifestyle. Research Design This is an observational study. Study Sample Twelve and twenty-seven adults with hearing impairment participated in Experiments 1 and 2, respectively. Data Collection and Analysis In the laboratory testing of Experiment 1, participants estimated their speech recognition performance in settings wherein the signal-to-noise ratio was fixed or constantly varied across sentences. In the field testing the participants reported the listening context (e.g., noisiness level) of several semicontrolled real-world conversations. Their reports were compared to (1) the context described by normal-hearing observers and (2) the background noise level measured using a sound level meter. In Experiment 2, participants repeatedly reported the degree of speech understanding, hearing aid use, and listening context using paper-and-pencil journals in their natural environments for 1 week. They also carried noise dosimeters to measure the sound level. The associations between (1) speech understanding, hearing aid use, and listening context, (2) dosimeter sound level and self-reported noisiness level, and (3) dosimeter data and lifestyle quantified using the journals were examined. Results For Experiment 1, the reported and measured speech recognition scores were highly correlated across all test conditions (r = 0.94 to 0.97). The field testing results revealed that most listening context properties reported by the participants were highly consistent with those described by the observers (74–95% consistency), except for noisiness rating (58%). Nevertheless, higher noisiness rating was associated with higher background noise level. For Experiment 2, the EMA results revealed several associations: better speech understanding was associated with the use of hearing aids, front-located speech, and lower dosimeter sound level; higher noisiness rating was associated with higher dosimeter sound level; listeners with more diverse lifestyles tended to have higher dosimeter sound levels. Conclusions Adults with hearing impairment were able to report their listeni...

“…Individual directional advantage scores for the 12 participants are listed in Table 1. In a previous study using the same test materials and procedures, 0 dB SNR corresponded to the midpoint of the performance-intensity function and was the condition in which 30 of the 31 participants obtained a directional advantage of at least 15% (Walden et al, 2005). The participants in the current study had mean key word scores of 30.3% (range: 12-47%) and 57.2% (range: 27-86%) for the binaural omnidirectional and binaural directional conditions respectively.…”

Section: Speech Recognition In Noise Testingmentioning

confidence: 76%

Field Evaluation of an Asymmetric Directional Microphone Fitting

Cord

Walden²,

Surr³

et al. 2007

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Laboratory evidence suggests that an asymmetric microphone fitting (omnidirectional processing in one ear and directional processing in the other) can provide a directional advantage in background noise that is as great, or nearly as great, as that provided by binaural directional processing (Bentler et al, 2004). The present study investigated whether the potential benefit of an asymmetric fitting observed in the laboratory extends to real-life listening. Specifically, ease of listening was compared across a variety of real-life listening situations for asymmetric microphone fittings and bilateral omnidirectional processing. These ratings were compared to determine whether the asymmetric fitting provided an advantage in listening situations in which directional microphone processing is generally preferred and/or a disadvantage in listening situations in which omnidirectional microphone processing is generally preferred. Results suggest that an asymmetric fitting may be a viable option for patients who cannot or do not switch microphone modes.