Performance of Directional Microphones for Hearing Aids: Real-World versus Simulation

2004 ◽  
Vol 15 (06) ◽  
pp. 440-455 ◽  
Author(s):  
Cynthia L. Compton-Conley ◽  
Arlene C. Neuman ◽  
Mead C. Killion ◽  
Harry Levitt

The purpose of this study was to assess the accuracy of clinical and laboratory measures of directional microphone benefit. Three methods of simulating a noisy restaurant listening situation ([1] a multimicrophone/multiloudspeaker simulation, the R-SPACE™, [2] a single noise source behind the listener, and [3] a single noise source above the listener) were evaluated and compared to the "live" condition. Performance with three directional microphone systems differing in polar pattern (omnidirectional, supercardioid, and hypercardioid array) and directivity indices (0.34, 4.20, and 7.71) was assessed using a modified version of the Hearing in Noise Test (HINT). The evaluation revealed that the three microphones could be ordered with regard to the benefit obtained using any of the simulation techniques. However, the absolute performance obtained with each microphone type differed among simulations. Only the R-SPACE simulation yielded accurate estimates of the absolute performance of all three microphones in the live condition. Performance in the R-SPACE condition was not significantly different from performance in the "live restaurant" condition. Neither of the single noise source simulations provided accurate predictions of real-world (live) performance for all three microphones.

2004 ◽  
Vol 15 (09) ◽  
pp. 649-659 ◽  
Author(s):  
Ruth A. Bentler ◽  
Jessica L.M. Egge ◽  
Jill L. Tubbs ◽  
Andrew B. Dittberner ◽  
Gregory A. Flamme

The purpose of this study was to assess the relationship between the directivity of a directional microphone hearing aid and listener performance. Hearing aids were fit bilaterally to 19 subjects with sensorineural hearing loss, and five microphone conditions were assessed: omnidirectional, cardioid, hypercardioid, supercardioid, and "monofit," wherein the left hearing aid was set to omnidirectional and the right hearing aid to hypercardioid. Speech perception performance was assessed using the Hearing in Noise Test (HINT) and the Connected Speech Test (CST). Subjects also assessed eight domains of sound quality for three stimuli (speech in quiet, speech in noise, and music). A diffuse soundfield system composed of eight loudspeakers forming the corners of a cube was used to output the background noise for the speech perception tasks and the three stimuli used for sound quality judgments. Results indicated that there were no significant differences in the HINT or CST performance, or sound quality judgments, across the four directional microphone conditions when tested in a diffuse field. Of particular interest was the monofit condition: Performance on speech perception tests was the same whether one or two directional microphones were used.


2006 ◽  
Vol 17 (07) ◽  
pp. 519-530 ◽  
Author(s):  
Peter J. Blamey ◽  
Hayley J. Fiket ◽  
Brenton R. Steele

Omnidirectional, supercardioid, and adaptive directional microphones (ADM) were evaluated in combination with the ADRO® amplification scheme for eight participants with moderate sloping hearing losses. The ADM produced better speech perception scores than the other two microphones in all noise conditions. Participants performed the Hearing in Noise Test sentences at -4.5 dB SNR or better, which is similar to the level achievable with normal hearing. The Speech, Spatial and Qualities of Hearing Scale indicated no disadvantages of using the ADM relative to the omnidirectional microphone in real-life situations. The ADM was preferred over the omnidirectional microphone in 54% of situations, compared to 17% preferences for the omnidirectional microphone, and 29% no preference. The combination of the ADM to improve SNR, and ADRO® to keep the signal output comfortable and audible provided near-normal hearing performance for people with moderate hearing loss. The ADM is the recommended microphone configuration for ADRO hearing aids.


2004 ◽  
Vol 15 (06) ◽  
pp. 426-439 ◽  
Author(s):  
M. Samantha Lewis ◽  
Carl C. Crandell ◽  
Michael Valente ◽  
Jane Enrietto Horn

The major consequence of sensorineural hearing loss (SNHL) is communicative difficulty, especially with the addition of noise and/or reverberation. The purpose of this investigation was to compare two types of technologies that have been shown to improve the speech-perception performance of individuals with SNHL: directional microphones and frequency modulation (FM) systems. Forty-six adult subjects with slight to severe SNHL served as subjects. Speech perception was assessed using the Hearing in Noise Test (HINT) with correlated diffuse noise under five different listening conditions. Results revealed that speech perception was significantly better with the use of the FM system over that of any of the hearing aid conditions, even with the use of the directional microphone. Additionally, speech perception was significantly better with the use of two hearing aids used in conjunction with two FM receivers rather than with just one FM receiver. Directional microphone performance was significantly better than omnidirectional microphone performance. All aided listening conditions were significantly better than the unaided listening condition.


2002 ◽  
Vol 13 (06) ◽  
pp. 295-307 ◽  
Author(s):  
Mary T. Cord ◽  
Rauna K. Surr ◽  
Brian E. Walden ◽  
Laurel Olson

This study explored the use patterns and benefits of directional microphone technology in real world situations experienced by patients who had been fitted with switchable omnidirectional/directional hearing aids. Telephone interviews and paper-and-pencil questionnaires were used to assess perceived performance with each microphone type in a variety of listening situations. Patients who used their hearing aids regularly and switched between the two microphone configurations reported using the directional mode, on average, about one-quarter of the time. From brief descriptions, patients could identify listening situations in which each microphone mode should provide superior performance. Further, they reported encountering listening situations in which an omnidirectional microphone should provide better performance more frequently than listening situations in which the directional microphones should be superior. Despite using the omnidirectional mode more often and encountering situations in which an omnidirectional microphone should provide superior performance more frequently, participants reported the same level of satisfaction with each microphone type.


2005 ◽  
Vol 16 (07) ◽  
pp. 473-484 ◽  
Author(s):  
Ruth A. Bentler

A systematic review of the literature was undertaken to find evidence of real-world effectiveness of directional microphone and digital noise reduction features in current hearing aids. The evidence was drawn from randomized controlled trials, nonrandomized intervention studies, and descriptive studies. The quality of each study was evaluated for factors such as blinding, power of statistical analyses, and use of psychometrically strong outcome measures. Weaknesses in the identified studies included small sample size, resultant poor power to detect potentially worthwhile differences, and overlapping experimental conditions. Nine studies were identified for directional microphones, and the evidence (albeit weak) supports effectiveness. Two studies were identified for the noise reduction feature, and the evidence was equivocal. For the researcher, such a systematic review should encourage the careful consideration of appropriate methodologies for assessing feature effectiveness. For the clinician, the outcomes reported herein should encourage use of such a systematic review to drive clinical practice.


2003 ◽  
Vol 56 (11) ◽  
pp. 40 ◽  
Author(s):  
Brian E. Walden ◽  
Rauna K. Surr ◽  
Mary T. Cord

2018 ◽  
Vol 27 (1) ◽  
pp. 95-103
Author(s):  
Adriana Goyette ◽  
Jeff Crukley ◽  
Jason Galster

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.


2007 ◽  
Vol 18 (09) ◽  
pp. 794-808
Author(s):  
Melissa N. Ruscetta ◽  
Catherine V. Palmer ◽  
John D. Durrant ◽  
Judith Grayhack ◽  
Carey Ryan

The chief complaint of individuals with hearing impairment is difficulty hearing in noise, with directional microphones emerging as the most capable remediation. Our purpose was to determine the impact of directional microphones on localization disability and concurrent handicap. Fifty-seven individuals participated unaided and then in groups of 19, using omni-directional microphones, directional-microphones, or toggle-switch equipped amplification. The outcome measure was a localization disabilities and handicaps questionnaire. Comparisons between the unaided group versus the aided groups, and the directional-microphone groups versus the other two aided groups revealed no significant differences. None of the microphone schemes either increased or decreased self-perceived localization disability or handicap. Objective measures of localization ability are warranted and if significance is noted, clinicians should caution patients when moving in their environment. If no significant objective differences exist, in light of the subjective findings in this investigation concern over decreases in quality of life and safety with directional microphones need not be considered. La principal queja de los individuos con trastornos auditivos es la dificultad para escuchar en medio de ruido, emergiendo los micrófonos direccionales como el más capaz remedio. Nuestro propósito fue determinar el impacto de los micrófonos direccionales en la incapacidad de localización y en los impedimentos concurrentes. Cincuenta y siete individuos participaron sin amplificación y luego, en grupos de 19, utilizando micrófonos omni-direccionales, micrófonos direccionales, o amplificación equipada con interruptores de palanca. La medida de resultado fue un cuestionario de discapacidades e impedimentos de localización. Las comparaciones entre el grupo sin amplificación versus los grupos con amplificación, y entre el grupo con micrófono direccional versus los otros dos grupos con amplificación no revelaron diferencias significativas. Ninguno de los esquemas de micrófono aumentó o disminuyó la discapacidad o el impedimento auto-percibido de localización. Las medidas objetivas de la habilidad de localización se garantizan y si se llega a notar algo significativo, los clínicos deberían advertir a los pacientes cuando se desplacen en sus ambientes. Si no existen diferencias objetivas significativas, a la luz de los hallazgos subjetivos de esta investigación, no debe considerarse ninguna preocupación sobre la disminución de la calidad de vida o la seguridad con el uso de micrófonos direccionales.


2009 ◽  
Vol 46 (5) ◽  
pp. 603 ◽  
Author(s):  
David Gnewikow ◽  
Todd Ricketts ◽  
Gene W. Bratt ◽  
Laura C. Mutchler

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