Method for calculating directivity index of a directional microphone in a hearing aid on a manikin

2005 ◽  
Vol 118 (3) ◽  
pp. 1860-1860
Author(s):  
Andrew Dittberner ◽  
Ruth Bentler
Keyword(s):  
Hearing Aid ◽  
Directional Microphone

Left-Right and Front-Back Spatial Hearing with Multiple Directional Microphone Configurations in Modern Hearing Aids

2014 ◽  
Vol 25 (09) ◽  
pp. 791-803 ◽  
Author(s):  
Evelyne Carette ◽  
Tim Van den Bogaert ◽  
Mark Laureyns ◽  
Jan Wouters
Keyword(s):  
Sound Localization ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Performance Measure ◽  
Frequency Dependent ◽  
Binaural Cues ◽  
Directional Microphone ◽  
Spectral Cues ◽  
Localization Performance ◽  
Asymmetric Configuration

Background: Several studies have demonstrated negative effects of directional microphone configurations on left-right and front-back (FB) sound localization. New processing schemes, such as frequency-dependent directionality and front focus with wireless ear-to-ear communication in recent, commercial hearing aids may preserve the binaural cues necessary for left-right localization and may introduce useful spectral cues necessary for FB disambiguation. Purpose: In this study, two hearing aids with different processing schemes, which were both designed to preserve the ability to localize sounds in the horizontal plane (left-right and FB), were compared. Research Design: We compared horizontal (left-right and FB) sound localization performance of hearing aid users fitted with two types of behind-the-ear (BTE) devices. The first type of BTE device had four different programs that provided (1) no directionality, (2–3) symmetric frequency-dependent directionality, and (4) an asymmetric configuration. The second pair of BTE devices was evaluated in its omnidirectional setting. This setting automatically activates a soft forward-oriented directional scheme that mimics the pinna effect. Also, wireless communication between the hearing aids was present in this configuration (5). A broadband stimulus was used as a target signal. The directional hearing abilities of the listeners were also evaluated without hearing aids as a reference. Study Sample: A total of 12 listeners with moderate to severe hearing loss participated in this study. All were experienced hearing-aid users. As a reference, 11 listeners with normal hearing participated. Data Collection and Analysis: The participants were positioned in a 13-speaker array (left-right, –90°/+90°) or 7-speaker array (FB, 0–180°) and were asked to report the number of the loudspeaker located the closest to where the sound was perceived. The root mean square error was calculated for the left-right experiment, and the percentage of FB errors was used as a FB performance measure. Results were analyzed with repeated-measures analysis of variance. Results: For the left-right localization task, no significant differences could be proven between the unaided condition and both partial directional schemes and the omnidirectional scheme. The soft forward-oriented system and the asymmetric system did show a detrimental effect compared with the unaided condition. On average, localization was worst when users used the asymmetric condition. Analysis of the results of the FB experiment showed good performance, similar to unaided, with both the partial directional systems and the asymmetric configuration. Significantly worse performance was found with the omnidirectional and the omnidirectional soft forward-oriented BTE systems compared with the other hearing-aid systems. Conclusions: Bilaterally fitted partial directional systems preserve (part of) the binaural cues necessary for left-right localization and introduce, preserve, or enhance useful spectral cues that allow FB disambiguation. Omnidirectional systems, although good for left-right localization, do not provide the user with enough spectral information for an optimal FB localization performance.

The Relationship between the Acceptance of Noise and Acoustic Environments in Young Adults with Normal Hearing: A Pilot Study

2014 ◽  
Vol 25 (06) ◽  
pp. 584-591 ◽  
Author(s):  
Clifford A. Franklin ◽  
Letitia J. White ◽  
Thomas C. Franklin ◽  
Laura Smith-Olinde
Keyword(s):  
Background Noise ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Data Logging ◽  
Directional Microphone ◽  
Hearing Aid Use ◽  
Listening Environments ◽  
Quasi Experimental ◽  
Acoustic Environments ◽  
Different Characteristics

Background: The acceptable noise level (ANL) indicates how much background noise a listener is willing to accept while listening to speech. The clinical impact and application of the ANL measure is as a predictor of hearing-aid use. The ANL may also correlate with the percentage of time spent in different listening environments (i.e., quiet, noisy, noisy with speech present, etc). Information retrieved from data logging could confirm this relationship. Data logging, using sound scene analysis, is a method of monitoring the different characteristics of the listening environments that a hearing-aid user experiences during a period. Purpose: The purpose of this study was to determine if the ANL procedure reflects the proportion of time a person spends in different acoustic environments. Research Design: This was a descriptive quasi-experimental design to collect pilot data in which participants were asked to maintain their regular, daily activities while wearing a data-logging device. Study Sample: After completing the ANL measurement, 29 normal-hearing listeners were provided a data-logging device and were instructed on its proper use. Data Collection/Analysis: ANL measures were obtained along with the percentage of time participants spent in listening environments classified as quiet, speech-in-quiet, speech-in-noise, and noise via a data-logging device. Results: An analysis of variance using a general linear model indicated that listeners with low ANL values spent more time in acoustic environments in which background noise was present than did those with high ANL values; the ANL data did not indicate differences in how much time listeners spent in environments of differing intensities. Conclusions: To some degree, the ANL is reflective of the acoustic environments and the amount of noise that the listener is willing to accept; data logging illustrates the acoustic environments in which the listener was present. Clinical implications include, but are not limited to, decisions in patient care regarding the need for additional counseling and/or the use of digital noise reduction and directional microphone technology.

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

2018 ◽  
Vol 27 (1) ◽  
pp. 95-103
Author(s):  
Adriana Goyette ◽  
Jeff Crukley ◽  
Jason Galster
Keyword(s):  
Hearing Impairment ◽  
High Frequency ◽  
Hearing Aid ◽  
Internal Noise ◽  
Normal Hearing ◽  
Noise Performance ◽  
Directional Microphones ◽  
Speech In Noise ◽  
Directional Microphone ◽  
Hearing In Noise

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.

Improved BTE hearing‐aid directivity using a directional microphone array

2004 ◽  
Vol 115 (5) ◽  
pp. 2598-2598
Author(s):  
Douglas L. Jones ◽  
Michael E. Lockwood ◽  
Charissa R. Lansing ◽  
Albert S. Feng
Keyword(s):  
Microphone Array ◽  
Hearing Aid ◽  
Directional Microphone

Comparative Performance of an Adaptive Directional Microphone System and a Multichannel Noise Reduction System

2006 ◽  
Vol 17 (04) ◽  
pp. 241-252 ◽  
Author(s):  
Kevin C.P. Yuen ◽  
Anna C.S. Kam ◽  
Polly S.H. Lau
Keyword(s):  
Noise Reduction ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Recognition Performance ◽  
Comparative Performance ◽  
Sentence Recognition ◽  
Side Condition ◽  
Directional Microphone ◽  
Reduction System ◽  
Front Condition

The amplification outcomes of two hearing aid prescriptions, NAL-NL1 and Digital Perception Processing (DPP), of nine moderate to moderately severe hearing-impaired adults were compared in the same digital hearing instrument. NAL-NL1 aims at optimizing speech intelligibility while amplifying the speech signal to a normal overall loudness level (Dillon, 1999). DPP focuses on restoring loudness based on normal and impaired cochlear excitation models (Launer and Moore, 2003). In this comparison, DPP resulted in better sentence recognition performance than the NAL-NL1 algorithm in the signal-front/noise-side condition, and the two prescriptions gave similar performance in the signal-front/noise-front condition. Subjective evaluations by the participants using the Abbreviated Profile for Hearing Aid Benefit and sound quality comparisons did not give conclusive results between the two prescriptions.With each hearing aid prescription, the ability of the hearing aid circuitry to reduce the effects of noise was evaluated by a sentence-in-noise test in three conditions: (1) adaptive directional microphone (DAZ), (2) multichannel noise reduction system (FNC), and (3) a combination of FNC and DAZ (FNC + DAZ). In the signal-front/noise-side condition, DAZ and FNC + DAZ gave better performance than FNC in nearly all participants, whereas in the signal-front and noise-front evaluation, the conditions revealed no significant differences.

scholarly journals The Effect of Hearing Aid Technologies on Listening in an Automobile

2013 ◽  
Vol 24 (06) ◽  
pp. 474-485 ◽  
Author(s):  
Yu-Hsiang Wu ◽  
Elizabeth Stangl ◽  
Ruth A. Bentler ◽  
Rachel W. Stanziola
Keyword(s):  
Signal Processing ◽  
Speech Recognition ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Recognition Performance ◽  
Road Noise ◽  
Processing Scheme ◽  
Repeated Measures Design ◽  
Directional Microphone ◽  
Omnidirectional Microphones

Background: Communication while traveling in an automobile often is very difficult for hearing aid users. This is because the automobile/road noise level is usually high, and listeners/drivers often do not have access to visual cues. Since the talker of interest usually is not located in front of the listener/driver, conventional directional processing that places the directivity beam toward the listener's front may not be helpful and, in fact, could have a negative impact on speech recognition (when compared to omnidirectional processing). Recently, technologies have become available in commercial hearing aids that are designed to improve speech recognition and/or listening effort in noisy conditions where talkers are located behind or beside the listener. These technologies include (1) a directional microphone system that uses a backward-facing directivity pattern (Back-DIR processing), (2) a technology that transmits audio signals from the ear with the better signal-to-noise ratio (SNR) to the ear with the poorer SNR (Side-Transmission processing), and (3) a signal processing scheme that suppresses the noise at the ear with the poorer SNR (Side-Suppression processing). Purpose: The purpose of the current study was to determine the effect of (1) conventional directional microphones and (2) newer signal processing schemes (Back-DIR, Side-Transmission, and Side-Suppression) on listener's speech recognition performance and preference for communication in a traveling automobile. Research Design: A single-blinded, repeated-measures design was used. Study Sample: Twenty-five adults with bilateral symmetrical sensorineural hearing loss aged 44 through 84 yr participated in the study. Data Collection and Analysis: The automobile/road noise and sentences of the Connected Speech Test (CST) were recorded through hearing aids in a standard van moving at a speed of 70 mph on a paved highway. The hearing aids were programmed to omnidirectional microphone, conventional adaptive directional microphone, and the three newer schemes. CST sentences were presented from the side and back of the hearing aids, which were placed on the ears of a manikin. The recorded stimuli were presented to listeners via earphones in a sound-treated booth to assess speech recognition performance and preference with each programmed condition. Results: Compared to omnidirectional microphones, conventional adaptive directional processing had a detrimental effect on speech recognition when speech was presented from the back or side of the listener. Back-DIR and Side-Transmission processing improved speech recognition performance (relative to both omnidirectional and adaptive directional processing) when speech was from the back and side, respectively. The performance with Side-Suppression processing was better than with adaptive directional processing when speech was from the side. The participants' preferences for a given processing scheme were generally consistent with speech recognition results. Conclusions: The finding that performance with adaptive directional processing was poorer than with omnidirectional microphones demonstrates the importance of selecting the correct microphone technology for different listening situations. The results also suggest the feasibility of using hearing aid technologies to provide a better listening experience for hearing aid users in automobiles.

Sign in / Sign up

Export Citation Format

Share Document