Acceptance Of Background Noise Research Articles

The effects of asymmetric directional microphone fittings on acceptance of background noise

Objective: The effects of asymmetric directional microphone fittings (i.e., an omnidirectional microphone on one ear and a directional microphone on the other) on speech understanding in noise and acceptance of background noise were investigated in 15 full-time hearing aid users. Design: Subjects were fitted binaurally with four directional microphone conditions (i.e., binaural omnidirectional, right asymmetric directional, left asymmetric directional and binaural directional microphones) using Siemens Intuis Directional behind-the-ear hearing aids. Speech understanding in noise was assessed using the Hearing in Noise Test, and acceptance of background noise was assessed using the Acceptable Noise Level procedure. Speech was presented from 0° while noise was presented from 180° azimuth. Results/Conclusions: The results revealed that speech understanding in noise improved when using asymmetric directional microphones compared to binaural omnidirectional microphone fittings and was not significantly hindered compared to binaural directional microphone fittings. The results also revealed that listeners accepted more background noise when fitted with asymmetric directional microphones as compared to binaural omnidirectional microphones. Lastly, the results revealed that the acceptance of noise was further increased for the binaural directional microphones when compared to the asymmetric directional microphones, maximizing listeners' willingness to accept background noise in the presence of noise. Clinical implications will be discussed.SumarioObjetivo: Se investigaron los efectos de la adaptación de micrófonos asimétricos direccionales (i.e., un micrófono omnidireccional en un oído y uno direccional en el otro) sobre la comprensión del lenguaje en ruido y la aceptación del ruido de fondo en 15 usuarios de auxiliares auditivos de tiempo completo. Diseño: A los sujetos se les adaptaron binauralmente micrófonos direccionales en cuatro condiciones: (i.e., binaural omnidireccional, direccional derecho asimétrico, izquierdo direccional asimétrico y binaural direccional) utilizando los auxiliares auditivos tipo retroauricular Siemens Intuis Direccional. La comprensión del lenguaje en ruido fue evaluada utilizando la Prueba de Audición en Ruido y la aceptación del ruido de fondo fue evaluada utilizando el procedimiento de Nivel de Ruido Aceptable. El lenguaje se presentó a 0° mientras que el ruido se presentó a un azimut de 180°. Resultados/Conclusiones: Los resultados revelan que la comprensión del lenguaje en ruido mejoró cuando se utilizan micrófonos direccionales asimétricamente, en comparación con los micrófonos omnidireccionales en forma binaural y no se dificultó significativamente al compararse con los micrófonos direccionales en forma binaural. Estos resultados también revelaron que los oyentes aceptan mayor ruido de fondo cuando se les adaptan micrófonos asimétricos direccionales en comparación con los micrófonos omnidireccionales en forma binaural. Por ultimo, los resultados revelan que la aceptación de ruido aumentó con los micrófonos direccionales bianurales cuando se compararon con los micrófonos direccionales asimétricos, maximizando la disposición de los oyentes para aceptar el ruido de fondo en presencia de ruido. Las implicaciones clínicas serán discutidas.

Effects of speech signal content and speaker gender on acceptance of noise in listeners with normal hearing

Objective: The purpose of this research was to determine if the content and/or speaker gender of a running speech sample affected the acceptance of background noise within a participant. Design: A male and a female recording of the Arizona Travelogue (Cosmos Inc.) and the ipsilateral competing message (ICM) from the synthetic sentence identification with ICM were created and used as the experimental speech signals. Two acceptable noise level measurements were obtained and averaged for each condition. Twenty-one participants rated interest level in the speech sample for each condition. Study Sample: Forty-three listeners with normal hearing participated. Results: Interest level was significantly greater for the ICM than the Arizona Travelogue speech samples, and was significantly greater for female samples. Neither the content of the sample nor the gender of the speaker significantly affected the most comfortable level or the acceptable noise level. Conclusions: Findings suggest that the acceptable noise level can be measured using various types of speech signals for normal-hearing listeners.SumarioObjetivo: El propósito de esta investigación fue determinar si el contenido y/o el género del locutor en una muestra de lenguaje corrido afectaba la aceptación del ruido de fondo en un mismo participante. Diseño: Se realizóuna grabación con la participación de un hombre y una mujer del Arizona Travelogue (Cosmos Inc.) y del Mensaje Competitivo Ipsilateral (ICM) de la prueba de identificación de Frases Sintéticas con ICM, y se creó una material que fue utilizado como señal lingûstica experimental. Se obtuvieron dos mediciones de niveles de ruido aceptables y se promediaron para cada condición. Veintiún participantes calificaron el nivel de interés de la muestra de lenguaje para cada condición. Muestra del Estudio: Participaron cuarenta y tres sujetos con audición normal. Resultados: El nivel de interés fue significativamente mayor para las muestras de lenguaje del ICM que para las del Arizona Travelogue y estas fueron significativamente mayores para muestras grabadas por mujeres. Ni el contenido de la muestra ni el género del locutor afectó significativamente el nivel más confortable o el nivel aceptable de ruido. Conclusiones: Los hallazgos sugieren que el nivel aceptable de ruido puede medirse usando varios tipos de señales de lenguaje para oyentes con audición normal.

Acceptance of background noise: Recent developments

Further evidence is coming in that the greater a patient's acceptance of background noise, the more likely he or she is to use hearing aids. The author discusses some of the benefits of determining patients' Acceptable Noise Level (ANL).

The Acceptance of Background Noise in Adult Cochlear Implant Users

The purpose of this study was to determine (a) if acceptable noise levels (ANLs) are different in cochlear implant (CI) users than in listeners with normal hearing, (b) if ANLs are related to sentence reception thresholds in noise in CI users, and (c) if ANLs and subjective outcome measures are related in CI users. ANLs and the Hearing in Noise Test (HINT; M. Nilsson, S. Soli, & J. Sullivan, 1994) were examined in 9 adult CI users and 15 adult listeners with normal hearing. In addition, the Abbreviated Profile of Hearing Aid Benefit (APHAB; R. M. Cox & G. C. Alexander, 1995) and a satisfaction questionnaire were administered to CI users only. Results indicated that (a) ANLs were not significantly different for CI users and listeners with normal hearing, (b) ANLs were not correlated with HINT values for either group, (c) ANL was not significantly correlated with APHAB scores, and (d) ANL was significantly correlated with overall CI benefit on the satisfaction questionnaire. CI users with large ANLs reported more benefit from implants than those with small ANLs. The results of this preliminary study of ANL in CI users suggest that ANL can be used as a tool for evaluating processing in noise in individual CI users.

Contribution of High-Frequency Information to the Acceptance of Background Noise in Listeners With Normal and Impaired Hearing

To determine whether information beyond 2.0 kHz affected the acceptance of background noise in listeners with normal and/or impaired hearing. Speech stimuli (Arizona Travelogue) and multitalker babble were low-pass filtered at cutoff frequencies of 2.0, 4.0, and 6.0 kHz and presented using an adaptive paradigm to determine the most comfortable level (MCL) and acceptable noise level (ANL) for 4 experimental conditions (unfiltered, 2.0, 4.0, and 6.0 kHz) for each listener. MCL for listening to speech in quiet was significantly increased when the speech stimuli were low-pass filtered at 2.0 kHz relative to the unfiltered and 6.0-kHz conditions. Acceptance of background noise was significantly poorer when the speech and noise stimuli were low-pass filtered at 2.0 kHz relative to the 6.0-kHz condition. Listeners with impaired hearing sensitivity had significantly greater MCL values than listeners with normal hearing, but ANL values were not significantly affected by the hearing sensitivity of the listener. Information beyond 2.0 kHz significantly affected MCL and ANL values in both listeners with normal hearing and impaired hearing; however, effects for both the MCL and ANL measurements were small and may not be significant clinically.

Differences in Responses from the Cochleae and Central Nervous Systems of Females with Low versus High Acceptable Noise Levels

Studies of acceptable noise level (ANL) consistently report large intersubject variability in acceptance of background noise while listening to speech. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, or efferent activity of the medial olivocochlear pathway. An exploratory study was conducted to determine if differences in aggregate responses from the peripheral and central auditory system can account for intersubject variability in ANL. Click-evoked otoacoustic emissions (CEOAEs), binaural auditory brainstem responses (ABRs), and middle latency responses (MLRs) were measured in females with normal hearing with low (n = 6) versus high (n = 7) ANLs. Results of this preliminary study indicate no differences between the groups for CEOAEs or waves I or III of the ABR. Differences between the two groups emerge for the amplitudes of wave V of the ABR and for the Na-Pa component of the MLR, suggesting that physiological variations arising from more central regions of the auditory system may mediate background noise acceptance.

Acceptable Noise Level: Reliability Measures and Comparison to Preference for Background Sounds

The present study (1) assessed the reliability of the acceptable noise level (ANL) measure using speech-spectrum and speech-babble noises as the competing stimuli, and (2) investigated the relationship between ANL and preference for background sounds in 30 young adults with normal hearing sensitivity. Listeners were evaluated during three test sessions approximately one week apart. Results demonstrated that ANLs are highly reliable over short periods of time, independent of the background noise distraction. Mean ANLs, however, were affected by type of background noise distraction, indicating ANLs obtained using different competing stimuli should not be compared directly. Results further demonstrated that participants' ratings of preference for background sound were consistent over time; however, listeners' preference for background sound was not related to their acceptance of background noise (i.e., ANL). This may indicate listeners cannot accurately assess their ability to accept background sounds, at least with the questionnaire used in the present study.

The Effects of Digital Noise Reduction on the Acceptance of Background Noise

Modern hearing aids commonly employ digital noise reduction (DNR) algorithms. The potential benefit of these algorithms is to provide improved speech understanding in noise or, at the least, to provide relaxed listening or increased ease of listening. In this study, 22 adults were fitted with 16-channel wide-dynamic-range compression hearing aids containing DNR processing. The DNR includes both modulation-based and Wiener-filter-type algorithms working simultaneously. Both speech intelligibility and acceptable noise level (ANL) were assessed using the Hearing in Noise Test (HINT) with DNR on and DNR off. The ANL was also assessed without hearing aids. The results showed a significant mean improvement for the ANL (4.2 dB) for the DNR-on condition when compared to DNR-off condition. Moreover, there was a significant correlation between the magnitude of ANL improvement (relative to DNR on) and the DNR-off ANL. There was no significant mean improvement for the HINT for the DNR on condition, and on an individual basis, the HINT score did not significantly correlate with either aided ANL (DNR on or DNR off). These findings suggest that at least within the constraints of the DNR algorithms and test conditions employed in this study, DNR can significantly improve the clinically measured ANL, which may result in improved ease of listening for speech-in-noise situations.

Auditory evoked potentials in females with high and low acceptance of background noise when listening to speech

Acceptable noise level (ANL) is a measure of a listener's acceptance of background noise when listening to speech. A consistent finding in research on ANL is large intersubject variability in the acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, cochlear responses, or efferent activity of the medial olivocochlear pathway. In the present study, auditory evoked potentials were examined in 21 young females with normal hearing with low and high acceptance of background noise to determine whether differences in judgments of background noise are related to differences measured in aggregate physiological responses from the auditory nervous system. Group differences in the auditory brainstem response, auditory middle latency response, and cortical, auditory late latency response indicate that differences in more central regions of the nervous system account for, at least in part, the variability in listeners' willingness to accept background noise when listening to speech.

The Effect of Speech Presentation Level on Acceptance of Background Noise in Listeners with Normal Hearing

A method has been established to measure the maximum acceptable background noise level (BNL) for a listener, while listening to speech at the most comfortable listening level (MCL). The acceptable noise level (ANL) is the difference between BNL and MCL. In the present study, the ANL procedure was used to measure acceptance of noise, first, in the presence of speech at MCL and, then, for speech presented at much lower and higher levels in listeners with normal hearing. This study used the term ANL to describe the results obtained at MCL and also at other speech presentation levels. The mean ANL at MCL was 15.5 dB, which is comparable to results obtained by previous investigators. ANL increases systematically with speech presentation level. Mean ANLs ranged from 10.6 dB when speech was presented at 20 dB HL to 24.6 dB when speech was presented at 76 dB HL. The results indicated that the acceptance of noise depends significantly on speech presentation level.

Effect of Stimulant Medication on the Acceptance of Background Noise in Individuals with Attention Deficit/Hyperactivity Disorder

Available data indicate that, on some auditory tasks, individuals with attention deficit/hyperactivity disorder (ADHD/ADD) perform more poorly than individuals without ADHD/ADD. Research also indicates that performance may improve with the use of stimulant medication. The present study (1) examined the effect of stimulant medication on acceptance of background noise in individuals with ADHD/ADD and (2) investigated the dependence of speech presentation level on acceptance of noise in persons with ADHD/ADD. Fifteen normal hearing female college students with ADHD/ADD served as the participants. The participants were medicated in one session and unmedicated in the other session. Results showed that medication significantly increased the acceptance of background noise for individuals with ADHD/ADD. Results also indicated that acceptance of noise depends on speech presentation level, but the improvement in acceptance of noise was not dependent on medication.

Acceptance of background noise may be key to successful fittings

There is growing interest in a theory that measuring a patient's acceptance of background noise may help predict the person's willingness to use and benefit from hearing aids. The developer of the theory explains how it may help clinicians improve their success rate.

Comparison of Speech Perception in Background Noise With Acceptance of Background Noise in Aided and Unaided Conditions

Background noise is a significant factor influencing hearing-aid satisfaction and is a major reason for rejection of hearing aids. Attempts have been made by previous researchers to relate the use of hearing aids to speech perception in noise (SPIN), with an expectation of improved speech perception followed by an increased acceptance of hearing aids. Unfortunately, SPIN was not related to hearing-aid use or satisfaction. A new measure of listener reaction to background noise has been proposed. The acceptable noise level (ANL), expressed in decibels, is defined as a difference between the most comfortable listening level for speech and the highest background noise level that is acceptable when listening to and following a story. The ANL measure assumes that speech understanding in noise may not be as important as is the willingness to listen in the presence of noise. It has been established that people who accept background noise have smaller ANLs and tend to be "good" users of hearing aids. Conversely, people who cannot accept background noise have larger ANLs and may only use hearing aids occasionally or reject them altogether. Because this is a new measure, it was important to determine the reliability of the ANL over time with and without hearing aids, to determine the effect of acclimatization to hearing aids, and to compare the ANL to well-established measures such as speech perception scores collected with the SPIN test. Results from 50 listeners indicate that for both good and occasional hearing aid users, the ANL is comparable in reliability to the SPIN test and that both measures do not change with acclimatization. The ANLs and SPIN scores are unrelated. Although the SPIN scores improve with amplification, the ANLs are unaffected by amplification, suggesting that the ANL is inherent to an individual and can be established prior to hearing aid fitting as a possible predictor of hearing-aid use.

Physiologic correlates to background noise acceptance

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

The Influence of Listener's Gender on the Acceptance of Background Noise

The acceptance of background noise can be assessed by having participants select the maximum background noise level (BNL) to which they are willing to listen while following speech at their most comfortable listening level (MCL). The difference between the selected BNL and MCL is the acceptable noise level (ANL). Preliminary investigations have revealed large between-participant ANL differences that are not related to age, hearing status, preference for background noise, or uncomfortable listening level. This study investigated listener's gender as a possible factor contributing to these between-participant differences. Comfortable listening levels for speech and accepted levels of speech-babble background noise were obtained binaurally, via the sound field, from 50 (25 male, 25 female) young, acoustically naive adults with normal hearing sensitivity. Results indicate that, although males had higher comfortable listening levels and accepted higher levels of background noise than females, ANL values were not different between males and females.

Relationship between acceptance of background noise and hearing aid use

Background noise produces complaints among hearing-aid users, however speech-perception-in-noise does not predict hearing-aid use. It is possible that hearing-aid users are complaining about the presence of background noise and not about speech perception. To test this possibility, acceptance of background noise is being investigated as a predictor of hearing-aid use. Acceptance of background noise is determined by having subjects select their most comfortable listening level (MCL) for a story. Next, speech-babble is added and the subjects select the maximum background noise level (BNL) which is acceptable while listening to and following the story. The difference between the MCL and the BNL is the acceptable noise level (ANL), all in dB. ANLs are being compared with hearing-aid use, subjective impressions of benefit (APHAB), speech perception in background noise (SPIN) scores, and audiometric data. Individuals who accept higher levels of background noise are more successful users than individuals who accept less background noise. Mean ANLs are 7.3 dB for full-time users (N=21), 12.6 dB for part-time users (N=44), and 13.8 dB for rejecters (N=17). ANLs are not related to APHAB, SPIN, or audiometric data. Results for about 120 subjects will be reported. [Work supported by NIDCD (NIH) RO1 DC 05018.]

Comparison of acceptance of background noise and speech reception threshold in quantifying the hearing aid directivity benefit

Hearing aid directivity benefit was compared as improvement in acceptance of background noise and speech reception threshold (SRT). Forty adult subjects were tested wearing binaural hearing aids in omnidirectional and directional listening conditions. Acceptance of background noise was determined by having subjects select their most comfortable listening level (MCL) for a story delivered from a loudspeaker (0). Next, speech babble was added (180) and the subjects selected the maximum background noise level (BNL) which was acceptable while listening to and following the story. The MCL minus the BNL yielded the acceptable noise level (ANL), all in dB. The difference between the ANL for the omni-directional and directional conditions is the directivity benefit. The SRT was determined by delivering spondaic words (0) at the subjects MCL. Next, speech babble was delivered (180) and adjusted until the subject could repeat 50% of the spondees. The difference between the SRT for the omni-directional and directional conditions is the directivity benefit. Mean directional benefit, ANL=3.50 dB and SRT=3.60 dB, were not significantly different. The individual ANLs and SRTs were significantly correlated (r=−0.36, p=0.002). The ANL procedure appears to be a viable tool for quantifying hearing aid directivity benefit. [Work supported by NIDCD (NIH) 3 RO1 DC 05018-01S1.]

Acceptance of background noise as a function of speech presentation level

The acceptance of background noise while listening to speech (ANL) at different speech presentation levels was assessed. Twenty listeners (10 male) between 18–30 years with normal hearing listened to a narrative at speech presentation levels of 20, 34, 48, 62, and 76 dB HL, then adjusted the background noise to the highest intensity level that they would be willing to accept for an extended listening period. The ANL is the intensity of the speech presentation level minus the intensity level of the background noise. The group mean ANLs for presentation levels of 20, 34, 48, 62, and 76 dB HL were 10.60, 14.25, 17.10, 21.80, and 24.55 dB, respectively. The group mean ANLs differ by approximately three and one half decibels between each presentation level. This difference between adjacent speech presentation levels is representative of a linear function. The average MCL was 43 dB HL with a standard deviation of 6.7 dB. The group mean ANL for speech presented at MCL was 15.5 dB with a standard deviation of 7.27 dB. A MANOVA for repeated measures indicated a statistically significant main effect for speech presentation level (F=18.624, p=0.001). [Work partially supported by NIDCD (NIH) R01 DC 05018.]