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Kim H, Ricketts TA. Test-retest reliability of probe-microphone verification in children fitted with open and closed hearing aid tips. J Am Acad Audiol 2014; 24:635-42. [PMID: 24047950 DOI: 10.3766/jaaa.24.7.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To investigate the test-retest reliability of real-ear aided response (REAR) measures in open and closed hearing aid fittings in children using appropriate probe-microphone calibration techniques (stored equalization for open fittings and concurrent equalization for closed fittings). RESEARCH DESIGN Probe-microphone measurements were completed for two mini-behind-the-ear (BTE) hearing aids which were coupled to the ear using open and closed eartips via thin (0.9 mm) tubing. Before probe-microphone testing, the gain of each of the test hearing aids was programmed using an artificial ear simulator (IEC 711) and a Knowles Electronic Manikin for Acoustic Research to match the National Acoustic Laboratories-Non-Linear, version 1 targets for one of two separate hearing loss configurations using an Audioscan Verifit. No further adjustments were made, and the same amplifier gain was used within each hearing aid across both eartip configurations and all participants. Probe-microphone testing included real-ear occluded response (REOR) and REAR measures using the Verifit's standard speech signal (the carrot passage) presented at 65 dB sound pressure level (SPL). Two repeated probe-microphone measures were made for each participant with the probe-tube and hearing aid removed and repositioned between each trial in order to assess intrasubject measurement variability. These procedures were repeated using both open and closed domes. STUDY SAMPLE Thirty-two children, ages ranging from 4 to 14 yr. RESULTS The test-retest standard deviations for open and closed measures did not exceed 4 dB at any frequency. There was also no significant difference between the open (stored equalization) and closed (concurrent equalization) methods. Reliability was particularly similar in the high frequencies and was also quite similar to that reported in previous research. There was no correlation between reliability and age, suggesting high reliability across all ages evaluated. CONCLUSIONS The findings from this study suggest that reliable probe-microphone measurements are obtainable on children 4 yr and older for both traditional unvented and open-canal hearing aid fittings. These data suggest that clinicians should not avoid fitting open technology to children as young as 4 y because of concerns regarding the reliability of verification techniques.
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Picou EM, Ricketts TA. Increasing motivation changes subjective reports of listening effort and choice of coping strategy. Int J Audiol 2014; 53:418-26. [DOI: 10.3109/14992027.2014.880814] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Picou EM, Ricketts TA, Hornsby BWY. Visual cues and listening effort: individual variability. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2011; 54:1416-1430. [PMID: 21498576 DOI: 10.1044/1092-4388(2011/10-0154)] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PURPOSE To investigate the effect of visual cues on listening effort as well as whether predictive variables such as working memory capacity (WMC) and lipreading ability affect the magnitude of listening effort. METHOD Twenty participants with normal hearing were tested using a paired-associates recall task in 2 conditions (quiet and noise) and 2 presentation modalities (audio only [AO] and auditory-visual [AV]). Signal-to-noise ratios were adjusted to provide matched speech recognition across audio-only and AV noise conditions. Also measured were subjective perceptions of listening effort and 2 predictive variables: (a) lipreading ability and (b) WMC. RESULTS Objective and subjective results indicated that listening effort increased in the presence of noise, but on average the addition of visual cues did not significantly affect the magnitude of listening effort. Although there was substantial individual variability, on average participants who were better lipreaders or had larger WMCs demonstrated reduced listening effort in noise in AV conditions. CONCLUSIONS Overall, the results support the hypothesis that integrating auditory and visual cues requires cognitive resources in some participants. The data indicate that low lipreading ability or low WMC is associated with relatively effortful integration of auditory and visual information in noise.
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Johnson EE, Ricketts TA. Dispensing rates of four common hearing aid product features: associations with variations in practice among audiologists. Trends Amplif 2010; 14:12-45. [PMID: 20457726 DOI: 10.1177/1084713810362988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The purpose of the study was to develop and examine a list of potential variables that may account for variability in the dispensing rates of four common hearing aid features. A total of 29 potential variables were identified and placed into the following categories: (1) characteristics of the audiologist, (2) characteristics of the hearing aids dispensed by the audiologist, (3) characteristics of the audiologist's patient population, and (4) evidence-based practice grades of recommendation for each feature. The potentially associative variables then were examined using regression analyses from the responses of 257 audiologists to a dispensing practice survey. There was a direct relation between price and level of hearing aid technology with the frequency of dispensing product features. There was also a direct relation between the belief by the audiologist that a feature might benefit patients and the frequency of dispensing that feature. In general, the results suggested that personal differences among audiologists and the hearing aids audiologists choose to dispense are related more strongly to dispensing rates of product features than to differences in characteristics of the patient population served by audiologists. An additional finding indicated that evidence-based practice recommendations were inversely related to dispensing rates of product features. This finding, however, may not be the result of dispensing trends as much as hearing aid manufacturing trends.
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Johnson EE, Mueller HG, Ricketts TA. Statistically derived factors of varied importance to audiologists when making a hearing aid brand preference decision. J Am Acad Audiol 2009; 20:40-8. [PMID: 19927681 DOI: 10.3766/jaaa.20.1.4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To determine the amount of importance audiologists place on various items related to their selection of a preferred hearing aid brand manufacturer. RESEARCH DESIGN Three hundred forty-three hearing aid-dispensing audiologists rated a total of 32 randomized items by survey methodology. RESULTS Principle component analysis identified seven orthogonal statistical factors of importance. In rank order, these factors were Aptitude of the Brand, Image, Cost, Sales and Speed of Delivery, Exposure, Colleague Recommendations, and Contracts and Incentives. While it was hypothesized that differences among audiologists in the importance ratings of these factors would dictate their preference for a given brand, that was not our finding. Specifically, mean ratings for the six most important factors did not differ among audiologists preferring different brands. A statistically significant difference among audiologists preferring different brands was present, however, for one factor: Contracts and Incentives. Its assigned importance, though, was always lower than that for the other six factors. CONCLUSIONS Although most audiologists have a preferred hearing aid brand, differences in the perceived importance of common factors attributed to brands do not largely determine preference for a particular brand.
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Ricketts TA, Dittberner AB, Johnson EE. High-frequency amplification and sound quality in listeners with normal through moderate hearing loss. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2008; 51:160-172. [PMID: 18230863 DOI: 10.1044/1092-4388(2008/012)] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
PURPOSE One factor that has been shown to greatly affect sound quality is audible bandwidth. Provision of gain for frequencies above 4-6 kHz has not generally been supported for groups of hearing aid wearers. The purpose of this study was to determine if preference for bandwidth extension in hearing aid processed sounds was related to the magnitude of hearing loss in individual listeners. METHOD Ten participants with normal hearing and 20 participants with mild-to-moderate hearing loss completed the study. Signals were processed using hearing aid-style compression algorithms and filtered using two cutoff frequencies, 5.5 and 9 kHz, which were selected to represent bandwidths that are achievable in modern hearing aids. Round-robin paired comparisons based on the criteria of preferred sound quality were made for 2 different monaurally presented brief sound segments, including music and a movie. RESULTS Results revealed that preference for either the wider or narrower bandwidth (9- or 5.5-kHz cutoff frequency, respectively) was correlated with the slope of hearing loss from 4 to 12 kHz, with steep threshold slopes associated with preference for narrower bandwidths. CONCLUSION Consistent preference for wider bandwidth is present in some listeners with mild-to-moderate hearing loss.
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Grantham DW, Ashmead DH, Ricketts TA, Labadie RF, Haynes DS. Horizontal-Plane Localization of Noise and Speech Signals by Postlingually Deafened Adults Fitted With Bilateral Cochlear Implants*. Ear Hear 2007; 28:524-41. [PMID: 17609614 DOI: 10.1097/aud.0b013e31806dc21a] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The main purpose of the study was to assess the ability of adults with bilateral cochlear implants to localize noise and speech signals in the horizontal plane. A second objective was to measure the change in localization performance in these adults between approximately 5 and 15 mo after activation. A third objective was to evaluate the relative roles of interaural level difference (ILD) and interaural temporal difference (ITD) cues in localization by these subjects. DESIGN Twenty-two adults, all postlingually deafened and all bilaterally fitted with MED-EL COMBI 40+ cochlear implants, were tested in a modified source identification task. Subjects were tested individually in an anechoic chamber, which contained an array of 43 numbered loudspeakers extending from -90 degrees to +90 degrees azimuth. On each trial, a 200-msec signal (either a noise burst or a speech sample) was presented from one of 17 active loudspeakers (span: +/-80 degrees ), and the subject had to identify which source from the 43 loudspeakers in the array produced the signal. Subjects were tested in three conditions: left device only active, right device only active, and both devices active. Twelve of the 22 subjects were retested approximately 10 mo after their first test. In Experiment 2, the spectral content and rise-decay time of the noise stimulus were manipulated. RESULTS The relationship between source azimuth and response azimuth was characterized in terms of the adjusted constant error (ĉ). (1) With both devices active, ĉ for the noise stimulus varied from 8.1 degrees to 43.4 degrees (mean: 24.1 degrees ). By comparison, ĉ for a group of listeners with normal hearing ranged from 3.5 degrees to 7.8 degrees (mean: 5.6 degrees ). When subjects listened in unilateral mode (with one device turned off), ĉ was at or near chance (50.5 degrees ) in all cases. However, when considering unilateral performance on each subject's better side, average ĉ for the speech stimulus was 47.9 degrees , which was significantly (but only slightly) better than chance. (2) When listening bilaterally, error score was significantly lower for the speech stimulus (mean ĉ = 21.5 degrees ) than for the noise stimulus (mean ĉ = 24.1 degrees ). (3) As a group, the 12 subjects who were retested 10 mo after their first visit showed no significant improvement in localization performance during the intervening time. However, two subjects who performed very poorly during their first visit showed dramatic improvement (error scores were halved) over the intervening time. In Experiment 2, removing the high-frequency content of noise signals resulted in significantly poorer performance, but removing the low-frequency content or increasing the rise-decay time did not have an effect. CONCLUSIONS In agreement with previously reported data, subjects with bilateral cochlear implants localized sounds in the horizontal plane remarkably well when using both of their devices, but they generally could not localize sounds when either device was deactivated. They could localize the speech signal with slightly, but significantly better accuracy than the noise, possibly due to spectral differences in the signals, to the availability of envelope ITD cues with the speech but not the noise signal, or to more central factors related to the social salience of speech signals. For most subjects the remarkable ability to localize sounds has stabilized by 5 mo after activation. However, for some subjects who perform poorly initially, there can be substantial improvement past 5 mo. Results from Experiment 2 suggest that ILD cues underlie localization ability for noise signals, and that ITD cues do not contribute.
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Hornsby BWY, Ricketts TA. Effects of Noise Source Configuration on Directional Benefit Using Symmetric and Asymmetric Directional Hearing Aid Fittings. Ear Hear 2007; 28:177-86. [PMID: 17496669 DOI: 10.1097/aud.0b013e3180312639] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The benefits of directional processing in hearing aids are well documented in laboratory settings. Likewise, substantial research has shown that speech understanding is optimized in many settings when listening binaurally. Although these findings suggest that speech understanding would be optimized by using bilateral directional technology (e.g., a symmetric directional fitting), recent research suggests similar performance with an asymmetrical fitting (directional in one ear and omnidirectional in the other). The purpose of this study was to explore the benefits of using bilateral directional processing, as opposed to an asymmetric fitting, in environments where the primary speech and noise sources come from different directions. DESIGN Sixteen older adults with mild-to-severe sensorineural hearing loss (SNHL) were recruited for the study. Aided sentence recognition using the Hearing in Noise Test (HINT) was assessed in a moderately reverberant room, in three different speech and noise conditions in which the locations of the speech and noise sources were varied. In each speech and noise condition, speech understanding was assessed in four different microphone modes (bilateral omnidirectional mode; bilateral directional mode; directional mode left and omnidirectional mode right; omnidirectional mode left and directional mode right). The benefits and limitations of bilateral directional processing were assessed by comparing HINT thresholds across the various symmetric and asymmetric microphone processing conditions. RESULTS Study results revealed directional benefit varied based on microphone mode symmetry (i.e., symmetric versus asymmetric directional processing) and the specific speech and noise configuration. In noise configurations in which the speech was located in the front of the listener and the noise was located to the side or surrounded the listener, maximum directional benefit (approximately 3.3 dB) was observed with the symmetric directional fitting. HINT thresholds obtained when using bilateral directional processing were approximately 1.4 dB better than when an asymmetric fitting (directional processing in only one ear) was used. When speech was located on the side of the listener, the use of directional processing on the ear near the speech significantly reduced speech understanding. CONCLUSIONS Although directional benefit is present in asymmetric fittings, the use of bilateral directional processing optimizes speech understanding in noise conditions in which the speech comes from in front of the listener and the noise sources are located to the side of or surround the listener. In situations in which the speech is located to the side of the listener, the use of directional processing on the ear adjacent to the speaker is likely to reduce speech audibility and thus degrade speech understanding.
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Hornsby BWY, Ricketts TA, Johnson EE. The effects of speech and speechlike maskers on unaided and aided speech recognition in persons with hearing loss. J Am Acad Audiol 2007; 17:432-47. [PMID: 16869056 DOI: 10.3766/jaaa.17.6.5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Speech understanding in noise is affected by both the energetic and informational masking components of the background noise. In addition, when the background noise is everyday speech, the relative contributions of the energetic and informational masking components to the overall difficulties in understanding speech are unclear. This study estimated informational masking effects, in conversational speech settings, on the speech understanding of persons with and without hearing loss. The benefits and limitations of amplification in settings containing both informational and energetic masking components were also explored. Speech recognition was assessed in the presence of two types of maskers (speech and noise) that varied in the amount of informational masking they were expected to produce. Persons with hearing loss were tested both unaided and aided. Study results suggest that background noise, consisting of individual talkers, results in both informational and energetic masking. In addition, the benefits of amplification are limited when the background noise contains both informational and energetic masking components.
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Ricketts TA, Grantham DW, Ashmead DH, Haynes DS, Labadie RF. Speech Recognition for Unilateral and Bilateral Cochlear Implant Modes in the Presence of Uncorrelated Noise Sources. Ear Hear 2006; 27:763-73. [PMID: 17086085 DOI: 10.1097/01.aud.0000240814.27151.b9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The purpose of the current investigation was to compare speech recognition in noise for bilateral and unilateral modes within postlingually deafened, adult bilateral cochlear implant recipients. In addition, it was of interest to evaluate the time course of the bilateral speech-recognition advantage and the effect of changing signal-to-noise ratio (SNR) on the magnitude of the bilateral advantage. DESIGN In the first experiment, 16 postlingually deafened adults who were bilaterally implanted with the MED-EL C40+ cochlear device were evaluated in unilateral left, unilateral right, and bilateral conditions 4 to 7 mo after activation. Speech recognition in the presence of five spatially separated, uncorrelated noise sources was evaluated using both a single fixed SNR of +10 dB and an adaptive-SNR method. In a follow-up study, a subset of 10 participants was re-evaluated using an identical fixed-SNR method 12 to 17 mo after activation to examine the time course of speech-recognition performance in both unilateral and bilateral modes at a single SNR. A third study was performed with a subset of six participants to examine performance over a range of SNRs. In this study, speech recognition was measured 12 to 17 mo after activation in quiet and at +5, +10, +15, and +20 dB SNRs using the same five uncorrelated noise sources. RESULTS The speech-recognition data revealed a significant bilateral advantage of 3.3 dB using the adaptive-SNR method. A significant bilateral advantage of 9% was also measured using a fixed +10 dB SNR. Results from the second study revealed that experience resulted in a significant (11 to 20%) increase in speech-recognition-in-noise performance for both unilateral and bilateral modes; however, the magnitude of the bilateral advantage was not affected by experience. Results from the third study revealed the largest bilateral advantage at the poorest SNR evaluated. In addition, performance in quiet was significantly better than that measured in the presence of noise, even at the +20 dB SNR. CONCLUSIONS The results of these experiments support a small but significant bilateral speech-recognition-in-noise advantage for cochlear implant recipients in an environment with multiple noise sources. This advantage is presumed to be attributable to the combined effects of binaural squelch and diotic summation. Although experience generally improved speech-recognition-in-noise performance in both unilateral and bilateral modes, a consistent bilateral advantage (approximately 10%) was measured at 4 to 7 mo and at 12 to 17 mo postactivation.
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Abstract
The purpose of this investigation was to examine the potential for directional hearing aid benefit in listeners with severe hearing loss at multiple SNRs for both auditory only and audio-visual presentation modes. Speech recognition performance was measured using the connected speech test at six SNRs individually determined for each subject in order to avoid floor and ceiling effects. The results revealed significant directional benefit was present at all tested SNRs in the presence of visual information. For auditory only presentations, significant directional benefit was only present at the least positive SNR. The largest directional benefit was measured at the poorest tested SNR for both auditory only and audiovisual presentation modes. The results of this study generally support small but significant directional for listeners with severe hearing loss benefit in a difficult listening environment both with and without the presence of visual information.
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Hornsby BWY, Ricketts TA. The effects of hearing loss on the contribution of high- and low-frequency speech information to speech understanding. II. Sloping hearing loss. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 119:1752-63. [PMID: 16583917 PMCID: PMC2735822 DOI: 10.1121/1.2161432] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The speech understanding of persons with sloping high-frequency (HF) hearing impairment (HI) was compared to normal hearing (NH) controls and previous research on persons with "flat" losses [Hornsby and Ricketts (2003). J. Acoust. Soc. Am. 113, 1706-1717] to examine how hearing loss configuration affects the contribution of speech information in various frequency regions. Speech understanding was assessed at multiple low- and high-pass filter cutoff frequencies. Crossover frequencies, defined as the cutoff frequencies at which low- and high-pass filtering yielded equivalent performance, were significantly lower for the sloping HI, compared to NH, group suggesting that HF HI limits the utility of HF speech information. Speech intelligibility index calculations suggest this limited utility was not due simply to reduced audibility but also to the negative effects of high presentation levels and a poorer-than-normal use of speech information in the frequency region with the greatest hearing loss (the HF regions). This deficit was comparable, however, to that seen in low-frequency regions of persons with similar HF thresholds and "flat" hearing losses suggesting that sensorineural HI results in a "uniform," rather than frequency-specific, deficit in speech understanding, at least for persons with HF thresholds up to 60-80 dB HL.
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Ricketts TA, Henry PP, Hornsby BWY. Application of Frequency Importance Functions to Directivity for Prediction of Benefit in Uniform Fields. Ear Hear 2005; 26:473-86. [PMID: 16230897 DOI: 10.1097/01.aud.0000179691.21547.01] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The purpose of the current investigation was to systematically examine two of the assumptions central to the application of Articulation Index weighted Directivity Index (AI-DI) to the prediction of directional benefit across three groups of listeners differentiated by degree and configuration of hearing loss. Specifically, the assumption that (1) changes in speech recognition performance are predictable from frequency specific changes in calculated audibility after applying directivity index (DI) values and (2) applying appropriate frequency importance functions would increase the accuracy of AI-DI predictions of directional benefit were evaluated. DESIGN The output of a single hearing aid for a speech in noise input was recorded to produce high and low directivity (directional and omnidirectional microphone modes) segments. These segments were then high-pass and low-pass filtered into low- and high-frequency regions and acoustically mixed to generate the eight frequency-specific directivity combinations. All recordings were made through an acoustic manikin placed in a single room, surrounded by five uncorrelated noise sources. The aided sentence recognition, in noise, for three groups of 12 adult participants with symmetrical sensorineural hearing impairment, was then measured across the eight listening conditions. The three groups were differentiated by degree and type of hearing loss including "sloping," "flat," and "severe" configurations. The frequency-specific DI values for each of the eight listening conditions were applied to the calculation of frequency specific noise levels. These corrected noise levels were then used to calculate an Articulation Index using the Speech Intelligibility Index (SII, ). These SII values were then compared with measured speech recognition under the same eight listening conditions. Directional benefit values were then calculated by subtracting the performance of individual participants on the Connected Speech Test (CST) in omnidirectional mode from performance in all other filter conditions. The changes in average DI and AI-DI (using three different frequency importance functions) that existed between omnidirectional and the other seven filter conditions were then calculated for comparison to directional benefit values. RESULTS The speech recognition data revealed a complex interaction between filter condition and group. Despite this interaction, highly significant positive correlations were found between participants' speech recognition scores and the corresponding SII calculation for all three hearing loss groups. Individual subjects' measured directional benefit was highly correlated with changes in DI. Similar correlations were found for average DI and all three AI-DI weighting methods. CONCLUSIONS As expected, performance and calculated SII values were in good agreement across conditions supporting the hypothesis that DI provides a reasonable frequency-specific estimate of signal-to-noise ratio changes in the test environment. The results further support the use of AI-DI or average DI for prediction of directional benefit. The choice of importance weighting across frequency (flat or frequency importance function based), however, did not improve the accuracy of these predictions; therefore, a simple average DI is advocated. Further, the prediction of absolute directional benefit across hearing loss groups from traditional AI-DI calculations may lead to error if the negative effects of hearing loss on speech understanding, and how these effects vary with degree of hearing loss, are not considered as a contributing factor.
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Ricketts TA. Directional hearing aids: then and now. JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT 2005; 42:133-44. [PMID: 16470469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Directional microphone hearing aids can lead to improved speech recognition when speech and noise are coming from different directions. This technology provides limited benefits, however, and in specific instances use of a directional hearing aid mode can be detrimental. This article discusses the benefits and limitations of directional amplification, summarizes some current work in directional amplification, and recommends clinical application relative to the use of directional amplification.
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Ricketts TA, Hornsby BWY, Johnson EE. Adaptive Directional Benefit in the Near Field: Competing Sound Angle and Level Effects. Semin Hear 2005. [DOI: 10.1055/s-2005-871003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Ricketts TA. From the Editor. Trends Amplif 2004; 8:v. [DOI: 10.1177/108471380400800401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ricketts TA. From the Editor. Trends Amplif 2004; 8:i-ii. [DOI: 10.1177/108471380400800301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ricketts TA. From the Editor. Trends Amplif 2004; 8:v-vi. [DOI: 10.1177/108471380400800201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ricketts TA. From the Editor. Trends Amplif 2003; 7:v-vi. [DOI: 10.1177/108471380300700101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
OBJECTIVE Understanding the potential benefits and limitations of directional hearing aids across a wide range of listening environments is important when counseling persons with hearing loss regarding realistic expectations for these devices. The purpose of this study was to examine the impact of speaker-to-listener distance on directional benefit in two reverberant environments, in which the dominate noise sources were placed close to the hearing aid wearer. In addition, speech transmission index (STI) measures made in the test environments were compared to measured sentence recognition to determine if performance was predictable across changes in distance, reverberation and microphone mode. DESIGN The aided sentence recognition, in noise, for fourteen adult participants with symmetrical sensorineural hearing impairment was measured in six environmental conditions in both directional and omnidirectional modes. A single room, containing four uncorrelated noise sources served as the test environment. The room was modified to exhibit either low (RT60 = 0.3 sec) or moderate (RT60 = 0.9 sec) levels of reverberation. Sentence recognition was measured in both reverberant environments at three different speech loudspeaker-to-listener distances (1.2 m, 2.4 m, and 4.8 m). STI measures also were made in each of the 12 listening conditions (2 microphone modes x 3 distances x 2 reverberation environments). RESULTS A decrease in directional benefit was measured with increasing distance in the moderate reverberation condition. Although reduced, directional benefit was still present in the moderately reverberant environment at the farthest speech speaker-to-listener distance tested in this experiment. A similar decrease with increasing speaker-to-listener distance was not measured in the low reverberation condition. The pattern of average sentence recognition results across varying distances and two different reverberation times agreed with the pattern of STI values measured under the same conditions. CONCLUSIONS Although these data support increased directional benefit in noise for reduced speaker-to-listener distance, some benefit was still obtained by listeners when listening beyond "effective" critical distance under conditions of low (300 msec) to moderate (900 msec) reverberation. It is assumed that the directional benefit was due to the reduction of the direct sound energy from the noise sources near the listener. The use of aided STI values for the prediction of average word recognition across listening conditions that differ in reverberation, microphone directivity, and speaker-to-listener distance also was supported.
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Hornsby BWY, Ricketts TA. The effects of hearing loss on the contribution of high- and low-frequency speech information to speech understanding. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2003; 113:1706-1717. [PMID: 12656402 DOI: 10.1121/1.1553458] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The speech understanding of persons with "flat" hearing loss (HI) was compared to a normal-hearing (NH) control group to examine how hearing loss affects the contribution of speech information in various frequency regions. Speech understanding in noise was assessed at multiple low- and high-pass filter cutoff frequencies. Noise levels were chosen to ensure that the noise, rather than quiet thresholds, determined audibility. The performance of HI subjects was compared to a NH group listening at the same signal-to-noise ratio and a comparable presentation level. Although absolute speech scores for the HI group were reduced, performance improvements as the speech and noise bandwidth increased were comparable between groups. These data suggest that the presence of hearing loss results in a uniform, rather than frequency-specific, deficit in the contribution of speech information. Measures of auditory thresholds in noise and speech intelligibility index (SII) calculations were also performed. These data suggest that differences in performance between the HI and NH groups are due primarily to audibility differences between groups. Measures of auditory thresholds in noise showed the "effective masking spectrum" of the noise was greater for the HI than the NH subjects.
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Chung K, Ricketts TA. From the Editors. Trends Amplif 2003; 7:v. [DOI: 10.1177/108471380300700401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ricketts TA. From the Editor. Trends Amplif 2003; 7:v. [DOI: 10.1177/108471380300700201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ricketts TA. From the Editor. Trends Amplif 2002; 6:NP. [DOI: 10.1177/108471380200600401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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