Evaluation of Speech Recognition in Noise with Cochlear Implants and Dynamic FM

2009 ◽  
Vol 20 (07) ◽  
pp. 409-421 ◽  
Author(s):  
Jace Wolfe ◽  
Erin C. Schafer ◽  
Benjamin Heldner ◽  
Hans Mülder ◽  
Emily Ward ◽  
...  

Background: Use of personal frequency-modulated (FM) systems significantly improves speech recognition in noise for users of cochlear implants (CIs). Previous studies have shown that the most appropriate gain setting on the FM receiver may vary based on the listening situation and the manufacturer of the CI system. Unlike traditional FM systems with fixed-gain settings, Dynamic FM automatically varies the gain of the FM receiver with changes in the ambient noise level. There are no published reports describing the benefits of Dynamic FM use for CI recipients or how Dynamic FM performance varies as a function of CI manufacturer. Purpose: To evaluate speech recognition of Advanced Bionics Corporation or Cochlear Corporation CI recipients using Dynamic FM vs. a traditional FM system and to examine the effects of Autosensitivity on the FM performance of Cochlear Corporation recipients. Research Design: A two-group repeated-measures design. Participants were assigned to a group according to their type of CI. Study Sample: Twenty-five subjects, ranging in age from 8 to 82 years, met the inclusion criteria for one or more of the experiments. Thirteen subjects used Advanced Bionics Corporation, and 12 used Cochlear Corporation implants. Intervention: Speech recognition was assessed while subjects used traditional, fixed-gain FM systems and Dynamic FM systems. Data Collection and Analysis: In Experiments 1 and 2, speech recognition was evaluated with a traditional, fixed-gain FM system and a Dynamic FM system using the Hearing in Noise Test sentences in quiet and in classroom noise. A repeated-measures analysis of variance (ANOVA) was used to evaluate effects of CI manufacturer (Advanced Bionics and Cochlear Corporation), type of FM system (traditional and dynamic), noise level, and use of Autosensitivity for users of Cochlear Corporation implants. Experiment 3 determined the effects of Autosensitivity on speech recognition of Cochlear Corporation implant recipients when listening through the speech processor microphone with the FM system muted. A repeated-measures ANOVA was used to examine the effects of signal-to-noise ratio and Autosensitivity. Results: In Experiment 1, use of Dynamic FM resulted in better speech recognition in noise for Advanced Bionics recipients relative to traditional FM at noise levels of 65, 70, and 75 dB SPL. Advanced Bionics recipients obtained better speech recognition in noise with FM use when compared to Cochlear Corporation recipients. When Autosensitivity was enabled in Experiment 2, the performance of Cochlear Corporation recipients was equivalent to that of Advanced Bionics recipients, and Dynamic FM was significantly better than traditional FM. Results of Experiment 3 indicate that use of Autosensitivity improves speech recognition in noise of signals directed to the speech processor relative to no Autosensitivity. Conclusions: Dynamic FM should be considered for use with persons with CIs to improve speech recognition in noise. At default CI settings, FM performance is better for Advanced Bionics recipients when compared to Cochlear Corporation recipients, but use of Autosensitivity by Cochlear Corporation users results in equivalent group performance.

2012 ◽  
Vol 23 (07) ◽  
pp. 501-509 ◽  
Author(s):  
Erin C. Schafer ◽  
Jody Pogue ◽  
Tyler Milrany

Background: Speech recognition abilities of adults and children using cochlear implants (CIs) are significantly degraded in the presence of background noise, making this an important area of study and assessment by CI manufacturers, researchers, and audiologists. However, at this time there are a limited number of fixed-intensity sentence recognition tests available that also have multiple, equally intelligible lists in noise. One measure of speech recognition, the AzBio Sentence Test, provides 10-talker babble on the commercially available compact disc; however, there is no published evidence to support equivalency of the 15-sentence lists in noise for listeners with normal hearing (NH) or CIs. Furthermore, there is limited or no published data on the reliability, validity, and normative data for this test in noise for listeners with CIs or NH. Purpose: The primary goals of this study were to examine the equivalency of the AzBio Sentence Test lists at two signal-to-noise ratios (SNRs) in participants with NH and at one SNR for participants with CIs. Analyses were also conducted to establish the reliability, validity, and preliminary normative data for the AzBio Sentence Test for listeners with NH and CIs. Research Design: A cross-sectional, repeated measures design was used to assess speech recognition in noise for participants with NH or CIs. Study Sample: The sample included 14 adults with NH and 12 adults or adolescents with Cochlear Freedom CI sound processors. Participants were recruited from the University of North Texas clinic population or from local CI centers. Data Collection and Analysis: Speech recognition was assessed using the 15 lists of the AzBio Sentence Test and the 10-talker babble. With the intensity of the sentences fixed at 73 dB SPL, listeners with NH were tested at 0 and −3 dB SNRs, and participants with CIs were tested at a +10 dB SNR. Repeated measures analysis of variance (ANOVA) was used to analyze the data. Results: The primary analyses revealed significant differences in performance across the 15 lists on the AzBio Sentence Test for listeners with NH and CIs. However, a follow-up analysis revealed no significant differences in performance across 10 of the 15 lists. Using the 10, equally-intelligible lists, a comparison of speech recognition performance across the two groups suggested similar performance between NH participants at a −3 dB SNR and the CI users at a +10 SNR. Several additional analyses were conducted to support the reliability and validity of the 10 equally intelligible AzBio sentence lists in noise, and preliminary normative data were provided. Conclusions: Ten lists of the commercial version of the AzBio Sentence Test may be used as a reliable and valid measure of speech recognition in noise in listeners with NH or CIs. The equivalent lists may be used for a variety of purposes including audiological evaluations, determination of CI candidacy, hearing aid and CI programming considerations, research, and recommendations for hearing assistive technology. In addition, the preliminary normative data provided in this study establishes a starting point for the creation of comprehensive normative data for the AzBio Sentence Test.


2010 ◽  
Vol 21 (08) ◽  
pp. 546-557 ◽  
Author(s):  
Kristi Oeding ◽  
Michael Valente ◽  
Jessica Kerckhoff

Background: Patients with unilateral sensorineural hearing loss (USNHL) experience great difficulty listening to speech in noisy environments. A directional microphone (DM) could potentially improve speech recognition in this difficult listening environment. It is well known that DMs in behind-the-ear (BTE) and custom hearing aids can provide a greater signal-to-noise ratio (SNR) in comparison to an omnidirectional microphone (OM) to improve speech recognition in noise for persons with hearing impairment. Studies examining the DM in bone anchored auditory osseointegrated implants (Baha), however, have been mixed, with little to no benefit reported for the DM compared to an OM. Purpose: The primary purpose of this study was to determine if there are statistically significant differences in the mean reception threshold for sentences (RTS in dB) in noise between the OM and DM in the Baha® Divino™. The RTS of these two microphone modes was measured utilizing two loudspeaker arrays (speech from 0° and noise from 180° or a diffuse eight-loudspeaker array) and with the better ear open or closed with an earmold impression and noise attenuating earmuff. Subjective benefit was assessed using the Abbreviated Profile of Hearing Aid Benefit (APHAB) to compare unaided and aided (Divino OM and DM combined) problem scores. Research Design: A repeated measures design was utilized, with each subject counterbalanced to each of the eight treatment levels for three independent variables: (1) microphone (OM and DM), (2) loudspeaker array (180° and diffuse), and (3) better ear (open and closed). Study Sample: Sixteen subjects with USNHL currently utilizing the Baha were recruited from Washington University's Center for Advanced Medicine and the surrounding area. Data Collection and Analysis: Subjects were tested at the initial visit if they entered the study wearing the Divino or after at least four weeks of acclimatization to a loaner Divino. The RTS was determined utilizing Hearing in Noise Test (HINT) sentences in the R-Space™ system, and subjective benefit was determined utilizing the APHAB. A three-way repeated measures analysis of variance (ANOVA) and a paired samples t-test were utilized to analyze results of the HINT and APHAB, respectively. Results: Results revealed statistically significant differences within microphone (p < 0.001; directional advantage of 3.2 dB), loudspeaker array (p = 0.046; 180° advantage of 1.1 dB), and better ear conditions (p < 0.001; open ear advantage of 4.9 dB). Results from the APHAB revealed statistically and clinically significant benefit for the Divino relative to unaided on the subscales of Ease of Communication (EC) (p = 0.037), Background Noise (BN) (p < 0.001), and Reverberation (RV) (p = 0.005). Conclusions: The Divino's DM provides a statistically significant improvement in speech recognition in noise compared to the OM for subjects with USNHL. Therefore, it is recommended that audiologists consider selecting a Baha with a DM to provide improved speech recognition performance in noisy listening environments.


2008 ◽  
Vol 18 (1) ◽  
pp. 19-24
Author(s):  
Erin C. Schafer

Children who use cochlear implants experience significant difficulty hearing speech in the presence of background noise, such as in the classroom. To address these difficulties, audiologists often recommend frequency-modulated (FM) systems for children with cochlear implants. The purpose of this article is to examine current empirical research in the area of FM systems and cochlear implants. Discussion topics will include selecting the optimal type of FM receiver, benefits of binaural FM-system input, importance of DAI receiver-gain settings, and effects of speech-processor programming on speech recognition. FM systems significantly improve the signal-to-noise ratio at the child's ear through the use of three types of FM receivers: mounted speakers, desktop speakers, or direct-audio input (DAI). This discussion will aid audiologists in making evidence-based recommendations for children using cochlear implants and FM systems.


2015 ◽  
Vol 26 (06) ◽  
pp. 532-539 ◽  
Author(s):  
Jace Wolfe ◽  
Mila Morais ◽  
Erin Schafer

Background: Cochlear implant (CI) recipients experience difficulty understanding speech in noise. Remote-microphone technology that improves the signal-to-noise ratio is recognized as an effective means to improve speech recognition in noise; however, there are no published studies evaluating the potential benefits of a wireless, remote-microphone, digital, audio-streaming accessory device (heretofore referred to as a remote-microphone accessory) designed to deliver audio signals directly to a CI sound processor. Purpose: The objective of this study was to compare speech recognition in quiet and in noise of recipients while using their CI alone and with a remote-microphone accessory. Research Design: A two-way repeated measures design was used to evaluate performance differences obtained in quiet and in increasing levels of competing noise with the CI sound processor alone and with the sound processor paired to the remote microphone accessory. Study Sample: Sixteen users of Cochlear Nucleus 24 Freedom, CI512, and CI422 implants were included in the study. Data Collection and Analysis: Participants were evaluated in 14 conditions including use of the sound processor alone and with the remote-microphone accessory in quiet and at the following signal levels: 65 dBA speech (at the location of the participant; 85 dBA at the location of the remote microphone) in quiet and competing noise at 50, 55, 60, 65, 70, and 75 dBA noise levels. Speech recognition was evaluated in each of these conditions with one full list of AzBio sentences. Results: Speech recognition in quiet and in all competing noise levels, except the 75 dBA condition, was significantly better with use of the remote-microphone accessory compared with participants’ performance with the CI sound processor alone. As expected, in all technology conditions, performance was significantly poorer as the competing noise level increased. Conclusions: Use of a remote-microphone accessory designed for a CI sound processor provides superior speech recognition in quiet and in noise when compared with performance obtained with the CI sound processor alone.


2012 ◽  
Vol 23 (03) ◽  
pp. 171-181 ◽  
Author(s):  
Rachel A. McArdle ◽  
Mead Killion ◽  
Monica A. Mennite ◽  
Theresa H. Chisolm

Background: The decision to fit one or two hearing aids in individuals with binaural hearing loss has been debated for years. Although some 78% of U.S. hearing aid fittings are binaural (Kochkin , 2010), Walden and Walden (2005) presented data showing that 82% (23 of 28 patients) of their sample obtained significantly better speech recognition in noise scores when wearing one hearing aid as opposed to two. Purpose: To conduct two new experiments to fuel the monaural/binaural debate. The first experiment was a replication of Walden and Walden (2005), whereas the second experiment examined the use of binaural cues to improve speech recognition in noise. Research Design: A repeated measures experimental design. Study Sample: Twenty veterans (aged 59–85 yr), with mild to moderately severe binaurally symmetrical hearing loss who wore binaural hearing aids were recruited from the Audiology Department at the Bay Pines VA Healthcare System. Data Collection and Analysis: Experiment 1 followed the procedures of the Walden and Walden study, where signal-to-noise ratio (SNR) loss was measured using the Quick Speech-in-Noise (QuickSIN) test on participants who were aided with their current hearing aids. Signal and noise were presented in the sound booth at 0° azimuth under five test conditions: (1) right ear aided, (2) left ear aided, (3) both ears aided, (4) right ear aided, left ear plugged, and (5) unaided. The opposite ear in (1) and (2) was left open. In Experiment 2, binaural Knowles Electronics Manikin for Acoustic Research (KEMAR) manikin recordings made in Lou Malnati's pizza restaurant during a busy period provided a typical real-world noise, while prerecorded target sentences were presented through a small loudspeaker located in front of the KEMAR manikin. Subjects listened to the resulting binaural recordings through insert earphones under the following four conditions: (1) binaural, (2) diotic, (3) monaural left, and (4) monaural right. Results: Results of repeated measures ANOVAs demonstrated that the best speech recognition in noise performance was obtained by most participants with both ears aided in Experiment 1 and in the binaural condition in Experiment 2. Conclusions: In both experiments, only 20% of our subjects did better in noise with a single ear, roughly similar to the earlier Jerger et al (1993) finding that 8–10% of elderly hearing aid users preferred one hearing aid.


2019 ◽  
Vol 30 (07) ◽  
pp. 607-618 ◽  
Author(s):  
Thomas Wesarg ◽  
Susan Arndt ◽  
Konstantin Wiebe ◽  
Frauke Schmid ◽  
Annika Huber ◽  
...  

AbstractPrevious research in cochlear implant (CI) recipients with bilateral severe-to-profound sensorineural hearing loss showed improvements in speech recognition in noise using remote wireless microphone systems. However, to our knowledge, no previous studies have addressed the benefit of these systems in CI recipients with single-sided deafness.The objective of this study was to evaluate the potential improvement in speech recognition in noise for distant speakers in single-sided deaf (SSD) CI recipients obtained using the digital remote wireless microphone system, Roger. In addition, we evaluated the potential benefit in normal hearing (NH) participants gained by applying this system.Speech recognition in noise for a distant speaker in different conditions with and without Roger was evaluated with a two-way repeated-measures design in each group, SSD CI recipients, and NH participants. Post hoc analyses were conducted using pairwise comparison t-tests with Bonferroni correction.Eleven adult SSD participants aided with CIs and eleven adult NH participants were included in this study.All participants were assessed in 15 test conditions (5 listening conditions × 3 noise levels) each. The listening conditions for SSD CI recipients included the following: (I) only NH ear and CI turned off, (II) NH ear and CI (turned on), (III) NH ear and CI with Roger 14, (IV) NH ear with Roger Focus and CI, and (V) NH ear with Roger Focus and CI with Roger 14. For the NH participants, five corresponding listening conditions were chosen: (I) only better ear and weaker ear masked, (II) both ears, (III) better ear and weaker ear with Roger Focus, (IV) better ear with Roger Focus and weaker ear, and (V) both ears with Roger Focus. The speech level was fixed at 65 dB(A) at 1 meter from the speech-presenting loudspeaker, yielding a speech level of 56.5 dB(A) at the recipient's head. Noise levels were 55, 65, and 75 dB(A). Digitally altered noise recorded in school classrooms was used as competing noise. Speech recognition was measured in percent correct using the Oldenburg sentence test.In SSD CI recipients, a significant improvement in speech recognition was found for all listening conditions with Roger (III, IV, and V) versus all no-Roger conditions (I and II) at the higher noise levels (65 and 75 dB[A]). NH participants significantly benefited from the application of Roger in noise for higher levels, too. In both groups, no significant difference was detected between any of the different listening conditions at 55 dB(A) competing noise. There was also no significant difference between any of the Roger conditions III, IV, and V across all noise levels.The application of the advanced remote wireless microphone system, Roger, in SSD CI recipients provided significant benefits in speech recognition for distant speakers at higher noise levels. In NH participants, the application of Roger also produced a significant benefit in speech recognition in noise.


2011 ◽  
Vol 22 (02) ◽  
pp. 065-080 ◽  
Author(s):  
Alison M. Brockmeyer ◽  
Lisa G. Potts

Background: Difficulty understanding in background noise is a common complaint of cochlear implant (CI) recipients. Programming options are available to improve speech recognition in noise for CI users including automatic dynamic range optimization (ADRO), autosensitivity control (ASC), and a two-stage adaptive beamforming algorithm (BEAM). However, the processing option that results in the best speech recognition in noise is unknown. In addition, laboratory measures of these processing options often show greater degrees of improvement than reported by participants in everyday listening situations. To address this issue, Compton-Conley and colleagues developed a test system to replicate a restaurant environment. The R-SPACE™ consists of eight loudspeakers positioned in a 360 degree arc and utilizes a recording made at a restaurant of background noise. Purpose: The present study measured speech recognition in the R-SPACE with four processing options: standard dual-port directional (STD), ADRO, ASC, and BEAM. Research Design: A repeated-measures, within-subject design was used to evaluate the four different processing options at two noise levels. Study Sample: Twenty-seven unilateral and three bilateral adult Nucleus Freedom CI recipients. Intervention: The participants’ everyday program (with no additional processing) was used as the STD program. ADRO, ASC, and BEAM were added individually to the STD program to create a total of four programs. Data Collection and Analysis: Participants repeated Hearing in Noise Test sentences presented at 0 degrees azimuth with R-SPACE restaurant noise at two noise levels, 60 and 70 dB SPL. The reception threshold for sentences (RTS) was obtained for each processing condition and noise level. Results: In 60 dB SPL noise, BEAM processing resulted in the best RTS, with a significant improvement over STD and ADRO processing. In 70 dB SPL noise, ASC and BEAM processing had significantly better mean RTSs compared to STD and ADRO processing. Comparison of noise levels showed that STD and BEAM processing resulted in significantly poorer RTSs in 70 dB SPL noise compared to the performance with these processing conditions in 60 dB SPL noise. Bilateral participants demonstrated a bilateral improvement compared to the better monaural condition for both noise levels and all processing conditions, except ASC in 60 dB SPL noise. Conclusions: The results of this study suggest that the use of processing options that utilize noise reduction, like those available in ASC and BEAM, improve a CI recipient's ability to understand speech in noise in listening situations similar to those experienced in the real world. The choice of the best processing option is dependent on the noise level, with BEAM best at moderate noise levels and ASC best at loud noise levels for unilateral CI recipients. Therefore, multiple noise programs or a combination of processing options may be necessary to provide CI users with the best performance in a variety of listening situations.


2012 ◽  
Vol 23 (01) ◽  
pp. 064-073 ◽  
Author(s):  
Francis Kuk ◽  
Denise Keenan

Background: Directional microphones have been shown to improve a listener's ability to communicate in noise by improving the signal to noise ratio. However, their efficacy may be questioned in situations where the listener needs to understand speech originating from the back. Purpose: The goal of the study was to examine the performance of a directional microphone mode that has an automatic reverse cardioid polar pattern. Research Design: A single-blinded, factorial repeated-measures design was used to study the effect of microphone modes (reverse cardioid, omnidirectional, and front hypercardioid) and stimulus azimuths (front and back) on three outcome variables (aided thresholds, nonsense syllable identification in quiet, and sentence recognition in noise). Study Sample: Twenty adults with a mild-to-severe bilaterally symmetrical (±5 dB) sensorineural hearing loss participated. Intervention: Audibility in quiet was evaluated by obtaining aided sound field thresholds and speech identification at an input level of 50 dB SPL presented at 0 and 180° azimuths. In addition, speech understanding in noise was also assessed with the Hearing In Noise Test (HINT) sentences presented at both azimuths (0 and 180°) with a diffuse noise. Data Collection and Analysis: Repeated-measures analyses of variance (ANOVAs) were conducted to examine the effects of microphone mode (omnidirectional, front hypercardioid, reverse cardioid) and stimulus azimuth (0°, 180°) on aided thresholds, nonsense syllable identification, and HINT performance. Results: Results with the reverse cardioid directional microphone in both quiet conditions were similar to the omnidirectional microphone. The results of the reverse cardioid microphone in noise were significantly better than the omnidirectional microphone and front hypercardioid microphone when speech was presented from the back (p < 0.001). Conclusions: These results support the possible benefits of a reverse cardioid directional microphone when used in specific listening situations.


2015 ◽  
Vol 26 (05) ◽  
pp. 443-450 ◽  
Author(s):  
Susan Gordon-Hickey ◽  
Holly Morlas

Background: The acceptable noise level (ANL) has been proposed as a prehearing aid fitting measure that could be used for hearing aid selection and counseling purposes. Previous work has demonstrated that a listener’s ANL is unrelated to their speech recognition in noise abilities. It is unknown what criteria a listener uses when they select their ANL. To date, no research has explored the amount of speech recognized at the listener’s ANL. Purpose: To examine the amount of speech recognized at the listener’s ANL to determine whether speech recognition in noise is utilized as a factor for setting ANL. Research Design: A descriptive quasi-experimental study was completed. For all listeners, ANL was measured and speech recognition in noise was tested at ANL and at two additional signal-to-noise ratio (SNR) conditions based on the listener’s ANL (ANL + 5 and ANL – 5). Study Sample: Forty-four older adults served as participants. Twenty-seven participants had normal hearing and seventeen participants had mild to moderately-severe, symmetrical, sensorineural hearing loss. Data Collection and Analysis: Acceptance of noise was calculated from the measures of most comfortable listening level and background noise level. Additionally, speech recognition in noise was assessed at three SNRs using the quick speech-in-noise test materials. Results: A significant interaction effect of SNR condition and ANL group occurred for speech recognition. At ANL, a significant difference in speech recognition in noise was found across groups. Those in the mid and high ANL groups had excellent speech recognition at their ANL. Speech recognition in noise at ANL decreased with ANL category. Conclusions: For listeners with mid and high ANLs, speech recognition appears to play a primary role in setting their ANL. For those with low ANLs, speech recognition may contribute to setting their ANL; however, it does not appear to be the primary determiner of ANL. For those with very low ANLs, speech recognition does not appear to be significant variable for setting their ANL.


2013 ◽  
Vol 24 (08) ◽  
pp. 714-724 ◽  
Author(s):  
Jace Wolfe ◽  
Mila Morais ◽  
Erin Schafer ◽  
Emily Mills ◽  
Hans E. Mülder ◽  
...  

Background: Previous research supports the use of frequency modulation (FM) systems for improving speech recognition in noise of individuals with cochlear implants (CIs). However, at this time, there is no published research on the potential speech recognition benefit of new digital adaptive wireless radio transmission systems. Purpose: The goal of this study was to compare speech recognition in quiet and in noise of CI recipients while using traditional, fixed-gain analog FM systems, adaptive analog FM systems, and adaptive digital wireless radio frequency transmission systems. Research Design: A three-way repeated-measures design was used to examine performance differences among devices, among speech recognition conditions in quiet and in increasing levels of background noise, and between users of Advanced Bionics and Cochlear CIs. Study Sample: Seventeen users of Advanced Bionics Harmony CI sound processors and 20 users of Cochlear Nucleus 5 sound processors were included in the study. Data Collection and Analysis: Participants were tested in a total of 32 speech-recognition-in noise-test conditions, which included one no-FM and three device conditions (fixed-gain FM, adaptive FM, and adaptive digital) at the following signal levels: 64 dBA speech (at the location of the participant) in quiet and 64 dBA speech with competing noise at 50, 55, 60, 65, 70, 75, and 80 dBA noise levels. Results: No significant differences were detected between the users of Advanced Bionics and Cochlear CIs. All of the radio frequency system conditions (i.e., fixed-gain FM, adaptive FM, and adaptive digital) outperformed the no-FM conditions in test situations with competing noise. Specifically, in conditions with 70, 75, and 80 dBA of competing noise, the adaptive digital system provided better performance than the fixed-gain and adaptive FM systems. The adaptive FM system did provide better performance than the fixed-gain FM system at 70 and 75 dBA of competing noise. At the lower noise levels of 50, 55, 60, and 65 dBA, no significant differences were detected across the three systems, and no significant differences were found across the quiet conditions. In all conditions, performance became poorer as the competing noise level increased. Conclusions: In high levels of noise, the adaptive digital system provides superior performance when compared to adaptive analog FM and fixed-gain FM systems.


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