Binaural Speech Understanding With Bilateral Cochlear Implants in Reverberation

2018 ◽  
Vol 27 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Kostas Kokkinakis
Keyword(s):  
Sound Field ◽  
Spatial Location ◽  
Speech Understanding ◽  
Spatial Cues ◽  
Bilateral Cochlear Implants ◽  
Positive Effects ◽  
Spatial Release ◽  
Listening Environments ◽  
Speech Reception Thresholds ◽  
Release From Masking

PurposeThe purpose of this study was to investigate whether bilateral cochlear implant (CI) listeners who are fitted with clinical processors are able to benefit from binaural advantages under reverberant conditions. Another aim of this contribution was to determine whether the magnitude of each binaural advantage observed inside a highly reverberant environment differs significantly from the magnitude measured in a near-anechoic environment.MethodTen adults with postlingual deafness who are bilateral CI users fitted with either Nucleus 5 or Nucleus 6 clinical sound processors (Cochlear Corporation) participated in this study. Speech reception thresholds were measured in sound field and 2 different reverberation conditions (0.06 and 0.6 s) as a function of the listening condition (left, right, both) and the noise spatial location (left, front, right).ResultsThe presence of the binaural effects of head-shadow, squelch, summation, and spatial release from masking in the 2 different reverberation conditions tested was determined using nonparametric statistical analysis. In the bilateral population tested, when the ambient reverberation time was equal to 0.6 s, results indicated strong positive effects of head-shadow and a weaker spatial release from masking advantage, whereas binaural squelch and summation contributed no statistically significant benefit to bilateral performance under this acoustic condition. These findings are consistent with those of previous studies, which have demonstrated that head-shadow yields the most pronounced advantage in noise. The finding that spatial release from masking produced little to almost no benefit in bilateral listeners is consistent with the hypothesis that additive reverberation degrades spatial cues and negatively affects binaural performance.ConclusionsThe magnitude of 4 different binaural advantages was measured on the same group of bilateral CI subjects fitted with clinical processors in 2 different reverberation conditions. The results of this work demonstrate the impeding properties of reverberation on binaural speech understanding. In addition, results indicate that CI recipients who struggle in everyday listening environments are also more likely to benefit less in highly reverberant environments from their bilateral processors.

scholarly journals The Contribution of Individual Differences in Memory Span and Language Ability to Spatial Release From Masking in Young Children

2019 ◽  
Vol 62 (10) ◽  
pp. 3741-3751 ◽  
Author(s):  
Douglas MacCutcheon ◽  
Florian Pausch ◽  
Christian Füllgrabe ◽  
Renata Eccles ◽  
Jeannie van der Linde ◽  
...  
Keyword(s):  
Individual Differences ◽  
Background Noise ◽  
Memory Span ◽  
Language Ability ◽  
Stream Segregation ◽  
Spatial Cues ◽  
Speech Reception ◽  
Spatial Release ◽  
Speech Reception Thresholds ◽  
Release From Masking

Purpose Working memory capacity and language ability modulate speech reception; however, the respective roles of peripheral and cognitive processing are unclear. The contribution of individual differences in these abilities to utilization of spatial cues when separating speech from informational and energetic masking backgrounds in children has not yet been determined. Therefore, this study explored whether speech reception in children is modulated by environmental factors, such as the type of background noise and spatial configuration of target and noise sources, and individual differences in the cognitive and linguistic abilities of listeners. Method Speech reception thresholds were assessed in 39 children aged 5–7 years in simulated school listening environments. Speech reception thresholds of target sentences spoken by an adult male consisting of number and color combinations were measured using an adaptive procedure, with speech-shaped white noise and single-talker backgrounds that were either collocated (target and back-ground at 0°) or spatially separated (target at 0°, background noise at 90° to the right). Spatial release from masking was assessed alongside memory span and expressive language. Results and Conclusion Significant main effect results showed that speech reception thresholds were highest for informational maskers and collocated conditions. Significant interactions indicated that individual differences in memory span and language ability were related to spatial release from masking advantages. Specifically, individual differences in memory span and language were related to the utilization of spatial cues in separated conditions. Language differences were related to auditory stream segregation abilities in collocated conditions that lack helpful spatial cues, pointing to the utilization of language processes to make up for losses in spatial information.

scholarly journals Spatial Release From Masking in Adults With Bilateral Cochlear Implants: Effects of Distracter Azimuth and Microphone Location

2018 ◽  
Vol 61 (3) ◽  
pp. 752-761 ◽  
Author(s):  
Timothy J. Davis ◽  
René H. Gifford
Keyword(s):  
Cochlear Implants ◽  
Spatial Configuration ◽  
Block Design ◽  
Speech Understanding ◽  
Traditional Assessment ◽  
Bilateral Cochlear Implants ◽  
Secondary Purpose ◽  
Spatial Release ◽  
Bilateral Cochlear Implant ◽  
Release From Masking

PurposeThe primary purpose of this study was to derive spatial release from masking (SRM) performance-azimuth functions for bilateral cochlear implant (CI) users to provide a thorough description of SRM as a function of target/distracter spatial configuration. The secondary purpose of this study was to investigate the effect of the microphone location for SRM in a within-subject study design.MethodSpeech recognition was measured in 12 adults with bilateral CIs for 11 spatial separations ranging from −90° to +90° in 20° steps using an adaptive block design. Five of the 12 participants were tested with both the behind-the-ear microphones and a T-mic configuration to further investigate the effect of mic location on SRM.ResultsSRM can be significantly affected by the hemifield origin of the distracter stimulus—particularly for listeners with interaural asymmetry in speech understanding. The greatest SRM was observed with a distracter positioned 50° away from the target. There was no effect of mic location on SRM for the current experimental design.ConclusionOur results demonstrate that the traditional assessment of SRM with a distracter positioned at 90° azimuth may underestimate maximum performance for individuals with bilateral CIs.

scholarly journals FreeHear: A New Sound-Field Speech-in-Babble Hearing Assessment Tool

2019 ◽  
Vol 23 ◽  
pp. 233121651987237 ◽  
Author(s):  
David R. Moore ◽  
Helen Whiston ◽  
Melanie Lough ◽  
Antonia Marsden ◽  
Harvey Dillon ◽  
...  
Keyword(s):  
Assessment Tool ◽  
Sound Field ◽  
Standard Test ◽  
Initial Assessment ◽  
Clinical Test ◽  
Older Children ◽  
Spatial Release ◽  
Hearing Devices ◽  
Release From Masking ◽  
Test Retest Reliability

Pure-tone threshold audiometry is currently the standard test of hearing. However, in everyday life, we are more concerned with listening to speech of moderate loudness and, specifically, listening to a particular talker against a background of other talkers. FreeHear delivers strings of three spoken digits (0–9, not 7) against a background babble via three loudspeakers placed in front and to either side of a listener. FreeHear is designed as a rapid, quantitative initial assessment of hearing using an adaptive algorithm. It is designed especially for children and for testing listeners who are using hearing devices. In this first report on FreeHear, we present developmental considerations and protocols and results of testing 100 children (4–13 years old) and 23 adults (18–30 years old). Two of the six 4 year olds and 91% of all older children completed full testing. Speech reception threshold (SRT) for digits and noise colocated at 0° or separated by 90° both improved linearly across 4 to 12 years old by 6 to 7 dB, with a further 2 dB improvement for the adults. These data suggested full maturation at approximately 15 years old SRTs at 90° digits/noise separation were better by approximately 6 dB than SRTs colocated at 0°. This spatial release from masking did not change significantly across age. Test–retest reliability was similar for children and adults (standard deviation of 2.05–2.91 dB SRT), with a mean practice improvement of 0.04–0.98 dB. FreeHear shows promise as a clinical test for both children and adults. Further trials in people with hearing impairment are ongoing.

scholarly journals The Effect of Simulated Interaural Frequency Mismatch on Speech Understanding and Spatial Release From Masking

2018 ◽  
Vol 39 (5) ◽  
pp. 895-905 ◽  
Author(s):  
Matthew J. Goupell ◽  
Corey A. Stoelb ◽  
Alan Kan ◽  
Ruth Y. Litovsky
Keyword(s):  
Speech Understanding ◽  
Frequency Mismatch ◽  
Spatial Release ◽  
Release From Masking
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