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• DSL v5: A new software-assisted approach for hearing aid prescription

• Integrating frequency-specific ABR thresholds with hearing aid fitting procedures

• Predicting speech recognition scores for children who use hearing aids

• Acceptability of background noise and hearing aid signal processing

• Hearing aid signal processing options for high-frequency hearing loss

• Prediction of sound quality and speech intelligibility for frequency-compressed speech

• Sound localization in children who use hearing aids

• Development of a new software-assisted approach for hearing aid prescription in the pediatric population.  

DSL v5: A new software-assisted approach for hearing aid prescription

• Project Manager: Sheila Moodie
• Software Engineer: Steve Beaulac
• Principal Investigators: Susan Scollie, Richard Seewald
• Team Members: Marlene Bagatto
• Collaborators: Leonard Cornelisse, John Pumford, Lorienne Jenstad
• Support: Canada Research Chair in Childhood Hearing, Masons Help2Hear Foundation, UWO Office of Industry Liason

This project has developed a revised version of the DSL Method (v5.0). Revisions address the differences in prescribing and fitting hearing instruments for infants versus children versus adults. New algorithms have been developed to accommodate and prescribe characteristics of digital signal processing features in modern hearing aids. These include multichannel signal processing, channel-dependent compression thresholds, multiple definitions of output limiting processing, and multimemory technology (specific to quiet versus noisy environments). Our age-dependent targets are the first to prescribe a somewhat lower listening level for adults (who presumably have acquired postlingual hearing loss) than for infants or children (who presumably have congenital/prelingual hearing loss). We have also developed a modification of the DSL v5.0 algorithm for use with the Adaptive Dynamic Range Optimization (ADROTM) digital signal processor in collaboration with Peter Blamey from Dynamic Hearing, Inc. For more information on this version of DSL, please visit: http://www.dslio.com.

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Integrating frequency-specific ABR thresholds with hearing aid fitting procedures

• Project Co-ordinator: Marlene Bagatto, Au.D.
• Project Participants: Rachel Liu (M.Sc. student), Richard Seewald (Advisor), Susan Scollie
• Support: Canadian Language and Literacy Research Network, Canada Research Chair in Childhoood Hearing

The purpose of this project was to compare behavioral and electrophysiologic threshold estimates, incorporating measures of external ear canal acoustics. We measured the accuracy of predicting behavioral thresholds from those estimated by frequency-specific ABR. The ABR threshold estimates will be converted to dB SPL in the ear canal through the use of the Real Ear to Coupler Difference (RECD) transform. The RECD is a commonly measured variable in clinical audiology. By including it, we can convert ABR threshold estimates to the dB SPL scale, which is more easily applied to infant hearing aid fitting. For more information on this project, see Bagatto et al., (2005).

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Predicting speech recognition scores for children who use hearing aids

• Project Participants: Stella Ng (M.Sc. student), Susan Scollie (advisor), Marlene Bagatto, Richard Seewald, Andreas Seelisch, Julianne Tenhaaf.
• Support: Masons Help2Hear Foundation, Etymotic Research

This project developed and tested a new method for predicting how well children who use hearing aids can understand speech. The prediction will be based on electroacoustic verification measurements that are commonly made in audiology clinics. That is, if a clinical audiologist prescribes and fits hearing aids for a child, it would be useful if the hearing aid tests could predict how well the child can understand speech when wearing the hearing aids. In studying this problem, we considered how children understand sentences that are quiet versus loud, sentences that are heard with varying levels of background noise, and the developmental status (i.e., language age) of the child. We applied the ANSI standardized Speech Intelligibility Index to take these variables into account within an SII-based performance-intelligibility function.

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Acceptability of background noise and hearing aid signal processing

• Project Participants: Christine Meston (M.Sc. student), Richard Seewald (advisor), Susan Scollie, Marlene Bagatto, Andreas Seelisch, Julianne Tenhaaf.
•  Support: Masons Help2Hear Foundation, Siemens Canada

This project measured how much background noise children can tolerate while trying to understand a spoken story. Children who use hearing aids rated acceptability of background noise while listening with conventional hearing aids or with variety of alternatives that are designed for use in noise.

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Hearing aid signal processing options for high-frequency hearing loss

• Project Manager: Marlene Bagatto, AuD
• Project Participants: Danielle Glista (Ph.D. student), Susan Scollie (advisor/principal investigator), Richard Seewald, Andreas Seelisch, Julianne Tenhaaf, Melissa Polonenko.
• Collaborators: Marilyn Kertoy, Marc Joanisse, Vijay Parsa
• Support: Hearing Foundation of Canada, NSERC Collaborative Health Research Projects, Phonak AG

This project will evaluate a new signal processing option designed to support hearing the high-frequency components of sounds, such as the letters "s" or "f". We are investigating the effects of this signal processing on a variety of outcome measures, including sound detection, speech recognition (vowels, consonants, sentences), speech production, sound quality, and self-reported outcomes, in both adults and children. This project is currently in data collection.

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Prediction of sound quality and speech intelligibility for frequency-compressed speech

• Project Manager: Marlene Bagatto, AuD
• Project Participants: Andreas Seelisch (Graduate student), Susan Scollie (advisor/principal investigator), Richard Seewald, Danielle Glista (Ph.D. student)
• Collaborators: Vijay Parsa, Rainer Huber, Michael Wirtzfeld.
• Support: NSERC Collaborative Health Research Projects, Phonak AG

This project will further evaluate a new signal processing option designed to support hearing the high-frequency components of sounds, such as the letters "s" or "f". We are investigating the effects of this signal processing on sound quality and speech intelligibility, with the specific goal of predicting both using standardized and custom-developed engineering models.

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Sound localization in children who use hearing aids

• Project participants: Jeff Crukley (graduate student), Susan Scollie (advisor, principal investigator), M. F. Cheesman, Vijay Parsa.
• Support: Hearing Foundation of Canada

This project will measure the effects of hearing impairment and hearing aid use on sound localization in two experimental conditions: (a) localization of isolated pink noise bursts; (b) localization of horn honks amidst a moving traffic noise scene. Unlike most previous studies, we will be testing both adults and children who use hearing aids in both ears. This project is currently in data collection, and is taking place in the NCA Anechoic Chamber. For more information about this study, or to volunteer, please leave a message 519-661-2111, extension 88927.

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Development of a new software-assisted approach for hearing aid prescription in the pediatric population.  

• Project coordinator: Sheila Moodie
• Software engineer: Steve Beaulac
• Project participants: Susan Scollie, Richard Seewald, Marlene Bagatto.
• Collaborators: Leonard Cornelisse, John Pumford, Lorienne Jenstad.
• Support: Canada Research Chair in Childhood Hearing, Masons Help2Hear Foundation. 

This project will develop a revised version of the DSL® Method (v5.0). Revisions and/or new algorithms have been  developed to address the unique features of fitting hearing aids to infants. Other revisions and/or new algorithms  have been developed to accommodate and prescribe characteristics of digital signal processing features in modern hearing aids. These include multichannel signal processing, channel-dependent compression thresholds, multiple definitions of output limiting  processing, and multimemory technology (specific to quiet versus noisy environments). A further revision includes  an age-dependent prescription that prescribes a somewhat lower listening level for adults (who presumably have acquired postlingual hearing loss) than for infants or children (who presumably have congenital/prelingual hearing loss).  We are also developing a modification of the DSL v5.0 algorithm for use with the Adaptive Dynamic Range Optimization (ADROTM) digital signal processor in collaboration with Peter Blamey from Dynamic Hearing, Inc.

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Other NCA labs include

Anechoic Chamber | Assistive Devices | Child Amplification |
Child Hearing Research | Digital Signal Processing | Speech Communication | Electrophysiology | Hearing Research Clinic | Hearing Science  | Robert B. Johnston Aural Rehabilitations