The primary goal of the research in the Listening and Learning Laboratory is to improve communication access in complex listening environments for children with hearing loss. Our current efforts focus on children with mild bilateral or unilateral hearing loss. To achieve our research goals we are developing techniques that accurately simulate and evaluate the complex listening tasks and environments that children with hearing loss encounter on a daily basis. These techniques include the creation of a simulated classroom environment which is used to create an experimental paradigm that includes auditory-visual cues from multiple sources, realistic amounts of background noise, and reverberation times that mimic those found in real classrooms. By using this simulated classroom we are able to achieve experimental control that would not be available in a real classroom. Our use of eye-tracking and wireless heard-tracking technologies provides innovative means of capturing looking behaviors during experimental tasks.
To facilitate our research, a large acoustically treated laboratory is equipped with an 8-channel loudspeaker reproduction system and five widescreen HGTVs to simulate multiple positioned around a subject, who is seated in the center of the room. Using custom room simulation, data collection, and video reproduction software, we are able to adjust the level of presented speech, background noise, and artificial reverberation levels depending on specific experimental tasks. Via a web camera and wireless microphone, subjects are monitored while performing an experiment, which may be recorded on a secondary laptop for further analysis. There also is access to probe microphone/hearing-aid analysis systems, audiometers, tympanometers, and programmable/digital hearing aid systems.
For our experiments, we also have access to the joint-use Auditory-Visual (AV) Core Facility that was developed as part of the Center for Perception and Communication in Children. This Facility supports research on spatial effects of auditory and visual sound sources on children’s speech perception and comprehension, with special emphasis on the listening needs of children with hearing loss. It includes a large single-walled, acoustically isolated sound booth, a control room, office space for core personnel and a waiting room.
Research in this laboratory is under the direction of Dawna Lewis, Ph.D., and is supported by NIH. Tessa McDermott, B.S. and Andrew Dergan, B.S. currently work as research assistants in the lab. Tim Vallier, M.M., a systems analyst provides support through our Technical Core. Sara Robinson, M.A. and Sarah Al-Salim, Au.D., provide speech-language and audiological support through our Clinical Measurement Core. BTNRH collaborators include Marc Brennan, Ph.D., Judy Kopun, M.A., Lori Leibold, Ph.D., Ryan McCreery, Ph.D., Mary Pat Moeller, Ph.D., Kanae Nishi, Ph.D., and Nicholas Smith, Ph.D.. Patricia Stelmachowicz, Ph.D. and Michael Gorga, Ph.D. have served as internal mentors in the development of my work. Outside collaborators include Kendra Schmid, Ph.D., University of Nebraska Medical Center and Bruce Tomblin, Ph.D., University of Iowa.
Real-world speech understanding is affected by interdependent factors including characteristics of the target and competing talker(s), the message/task, the acoustic environment, and the listener. For children with hearing loss, both the degree of hearing loss and whether the loss affects one or both ears also contributes to speech understanding in real-world environments. The long-term goal of this research program is to disentangle these issues by determining the influence of the above factors in isolation and in combination on speech understanding in children with MBHL and UHL. The rationale for our approach is that these factors are alterable as points of intervention to improve comprehension.
Current studies in this laboratory aim to systematically examine the impact of mild bilateral and unilateral hearing loss on a range of functional auditory and audiovisual skills that support learning.
Planned projects will evaluate talker related effects that impact speech perception in complex listening conditions for children with mild bilateral and unilateral hearing loss and children with normal hearing, including the effects of visual and spatial cues. Additional tasks are being designed to incorporate active learning tasks representative of typical classroom activities within a laboratory environment that mimics classroom environments. These studies will examine comprehension and attention during complex listening tasks with and without assistance from classroom amplification systems.
The work in this laboratory is concerned with how children with hearing loss hear and understand in complex listening environments. Currently, we are examining these issues in children with mild bilateral or unilateral hearing loss. The speech perception difficulties experienced by these children have the potential to affect their speech and language development and educational progress, as well as social-emotional functioning. However, at present there does not appear to be a consensus on either the difficulties experienced by these children or the optimum course of treatment. Our studies are designed as a systematic examination of a range of auditory and audiovisual skills that support language and learning in these populations. The results of these studies will lead to greater understanding of their auditory and educational needs. Additional studies are being designed to quantify the difficulties these children experience in classrooms as well as the impact of hearing assistance technologies and acoustics on performance. The results of those studies have the potential to influence habilitative strategies for children with mild bilateral or unilateral hearing loss and improve communication access in complex listening environments.