The primary goal of the research in this laboratory is to improve communication access in complex listening environments for children with hearing loss. Our current efforts focus on children with minimal/mild hearing loss. To achieve our research goals we are developing techniques that accurately simulate and evaluate the complex learning 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 ecologically valid experimental paradigm that includes auditory-visual cues from multiple sources, realistic amounts of background noise, and a reverberation time typical of what would be 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.
To facilitate research in this laboratory, a large classroom-sized acoustically treated laboratory is equipped with an 8-channel loudspeaker reproduction system and five widescreen LCD monitors to simulate a teacher and four students positioned around a subject, who is seated at a desk 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 the specific learning task we are studying. The loudspeaker and monitor arrays are controlled by an Apple MacPro and Firewire 16-channel A/D and D/A (Apogee, Ensemble). Six channels of video output are available from the computer. Using closed-circuit television, subjects are monitored while performing an experiment, which may be recorded on a secondary PC laptop for further analysis. In addition to video recording capabilities, we have developed a head-mounted gyroscope to track head movement during experiments.
The laboratory also includes a second Macintosh computer (Apple iMac) as well as a networked RAID storage array for audio-visual materials. Both Mac computers are equipped with professional audio and video editing software (Apple, Logic Studio and Final Cut Studio). An acoustical curtain separates the experimental area from the “off-stage” area where up to two researchers can monitor the progress of an experiment. The laboratory also stores calibration equipment including multiple measurement microphones, and a KEMAR artificial head/torso that are available for use in all BTNRH laboratories. Probe-microphone systems for recording and analysis of stimuli in the ear canal are available. Specialized software is available for implementing psychoacoustic paradigms, measuring acoustic stimuli, and analyzing data. There also is access to probe microphone/hearing-aid analysis systems, audiometers, tympanometers, and programmable/digital hearing aid systems.
Research in this laboratory is under the direction of Dawna Lewis, Ph.D., and is supported by NIDCD. Daniel Valente, Ph.D., is currently working in the laboratory as a post-doctoral fellow. In addition to other duties, Dr. Valente is responsible for the design and development of specific software for audio-visual room simulation and data acquisition. Jody Spalding, M.A., is a research audiologist and Elizabeth Heinrichs, B.S., is a research assistant. Other BTNRH collaborators include Nicholas Smith, Ph.D., Mary Pat Moeller, Ph.D., Pat Stelmachowicz, Ph.D., and Ryan McCreery, Ph.D. candidate.
Summary of Research Program
For Clinicians and Scientists
Current studies in this laboratory aim to systematically examine the impact of minimal hearing loss on a range of functional auditory and language skills that support learning. Structured interviews and standardized questionnaires are being used to examine and quantify perceived communication difficulties experienced by children with minimal hearing loss from three perspectives (child, parent, and teacher).In addition, speech perception abilities of children with minimal hearing loss are being examined in three studies involving realistic listening environments where conditions may impede the ability to hear and understand. Advanced language skills also are being examined in this population using standardized language tasks and elicited narratives using cartoon and theme-based pictured materials. Results from these studies will provide a multi-dimensional view of this population that will lead to improved evaluation and management.
Future projects are being designed to incorporate active learning tasks representative of typical classroom activities within a laboratory environment that provides real-time simulation of plausible classroom environments. These studies will examine comprehension, listening effort, and multitasking abilities during complex learning tasks in a simulated classroom with and without assistance from classroom amplification systems. We also plan to examine how differing room acoustics and classroom technologies interact to affect listening preference and performance in these environments.
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 minimal/mild 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 current studies involve a systematic examination of a range of functional skills that support language and learning in this population. 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 minimal/mild hearing loss and improve communication access in complex listening environments.