Waveform of a naturally spoken speech stimulus used for measuring envelope following responses
Waveform of a naturally spoken speech stimulus used for measuring envelope following responses

Research in our lab covers 5 main areas:

  1. Neural encoding of speech properties in normal development: We understand speech, the main signal of interest in human communication, by relying on its temporal (time-based) and spectral (frequency-based) properties. In this lab, we are interested in evaluating how the representation of time-based cues in speech, such as the fundamental frequency of voice, develops from infancy to later in childhood in quiet as well as in adverse listening situations. We are also interested in evaluating how the neural encoding of time-based cues predicts behaviour during development.
  2. Influence of hearing loss and the use of hearing aids in childhood on the neural encoding of speech properties: The main goal of auditory (re)-habilitation in children with hearing loss is to provide access to speech. Despite early intervention and adequate audibility of speech sounds, children with hearing loss experience significant speech understanding abilities difficulties, especially in the presence of a competing signal (e.g., noise). We are interested in evaluating how time-based cues in speech are influenced by hearing loss and the use of hearing aids.
  3. Variables influencing the characteristics of envelope following responses (EFR) evoked by speech and non-speech stimuli: EFRs, also commonly called FFRs, are scalp-based potentials that reflect the ability of the auditory system to code fluctuations in stimuli including speech. EFRs are of special interest in this lab because they can be elicited by naturally spoken vowels, that are part of syllables or even words and sentences. This feature enables the use of stimuli that resemble running speech and therefore facilitate simulation of device (e.g., hearing aid) function during everyday use. However, the characteristics of EFRs show significant between-subject variability. We are interested in stimulus-related variables (e.g., acoustic elements preceding the stimulus) as well as physiological variables (e.g., ear canal and middle ear filtering) that influence EFR characteristics.
  4. Development and clinical translation of EEG-based tools for clinical care of children with hearing loss: EEG-based tools, often called auditory evoked potentials,  enable us to infer about auditory function without the individual’s participation. This is an important advantage in babies who are not quite developmentally ready to participate in hearing tests or in older children with additional developmental concerns that may impede their participation. In collaboration with the National Center for Audiology in Canada, our lab is working towards developing EFR-based tools that can measure hearing aid benefit in babies.
  5. Audiological profiles in children with neuro-developmental disorders: Intervention outcomes in children with hearing loss are influenced by the presence of another co-morbid developmental disorder. In collaboration with the American Family Children’s Hospital, we are investigating sensory and non-sensory factors that influence intervention outcomes in children with autism spectrum disorder, Down Syndrome, global developmental delay, cerebral palsy and cytomegalovirus infection.

Research in our lab is funded by:

  1. American Speech-Language-Hearing Foundation (New Investigator Research grant)
  2. Hearing Health Foundation (Emerging Research grant)
  3. National Institutes of Health – National Institute on Deafness and Other Communication Disorders (R21)
  4. UW-Madison, Office of the Vice Chancellor for Research and Graduate Education (OVCRGE) – Promoting Industry Collaboration Initiative