Tim Murphy, PhD
Postdoctoral Research Associate, Speech Motor Neuroscience Group
Department of Communication Sciences and Disorders, University of Wisconsin-Madison
Characterizing adaptation and retention of a nonuniform auditory perturbation in speech
When speakers detect an unexpected change in the acoustics of their vocal output, they adapt their productions to oppose these changes. Researchers investigate this sensorimotor adaptation using altered auditory feedback, a technique that alters speech in near-real time to measure how the speakers adjust to auditory errors. Because adaptation is implicit and unconscious, targeting sensorimotor adaptation through altered auditory feedback has the potential to complement traditional speech therapies that rely heavily on conscious, effortful practice. Our lab is investigating whether altered auditory feedback can increase vowel distinctiveness in speech, with the long term goal of using this technique to improve speech intelligibility in individuals with hypokinetic dysarthria. We have found that sensorimotor adaptation can be used to increase speakers’ average vowel spacing, which in turn correlates with changes in speech intelligibility. I will share findings from our study examining whether this adaptation is retained across multiple days and how repeated sessions modulate adaptation over time. Participants visited our lab twice weekly for four weeks, completing eight total sessions of reading monosyllabic words and sentences. Half of these participants received altered auditory feedback across all sessions, while the remaining half did not. Our preliminary results indicate that robust adaptation occurs within individual sessions, but that the magnitude of adaptation attenuates across consecutive sessions. Importantly, adaptation does not appear to be retained across sessions. I will conclude by contextualizing these findings within the broader speech and motor learning literature to interpret their implications for designing effective, long-term auditory feedback therapies.