Auditory skills and brain morphology predict individual differences in adaptation to degraded speech

Julia Erb*, Molly J. Henry, Frank Eisner, Jonas Obleser

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

37 Citations (Web of Science)

Abstract

Noise-vocoded speech is a spectrally highly degraded signal, but it preserves the temporal envelope of speech. Listeners vary considerably in their ability to adapt to this degraded speech signal. Here, we hypothesised that individual differences in adaptation to vocoded speech should be predictable by non-speech auditory, cognitive, and neuroanatomical factors. We tested 18 normal-hearing participants in a short-term vocoded speech-learning paradigm (listening to 100 4-band-vocoded sentences). Non-speech auditory skills were assessed using amplitude modulation (AM) rate discrimination, where modulation rates were centred on the speech-relevant rate of 4 Hz. Working memory capacities were evaluated (digit span and nonword repetition), and structural MRI scans were examined for anatomical predictors of vocoded speech learning using voxel-based morphometry. Listeners who learned faster to understand degraded speech also showed smaller thresholds in the AM discrimination task. This ability to adjust to degraded speech is furthermore reflected anatomically in increased grey matter volume in an area of the left thalamus (pulvinar) that is strongly connected to the auditory and prefrontal cortices. Thus, individual non-speech auditory skills and left thalamus grey matter volume can predict how quickly a listener adapts to degraded speech.
Original languageEnglish
Pages (from-to)2154-2164
JournalNeuropsychologia
Volume50
Issue number9
DOIs
Publication statusPublished - Jul 2012
Externally publishedYes

Keywords

  • Language
  • Noise-vocoded speech
  • Cochlear implant simulation
  • Perceptual learning
  • Amplitude modulation rate
  • Voxel-based morphometry

Cite this