Preliminary Investigation of the Passively Evoked N400 as a Tool for Estimating Speech-in-Noise Thresholds Purpose Speech-in-noise testing relies on a number of factors beyond the auditory system, such as cognitive function, compliance, and motor function. It may be possible to avoid these limitations by using electroencephalography. The present study explored this possibility using the N400. Method Eleven adults with typical hearing heard ... Research Article
Research Article  |   December 01, 2016
Preliminary Investigation of the Passively Evoked N400 as a Tool for Estimating Speech-in-Noise Thresholds
 
Author Affiliations & Notes
  • Caroline Jamison
    School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
  • Steve J. Aiken
    School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
    School of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada
    Division of Otolaryngology, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
  • Michael Kiefte
    School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
  • Aaron J. Newman
    School of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada
  • Manohar Bance
    School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
    Division of Otolaryngology, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
  • Lauren Sculthorpe-Petley
    School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia, Canada
    School of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada
    Division of Otolaryngology, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
    Biomedical Translational Imaging Centre, IWK Health Centre, Halifax, Nova Scotia, Canada
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Lauren Sculthorpe-Petley: lauren_petley@starkey.com
  • Editor: Sumitrajit Dhar
    Editor: Sumitrajit Dhar×
  • Associate Editor: Ann Eddins
    Associate Editor: Ann Eddins×
Article Information
Hearing Disorders / Research Articles
Research Article   |   December 01, 2016
Preliminary Investigation of the Passively Evoked N400 as a Tool for Estimating Speech-in-Noise Thresholds
American Journal of Audiology, December 2016, Vol. 25, 344-358. doi:10.1044/2016_AJA-15-0080
History: Received December 15, 2015 , Revised April 14, 2016 , Accepted May 20, 2016
 
American Journal of Audiology, December 2016, Vol. 25, 344-358. doi:10.1044/2016_AJA-15-0080
History: Received December 15, 2015; Revised April 14, 2016; Accepted May 20, 2016

Purpose Speech-in-noise testing relies on a number of factors beyond the auditory system, such as cognitive function, compliance, and motor function. It may be possible to avoid these limitations by using electroencephalography. The present study explored this possibility using the N400.

Method Eleven adults with typical hearing heard high-constraint sentences with congruent and incongruent terminal words in the presence of speech-shaped noise. Participants ignored all auditory stimulation and watched a video. The signal-to-noise ratio (SNR) was varied around each participant's behavioral threshold during electroencephalography recording. Speech was also heard in quiet.

Results The amplitude of the N400 effect exhibited a nonlinear relationship with SNR. In the presence of background noise, amplitude decreased from high (+4 dB) to low (+1 dB) SNR but increased dramatically at threshold before decreasing again at subthreshold SNR (−2 dB).

Conclusions The SNR of speech in noise modulates the amplitude of the N400 effect to semantic anomalies in a nonlinear fashion. These results are the first to demonstrate modulation of the passively evoked N400 by SNR in speech-shaped noise and represent a first step toward the end goal of developing an N400-based physiological metric for speech-in-noise testing.

Acknowledgments
All work was supported by the IWK Health Centre in the form of a Category B research grant awarded to the sixth author. The work described herein was completed in partial fulfillment of the first author's master's degree in speech–language pathology.
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