The effect of stimulus choice on cortical auditory evoked potentials (CAEP): Consideration of speech segment positioning within naturally produced speech

Abstract

Objective: Cortical auditory evoked potentials (CAEPs) can be elicited to stimuli generated from different parts of speech. The aim of this study was to compare the phoneme /ʃ/ from word medial and word initial positions and its influence on the CAEP. Design: Stimuli from word medial positions were found to have shorter rise times compared to the same phonemes from word initial positions. A repeated measures design was carried out with CAEPs elicited using /ʃ/ from a word initial and a word medial position. Study sample: Sixteen individuals with audiometric thresholds within normal limits participated in the study. Results: Stimuli /ʃ/ from a word medial position elicited CAEPs with significantly larger amplitudes and shorter latencies compared to /ʃ/ from a word initial position (p < 0.05). Conclusions: Findings from this study, incorporating naturally produced speech sounds, suggest the need to consider spectral and temporal variations when choosing stimuli to optimize the amplitude and latency characteristics of the CAEP. Overall, findings illustrate good test-retest reliability of CAEP measures using speech stimuli with clinical equipment.

Key Words::

• Natural speech
• stimulus
• cortical auditory evoked potentials
• rise time
• spectrum
• single-channel
• clinical equipment
• test-retest reliability

Acknowledgements

This work was supported by an Early Researcher Award (ERA07-03-051, Ontario Ministry of Research and Innovation) and a New Opportunities Award (Canada Foundation for Innovation/Ontario Innovation Trust) to Dr. Susan Scollie. The authors would also like to thank Dr. Janis Oram Cardy for her assistance on data analysis and interpretation, and the reviewers for their comments.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and the writing of the paper.