Effect of pre-transition stimulus duration on acoustic change complex

Abstract

Objective: To investigate the effect of pre-transition duration on acoustic change complex (ACC) for speech and tonal stimulus. Design: Cortical potentials were recorded for consonant-vowel syllable and tonal complex stimuli with varying pre-transition durations. Study sample: Ten individuals (three male and seven female) in the age range from 18 to 26 years, with normal hearing sensitivity, participated in the study. Results: The results revealed that a minimum pre-transition duration of 100 ms for tonal stimulus (with spectral change) and 80 ms for consonant-vowel syllable is necessary in order to elicit ACC. The latency of N1¹ and P2¹, which is the response for change within the ongoing stimulus, increased with increase in pre-transition duration. The amplitude of the evoked responses did not show any significant change. Conclusions: It was found that minimum pre-transition duration required in eliciting ACC for speech and non-speech stimulus is not same. The speech stimulus required lesser duration of pre-transition than non-speech stimulus. Further studies regarding the acoustic aspects of sound on CAEP in isolation are warranted.

Key Words::

• Acoustic change complex (ACC)
• pre-transition

Acknowledgements

The authors would like to thank the Director, All India Institute of Speech and Hearing, for granting permission to carry out the study. The authors would like to thank the late Dr. Vijayalakshmi Basavaraj for providing valuable guidance to start with this research paper. The authors are immensely grateful to the reviewers for their constructive suggestions. The authors would also like to thank all the participants of the study for their co-operation.

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