Recording human evoked potentials that follow the pitch contour of a natural vowel.
We investigated whether pitch-synchronous neural activity could be recorded in humans, with a natural vowel and a vowel in which the fundamental frequency was suppressed. Small variations of speech periodicity were detected in the evoked responses using a fine structure spectrograph (FSS). A significant response (P < 0.001) was measured in all seven normal subjects even when the fundamental frequency was suppressed, and it very accurately tracked the acoustic pitch contour (normalized mean absolute error < 0.57%). Small variations in speech periodicity, which humans can detect, are therefore available to the perceptual system as pitch-synchronous neural firing. These findings suggest that the measurement of pitch-evoked responses may be a viable tool for objective speech audiometry.
Dajani
Hilmi R
HR
Institute of Biomaterials and Biomedical Engineering and the Edward S. Rogers Sr Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada. h.dajani@utoronto.ca
Purcell
David
D
Wong
Willy
W
Kunov
Hans
H
Picton
Terence W
TW
D000328:Adult; D000368:Aged; D000465:Algorithms; D001300:Audiometry, Evoked Response / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009323:Natural Language Processing; D010898:Pitch Perception / Q000502:physiology*; D012660:Semantics; D013067:Speech Perception / Q000502:physiology*