Katlyn B Van Dyke1, Rachel Lieberman1, Alessandro Presacco1,2, Samira Anderson1,2,3. 1. Department of Hearing and Speech Sciences, University of Maryland, College Park. 2. Program in Neuroscience and Cognitive Science, University of Maryland, College Park. 3. Language Science Center, University of Maryland, College Park.
Abstract
PURPOSE: This study investigates the development of phase locking and frequency representation in infants using the frequency-following response to consonant-vowel syllables. METHOD: The frequency-following response was recorded in 56 infants and 15 young adults to 2 speech syllables (/ba/ and /ga/), which were presented in randomized order to the right ear. Signal-to-noise ratio and Fsp analyses were used to verify that individual responses were present above the noise floor. Thirty-six and 39 infants met these criteria for the /ba/ or /ga/ syllables, respectively, and 31 infants met the criteria for both syllables. Data were analyzed to obtain measures of phase-locking strength and spectral magnitudes. RESULTS: Phase-locking strength to the fine structure in the consonant-vowel transition was higher in young adults than in infants, but phase locking was equivalent at the fundamental frequency between infants and adults. However, frequency representation of the fundamental frequency was higher in older infants than in either the younger infants or adults. CONCLUSION: Although spectral amplitudes changed during the first year of life, no changes were found with respect to phase locking to the stimulus envelope. These findings demonstrate the feasibility of obtaining these measures of phase locking and fundamental pitch strength in infants as young as 2 months of age.
PURPOSE: This study investigates the development of phase locking and frequency representation in infants using the frequency-following response to consonant-vowel syllables. METHOD: The frequency-following response was recorded in 56 infants and 15 young adults to 2 speech syllables (/ba/ and /ga/), which were presented in randomized order to the right ear. Signal-to-noise ratio and Fsp analyses were used to verify that individual responses were present above the noise floor. Thirty-six and 39 infants met these criteria for the /ba/ or /ga/ syllables, respectively, and 31 infants met the criteria for both syllables. Data were analyzed to obtain measures of phase-locking strength and spectral magnitudes. RESULTS: Phase-locking strength to the fine structure in the consonant-vowel transition was higher in young adults than in infants, but phase locking was equivalent at the fundamental frequency between infants and adults. However, frequency representation of the fundamental frequency was higher in older infants than in either the younger infants or adults. CONCLUSION: Although spectral amplitudes changed during the first year of life, no changes were found with respect to phase locking to the stimulus envelope. These findings demonstrate the feasibility of obtaining these measures of phase locking and fundamental pitch strength in infants as young as 2 months of age.
Authors: Antoine J Shahin; Laurel J Trainor; Larry E Roberts; Kristina C Backer; Lee M Miller Journal: J Neurophysiol Date: 2009-10-28 Impact factor: 2.714