(1) What is the feasibility of recording PCFR from infants?

1. This study is supported in part by (1) Advancing Academic-Research Career (AARC) Award, American Speech-Language-Hearing Association and (2) Scholarly Activity Award, Ohio University. FIGURE 2 Spectrograms and Autocorrelations from all Infant participant according to age in months. PARTICIPANTS • 6 normal-hearing infants • Age range: 1-10 months • Mean ± SD = 4.7 ± 3.5 months • 9 normal-hearing adults • Age range: 23-28 years • Mean ± SD = 24.2 ± 2.0 years STIMULUS • Voiced Mandarin Chinese syllable with a rising lexical tone “yi” meaning “aunt” PROCEDURE • Normal hearing was established for participants • Infant: Distortion Product Otoacoustic Emissions • Adult: Air conduction <20dB between 250-8000Hz • Electrodes placed on Fpz and on each mastoid • State of restfulness was achieved • Stimuli • 2 trials of 1200 tokens • 2 trials of 1200 control – ear tip removed and plugged (1) What is the feasibility of recording PCFR from infants? (2) How does age relate to the PCFR response? (3) How does infant response compare to adult response? Methods Introduction Reference Research Questions Voice pitch is an important auditory perception that reflects the brain’s ability to differentiate the pitch contour of speech signals. One way to measure this ability is through an evoked neural response from the brainstem which is phase locked period/pitch of the stimulus harmonics called a Frequency Following Response (FFR). When the FFR follows the spectral changes in the stimuli, the response is then referred to as a Pitch Contour Following Response (PCFR). Recent studies have demonstrated the feasibility of recording the PCFR from normal hearing adults by using the stimuli of Mandarin tones and iterated rippled noise (IRN). (Krishnan, 2004; Krishnan, Xu, Gandour, and Cariani, 2005; Swaminathan, Krishnan, and Gandour, 2008) Further defining the characteristics of the PCFR and its developmental trajectory will facilitate a better understanding of how we discriminate pitch changes from infancy to adulthood. The implications of the PCFR will be to use it as a non-invasive and objective way to study infant pitch perception and advance our knowledge in what features in speech are most important to achieve better speech perception. Hu, J., Jeng, F.-C. (2009). An automatic algorithm for detection human frequency following response to voice pitch. In: Abstracts of American Auditory Society Annual Meeting, Poster #31, Scottsdale, Arizona, March 5-7, Krishnan, A., Xu, Y. (2004). Human frequency-following response: Representation of pitch contours in Chinese tones. Hearing Research,189,1-12. Krishnan, A., Xu, Y., Gandour, J., Cariani, P. (2005). Encoding of pitch in the human brainstem is sensitive to language experience. Cognitive Brain Research, 25(1), 161-168. Swaminathan, J., Krishnan, A., Gandour, J.T. (2008b). Pitch encoding in speech and nonspeech contexts in the human auditory brainstem. NeuroReport, 19(11), 1163-1167. FIGURE 1 Typical spectrogram and autocorrelation of Infant, Adult, and Control PCFR. Infant_003 Adult_010 Control Results Preliminary data indicates It is feasible to record PCFR in infants to as early as one month of age. Further data is needed to be obtain from more infants to better delineate the developmental trajectory of infant PCFR. There is a significant difference between the mean of infant and adult pitch strength . Discussion Pitch Contour Following Response in Infants Elizabeth Schnabel Advised by: Fuh-Cherng Jeng PhD. School of Hearing, Speech and Language Sciences, Ohio University, Athens, Ohio FIGURE 5 Extracted F0 contour comparisons of the stimulus, Trial 1, and Trial 2 from Infant participants. The f0 contours were extracted using a “spectral-density-maxima” algorithm (Hu & Jeng, 2009). FIGURE 6 Comparison between Infant and Adult r values, dc offset, and slope. One Month One Month Four Month Five Month Seven Month Ten Month I_003 I_001 I_007 I_002 I_006 I_008 FIGURE 3 Infant and Adult PCFR latencies according to age. FIGURE 4 Infant and Adult PCFR amplitudes according to age. Email: es213499@ohio.edu