RESULTS

1. Frequency-Following Responses To Voice Pitch In Chinese Neonates: Representation Of Innate Processing Kristen Mitchell, Fuh-CherngJeng Ohio University, Athens, Ohio, USA INTRODUCTION RESULTS CONCLUSIONS Voice pitch can be used to help with speech understanding for individuals using tonal and non-tonal languages. Voice pitch can also have different meanings depending on whether or not you use a tonal or non-tonal language. To help us identify and track changes in voice pitch, we use what is known as the frequency-following response. Frequency-Following Response (FFR) is a scalp-recorded, non-invasive, electrophysiological measure that can be used to provide information about pitch coding at the level of the brainstem (Gardi et al., 1979; Krishnan, 2002; Jeng et al., 2011). Previous studies have examined FFR in adults and infants using speech (Krishnan et al., 2004; Aiken & Picton 2006; Jeng et al., 2011) and nonspeech stimuli (Krishnan 2002). What remains unclear is whether FFR to voice pitch can be recorded in newborn infants (≤ 3 days old) using more than one tone. The current aim of this research study is to determine if FFR is recordable in newborn infants to voice pitch using four different Mandarin Chinese tones. It was hypothesized that FFR will be recordable in newborn infants to voice pitch using four different Mandarin Chinese tones and that the responses to the four tones will all be the same in the Chinese newborn infants. • This study demonstrated FFR is recordable is newborn infants that are less than three days old to four different Mandarin Chinese tones, supporting the possibility that we are born with the ability to perceive and track changes in voice pitch (Figure 1). The human auditory brainstem has the ability to follow the f0 contours of the recordings. • Significant differences in slope error, spectral amplitude and pitch strength were revealed between the four tones (Figure 2). • Slope error • Tone 1 and Tone 2 (p = 0.014) • Tone 1 and Tone 4 (p = 0.006) • Tone 2 and Tone 4 (p = 0.000) • Tone 3 and Tone 4 (p = 0.000) • Spectral amplitude • Tone 1 and Tone 2 (p = 0.046) • Tone 2 and Tone 4 (p = 0.016) • Tone 3 and Tone 4 (p = 0.049) • Pitch strength • Tone 1 and Tone 2 (p = 0.011) • Tone 1 and Tone 3 (p = 0.033) METHODS ACKNOWLEDGMENTS • Participants • 44 normal-hearing Chinese-born neonates (≤ 3 days old) • Stimulus • Four different Mandarin Chinese tones that mimic the English vowel /i/ • /yi¹/-clothing (flat pitch); /yi²/-aunt (unidirectional rising pitch); /yi³/-chair (bidirectional falling-rising pitch); /yi4/-easy • (unidirectional falling pitch) • Procedure • 3 gold-plated surface recording electrodes (FPZ, FZ and M2) • Participant resting or fast-asleep prior to recording • Stimuli presented in left or right ear • 60 dB SPL for newborn infants • 4001 sweeps were collected for each newborn infant • Data Analysis • All data were analyzed using MATLAB • Frequency spectrogram used to estimate the f0 contours of the recordings • Six objective indices were applied to calculate the pitch-tracking accuracy and phase-locking magnitude for all participants • Frequency Error- defined in Hz; represents the pitch-encoding accuracy during the stimulus presentation • Slope Error-defined in Hz/s; indicates how the pitch contours are preserved in the brainstem • Tracking Accuracy- defined by regression “r” values; reflects the overall faithfulness of pitch tracking between the stimulus and response f0 contours • Spectral Amplitude- defined in nV; represents the response amplitude in the frequency domain of the spectrograms • Pitch Strength- measures the magnitude of the neural-phase locking to the f0 contour of the stimulus waveform • RMS Amplitude-defined in uV; represents the robustness of the neural phase-locking for each of the four tones • This study is supported in part by the National Science Foundation. • We wish to thank Joe Hu, Grant Hollister, Johnny Sabol and the staff at China Medical University Hospital nursery for their help with this study. Fig. 1 (above). Grand-averaged spectrograms and time waveforms of the four different Mandarin Chinese tones REFERENCES • Gardi, J., Salamy, A., Mendelson, T. (1979). Scalp-recorded frequency-following responses in neonates. Audiology: Journal of Auditory Communication, 18(6), 494-506. • Krishnan, A. (2002). Human frequency-following responses: Representation of steady-state synthetic vowels. Hearing Research,166,192-201. • Krishnan, A., Xu, Y., Gandour, J., Cariani, P. (2004). Human frequency-following response: Representation of pitch contours in Chinese tones. Hearing Research,189,1-12. • Aiken, S.J., Picton, T.W. (2006). Envelope Following Responses to Natural Vowels. AudiolNeurotol, 11, 213-232. • Jeng, F.-C., Hu, J., Dickman, B., Montgomery-Reagan, K., Meiling, T., Guangqiang, L., Chia, D. (2011). Cross-Linguistic Comparison of Frequency-Following Responses to Voice Pitch in American and Chinese Neonates and Adults. Ear & Hearing, 32, 699-707. • km308707@ohio.edu Fig. 2 (above). Six FFR indices plotted to quantify pitch-tracking accuracy between the four different Mandarin Chinese tones: Frequency error (top left), p= 0.170; Slope error (top middle), p= 0.000; Tracking accuracy (topright), p= 0.152; Spectral amplitude (bottom left), p= 0.005; Pitch strength (bottom middle), p= 0.001 and RMS amplitude (bottom right), p= 0.176. There were significant differences in slope error, spectral amplitude and pitch strength for all four tones.