Frequency-Following Responses to Voice Pitch in American Neonates and Adults

1. Frequency-Following Responses to Voice Pitch in American Neonates and Adults Brenda Dickman, Au.D. Candidate Fuh-CherngJeng, M.D., Ph.D.

2. Introduction: Pitch • Pitch is an auditory percept that can facilitate the encoding of speech and other sounds • Perceptual correlate of frequency • Pitch characteristics within speech signals can convey important information

3. Introduction: FFR • Frequency-Following Response (FFR) is a non-invasive, objective measure of the auditory brainstem’s response to pitch • Obtained via recording electrodes placed on the participants’ skin • Recorded response reflects neural impulse measurements of the brainstem in response to frequency information of an acoustic stimulus (Worden and Marsh, 1968; Moushegian et al., 1973)

4. Introduction: FFR Spectrogram Krishnan et al., 2005

5. Introduction: Past Research • FFR in adults • Krishnan et al. (2004; 2005) • Russo et al. (2008) • Swaminathan et al. (2008) • Wong et al. (2007) • Young and Sachs (1979) • FFR in infants • Jeng et al. (2010) • FFR in neonates • Gardi et al. (1979) • Hu and Jeng (2010)

6. Introduction: Specific Aims • Determine the ability to record FFR to voice pitch in American newborn infants • Examine developmental characteristics of the neonate FFRs as compared to adults

7. FFR to voice pitch will be recordable in neonates • Gardi et al. (1979) • Jeng et al. (2010) • Hu and Jeng (2010) • If neonatal FFR to voice pitch is recordable, it will differ significantly from adult FFR • Jeng et al. (2010) • Hu and Jeng (2010)

8. Methods: Subjects • 9 neonates (4 Females; 1-3 days) • Parents were native speakers of American English • 8 adults (4 Females; 26 ± 4 years) • Native speakers of American English • All normal-hearing participants • Able to rest comfortably/fall asleep during testing

9. Methods: Stimulus • Monosyllabic speech token /i/ • Rising pitch contour • 250 ms duration, 45 ms inter-stimulus interval • Monaural stimulation • Presented 2000 times per trial; 2 trials • Presentation level • 65 dB SPL for infants • 70 dB SPL for adults • One control condition

10. Methods: Recording • Test sessions lasted 1-2 hours per participant • Neonates - O’Bleness Memorial Hospital • Adults - Ohio University AEP lab • Recording electrode placed on high forehead and each mastoid • Non-inverting (Fz); Inverting (M2); Gnd (M1)

11. Methods: Data Analysis • All data analyzed offline • Continuous recordings analyzed and averaged over the two trials for each participant • Evaluated within and across group averages • Tracking Accuracy • Frequency Error • Slope Error • Pitch Strength

12. Stimulus Neonates Adults Results • Spectrograms of the stimulus and averaged FFR for each group • Both groups show visible FFR at f0 • Difference in representation of harmonics

13. Neonate • f0 contours of the response plotted with the stimulus • Typical Neonate • Typical Adult • Both examples show the response f0 follows the stimulus f0 Adult

14. p=0.047 p=0.084 p=0.024 p=0.375 • No significant difference found between groups for any of the 4 indices • Bonferroni correction • p=0.0125 • Overall, pitch tracking ability for neonates and adults is statistically similar

15. Discussion • Factors to consider • Head Size • Individual variability • Sample size • Electrical interference/Environment • Mobile AEP lab • Future goals • Continue data collection • Developmental trajectory of FFR • English vs. Chinese

16. Conclusion • FFR is recordable in neonates during immediate post-natal days • No significant difference between neonate and adult FFR to voice pitch • Visual differences noted • Adult FFR showed energy at harmonics • This suggests that neural processing of harmonics beyond f0 may depend on age or linguistic experience

17. References • Gardi, J., Salamy, A., Mendelson, T. (1979). Scalp-recorded frequency-following responses in neonates. Audiology: Journal of Auditory Communication, 18(6), 494-506. • Hu, J., Jeng, F.-C. Frequency-Following Responses to Voice Pitch in Chinese Neonates and Adults. Ohio University Research Colloquium Series Winter 2010. • Jeng, F.-C., Hu, J., Dickman, B., Lin, C.-Y., Lin, C.-D., Wang, C.-Y., Chung, H.-K. (2010). Evaluation of Two Algorithms for Detecting Human Frequency-Following Responses to Voice Pitch. International Journal of Audiology (Submitted March 2010). • Jeng, F.-C., Schnabel, E.A., Dickman, B.M., Hu, J., Li, X., Lin, C.-D., Chung, H.-K. (2010). Early Maturation of Frequency-Following Responses to Voice Pitch in Normal-Hearing Infants. AudiolNeurotol(Submitted March 2010). • 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. • 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. • Moushegian, G., Rupert, A.L., Stillman, R.D. (1973). Laboratory note. Scalp-recorded early responses in man to frequencies in the speech range. Electroencephalography and Clinical Neurophysiology, 35(6), 665-667. • Russo, N.M. et al. (2008). Deficit brainstem encoding of pitch in children with Autism Spectrum Disorders. Clinical Neurophysiology, 119, 1720-1731. • Swaminathan, J., Krishnan, A., Gandour, J.T. (2008). Pitch encoding in speech and nonspeech contexts in the human auditory brainstem. NeuroReport, 19(11), 1163-1167. • Wong, P.C.M., Skoe, E., Russo, N.M., Dees, T., Kraus, N. (2007). Musical experience shapes human brainstem encoding of linguistic pitch patterns. Nature Neuroscience, 10(4), 420-422. • Worden, F.G., Marsh J.T. (1968). Frequency-following (microphonic-like) neural responses evoked by sound. ElectroencephalogrClinNeurophysiol, 25, 42-52.

18. Acknowledgements • THANK YOU!!! • Dr. Jeng • Jiong Hu • O’Bleness Memorial Hospital

19. Questions