Subjects : Ten participants (6 Female, 19-28 years old) were recruited in the results

1. Binaural Interaction of Frequency-Following Responses in Normal-Hearing Chinese AdultsAbbie Davis, Fuh-CherngJengCommunication Sciences and Disorders, Ohio University, Athens, Ohio • Recording procedures: • Participants reclined in a sound proof booth and were asked to be as relaxed as possible and have their eyes closed. • The stimuli was presented in four conditions through an insert earphone with a silent interval of 45ms. • To obtain the EEG electrodes were placed on three spots on the scalp. • Recording montage: High Forehead (non-inverting), C7, Back of the Neck (inverting), and Low Forehead (ground). • Impedance maintained below 3 kΩ. • Data Analysis: • Analyzing the data was completed in MatLab. • Five Objective Measures: • 1. Tracking Accuracy: Reflects accurateness of pitch encoding in the brainstem • 2. Root Mean Square Amplitude: Represents the response amplitude in the • time domain. • 3. Slope Error: Indicates how well the brain follows the overall shape of the • pitch contour • 4.Frequency Error: Represents the accuracy of pitch tracking • 5.Pitch Strength: Reflects robustness of the response Figure 2: Spectrogram grand averages of all conditions. The stimulus shows what the participant heard. Notice the robust response of Both-0° and the robust response in the 2nd harmonic in Both-180°. References The results of this study showed that the brain does infuse frequency sweeps binaurally and obtains a Binaural Interaction Component. The condition of the 180° phase in the left ear was detrimental to the statistics of tracking accuracy, slope error, and frequency error. •In the Both-180° condition the second the spectrogram showed a very strong 2nd harmonic. Questions can be emailed to ad894908@ohio.edu Results Introduction Conclusions Methods A frequency-following response (FFR) is an electrophysiological test that can be used to examine the brainstem’s processing of sound. The reason why FFR is important to research is because human speech is conducted in different frequencies, such as word stress and intonation common to English. The stimuli used in this project is a frequency sweep, which is significant because of an existing gap in the literature between tone-burst-elicited FFRs and human-speech-elicited FFRs. In an attempt to bridge this gap, the stimuli used is a frequency sweep of 117-166 Hz. The participants in this study are native Chinese speakers. The Chinese language is a tonal language, meaning while there are words that are phonetically similar, these differences in meaning rely on the frequency of different rising and falling tones. Because of their linguistic background, Chinese speakers are much more susceptible to frequency changes and show a more robust FFR compared to Americans (Krishnan et al., 2005; Jeng, 2011). The purpose of this study is to further understand how the brainstem interprets binaural stimulation, which can be done by investigating the binaural interaction component (BIC). This is discovered by adding the sums of the monaural responses in both ears and then subtracting the binaural response. BIC = (Binaural stimulation) – (Right + Left) If the brain is a linear system, it will simply reflect a sum of both ears (i.e., Right + Left = Both). However, human brain is never a linear system. Our brain is not a simple machine. Instead, it is a complex system that allows us to think creatively and outside of the box. Because the brain is not a linear function, there should be a small amount of response left over. Jeng, F., Hu, J., Dickman, B., Montgomery-Reagan, K., Tong, M., Wu, G., & Lin. C. (2011). Cross-linguistic comparison of frequency-following responses to voice pitch in American and Chinese neonates and adults. Ear and Hearing,32(3), 1-8. •Krishnan, A., Xua, Y., Gandoura, J., Carianib, P., (2005). Encoding of pitch in the human brainstem is sensitive to language experience. Cognitive Brain Research, 25, 161-168. Subjects: Ten participants (6 Female, 19-28 years old) were recruited in the results Hearing thresholds ≤ 20 dB HL at 125, 250, 500, 1000, 2000, 4000, and 8000 Hz. Native speakers of Chinese Stimulus: A total of 4 conditions were presented to each participant • Right Ear Only • Left Ear Only • Both ears with 0°phase • Both ears, left ear with 180°phase The stimulus was a frequency sweep of 117-166 Hz for 150 milliseconds 5000 sweeps were collected for each condition, to ensure a BIC response. The participants were in the booth for roughly two hours. Figure 3: Frequency Error. The condition of Both-180° was significantly different than the rest of the conditions. Figure 4: Root Mean Square Amplitude. The Both-0° is significantly higher than the other conditions. Figure 1: Time waveform of grand averages in all conditions. Notice that the condition of Both-0° appears the largest while Both-180° appears smaller. Also theBinaural Interaction Component-0° is represented. 180°