Effects of Aging and Language Background in Pitch Processing at the Brainstem Level
Background: It has been well established that younger adults have stronger brainstem responses compared to older adults. Recent studies have also demonstrated that for people who speak tonal languages, their brainstems’ pitch coding ability appear to be more robust and precise than those who do not. It has been proposed that such discrepancies may be due to the degradation in temporal processing due to aging, and the neural plasticity at the brainstem level resulted from long time auditory input from tonal language, respectively. However, no study to date has looked at the combined effect of aging and long term auditory input on listeners’ pitch coding ability. The purpose of this study is to examine the voice pitch elicited brainstem responses, in listeners who are in different age and language back grounds.
Method: Four groups of participants were evaluated in this study: Mandarin speaking young adults, Mandarin speaking older adults, English speaking young adults and English speaking older adults. They all had normal audiometric test results as well as normal suprathreshold click evoked ABR timing. Two Mandarin Chinese syllables with different fundamental frequency pitch contours were used to elicit brainstem responses. All stimulus tokens were controlled by Intelligent Hearing System and presented monaurally at 70 dB SPL. EEG signals were collected using standard one-channel montage. Fundamental frequencies (f0) of both the stimulus and the responses were digitally extracted and compared to individual brainstem responses. Spectral energies at the F0 and first formant (F1) ranges were also calculated. Several indices were used to examine different aspects of pitch processing ability at the brainstem level: Pitch Strength, Pitch Correlation, Response Robustness, and the F0 and F1 spectral energies. Responses elicited by different tones were also compared across and within the elderly and young adult groups, as well as different language groups.
Results: Results obtained from the younger listeners’ group were more robust than their older counterparts, in both language backgrounds. Similarly, listeners with tonal language backgrounds had stronger pitch coding ability than those who speak non-tonal languages, in different age groups.
Conclusion: Results of this study suggest that aging plays an important role in listeners’ pitch coding capacity, regardless of their language backgrounds. Results also re-established that long-term auditory inputs, such as tonal languages, certainly help enhancing the efficiency in processing ability in our auditory system.
Association for Research in Otolaryngology
01/25/2020 - 01/29/2020
Hu, Jiong; Henderson Sabes, Jennifer; Wang, Shuo; and Liu, Dongxin, "Effects of Aging and Language Background in Pitch Processing at the Brainstem Level" (2020). All Faculty Scholarship. 179.