Testing Native Language Neural Commitment at the Subcortical Level

Study Overview
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Brief Summary
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This mentored student research project is funded by the Graduate Research Partnership Program with a projected timeline for data collection in the summer of 2015. Previous research has shown that language experience alters the way the human brain processes speech information. This phenomenon takes place very early in life and is referred to as Native Language Neural Commitment. For instance, as the Japanese language does not have the l-r speech sound contrast, Japanese infants start to show difficulty in hearing differences between the English l and r sounds at 12 months of age but not when they were at 6 months old. Learning the l-r distinction later in life proves to be very difficult for the Japanese school students and adults. Brain imaging studies have further revealed specific brain regions that are changed by language learning. But the evidence in support of the Native Language Neural Commitment theory is based on cortical-level measures. The proposed study extends the measurement to the subcortical level at the brainstem. The target language that the investigators are interested in studying is Mandarin Chinese, which is known for its use of lexical tones to express different words. For instance, the Chinese syllable ma means mother when it is spoken with a flat tone, and it means hemp when spoken with a rising tone. English, by contrast, does not employ lexical tones, and it is considered a non-tonal language. Does the Chinese learning experience fundamental change the way that pitch information is coded in the human brain? Does it happen at both cortical and subcortical levels? Previous research has shown evidence for a positive answer to both questions. But the direct evidence for brain-behavior correlations at the subcortical level is still missing. The proposed cross-language study will test Chinese-speaking and English-speaking adults to investigate Native Language Neural Commitment at the subcortical level. The investigators are interested in differences in the two subject populations by examining the relationship between brainstem pitch tracking and behavioral pitch perception in linguistic and nonlinguistic stimuli. The results of the proposed project will contribute to the understanding the role of the subcortical brainstem in Native Language Neural Commitment, which have significant implications for the development of auditory/speech training programs and assessment tools utilizing the brainstem frequency following measure to monitor progress in second language learning and test clinical populations.

Official Title
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Testing Native Language Neural Commitment at the Subcortical Level: Links Between Brainstem Frequency Following Responses and Behavioral Perception for Lexical Tones

Conditions
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Language Development

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Native Mandarin Chinese speakers Native English speakers Non-musicians. English speakers must have no prior experience with a tonal language. Normal hearing Age range to 18-50. Exclusion Criteria: Speech-language-hearing disorders, neurophysiological/psychiatric conditions, including stroke or brain injuries, which would prevent the subject from sitting still and performing the experimental tasks. Subjects with three or more than three years of musical practice/training will be excluded.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Native Chinese speakers<br> | |
| Native English speakers without experience of a tonal language<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pitch strength of Brainstem EEG (electroencephalography) responses | EEG signals to pitch changes in speech and nonspeech sounds are analyzed to obtain the brainstem frequency following responses (FFRs). Autocorrelation method will be applied to the FFRs to quantify each participant's brainstem pitch strength. Higher average autocorrelation value indicates greater pitch strength. This EEG measure is to see whether tonal-language speakers and nontonal language speakers differ in brainstem encoding of pitch information. | Outcome will be measured at one 1.5-hr session after the participant is recruited. | 
| Reaction time in millesecond for speech perception of syllables with varying pitch contour | This behavioral measure in terms of syllable perception is to test whether syllabic perception is influenced by pitch information and whether tonal-language speakers' sensitivity towards pitch differences would affect the speech perception differently. | Outcome will be measured at one 1.5-hr session after the participant is recruited. | 
| Correlation between the EEG and the Behavioral measures |  | Outcome will be measured at one 1.5-hr session after the participant is recruited. | 
| Pitch tracking accuracy of Brainstem EEG (electroencephalography) responses | Strength of stimulus-to-response correlation will assessed. Higher correlation coefficient between the fundamental frequency of the stimulus and that of the FFR response will indicate greater accuracy of the brainstem pitch tracking. This EEG measure is to see whether tonal-language speakers and nontonal language speakers differ in brainstem encoding of pitch information. | Outcome will be measured at one 1.5-hr session after the participant is recruited. | 
| Duration estimate of syllables with varying pitch contour | This behavioral measure in terms of syllable duration estimation is to test whether duration estimation is influenced by pitch information and whether tonal-language speakers' sensitivity towards pitch differences would affect the duration estimation differently. | Outcome will be measured at one 1.5-hr session after the participant is recruited. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Brainstem, Encoding, Pitch