Matching Items (2)
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- All Subjects: Speech Perception
- All Subjects: Primary Motor Cortex
- Creators: Barragan, Beatriz
- Creators: Boothroyd, Arthur
- Member of: Theses and Dissertations
Description
The activation of the primary motor cortex (M1) is common in speech perception tasks that involve difficult listening conditions. Although the challenge of recognizing and discriminating non-native speech sounds appears to be an instantiation of listening under difficult circumstances, it is still unknown if M1 recruitment is facilitatory of second language speech perception. The purpose of this study was to investigate the role of M1 associated with speech motor centers in processing acoustic inputs in the native (L1) and second language (L2), using repetitive Transcranial Magnetic Stimulation (rTMS) to selectively alter neural activity in M1. Thirty-six healthy English/Spanish bilingual subjects participated in the experiment. The performance on a listening word-to-picture matching task was measured before and after real- and sham-rTMS to the orbicularis oris (lip muscle) associated M1. Vowel Space Area (VSA) obtained from recordings of participants reading a passage in L2 before and after real-rTMS, was calculated to determine its utility as an rTMS aftereffect measure. There was high variability in the aftereffect of the rTMS protocol to the lip muscle among the participants. Approximately 50% of participants showed an inhibitory effect of rTMS, evidenced by smaller motor evoked potentials (MEPs) area, whereas the other 50% had a facilitatory effect, with larger MEPs. This suggests that rTMS has a complex influence on M1 excitability, and relying on grand-average results can obscure important individual differences in rTMS physiological and functional outcomes. Evidence of motor support to word recognition in the L2 was found. Participants showing an inhibitory aftereffect of rTMS on M1 produced slower and less accurate responses in the L2 task, whereas those showing a facilitatory aftereffect of rTMS on M1 produced more accurate responses in L2. In contrast, no effect of rTMS was found on the L1, where accuracy and speed were very similar after sham- and real-rTMS. The L2 VSA measure was indicative of the aftereffect of rTMS to M1 associated with speech production, supporting its utility as an rTMS aftereffect measure. This result revealed an interesting and novel relation between cerebral motor cortex activation and speech measures.
ContributorsBarragan, Beatriz (Author) / Liss, Julie (Thesis advisor) / Berisha, Visar (Committee member) / Rogalsky, Corianne (Committee member) / Restrepo, Adelaida (Committee member) / Arizona State University (Publisher)
Created2018
Description
The purpose of the present study was to determine if an automated speech perception task yields results that are equivalent to a word recognition test used in audiometric evaluations. This was done by testing 51 normally hearing adults using a traditional word recognition task (NU-6) and an automated Non-Word Detection task. Stimuli for each task were presented in quiet as well as in six signal-to-noise ratios (SNRs) increasing in 3 dB increments (+0 dB, +3 dB, +6 dB, +9 dB, + 12 dB, +15 dB). A two one-sided test procedure (TOST) was used to determine equivalency of the two tests. This approach required the performance for both tasks to be arcsine transformed and converted to z-scores in order to calculate the difference in scores across listening conditions. These values were then compared to a predetermined criterion to establish if equivalency exists. It was expected that the TOST procedure would reveal equivalency between the traditional word recognition task and the automated Non-Word Detection Task. The results confirmed that the two tasks differed by no more than 2 test items in any of the listening conditions. Overall, the results indicate that the automated Non-Word Detection task could be used in addition to, or in place of, traditional word recognition tests. In addition, the features of an automated test such as the Non-Word Detection task offer additional benefits including rapid administration, accurate scoring, and supplemental performance data (e.g., error analyses) beyond those obtained in traditional speech perception measures.
ContributorsStahl, Amy Nicole (Author) / Pittman, Andrea (Thesis director) / Boothroyd, Arthur (Committee member) / McBride, Ingrid (Committee member) / School of Human Evolution and Social Change (Contributor) / Department of Speech and Hearing Science (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05