Matching Items (3)
Filtering by
- All Subjects: Speech And Hearing Sciences
- Creators: Daliri, Ayoub
- Creators: Mcguffin, Brianna Jean
- Member of: Theses and Dissertations
- Resource Type: Text
Description
Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel out the resulting sensory feedback. Currently, there are no published accounts of the perception of tactile signals for motor tasks and contexts related to the lips during both speech planning and production. In this study, we measured the responsiveness of the somatosensory system during speech planning using light electrical stimulation below the lower lip by comparing perception during mixed speaking and silent reading conditions. Participants were asked to judge whether a constant near-threshold electrical stimulation (subject-specific intensity, 85% detected at rest) was present during different time points relative to an initial visual cue. In the speaking condition, participants overtly produced target words shown on a computer monitor. In the reading condition, participants read the same target words silently to themselves without any movement or sound. We found that detection of the stimulus was attenuated during speaking conditions while remaining at a constant level close to the perceptual threshold throughout the silent reading condition. Perceptual modulation was most intense during speech production and showed some attenuation just prior to speech production during the planning period of speech. This demonstrates that there is a significant decrease in the responsiveness of the somatosensory system during speech production as well as milliseconds before speech is even produced which has implications for speech disorders such as stuttering and schizophrenia with pronounced deficits in the somatosensory system.
ContributorsMcguffin, Brianna Jean (Author) / Daliri, Ayoub (Thesis director) / Liss, Julie (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Speech perception and production are bidirectionally related, and they influence each other. The purpose of this study was to better understand the relationship between speech perception and speech production. It is known that applying auditory perturbations during speech production causes subjects to alter their productions (e.g., change their formant frequencies). In other words, previous studies have examined the effects of altered speech perception on speech production. However, in this study, we examined potential effects of speech production on speech perception. Subjects completed a block of a categorical perception task followed by a block of a speaking or a listening task followed by another block of the categorical perception task. Subjects completed three blocks of the speaking task and three blocks of the listening task. In the three blocks of a given task (speaking or listening) auditory feedback was 1) normal, 2) altered to be less variable, or 3) altered to be more variable. Unlike previous studies, we used subject’s own speech samples to generate speech stimuli for the perception task. For each categorical perception block, we calculated subject’s psychometric function and determined subject’s categorical boundary. The results showed that subjects’ perceptual boundary remained stable in all conditions and all blocks. Overall, our results did not provide evidence for the effects of speech production on speech perception.
ContributorsDaugherty, Allison (Author) / Daliri, Ayoub (Thesis director) / Rogalsky, Corianne (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This longitudinal study aimed to determine whether significant differences existed between the baseline inaccurate signals of the /r/ phoneme for children that eventually acquire or do not acquire /r/. Seventeen participants ages 5-8 who had not acquired /r/ in any of its allophonic contexts were recorded approximately every 3 months from the age of recruitment until they either acquired /r/ in conversation (80% accuracy) or turned eight years old. The recorded audio files were trimmed and labelled using Praat, and signal processing was used to compare initial and final recordings of three allophonic variations of /r/ (vocalic, prevocalic, postvocalic) for each participant. Differences were described using Mel-log Spectral plots. For each age group, initial recordings of participants that eventually acquired /r/ were compared to those of participants that did not acquire /r/. Participants that had not acquired /r/ and had yet to turn eight years old were compared by whether they were perceived to be improving or perceived not to be improving. Significant differences in Mel-log spectral plots will be discussed, and the implications of baseline differences will be highlighted, specifically with respect to the feasibility of identifying predictive markers for acquisition
on-acquisition of the difficult /r/ phoneme.
on-acquisition of the difficult /r/ phoneme.
ContributorsHom, Rachel (Author) / Weinhold, Juliet (Thesis director) / Daliri, Ayoub (Committee member) / College of Health Solutions (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05