Matching Items (5)
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- All Subjects: Vowels
- All Subjects: Dyslexia
- Creators: Daliri, Ayoub
Description
Distorted vowel production is a hallmark characteristic of dysarthric speech, irrespective of the underlying neurological condition or dysarthria diagnosis. A variety of acoustic metrics have been used to study the nature of vowel production deficits in dysarthria; however, not all demonstrate sensitivity to the exhibited deficits. Less attention has been paid to quantifying the vowel production deficits associated with the specific dysarthrias. Attempts to characterize the relationship between naturally degraded vowel production in dysarthria with overall intelligibility have met with mixed results, leading some to question the nature of this relationship. It has been suggested that aberrant vowel acoustics may be an index of overall severity of the impairment and not an "integral component" of the intelligibility deficit. A limitation of previous work detailing perceptual consequences of disordered vowel acoustics is that overall intelligibility, not vowel identification accuracy, has been the perceptual measure of interest. A series of three experiments were conducted to address the problems outlined herein. The goals of the first experiment were to identify subsets of vowel metrics that reliably distinguish speakers with dysarthria from non-disordered speakers and differentiate the dysarthria subtypes. Vowel metrics that capture vowel centralization and reduced spectral distinctiveness among vowels differentiated dysarthric from non-disordered speakers. Vowel metrics generally failed to differentiate speakers according to their dysarthria diagnosis. The second and third experiments were conducted to evaluate the relationship between degraded vowel acoustics and the resulting percept. In the second experiment, correlation and regression analyses revealed vowel metrics that capture vowel centralization and distinctiveness and movement of the second formant frequency were most predictive of vowel identification accuracy and overall intelligibility. The third experiment was conducted to evaluate the extent to which the nature of the acoustic degradation predicts the resulting percept. Results suggest distinctive vowel tokens are better identified and, likewise, better-identified tokens are more distinctive. Further, an above-chance level agreement between nature of vowel misclassification and misidentification errors was demonstrated for all vowels, suggesting degraded vowel acoustics are not merely an index of severity in dysarthria, but rather are an integral component of the resultant intelligibility disorder.
ContributorsLansford, Kaitlin L (Author) / Liss, Julie M (Thesis advisor) / Dorman, Michael F. (Committee member) / Azuma, Tamiko (Committee member) / Lotto, Andrew J (Committee member) / Arizona State University (Publisher)
Created2012
Description
In this study, the Bark transform and Lobanov method were used to normalize vowel formants in speech produced by persons with dysarthria. The computer classification accuracy of these normalized data were then compared to the results of human perceptual classification accuracy of the actual vowels. These results were then analyzed to determine if these techniques correlated with the human data.
ContributorsJones, Hanna Vanessa (Author) / Liss, Julie (Thesis director) / Dorman, Michael (Committee member) / Borrie, Stephanie (Committee member) / Barrett, The Honors College (Contributor) / Department of Speech and Hearing Science (Contributor) / Department of English (Contributor) / Speech and Hearing Science (Contributor)
Created2013-05
Description
More than a century of research has investigated the etiology of dyslexia, coalescing around ‘phonological awareness’ – the ability to recognize and manipulate phonemes – as a trait typically deficient in reading disorders. Meanwhile, the last few decades of research in neuroscience have highlighted the brain as a predictive organ, which subliminally calibrates sensory expectations according to experience. Do the brains of adults with dyslexia respond differently than those of matched controls to expected tones and unexpected omissions? While auditory oddball paradigms have previously been used to study dyslexia, these studies often interpret group differences to indicate deficit auditory discrimination rather than deficit auditory prediction. The current study takes a step toward fusing theories of predictive coding and dyslexia, finding that event-related potentials related to auditory prediction are attenuated in adults with dyslexia compared with typical controls. It further suggests that understanding dyslexia, and perhaps other psychiatric disorders, in terms of contributory neural systems will elucidate shared and distinct etiologies.
ContributorsBennett, Augustin (Author) / Peter, Beate (Thesis advisor) / Daliri, Ayoub (Committee member) / Goldinger, Stephen (Committee member) / Arizona State University (Publisher)
Created2023
Description
Objective: A recent electroencephalogram (EEG) study of adults with dyslexia showed that individuals with dyslexia have diminished auditory sensory gating compared to typical controls. Previous studies done involving intoxication and its effect on sensory gating and creativity have shown that there is a positive correlation between creativity (divergent thinking problem solving) and sensory gating deficiency. With previous study findings, the link between dyslexia and sensory gating deficiency and the link between sensory gating deficiency and creativity have been shown, but not the link between dyslexia and creativity. This pilot study aims to address this knowledge gap using event-related potentials.
Methods: Two adults with dyslexia and 4 control adults participated in an auditory gating test using tone pairs. Latencies and Amplitudes for the N100 and P200 responses were recorded and analyzed. Participants were also administered the Abbreviated Torrance Test for Adults (ATTA), a test of creative ability designed to evaluate divergent thinking in individuals. Results were averaged and compared.
Results: The averaged difference in measured N100 amplitudes between tone 1 and tone 2 was significantly larger in the control group compared to the difference observed in the dyslexia group. In particular, one participant with dyslexia who had low scores on a task of rapid word recognition also showed no evidence of gating at the N100 component, whereas the other participant with dyslexia with good word recognition scores showed evidence of intact gating. The averaged difference in measured P200 amplitude between tone 1 and tone 2 was larger in the dyslexia group compared to the control group; however, the difference was small enough to be considered insignificant. The total average ATTA score for the control group was higher than the average of the dyslexia group. This difference in total average was less than one point on a 106-point scale.
Conclusions: Neural sensory gating occurs approximately 100 ms after the onset of a stimulus and is diminished in adults with dyslexia who also have deficits in rapid word recognition. There is a difference in creativity, in terms of divergent thinking, between those with dyslexia and those without (controls scored higher on average); however, the difference is not significant (less than one point). Dyslexia scores were more consistent than controls.
Methods: Two adults with dyslexia and 4 control adults participated in an auditory gating test using tone pairs. Latencies and Amplitudes for the N100 and P200 responses were recorded and analyzed. Participants were also administered the Abbreviated Torrance Test for Adults (ATTA), a test of creative ability designed to evaluate divergent thinking in individuals. Results were averaged and compared.
Results: The averaged difference in measured N100 amplitudes between tone 1 and tone 2 was significantly larger in the control group compared to the difference observed in the dyslexia group. In particular, one participant with dyslexia who had low scores on a task of rapid word recognition also showed no evidence of gating at the N100 component, whereas the other participant with dyslexia with good word recognition scores showed evidence of intact gating. The averaged difference in measured P200 amplitude between tone 1 and tone 2 was larger in the dyslexia group compared to the control group; however, the difference was small enough to be considered insignificant. The total average ATTA score for the control group was higher than the average of the dyslexia group. This difference in total average was less than one point on a 106-point scale.
Conclusions: Neural sensory gating occurs approximately 100 ms after the onset of a stimulus and is diminished in adults with dyslexia who also have deficits in rapid word recognition. There is a difference in creativity, in terms of divergent thinking, between those with dyslexia and those without (controls scored higher on average); however, the difference is not significant (less than one point). Dyslexia scores were more consistent than controls.
ContributorsDuran, Isaac (Author) / Peter, Beate (Thesis director) / Daliri, Ayoub (Committee member) / Rogalsky, Corianne (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Past studies have shown that auditory feedback plays an important role in maintaining the speech production system. Typically, speakers compensate for auditory feedback alterations when the alterations persist over time (auditory motor adaptation). Our study focused on how to increase the rate of adaptation by using different auditory feedback conditions. For the present study, we recruited a total of 30 participants. We examined auditory motor adaptation after participants completed three conditions: Normal speaking, noise-masked speaking, and silent reading. The normal condition was used as a control condition. In the noise-masked condition, noise was added to the auditory feedback to completely mask speech outputs. In the silent reading condition, participants were instructed to silently read target words in their heads, then read the words out loud. We found that the learning rate in the noise-masked condition was lower than that in the normal condition. In contrast, participants adapted at a faster rate after they experience the silent reading condition. Overall, this study demonstrated that adaptation rate can be modified through pre-exposing participants to different types auditory-motor manipulations.
ContributorsNavarrete, Karina (Author) / Daliri, Ayoub (Thesis director) / Peter, Beate (Committee member) / College of Health Solutions (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05