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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

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
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Description
An increasing number of military veterans are enrolling in college, primarily due to the Post-9/11 GI Bill, which provides educational benefits to veterans who served on active duty since September 11, 2001. With rigorous training, active combat situations, and exposure to unexpected situations, the veteran population is at a higher

An increasing number of military veterans are enrolling in college, primarily due to the Post-9/11 GI Bill, which provides educational benefits to veterans who served on active duty since September 11, 2001. With rigorous training, active combat situations, and exposure to unexpected situations, the veteran population is at a higher risk for traumatic brain injury (TBI), Post Traumatic Stress Disorder (PTSD), and depression. All of these conditions are associated with cognitive consequences, including attention deficits, working memory problems, and episodic memory impairments. Some conditions, particularly mild TBI, are not diagnosed or treated until long after the injury when the person realizes they have cognitive difficulties. Even mild cognitive problems can hinder learning in an academic setting, but there is little data on the frequency and severity of cognitive deficits in veteran college students. The current study examines self-reported cognitive symptoms in veteran students compared to civilian students and how those symptoms relate to service-related conditions. A better understanding of the pattern of self-reported symptoms will help researchers and clinicians determine the veterans who are at higher risk for cognitive and academic difficulties.
ContributorsAllen, Kelly Anne (Author) / Azuma, Tamiko (Thesis director) / Gallagher, Karen (Committee member) / Department of Speech and Hearing Science (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
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Description
The increase of Traumatic Brain Injury (TBI) cases in recent war history has increased the urgency of research regarding how veterans are affected by TBIs. The purpose of this study was to evaluate the effects of TBI on speech recognition in noise. The AzBio Sentence Test was completed for signal-to-noise

The increase of Traumatic Brain Injury (TBI) cases in recent war history has increased the urgency of research regarding how veterans are affected by TBIs. The purpose of this study was to evaluate the effects of TBI on speech recognition in noise. The AzBio Sentence Test was completed for signal-to-noise ratios (S/N) from -10 dB to +15 dB for a control group of ten participants and one US military veteran with history of service-connected TBI. All participants had normal hearing sensitivity defined as thresholds of 20 dB or better at frequencies from 250-8000 Hz in addition to having tympanograms within normal limits. Comparison of the data collected on the control group versus the veteran suggested that the veteran performed worse than the majority of the control group on the AzBio Sentence Test. Further research with more participants would be beneficial to our understanding of how veterans with TBI perform on speech recognition tests in the presence of background noise.
ContributorsCorvasce, Erica Marie (Author) / Peterson, Kathleen (Thesis director) / Williams, Erica (Committee member) / Azuma, Tamiko (Committee member) / Barrett, The Honors College (Contributor) / Department of Speech and Hearing Science (Contributor)
Created2015-05
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Description
Mild TBI (mTBI) has been associated with subtle executive function (EF) and

cognitive-communication deficits. In bilinguals, there are unique cognitive demands required to control and process two languages effectively. Surprisingly, little is known about the impact of mTBI on EF, communication, and language control in bilinguals. Therefore, the aim of this

Mild TBI (mTBI) has been associated with subtle executive function (EF) and

cognitive-communication deficits. In bilinguals, there are unique cognitive demands required to control and process two languages effectively. Surprisingly, little is known about the impact of mTBI on EF, communication, and language control in bilinguals. Therefore, the aim of this study was to examine the cognitive-communication abilities in bilinguals with a history of mTBI, identify any language control impairments, and explore the relationship between these language control impairments and domain-general cognitive control abilities. To this end, three-hundred and twenty-seven monolingual and bilingual college students with and without mTBI history participated in two experiments. In these experiments, EF, communication, and language control were examined using experimental and clinical tasks as well as self-rating scales. In Experiment 1, there was an interaction between mTBI history and language group (monolinguals vs. bilinguals) in how participants performed on a clinical measure of EF and a verbal fluency task. That is, only bilinguals with mTBI scored significantly lower on these tasks. In addition, there was a significant correlation between errors on a language switching task and performance on non-verbal EF tasks. In Experiment 2, a subgroup of bilinguals with persistent cognitive and behavioral symptoms reported greater everyday communication challenges in their first and second languages. Also, unbalanced bilinguals reported greater EF difficulties than monolinguals and balanced bilinguals regardless of mTBI history. In conclusion, bilinguals may face unique cognitive-communication challenges after mTBI. Factors related to the bilingual experience (e.g., language balance, daily language use) should be

considered in clinical evaluation and future research.
ContributorsAlateeq, Halah (Author) / Azuma, Tamiko (Thesis advisor) / Ratiu, Ileana (Committee member) / Lavoie, Michael (Committee member) / Arizona State University (Publisher)
Created2020