Matching Items (4)
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- All Subjects: Speech therapy
- All Subjects: Articulation disorders
- Creators: Dorman, Michael
Description
The recent spotlight on concussion has illuminated deficits in the current standard of care with regard to addressing acute and persistent cognitive signs and symptoms of mild brain injury. This stems, in part, from the diffuse nature of the injury, which tends not to produce focal cognitive or behavioral deficits that are easily identified or tracked. Indeed it has been shown that patients with enduring symptoms have difficulty describing their problems; therefore, there is an urgent need for a sensitive measure of brain activity that corresponds with higher order cognitive processing. The development of a neurophysiological metric that maps to clinical resolution would inform decisions about diagnosis and prognosis, including the need for clinical intervention to address cognitive deficits. The literature suggests the need for assessment of concussion under cognitively demanding tasks. Here, a joint behavioral- high-density electroencephalography (EEG) paradigm was employed. This allows for the examination of cortical activity patterns during speech comprehension at various levels of degradation in a sentence verification task, imposing the need for higher-order cognitive processes. Eight participants with concussion listened to true-false sentences produced with either moderately to highly intelligible noise-vocoders. Behavioral data were simultaneously collected. The analysis of cortical activation patterns included 1) the examination of event-related potentials, including latency and source localization, and 2) measures of frequency spectra and associated power. Individual performance patterns were assessed during acute injury and a return visit several months following injury. Results demonstrate a combination of task-related electrophysiology measures correspond to changes in task performance during the course of recovery. Further, a discriminant function analysis suggests EEG measures are more sensitive than behavioral measures in distinguishing between individuals with concussion and healthy controls at both injury and recovery, suggesting the robustness of neurophysiological measures during a cognitively demanding task to both injury and persisting pathophysiology.
ContributorsUtianski, Rene (Author) / Liss, Julie M (Thesis advisor) / Berisha, Visar (Committee member) / Caviness, John N (Committee member) / Dorman, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
A multitude of individuals across the globe suffer from hearing loss and that number continues to grow. Cochlear implants, while having limitations, provide electrical input for users enabling them to "hear" and more fully interact socially with their environment. There has been a clinical shift to the bilateral placement of implants in both ears and to bimodal placement of a hearing aid in the contralateral ear if residual hearing is present. However, there is potentially more to subsequent speech perception for bilateral and bimodal cochlear implant users than the electric and acoustic input being received via these modalities. For normal listeners vision plays a role and Rosenblum (2005) points out it is a key feature of an integrated perceptual process. Logically, cochlear implant users should also benefit from integrated visual input. The question is how exactly does vision provide benefit to bilateral and bimodal users. Eight (8) bilateral and 5 bimodal participants received randomized experimental phrases previously generated by Liss et al. (1998) in auditory and audiovisual conditions. The participants recorded their perception of the input. Data were consequently analyzed for percent words correct, consonant errors, and lexical boundary error types. Overall, vision was found to improve speech perception for bilateral and bimodal cochlear implant participants. Each group experienced a significant increase in percent words correct when visual input was added. With vision bilateral participants reduced consonant place errors and demonstrated increased use of syllabic stress cues used in lexical segmentation. Therefore, results suggest vision might provide perceptual benefits for bilateral cochlear implant users by granting access to place information and by augmenting cues for syllabic stress in the absence of acoustic input. On the other hand vision did not provide the bimodal participants significantly increased access to place and stress cues. Therefore the exact mechanism by which bimodal implant users improved speech perception with the addition of vision is unknown. These results point to the complexities of audiovisual integration during speech perception and the need for continued research regarding the benefit vision provides to bilateral and bimodal cochlear implant users.
ContributorsLudwig, Cimarron (Author) / Liss, Julie (Thesis advisor) / Dorman, Michael (Committee member) / Azuma, Tamiko (Committee member) / Arizona State University (Publisher)
Created2015
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
Children with hearing impairment are at risk for poor attainment in reading decoding and reading comprehension, which suggests they may have difficulty with early literacy skills prior to learning to read. The first purpose of this study was to determine if young children with hearing impairment differ from their peers with normal hearing on early literacy skills and also on three known predictors of early literacy skills – non-verbal cognition, executive functioning, and home literacy environment. A second purpose was to determine if strengths and weaknesses in early literacy skills of individual children with hearing impairment are associated with degree of hearing loss, non-verbal cognitive ability, or executive functioning.
I assessed seven children with normal hearing and 10 children with hearing impairment on assessments of expressive vocabulary, expressive morphosyntax, listening comprehension, phonological awareness, alphabet knowledge, non-verbal cognition, and executive functioning. Two children had unilateral hearing loss, two had mild hearing loss and used hearing aids, two had moderate hearing loss and used hearing aids, one child had mild hearing loss and did not use hearing aids, and three children used bilateral cochlear implants. Parents completed a questionnaire about their home literacy environment.
Findings showed large between-group effect sizes for phonological awareness, morphosyntax, and executive functioning, and medium between-group effect sizes for expressive vocabulary, listening comprehension, and non-verbal cognition. Visual analyses provided no clear pattern to suggest that non-verbal cognition or degree of hearing loss were associated with individual patterns of performance for children with hearing impairment; however, three children who seemed at risk for reading difficulties had executive functioning scores that were at the floor.
Most prekindergarten and kindergarten children with hearing impairment in this study appeared to be at risk for future reading decoding and reading comprehension difficulties. Further, based on individual patterns of performance, risk was not restricted to one type of early literacy skill and a strength in one skill did not necessarily indicate a child would have strengths in all early literacy skills. Therefore, it is essential to evaluate all early literacy skills to pinpoint skill deficits and to prioritize intervention goals.
I assessed seven children with normal hearing and 10 children with hearing impairment on assessments of expressive vocabulary, expressive morphosyntax, listening comprehension, phonological awareness, alphabet knowledge, non-verbal cognition, and executive functioning. Two children had unilateral hearing loss, two had mild hearing loss and used hearing aids, two had moderate hearing loss and used hearing aids, one child had mild hearing loss and did not use hearing aids, and three children used bilateral cochlear implants. Parents completed a questionnaire about their home literacy environment.
Findings showed large between-group effect sizes for phonological awareness, morphosyntax, and executive functioning, and medium between-group effect sizes for expressive vocabulary, listening comprehension, and non-verbal cognition. Visual analyses provided no clear pattern to suggest that non-verbal cognition or degree of hearing loss were associated with individual patterns of performance for children with hearing impairment; however, three children who seemed at risk for reading difficulties had executive functioning scores that were at the floor.
Most prekindergarten and kindergarten children with hearing impairment in this study appeared to be at risk for future reading decoding and reading comprehension difficulties. Further, based on individual patterns of performance, risk was not restricted to one type of early literacy skill and a strength in one skill did not necessarily indicate a child would have strengths in all early literacy skills. Therefore, it is essential to evaluate all early literacy skills to pinpoint skill deficits and to prioritize intervention goals.
ContributorsRunnion, Elizabeth (Author) / Gray, Shelley (Thesis advisor) / Dorman, Michael (Committee member) / Thompson, Marilyn (Committee member) / Arizona State University (Publisher)
Created2017