Browsing by Author "Department of Otolaryngology--Head & Neck Surgery, School of Medicine"

Now showing 1 - 5 of 5
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    AUDIOVISUAL INTEGRATION OF SPEECH BY CHILDREN AND ADULTS WITH COCHEAR IMPLANTS
    (Institute of Electrical and Electronics Engineers, 2002) Kirk, Karen Iler; Pisoni, David B.; Lachs, Lorin; Department of Otolaryngology--Head & Neck Surgery, School of Medicine
    The present study examined how prelingually deafened children and postlingually deafened adults with cochlear implants (CIs) combine visual speech information with auditory cues. Performance was assessed under auditory-alone (A), visual- alone (V), and combined audiovisual (AV) presentation formats. A measure of visual enhancement, RA, was used to assess the gain in performance provided in the AV condition relative to the maximum possible performance in the auditory-alone format. Word recogniton was highest for AV presentation followed by A and V, respectively. Children who received more visual enhancement also produced more intelligible speech. Adults with CIs made better use of visual information in more difficult listening conditions (e.g., when mutiple talkers or phonemically similar words were used). The findings are discussed in terms of the complementary nature of auditory and visual sources of information that specify the same underlying gestures and articulatory events in speech.
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    Executive Functioning Skills in Preschool-Age Children With Cochlear Implants
    (ASHA Publications, 2014-08) Beer, Jessica; Kronenberger, William G.; Castellanos, Irina; Colson, Bethany G.; Henning, Shirley C.; Pisoni, David B.; Department of Otolaryngology--Head & Neck Surgery, School of Medicine
    Purpose The purpose of this study was to determine whether deficits in executive functioning (EF) in children with cochlear implants (CIs) emerge as early as the preschool years. Method Two groups of children ages 3 to 6 years participated in this cross-sectional study: 24 preschoolers who had CIs prior to 36 months of age and 21 preschoolers with normal hearing (NH). All were tested on normed measures of working memory, inhibition-concentration, and organization-integration. Parents completed a normed rating scale of problem behaviors related to EF. Comparisons of EF skills of children with CIs were made to peers with NH and to published nationally representative norms. Results Preschoolers with CIs showed significantly poorer performance on inhibition-concentration and working memory compared with peers with NH and with national norms. No group differences were found in visual memory or organization-integration. When data were controlled for language, differences in performance measures of EF remained, whereas differences in parent-reported problems with EF were no longer significant. Hearing history was generally unrelated to EF. Conclusions This is the first study to demonstrate that EF deficits found in older children with CIs begin to emerge as early as preschool years. The ability to detect these deficits early has important implications for early intervention and habilitation after cochlear implantation.
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    Information theoretic evaluation of a noiseband-based cochlear implant simulator
    (Elsevier, 2016-03) Aguiar, Daniel E.; Taylor, N. Ellen; Li, Jung; Gazanfari, Daniel K.; Talavage, Thomas M.; Laflen, J. Brandon; Neuberger, Heidi; Svirsky, Mario A.; Department of Otolaryngology--Head & Neck Surgery, School of Medicine
    Noise-band vocoders are often used to simulate the signal processing algorithms used in cochlear implants (CIs), producing acoustic stimuli that may be presented to normal hearing (NH) subjects. Such evaluations may obviate the heterogeneity of CI user populations, achieving greater experimental control than when testing on CI subjects. However, it remains an open question whether advancements in algorithms developed on NH subjects using a simulator will necessarily improve performance in CI users. This study assessed the similarity in vowel identification of CI subjects and NH subjects using an 8-channel noise-band vocoder simulator configured to match input and output frequencies or to mimic output after a basalward shift of input frequencies. Under each stimulus condition, NH subjects performed the task both with and without feedback/training. Similarity of NH subjects to CI users was evaluated using correct identification rates and information theoretic approaches. Feedback/training produced higher rates of correct identification, as expected, but also resulted in error patterns that were closer to those of the CI users. Further evaluation remains necessary to determine how patterns of confusion at the token level are affected by the various parameters in CI simulators, providing insight into how a true CI simulation may be developed to facilitate more rapid prototyping and testing of novel CI signal processing and electrical stimulation strategies.
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    Morbidity, mortality and cost from HPV-related oropharyngeal cancer: Impact of 2-, 4- and 9-valent vaccines
    (Informa UK (Taylor & Francis), 2016-06-02) Ward, Greg; Mehta, Vikas; Moore, Michael; Department of Otolaryngology--Head & Neck Surgery, School of Medicine
    OBJECTIVE: The incidence of oropharyngeal squamous cell carcinoma (OPSCC) related to human papillomavirus (HPV) is increasing at a dramatic rate, with men affected more commonly than women. Individuals who develop this disease suffer significant morbidity and potential mortality from their cancer and its associated treatment. We aim to evaluate the possible impact that the currently available HPV vaccines will have on this group of cancers. DATA SOURCES: Available peer-reviewed literature, practice guidelines, and statistics published by the Center for Disease Control and Prevention. REVIEW METHODS: Contemporary peer-reviewed medical literature was selected based on its scientific validity and relevance to the impact HPV vaccination may have on the morbidity, mortality and cost resulting from HPV-related OPSCC in the United States. CONCLUSIONS: The incidence of HPV-related OPSCC is increasing at a near epidemic rate in the United States. The cost of treatment of HPV-related OPSCC is high, and the disease and its therapy result in significant morbidity and potential mortality to individuals. Using a cut-off of $50,000/Quality-Adjusted Life Year, expansion of current HPV vaccine indications to include prevention of OPSCC in both men and women should be recommended.
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    Tissue Transglutaminase Activates Cancer-Associated Fibroblasts and Contributes to Gemcitabine Resistance in Pancreatic Cancer
    (Elsevier, 2016-11) Lee, Jiyoon; Yakubov, Bakhtiyor; Ivan, Cristina; Jones, David R.; Caperell-Grant, Andrea; Fishel, Melissa; Cardenas, Horacio; Matei, Daniela; Department of Otolaryngology--Head & Neck Surgery, School of Medicine
    Resistance to chemotherapy is a hallmark of pancreatic ductal adenocarcinoma (PDA) and has been partly attributed to the dense desmoplastic stroma, which forms a protective niche for cancer cells. Tissue transglutaminase (TG2), a Ca(2+)-dependent enzyme, is secreted by PDA cells and cross-links proteins in the tumor microenvironment (TME) through acyl-transfer between glutamine and lysine residues, promoting PDA growth. The objective of the current study was to determine whether secreted TG2 by PDA cells alters the response of pancreatic tumors to gemcitabine. Orthotopic pancreatic xenografts and co-culture of PDA and stromal cells were employed to determine the mechanisms by which TG2 alters tumor-stroma interactions and response to gemcitabine. Analysis of the pancreatic The Cancer Genome Atlas (TCGA) database demonstrated that increased TG2 expression levels correlate with worse overall survival (hazard ratio=1.37). Stable TG2 knockdown in PDA cells led to decreased size of pancreatic xenografts and increased sensitivity to gemcitabine in vivo. However, TG2 downregulation did not increase cytotoxicity of gemcitabine in vitro. Additionally, multivessel density and gemcitabine uptake in pancreatic tumor tissue, as measured by mass spectrometry (MS-HPLC), were not significantly different in tumors expressing TG2 versus tumors in which TG2 was knocked down. Fibroblasts, stimulated by TG2 secreted by PDA cells, secrete laminin A1, which protects cancer cells from gemcitabine-induced cytotoxicity. In all, our results demonstrate that TG2 secreted in the pancreatic TME orchestrates the cross talk between cancer cells and stroma, impacting tumor growth and response to chemotherapy. Our study supports TG2 inhibition to increase the antitumor effects of gemcitabine in PDA.