Staff and Student Research

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    Enhancement of Consonant Recognition in Bimodal and Normal Hearing Listeners
    (Sage Publications Inc., 2019-05-15) Yoon, Y. -S; Riley, B.; Patel, H.; Frost, Amanda; Fillmore, P.; Gifford, R.; Hansen, John H. L.; Frost, Amanda; Hansen, John H. L.
    Objectives: The present study investigated the effects of 3-dimensional deep search (3DDS) signal processing on the enhancement of consonant perception in bimodal and normal hearing listeners. Methods: Using an articulation-index gram and 3DDS signal processing, consonant segments that greatly affected performance were identified and intensified with a 6-dB gain. Then consonant recognition was measured unilaterally and bilaterally before and after 3DDS processing both in quiet and noise. Results: The 3DDS signal processing provided a benefit to both groups, with greater benefit occurring in noise than quiet. The benefit rendered by 3DDS was the greatest in binaural listening condition. Ability to integrate acoustic features across ears was also enhanced with 3DDS processing. In listeners with normal hearing, manner and place of articulation were improved in binaural listening condition. In bimodal listeners, voicing and manner and place of articulation were also improved in bimodal and hearing aid ear–alone conditions. Conclusions: Consonant recognition was improved with 3DDS in both groups. This observed benefit suggests 3DDS can be used as an auditory training tool for improved integration and for bimodal users who receive little or no benefit from their current bimodal hearing. © The Author(s) 2019.
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    Implementation and Analysis of a Free Water Protocol in Acute Trauma and Stroke Patients
    (American Association of Critical Care Nurses, 2019-06-01) Kenedi, Helen; Campbell-Vance, J.; Reynolds, J.; Foreman, M.; Dollaghan, Cristine A.; Graybeal, D.; Warren, A. M.; Bennett, M.; 0000-0002-0431-140X (Dollaghan, CA); Kenedi, Helen; Dollaghan, Cristine A.
    Background Free water protocols allow patients who aspirate thin liquids and meet eligibility criteria to have access to water or ice according to specific guidelines. Limited research is available concerning free water protocols in acute care settings. Objectives To compare rates of positive clinical outcomes and negative clinical indicators of a free water protocol in the acute care setting and to continue monitoring participants discharged into the hospital system's rehabilitation setting. Positive clinical outcomes were diet upgrade, fewer days to diet upgrade, and fewer days in the study. Negative clinical indicators were pneumonia, intubation, and diet downgrade. Methods A multidisciplinary team developed and implemented a free water protocol. All eligible stroke and trauma patients (n = 104) treated over a 3-year period were randomly assigned to an experimental group with access to water and ice or a control group without such access. Trained study staff recorded data on positive outcomes and negative indicators; statistical analyses were conducted with blinding. Results No significant group differences in positive outcomes were found (all P values were > .40). Negative clinical indicators were too infrequent to allow for statistical comparison of the 2 groups. Statistical analyses could not be conducted on the small number (n = 15) of patients followed into rehabilitation, but no negative clinical indicators occurred in these patients. Conclusions Larger-scale studies are needed to reach decisive conclusions on the positive outcomes and negative indicators of a free water protocol in the acute care setting. ©2019 American Association of Critical-Care Nurses.
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    Automatic Speech Activity Recognition from MEG Signals Using Seq2Seq Learning
    (IEEE Computer Society, 2019-03) Dash, Debadatta; Ferrari, P.; Malik, S.; Wang, Jun; 0000-0001-7265-217X (Wang, J); Dash, Debadatta; Wang, Jun
    Accurate interpretation of speech activity from brain signals is critical for understanding the relationship between neural patterns and speech production. Current research on speech activity recognition from the brain activity heavily relies on the region of interest (ROI) based functional connectivity analysis or source separation strategies to map the activity as a spatial localization of a brain function. Albeit effective, these methods require prior knowledge of the brain and expensive computational effort. In this study, we investigated automatic speech activity recognition from brain signals using machine learning. Neural signals of four subjects during four stages of a speech task (i.e., rest, perception, preparation, and production) were recorded using magnetoencephalography (MEG), which has an excellent temporal and spatial resolution. First, a deep neural network (DNN) was used to classify the four whole tasks from the MEG signals. Further, we trained a sequence to sequence (Seq2Seq) long short-term memory-recurrent neural network (LSTM-RNN) for continuous (sample by sample) prediction of the speech stages/tasks by leveraging its sequential pattern learning paradigm. Experimental results indicate the effectiveness of both DNN and LSTM-RNN for automatic speech activity recognition from MEG signals. © 2019 IEEE.
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    Optimization of Transcranial Direct Current Stimulation of Dorsolateral Prefrontal Cortex for Tinnitus: A Non-Linear Dose-Response Effect
    (Nature Publishing Group) Shekhawat, Giriraj Singh; Vanneste, Sven; Shekhawat, Giriraj Singh; 0000-0002-9906-1836 (Vanneste, S); Vanneste, Sven
    Neuromodulation is defined as the process of augmenting neuroplasticity via invasive or non-invasive methods. Tinnitus is the perception of sound in the absence of its external source. The objective of this study was to optimize the parameters of transcranial direct current stimulation (tDCS) of dorsolateral prefrontal cortex (DLPFC) for tinnitus suppression. The following factors were optimized in the dose-response design (n = 111): current intensity (1.5 mA or 2 mA), stimulation duration (20 min or 30 min), and number of stimulation sessions (2, 4, 6, 8, or 10), with a 3-4 day washout period between each session. Participants underwent a minimum of 2 sessions in 1 week or maximum of 10 sessions in 5 weeks' time. Tinnitus loudness was measured in pre-post design using a 10-point numeric rating scale. There was a significant reduction in tinnitus loudness after tDCS of DLPFC. There was no significant difference between the intensity and duration of stimulation. As the number of sessions increased, there was a higher reduction in the tinnitus loudness; however, this effect plateaued after 6 sessions.
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    The Impact of Brief Restriction to Articulation on Children's Subsequent Speech Production
    (Acoustical Soc America) Seidl, Amanda; Brosseau-Lapré, Françoise; Goffman, Lisa; Goffman, Lisa
    This project explored whether disruption of articulation during listening impacts subsequent speech production in 4-yr-olds with and without speech sound disorder (SSD). During novel word learning, typically-developing children showed effects of articulatory disruption as revealed by larger differences between two acoustic cues to a sound contrast, but children with SSD were unaffected by articulatory disruption. Findings suggest that, when typically developing 4-yr- olds experience an articulatory disruption during a listening task, the children's subsequent production is affected. Children with SSD show less influence of articulatory experience during perception, which could be the result of impaired or attenuated ties between perception and articulation.
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    The Role of Nonverbal Working Memory in Morphosyntactic Processing by Children with Specific Language Impairment and Autism Spectrum Disorders
    (BioMed Central, 2018-09-24) Ellis Weismer, S.; Davidson, Meghan M.; Gangopadhyay, I.; Sindberg, H.; Roebuck, H.; Kaushanskaya, M.; Davidson, Meghan M.
    Background: Both children with autism spectrum disorders (ASD) and children with specific language impairment (SLI) have been shown to have difficulties with grammatical processing. A comparison of these two populations with neurodevelopmental disorders was undertaken to examine similarities and differences in the mechanisms that may underlie grammatical processing. Research has shown that working memory (WM) is recruited during grammatical processing. The goal of this study was to examine morphosyntactic processing on a grammatical judgment task in children who varied in clinical diagnosis and language abilities and to assess the extent to which performance is predicted by nonverbal working memory (WM). Two theoretical perspectives were evaluated relative to performance on the grammatical judgment task - the "working memory" account and the "wrap-up" account. These accounts make contrasting predictions about the detection of grammatical errors occurring early versus late in the sentence. Methods: Participants were 84 school-age children with SLI (n = 21), ASD (n = 27), and typical development (TD, n = 36). Performance was analyzed based on diagnostic group as well as language status (normal language, NL, n = 54, and language impairment, LI, n = 30). A grammatical judgment task was used in which the position of the error in the sentence (early versus late) was manipulated. A visual WM task (N-back) was administered and the ability of WM to predict morphosyntactic processing was assessed. Results: Groups differed significantly in their sensitivity to grammatical errors (TD > SLI and NL > LI) but did not differ in nonverbal WM. Overall, children in all groups were more sensitive and quicker at detecting errors occurring late in the sentence than early in the sentence. Nonverbal WM predicted morphosyntactic processing across groups, but the specific profile of association between WM and early versus late error detection was reversed for children with and without language impairment. Conclusions: Findings primarily support a "wrap up" account whereby the accumulating sentence context for errors positioned late in the sentence (rather than early) appeared to facilitate morphosyntactic processing. Although none of the groups displayed deficits in visual WM, individual differences in these nonverbal WM resources predicted proficiency in morphosyntactic processing.