Browsing by Subject "outcome measures"

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    Acute contraction-induced strength loss, muscle inexcitability and recovery after exercise in males with Duchenne muscular dystrophy
    (2020-11) Trost, Joyceann
    This dissertation had three objectives with the overall goal to explore contraction-induced strength loss and recovery in males with Duchenne muscular dystrophy (DMD) specifically to: 1) evaluate a novel protocol, combining voluntary and evoked contractions to measure strength and excitability of wrist extensor muscles, for safety, feasibility, reliability and discriminant validity for males with DMD and aged-matched controls, 2) explore strength loss and muscle fiber inexcitability contribution to strength loss after submaximal isometric contractions in males with DMD, and. 3) determine the recovery of strength and muscle excitability immediately following contraction-induced force loss in males with DMD. Through the literature review, I discovered a need for a reliable and valid measurement protocol of muscle contractile function that could be used for DMD across all disease levels. Several measures for walking and upper extremity function are currently used to measure outcomes during clinical trials. However, none of the current measurements for DMD incorporate a way to quantitatively measure both voluntary and evoked strength along with muscle excitability over disease progression or in response to an intervention. The key to the assessment and protocol design needed to be feasibility and safety for boys and men with DMD at different stages of the disease process. I was able to design and evaluate a novel protocol, combining voluntary and evoked contractions to measure strength and excitability of wrist extensor muscles for safety, feasibility, reliability and discriminant validity between males with DMD and controls (Chapter 3). Wrist extensor muscle strength and excitability were assessed in males with DMD (N=10; mean 15.4 [SD 5.9] years) (Brooke 1-6) and age-matched healthy male controls (N=15; mean 15.5 [SD 5.0] years). Torque and EMG measurements were analyzed under maximum voluntary and stimulated conditions at two visits. I discovered that our protocol of multiple maximal voluntary contractions (MVC) and evoked twitch contractions was feasible and safe, with 96% of the participants able to complete the assessment protocol maintaining >93% strength both for DMD and controls (P≥0.074). Reliability was excellent for voluntary and evoked measurements. Torque, EMG and timing of twitch onset measurements discriminated between DMD and controls (P<0.001). This first part of the study demonstrated a useful protocol for measuring skeletal muscle function in clinical trials in males with DMD across various ages and disease levels. The second part of the study addressed in the context of a neuromuscular disease the concern of injury to dystrophic deficient skeletal muscle during and after repeated contractions (exercise) that result in acute strength loss. I knew that a feature of dystrophin-deficient skeletal muscle in the mdx mouse model was a hypersensitivity to strength loss from eccentric exercise due to fibers becoming unexcitable. I wanted to explore how this feature translated to humans lacking dystrophin. We hypothesized that there would be no difference in strength loss during exercise and that males with Duchenne muscular dystrophy (DMD) would have more significant impairment in muscle excitability corresponding with a loss of strength than age-matched controls (Chapter 4). Males with DMD and a group of age-matched controls performed a sub-maximal voluntary isometric wrist extensor exercise protocol until 55% of maximal voluntary contraction (MVC) could no longer be sustained. Voluntary and evoked force and EMG were accessed before, during, and after exercise. There was a significant interaction (time*group) (p<0.001) for MVC torque during exercise, suggesting that the two groups were different in how they reached muscle fatigue. No difference was measured between groups in MVC torque decrement at the time of exercise cessation (by design). Evoked twitch torque decrement was 34% for DMD and 36% for control with no group*time interaction observed (p=0.834). Muscle excitability contributed to the evoked torque variance in DMD (76%) and control (59%). The groups were not different in RMS EMG decrement (P=0.986) or M-wave decrement (P=0.911) during exercise, which does not support our hypothesis that the DMD groups had a more considerable decline in muscle excitability with fatigue during exercise. Lastly, the recovery of both strength and muscle excitability was explored and compared between groups. The DMD group recovered MVC baseline strength by 10 minutes post-exercise (P=0.530) and evoked torque by 5 minutes (P=0.266). In contrast, controls were still different from MVC and evoked torque baseline at 15 minutes after exercise (P<0.002). Strength loss from submaximal intermittent isometric exercise does not result in more significant impairment of muscle excitability is transient, and recovers faster in males with DMD than controls, suggesting a different mechanism of peripheral fatigue between the groups. The work contained in my dissertation begins to address the fear of exercise that has been a common concern for individuals with DMD and will contribute to knowledge of evidence-based exercise prescription in the future.
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    Improving hearing aid outcomes in background noise: An investigation of outcome measures and patient factors
    (2022-11) Oeding, Kristi
    Background noise is reported to be one of the most difficult listening environments by hearing aid users. Digital noise reduction and directional microphones have been added to hearing aids and remote microphones and frequency modulation systems as accessories to help augment speech understanding in background noise for hearing aid users. Despite having this technology, patients still have concerns in background noise. This indicates that there is still a need for evidence-based tools for assessing patient speech understanding needs as well as quantifying amplification benefits in noise to help improve these situations. This dissertation seeks to investigate the advantages and disadvantages of current evidence-based practices tools available for improving speech understanding in noise for individuals with hearing loss. Three main research findings are reported in this dissertation. The first study examined the viability of using functional near infrared spectroscopy (fNIRS), a tool that can be used to measure the hemodynamic response to neural activity in the brain. This study sought to examine if fNIRS is a viable clinical tool for assessing the impact of different listening conditions, speech materials, and hearing aid settings on listening effort. Behavioral data supported the impact of signal degradation on intelligibility and that syntactically complex speech results in greater difficulty parsing content. fNIRS data supported that this difficulty in parsing content could be considered listening effort due to contrasts in hemodynamic responses in the lateral inferior frontal gyrus between grammatically simple and complex constructions. Future work should consider evaluating fNIRS in an older hearing loss group with contrasting degrees of hearing loss and speech complexity. The second study examined the viability of using spectral-ripple modulation detection thresholds (SMD), a tool that could help assess a person's broadband spectral processing abilities as an alternative for a person's speech understanding in noisy environments. In this study, SMD thresholds were examined in a group with normal hearing and a group with hearing loss to determine the impact of bandwidth and intensity on SMD thresholds. Results revealed a significant difference in bandwidth and level within the hearing loss and normal hearing groups, but not across groups. Future work should examine this effect using audibility-controlled conditions across the listener groups, such as simulating a hearing aid in these situations to determine the impact of amplification on SMD thresholds. The final study examined various listener factors that could influence a person's noise tolerance. The acceptable noise level test was used as a metric for noise tolerance. The listener factors that were examined included personality traits, digits in noise ability, and working memory along with hearing aid factors to determine if they can predict a person’s acceptable noise level. Results revealed that the Device Oriented Subjective Outcome subscale of listening effort and the digits in noise task were able to predict the acceptable noise level of a hearing aid user. Future work should look at other patient factors to predict noise tolerance. These three research studies aimed to determine what tests can provide a better assessment of listening needs in noise for persons with hearing loss. The second goal was to determine if individual factors were able to predict a person’s ability to tolerate background noise. The end goal of these studies is to use this information along with future research to determine which individuals would benefit from specific hearing aid settings and/or auditory training based on outcome measures and individual factors.
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    Outcome Measures Following Traumatic Brain Injury: A Synthesis of Speech-Language Pathologist’s Perspectives
    (2022-05) Grabowski, Annelise
    AbstractPurpose. Traumatic brain injury (TBI) is a major public health concern and impacts several different cognitive domains, often simultaneously. Outcome measures are used to evaluate progress in the clinic, and treatment efficacy in research. However, there can be mismatches between the cognitive impairments that commonly-used outcome measures assess and how these impairments impact the individual in real life. Historically, TBI research has relied on the opinions of researchers, rather than key stakeholders, to decide what is most important in assessment, treatment, and outcome measurement in TBI. By ignoring the opinions of individuals who hold lived experiences with TBI, there is a risk of treating and measuring domains that have less relevance to the individuals most closely impacted by TBI. This thesis is part of a larger study that aims to solicit the opinions of key stakeholders (individuals with TBI, their families, and speech-language pathologists) to find what matters most during TBI rehabilitation, in order to inform the selection of outcome measures for treatment efficacy research as well as the development of new outcome measures for domains not currently assessed in clinical and research settings. Here, we consider the perspectives of speech-language pathologists. Method. 41 speech-language pathologists (SLPs) across the United States completed an online survey. The two-part survey included: a clinical experience section and an open-ended response section including questions designed to elicit measurable outcome domains in TBI rehabilitation. The clinical experience section was analyzed using descriptive statistics. Open-ended responses were analyzed using qualitative thematic analysis. Data-driven thematic analyses included creating and refining a codebook, coding the data set, and organizing codes into themes for interpretation. Results. Results from the clinical experience section revealed the respondents had experience as SLPs averaging 14 years with CCCs (Certificate of Clinical Competence), and an average of 9.5 years of experience with TBI. Respondents worked in varied practice settings ranging from acute care to outpatient. The inductive qualitative analysis of the open-ended responses resulted in three themes that are of value to speech-language pathologists in TBI rehabilitation: Primary Impairments Following TBI (with 41 [100%] of 41 participants contributing to this theme), Changes to Activities and Participation (41 [100%]), and Process Factors in TBI Rehabilitation (40 [96%]). Conclusion. Many of the frequently cited domains reported by SLPs (e.g. memory, attention, executive function) are captured currently used outcome measures for TBI; however, some of the domains cited by SLPs are rarely or never measured in current outcome measures for TBI rehabilitation (e.g. acceptance, ease-effort, use of compensatory strategies). Future work should synthesize findings from the current study with perspectives of other key stakeholder groups (e.g. individuals with TBI and their families) to inform the development of new outcome measures. Limitations of the current study and opportunities for future research are discussed.