The works contained in this dissertation were motivated by a desire to better understand the variability of patient performance on videofluoroscopic assessments of swallowing. Specifically, the variation present in kinematic and temporal measures of swallowing was investigated in three main phases: narrative literature review, healthy swallowing, and disordered swallowing. The primary goals were to identify which factors explain (or do not explain) variation, to develop methods to control for variation and to investigate the association between swallowing physiology and swallowing impairment. The literature reviews revealed wide ranges of variation for kinematic (Chapter 2) and temporal (Chapter 3) measures of swallowing in the existing literature on healthy deglutition. The kinematics (Chapter 4) and timing (Chapter 5) of swallowing were investigated in a prospectively collected sample of young healthy participants stratified by height. One main objective was to investigate the impact of participant size on physiological parameters of swallowing. Finally, kinematic and temporal measures of swallowing were investigated in a sample of patients referred for swallowing assessment (Chapter 6) to explore associations between swallowing physiology and impairment. The findings of this dissertation make several unique contributions to the dysphagia literature. It has demonstrated that inherent variation appears to exist in physiological measures of both healthy and disordered swallowing. Further, when certain sources of variation are controlled (such as participant size), men and women do not demonstrate significant differences for any of the parameters tested. Importantly, this work has demonstrated that participant size impacts the expected extent of hyoid excursion and that this variation can be controlled through normalization of hyoid movement to internal anatomical scalars. Two temporal variables trended toward detecting functional swallowing impairment. Finally, this dissertation provides the first set of normative reference values for parameters of swallowing with an ultra-thin liquid barium. Limitations are acknowledged and future work is suggested.

Patients with an impaired reflexive cough response are at increased risk of pneumonia. This study examined the correlation between cough sensitivity to citric acid and radiographic features of airway compromise. Eighty patients referred for a radiographic assessment of swallowing at an acute hospital over an 8-month period participated in the study. Nebulised citric acid diluted in 0.9% sodium chloride was inhaled through a facemask at four concentrations to assess cough sensitivity. These data were then compared to Penetration Aspiration Scale scores based on radiographic swallowing studies. There was a statistically significant correlation between cough response/lack of response and the radiographic features of airway compromise; that is, patients who had a weak or absent response to inhalation of citric acid were also likely to aspirate silently during radiographic assessment. Sensitivity for identifying absent cough was found to be high at all 4 concentrations (0.750, 0.833, 0.941, 1.000), however specificity was consistently quite low (0.344, 0.456, 0.238, 0.078). The significant findings of this research suggest that clinicians adopting cough reflex testing into their clinical practice will have a reliable screen for silent aspiration at bedside. Clinicians will be able to identify patients who require instrumental assessment and are at high risk of pneumonia. This will likely, in turn, decrease length and cost of hospital admissions as well as decrease aspiration pneumonia related morbidities.

Objective: Traditionally, swallowing rehabilitation has involved the use of muscle strengthening exercises, such as the head-lift manoeuvre (Shaker et al., 1997), to strengthen the floor of mouth muscles. Clinical reasoning suggests that this particular exercise may be problematic for patients with cervical spine injuries or increased frailty. Recently, Bauer and Huckabee (2010) attempted to determine the efficacy of an alternative exercise for the floor of mouth muscles in healthy adults. The present study aims to expand on this work in a larger population of healthy adults. Study design: Controlled trial; participants matched for age and sex. Participants: 23 healthy adults with no history of neurological or muscular impairment. Method: Participants were assigned into one of two groups: jaw opening exercise (JOE; n = 12) and sham exercise (SE; n = 11). Groups were matched for age and gender. Participants performed their respective exercises three times per day, five days per week, over a six week period. At three times during this period, measures of submental 2-D cross-sectional area and anterior hyoid movement were taken via ultrasound. Additionally, measures of submental muscle myoelectrical activity were taken via surface electromyography. Pre- and post-treatment comparisons, as well as inter-group comparisons, were undertaken. Results: No significant differences were observed between groups on measures of muscle size, anterior hyoid movement, or myoelectrical activity over time. However, this study has contributed to the future development of an alternative exercise to target the submental muscle group.

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Screening acute stroke patients for dysphagia (difficulty swallowing) is recommended within 24 hours due to risks of morbidity and mortality. A review of the international literature identified no universal consensus for a valid method of screening. This thesis describes a multi-method Action Research (AR) programme of study focused on the design, development and evaluation of a reliable and valid dysphagia screening tool (the ‘Head Dysphagia Screen for Stroke’ or HeDSS) for use by Registered General Nurses (RGNs). As a component of the assessment phase of the AR programme, a survey of dysphagia screening practices in England and Wales highlighted widely varied screening practices. Many of these practices were based on limited research evidence, reflecting the lack of consensus for valid dysphagia screening criteria reported in the literature. The design phase of the AR programme involved the development of the HeDSS tool, which centred on the use of research-based screening criteria. Focus group activity determined nurses’ perceptions of the design and subsequent refinement of the HeDSS tool. The intervention and evaluation phases of the AR programme followed three empirical stages. Stage one established the inter-rater reliability of the Speech and Language Therapist Researcher’s (SLTR’s) clinical dysphagia assessment, which acted as a reference standard against which the validity of the HeDSS tool was to be measured. Clinical judgements for the presence and absence of dysphagia in the same 30 referred patients were compared between the SLTR and a Speech and Language Therapist (SLT) of equivalent experience. Inter-rater reliability was substantial (k = .71). The second empirical stage established inter-rater reliability of the HeDSS measurement outcomes (indicative signs of dysphagia and appropriateness of referral for SLT clinical dysphagia assessment) when employed by two RGNs compared against the SLTR when screening two samples of 20 acute stroke patients. Rater agreement was substantial (k = .71 and k = .79, for detection of signs of dysphagia and k = .79 and k = .87 for appropriateness of referral). The final empirical stage evaluated the concurrent validity of the HeDSS tool measurement outcomes when employed by a second sample of two RGNs compared with the SLTR’s clinical dysphagia assessment outcomes in a sample of 100 acute stroke patients. The HeDSS tool measurement outcomes correlated highly with the clinical dysphagia assessment outcomes (sensitivity .88 - .96 and specificity .85 - .88 for detection of dysphagia; sensitivity .90 - .96 and specificity .84 - .88 for determining patients appropriate for assessment). Correlation coefficient measures confirmed high concurrent validity for the HeDSS tool (Phi ranged between .76 - .82). This study is the first in the UK to establish a reliable and valid dysphagia screening tool for use with acute stroke patients and has significantly advanced the professional knowledge base within this domain of practice. It is recommended that a multi-centred programme of research be undertaken to replicate this study with a larger nurse and patient sample.

Magister Scientiae (Physiotherapy) - MSc(Physio) / Dysphagia is commonly known as a swallowing disorder associated with stroke patients. Between 37% - 78% of stroke patients suffer from it initially. Complications of dysphagia include aspiration leading to chest infection and pneumonia, malnutrition, dehydration, and an increased risk of death. Its early diagnosis and management is an important prerequisite for recovery from stroke during the rehabilitation phase. As healthcare professionals, nurses play an important role in the diagnosis and management of dysphagia in stroke patients. Studies have shown that nurses display a lack of knowledge about dysphagia in stroke patients. The aim of the study was to determine the knowledge of nurses regarding dysphagia in patients with stroke, at an Intermediate Hospital, in Namibia. The objectives of the study were to determine the knowledge of nurses regarding dysphagia, the association between the knowledge and socio demographic factors and to design an intervention program based on the knowledge of the nurses. The study was carried out in a selected hospital in Namibia. All nurses, who were employed at the Intermediate Hospital at the time of the study, were invited to participate. Of the 500 employed nurses, 188 accepted the invitation to participate in the study. The study used a quantitative method consisting of a survey to determine the knowledge of the nurses. Data was collected using a self-administered questionnaire with closed-ended questions which was developed by the researcher. The quantitative data were captured and analysed using SPSS (22.0 version). Descriptive statistics was used to summarize the study findings by using means, standard deviations, frequencies and percentages. To determine the association between the knowledge of dysphagia and the socio-demographic factors, therefore inferential statistics were used to in three levels of analysis. The findings of the study shows that nurses have a moderate knowledge regarding to the signs and symptoms and complications of dysphagia. Poor knowledge was identified in management of dysphagia. Further, the results also indicated that further training and experience in caring for stroke patients was more relevant to knowledge than the position and qualification of a nurse. Training and experience in the care of dysphagia patients is a stronger predictor of knowledge than the initial qualification or years of experience of a nurse. An intervention program was designed based on the information obtained from the findings of the questionnaire and supporting literature. Permission to conduct this study was obtained from the Senate Research Grants and Study Leave Committee at the University of the Western Cape. Written permission was obtained from the Ministry of Health and Social Services, Office of the Permanent Secretary, as well from the Acting Medical Superintendent of the Intermediate Hospital Oshakati. The aim of the study, confidentiality and the participants' freedom to withdraw from the study was explained. In order to maintain anonymity, nurses were asked to place informed consent forms and questionnaires in separate boxes. The outcomes of the study could be used to offer appropriate training programs to increase nurses’ knowledge of dysphagia in stroke patients.

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The goal of antibiotic stewardship is to improve antibiotic use, often by reducing unnecessary treatment. Bedside dysphagia screening tools help identify patients at high risk of aspiration following stroke. Presence of dysphagia does not indicate a need for antibiotic treatment. Therefore, this retrospective, cohort study was developed to evaluate the association of dysphagia and antibiotic prescribing following stroke. There were 117 patients included. Patients were placed into 2 cohorts based on the results of the dysphagia screening, with 55 patients positive for dysphagia and 62 patients negative for dysphagia. Patients with dysphagia tended to be older, had higher National Institutes of Health stroke scores, and lower renal function. Patients with dysphagia were prescribed more empiric antibiotics than those without dysphagia (18.2% vs. 3.2%, p = 0.01). This resulted in 53 antibiotic days of therapy in the dysphagia cohort compared to 19 antibiotic days of therapy in the no dysphagia cohort (p = 0.1). No patients later developed pneumonia and only one patient was started antibiotics after 48 h. Two cases of Clostridioides difficile were reported. Both patients were in the dysphagia cohort and received antibiotics. Multivariable logistic regression demonstrated that positive chest x-ray findings and failed dysphagia screen were independent conditions associated with initiating antibiotics. These findings indicate that antibiotic use was higher in patients following stroke with a positive dysphagia screen. Close monitoring of stroke patients, particularly when positive for dysphagia, might be an under-recognized antibiotic stewardship opportunity.

No description available.