Thesis (M.S.)--Simon Fraser University, 2000. / Includes bibliographical references.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / Dysphagia with aspiration (DA) is the most common presenting symptom of patients at Phoenix Children’s Hospital’s Aerodigestive Clinic (ADC). Dysphagia with aspiration is associated with respiratory and gastrointestinal symptoms, chronic oral thickener use to prevent aspiration, secondary constipation, and occasionally, enteral tube dependency. MBS is considered the gold standard in instrumental assessment of dysphagia; it is used to evaluate severity and guide thickener treatment of DA patients, monitor progress with serial studies, and for re‐evaluation after intervention when appropriate. Previous evaluation of patients with deep interarytenoid notch given laryngoplasty injection included patients with improvement in symptoms despite post‐intervention MBS scores worsening, and vice versa, challenging the use of MBS as a longitudinal tool in clinical evaluation of patients with dysphagia and aspiration. Is MBS severity score reflective of clinical symptoms in pediatric patients with dysphagia and aspiration? A clinical questionnaire of DA symptoms was developed with input from the ADC physicians. The questionnaire was administered over 3 months to patients aged 1‐3 years who had an MBS evaluation within 6 months of their initial ADC visit, standard of care for patients with DA. 17 symptoms (12 GI and 5 pulmonary) were given a numerical score 0‐4 based on parent recall of frequency. MBS was scored 1‐10 on the thickness of liquid recommended for aspiration prevention. Individual symptoms and symptom sets (total questionnaire score, GI score, pulmonary score) were compared to MBS score using linear regression model. 30 patients were surveyed with median MBS score of 6 and range from 0 to 8. 18 patients had an MBS score above 6. Median questionnaire score was 18, with a range from 4 to 53. All analysis showed no significant correlation between individual symptoms or symptom sets and MBS score; the highest R2 value for any individual symptoms was 0.05. Among ADC patients with DA, MBS severity score did not correlate with severity or specificity of symptoms, questioning the use of MBS as a tool for diagnosing severity of persistent DA or as a repetitive tool in assessing response to laryngeal cleft surgical interventions and thickener wean therapy. These findings challenge the use of repetitive MBS in the ADC patient population. Our ultimate goal is to develop a combined clinical and radiologic tool that would minimize radiation exposure and unnecessary thickener treatment while promoting best clinical outcomes.

Thesis (Honors)--College of William and Mary, 2009. / Includes bibliographical references (leaves 96-112). Also available via the World Wide Web.

Dysphagia is a leading complication of a stroke. A nurse-driven bedside swallow screen can identify dysphagia and decrease the risk for complications such as aspiration pneumonia. At the project site, the use of the bedside swallow screen was at 33%; there was noncompliance with the use of the bedside swallow screen by the emergency department nurses. The purpose of the doctoral project was to increase the use of the bedside swallow screen. Published outcomes, research, and reports generated from archived data were the sources of evidence. The six sigma methodology was used to inform the quality improvement doctoral project. At the end of the quality improvement project, the posttest scores were statistically significantly higher than the pretest scores mean. The nurses' scores demonstrating level of confidence before the training (M = 68.39, SD = 10.86) were lower than scores indicating their level of confidence after the training (M = 79.55, SD = 10.56), and the paired t test showed statistical significance p < .001. The training made a statistically significant difference in the emergency department nurses' knowledge and confidence in performing the dysphagia screen. After the causes of low compliance were identified, strategies developed and implementation of the swallow screen in the emergency department increased. The quality improvement project improved the use of the dysphagia screen at the project site from 33% to 60%. The project made a positive impact on social change by reducing stroke patients' risk for complications.

Thesis (M.S.)--California State University, Chico. / Includes abstract. "Located in the Chico Digital Repository." Includes bibliographical references (p. 74-80).

Background and Aims The accurate differentiation between a delayed pharyngeal swallow (sensory impairment) and premature spillage secondary to poor oro-lingual control (motor impairment) is essential to effective dysphagia management. However both physiologic abnormalities result in an identical radiographic sign, that of pre-swallow pooling of the bolus in the pharynx. The dysphagia literature does not provide satisfactory guidelines for making this distinction on videofluoroscopy. The purpose of this study was to assess the validity of a three-part rating scale for differentiating between these two impairments. Methods Videofluoroscopy was used to evaluate the swallowing of 29 participants presenting with dysphagia following stroke. Sensory thresholds for these participants were established by electrical stimulation of the anterior faucial pillars. The videofluoroscopic swallowing studies were analysed using the three-part rating scale and results from this were compared to sensory thresholds using Pearson's product moment correlation. Results There was no significant correlation between the three-part criteria and sensory thresholds. Inter-rater reliability for some measures was poor. Conclusions The three-part criteria was not shown to be a valid measure for differentiating between delayed pharyngeal swallow and premature spillage secondary to poor oro-lingual control. Possible explanations for these findings are discussed, including the relevance of faucial pillar sensation to swallowing.

Background and Aims The accurate differentiation between a delayed pharyngeal swallow (sensory impairment) and premature spillage secondary to poor oro-lingual control (motor impairment) is essential to effective dysphagia management. However both physiologic abnormalities result in an identical radiographic sign, that of pre-swallow pooling of the bolus in the pharynx. The dysphagia literature does not provide satisfactory guidelines for making this distinction on videofluoroscopy. The purpose of this study was to assess the validity of a three-part rating scale for differentiating between these two impairments. Methods Videofluoroscopy was used to evaluate the swallowing of 29 participants presenting with dysphagia following stroke. Sensory thresholds for these participants were established by electrical stimulation of the anterior faucial pillars. The videofluoroscopic swallowing studies were analysed using the three-part rating scale and results from this were compared to sensory thresholds using Pearson's product moment correlation. Results There was no significant correlation between the three-part criteria and sensory thresholds. Inter-rater reliability for some measures was poor. Conclusions The three-part criteria was not shown to be a valid measure for differentiating between delayed pharyngeal swallow and premature spillage secondary to poor oro-lingual control. Possible explanations for these findings are discussed, including the relevance of faucial pillar sensation to swallowing.

Swallowing is an essential motor act that coordinates the movement of food or saliva from the mouth through the pharynx and into the esophagus while protecting the upper airways from aspiration of those materials. Disordered swallowing, or dysphagia, results when bolus movement from the oropharyngeal phase into the esophageal phase is uncoordinated. Dysphagia directly causes or increases the risk of aspiration during swallowing in many clinical pathologies including Parkinson’s disease, Alzheimer’s disease, cerebrovascular incidents (stroke) in addition to being prevalent among the elderly population. The coordination between breathing and swallowing is mediated through the interaction of the swallow and respiratory Central Pattern Generators (CPGs) located in the brainstem. In the pharyngeal phase of swallow respiratory airflow is temporarily interrupted, and then reset, when the bolus moves through the pharyngeal space. The lungs retain enough air during the swallow apnea to protect the lower airways from accidental aspiration of residual bolus material, modulate the latency to initiate the swallow, while providing sensory feedback for processing within the brainstem network. The timing of the pharyngeal phase of swallow with respiration occurs across a continuum of lung volumes. Following swallow, the latency to initiate inspiration of the subsequent respiratory cycle increases. The swallow-mediated increase in cycle duration on respiration may depend upon the central processing of pulmonary afferents that may also affect reconfiguration of the respiratory CPG to express the swallow CPG. The peripheral and central mechanisms of swallow-breathing coordination remain poorly understood. Here, the relationship between central inspiratory output and the resultant mechanical inflation of the lungs was manipulated and dissociated to test the hypothesis that a centrally- and peripherally-mediated “swallow gate” coordinates swallow initiation with central respiratory activity and vagally-mediated pulmonary feedback. We obtained data from decerebrate adult cats of either sex that fully recovered from isoflurane anesthesia prior to the decerebration procedure. Fictive swallows were elicited using electrical stimulation of the superior laryngeal nerves (SLN) or injection of water (Water) into the pharyngeal cavity. Both stimuli were presented at random during the central respiratory cycle and/or the mechanical ventilation cycle. Mechanical ventilation was either triggered in-phase with phrenic discharge activity or it was set independent of phrenic discharge activity. These two modes of mechanical ventilation facilitated our ability to analyze the collective and individual effect of lower airway feedback on swallow-breathing coordination. The efferent discharge activities were recorded from the right hypoglossal (XII), left phrenic (Phr), left lumbar iliohypogastric (Lum) and right vagus (X) or the right recurrent laryngeal (RLN) nerves using silver bipolar hooked electrodes. All nerve activity was full-wave rectified, amplified, RC integrated (τ=200-500 ms) and low-pass filtered prior to analysis for effects on swallow-breathing coordination across stimulation-ventilation conditions. We observed post-inspiratory type (Post-I) and expiratory type (Exp) swallows that produced discrete effects on central respiratory rhythm across all conditions. The Post-I type swallows disturbed the duration and amplitude of preceding central inspiratory activity, without affecting the duration of central expiratory activity. The Exp type swallows prolonged central expiration but produced no effect on central inspiratory activity. We observed that lung inflation negatively modulated swallow initiation during fixed mechanical ventilation in the absence of central respiratory output, i.e., during central apnea. Most swallow elicited during central apnea initiated during periods of low lower airway afferent feedback. Collectively, these findings extend the role for lower airway feedback beyond its role as a provider of lung afferent surveillance and identifies lower airway feedback as a modulator of swallow-breathing coordination.

Although nest reuse is most commonly associated with costs such as nest instability and increased ectoparasite loads,contrary evidence supports the possibility that nest reuse might provide an adaptive function in the form of time and energy savings. The Cave Swallow (Petrochelidon fulva), which nests under bridges and culverts in east-central Texas, chooses predominately to reuse nests when old nests are available. I conducted a field experiment involving bridge pairs and single bridges, in which I applied a treatment of nest removal to one bridge of each pair and one half of each single bridge in order to test whether control bridges and nests exhibited increased productivity from the availability of old nests. I found that a higher percentage of young fledged from control bridges and more fledged per clutch from control bridges. Small sample sizes diminished the ability to detect differences within the single bridge experiment. Results from this research support the time-energy savings concept and may be reconciled with conflicting research through fundamental differences between studies in immunity to ectoparasites, infestation type, and nest microclimate.

Although nest reuse is most commonly associated with costs such as nest instability and increased ectoparasite loads,contrary evidence supports the possibility that nest reuse might provide an adaptive function in the form of time and energy savings. The Cave Swallow (Petrochelidon fulva), which nests under bridges and culverts in east-central Texas, chooses predominately to reuse nests when old nests are available. I conducted a field experiment involving bridge pairs and single bridges, in which I applied a treatment of nest removal to one bridge of each pair and one half of each single bridge in order to test whether control bridges and nests exhibited increased productivity from the availability of old nests. I found that a higher percentage of young fledged from control bridges and more fledged per clutch from control bridges. Small sample sizes diminished the ability to detect differences within the single bridge experiment. Results from this research support the time-energy savings concept and may be reconciled with conflicting research through fundamental differences between studies in immunity to ectoparasites, infestation type, and nest microclimate.