Background: Non-obstructive Dysphagia (NOD) is one of the most common symptoms evaluated using esophageal manometry. Although manometry is considered the gold standard, many NOD patients have normal evaluations. Esophageal function testing with combined multichannel intraluminal impedance and esophageal manometry (MII-EM) is performed using ten 5-mL swallows of a liquid and a viscous material and provides supplemental information about bolus transit. The aim of this study was to evaluate esophageal function using combined MII-EM in patients with NOD who had normal evaluations with liquid manometry. Methods: Multichannel intraluminal impedance and esophageal manometry was performed in consecutive patients presenting for evaluation of NOD. Patients were excluded if any abnormality was detected during liquid manometry. Viscous manometry and liquid and viscous impedance data were analyzed to detect manometric or bolus transit abnormalities. Patients referred for GERD evaluation without any swallowing complaints were used as patient controls and were subject to the same exclusion criteria as the NOD group. All swallow evaluations were performed with 10 liquid and 10 viscous swallows. Key Results: Data from 240 patients were evaluated, 129 with NOD and 111 patient controls. In the NOD group, 9% (12/129) had abnormal liquid impedance and 29% (37/129) had abnormal viscous impedance. In the control group, 4% (4/111) had abnormal liquid impedance and 16% (18/111) had abnormal viscous impedance. Chi-square analysis showed a significant difference between the two study groups for viscous impedance (P = 0.02) but not for liquid impedance (P = 0.12). Conclusions and Inferences: Our data support our belief that a normal liquid manometry with an abnormal viscous impedance analysis in a patient with NOD indicates abnormal esophageal motility. Therefore, viscous impedance should be performed on all patients during the evaluation of NOD.

The anterior approach to cervical spine surgery is associated with many possible complications. Dysphagia has commonly been reported as one of these complications. A closer examination of the reports of dysphagia following anterior cervical spine surgery, however, reveals that while new onset transient dysphagia is often mentioned, long-term (greater than 48 hours) dysphagia has not been well described. In this article, we report the case of a 29-year-old female with long-term recurrent dysphagia following cervical spine surgery using the anterior approach. The important point about this case is that our patient's symptoms suddenly recurred for the first time after, nearly a two-month period of normal swallowing. Consequently, this patient has required multiple dilations. As a result, despite an initial lack of swallowing dysfunction or the return of normal swallowing, clinicians should be aware of the importance of reassessing swallowing in patients who have undergone cervical spine surgery using the anterior approach.

No description available.

Many research questions in dysphagia research require frame-by-frame annotation of anatomical landmarks visible in videofluorographs as part of the research workflow, which can be a tedious and error prone process. Such annotation is done manually using image analysis tools, is error prone, and characterized by poor rater reliability. In this thesis, a computer-assisted workflow that uses a point tracking technique based on the Kanade-Lucas-Tomasi tracker to semi-automate the annotation process, is developed and evaluated. Techniques to semi-automate the annotation process have been explored but none have had their research value demonstrated. To demonstrate the research value of a workflow based on point tracking in enhancing the annotation process, the developed workflow was used to perform an enhanced version of the recently published Coordinate Mapping swallowing study annotation technique to determine several swallowing parameters. Evaluation was done on eight swallow studies obtained from a variety of clinical sources and showed that the workflow produced annotation results with clinically insignificant spatial errors. The workflow has the potential to significantly enhance research processes that require frame-by-frame annotation of anatomical landmarks in videofluorographs as part of their data preparation steps, by reducing the total time required to annotate clinical cases

Dysphagia (swallowing disorder) is a common health problem that degrades the quality of life of many people. The videofluoroscopic swallowing study (VFSS) is the current gold standard in dysphagia assessment but is associated with high cost, long wait times, and a lack of portability. As a result, there is a pining need for an alternative technique that can serve day-to-day monitoring of dysphagia as well as screening for VFSS referral. The primary objective of this thesis was to investigate three non-invasive signal modalities, namely dual-axis accelerometry, submental mechanomyography (MMG), and nasal airflow, for their potential as alternatives to VFSS. To this end, signals were acquired from 17 healthy individuals and 24 patients with dysphagia, with various stimuli. In a characterization study, the anterior-posterior (A-P) and superior-inferior (S-I) axes in dual-axis accelerometry were found to contain non-overlapping information about swallowing, justifying the extension of single-axis (A-P only) to dual-axis (A-P and S-I) accelerometry. Also, several dual-axis accelerometry signal features were found to be stimulus dependent, and the observed stimulus effects were linked to slower swallowing function with increasing bolus viscosity. Age and stimulus effects on submental MMG were scrutinized, as an analogy to previous electromyography (EMG) studies of similar design. Similarities to EMG confirmed the validity of MMG as a muscle activity measurement tool in swallowing research. Automatic swallow segmentation, which is a crucial precursory step to swallow diagnosis, was investigated with artificial neural networks. Segmentation performance was shown to improve as more signal modalities were included, verifying the value of multi-sensor fusion. When all signal modalities were utilized, an adjusted accuracy of 89.6% was achieved. Automatic discrimination between healthy and abnormal swallows was investigated in two studies. Using previously collected pediatric data, a radial basis classifier based only on A-P accelerometry resulted in an adjusted accuracy of 81.3% in aspiration detection. In an adult study, linear discriminant classifiers resulted in adjusted accuracies of 74.7%, 83.7%, and 84.2% for aspiration, valleculae residue, and pyriform sinus residue detection, respectively. It was concluded that the three signal modalities analyzed in this thesis possess promising potential for abnormal swallow detection.

Swallowing accelerometry may provide a portable and cost-effective bedside alternative to currently available instrumentation. In this study, dual-axis accelerometry signals were collected simultaneous to videofluoroscopic records from 29 pediatric participants (age 6.8 $\pm$ 4.8 years; 20 males) previously diagnosed with neurogenic dysphagia. Videofluoroscopic records were reviewed by a clinical expert to extract swallow timings and ratings. The dual-axis accelerometry signals corresponding to each identified swallow were pre-processed, segmented and trimmed prior to feature extraction from time, frequency, time-frequency and information theoretic domains. Feature space dimensionality was reduced via principal components. Using 8-fold cross-validation, 16-18 dimensions and a support vector machine classifier with an RBF kernel, an adjusted accuracy of 89.6\% $\pm$ 0.9 was achieved for the discrimination between swallows with and without airway entry. Our results suggest that dual-axis accelerometry has merit in the non-invasive detection of unsafe swallows in children and deserves further consideration as a pediatric medical device.

Swallowing accelerometry may provide a portable and cost-effective bedside alternative to currently available instrumentation. In this study, dual-axis accelerometry signals were collected simultaneous to videofluoroscopic records from 29 pediatric participants (age 6.8 $\pm$ 4.8 years; 20 males) previously diagnosed with neurogenic dysphagia. Videofluoroscopic records were reviewed by a clinical expert to extract swallow timings and ratings. The dual-axis accelerometry signals corresponding to each identified swallow were pre-processed, segmented and trimmed prior to feature extraction from time, frequency, time-frequency and information theoretic domains. Feature space dimensionality was reduced via principal components. Using 8-fold cross-validation, 16-18 dimensions and a support vector machine classifier with an RBF kernel, an adjusted accuracy of 89.6\% $\pm$ 0.9 was achieved for the discrimination between swallows with and without airway entry. Our results suggest that dual-axis accelerometry has merit in the non-invasive detection of unsafe swallows in children and deserves further consideration as a pediatric medical device.

Dysphagia (swallowing disorder) is a common health problem that degrades the quality of life of many people. The videofluoroscopic swallowing study (VFSS) is the current gold standard in dysphagia assessment but is associated with high cost, long wait times, and a lack of portability. As a result, there is a pining need for an alternative technique that can serve day-to-day monitoring of dysphagia as well as screening for VFSS referral. The primary objective of this thesis was to investigate three non-invasive signal modalities, namely dual-axis accelerometry, submental mechanomyography (MMG), and nasal airflow, for their potential as alternatives to VFSS. To this end, signals were acquired from 17 healthy individuals and 24 patients with dysphagia, with various stimuli. In a characterization study, the anterior-posterior (A-P) and superior-inferior (S-I) axes in dual-axis accelerometry were found to contain non-overlapping information about swallowing, justifying the extension of single-axis (A-P only) to dual-axis (A-P and S-I) accelerometry. Also, several dual-axis accelerometry signal features were found to be stimulus dependent, and the observed stimulus effects were linked to slower swallowing function with increasing bolus viscosity. Age and stimulus effects on submental MMG were scrutinized, as an analogy to previous electromyography (EMG) studies of similar design. Similarities to EMG confirmed the validity of MMG as a muscle activity measurement tool in swallowing research. Automatic swallow segmentation, which is a crucial precursory step to swallow diagnosis, was investigated with artificial neural networks. Segmentation performance was shown to improve as more signal modalities were included, verifying the value of multi-sensor fusion. When all signal modalities were utilized, an adjusted accuracy of 89.6% was achieved. Automatic discrimination between healthy and abnormal swallows was investigated in two studies. Using previously collected pediatric data, a radial basis classifier based only on A-P accelerometry resulted in an adjusted accuracy of 81.3% in aspiration detection. In an adult study, linear discriminant classifiers resulted in adjusted accuracies of 74.7%, 83.7%, and 84.2% for aspiration, valleculae residue, and pyriform sinus residue detection, respectively. It was concluded that the three signal modalities analyzed in this thesis possess promising potential for abnormal swallow detection.

Electrical stimulation has been a controversial treatment option for acquired dysphagia since the initial study by Freed, Freed, Chatburn, and Christian (2001). This report investigates the efficacy of electrical stimulation by addressing three issues related to the use of this technique: 1) the movement of the hyolaryngeal complex during stimulation, 2) the population(s) for which electrical stimulation is efficacious, and 3) the necessity of combining electrical stimulation with traditional treatments for the treatment to be effective. Twenty-two studies were evaluated and revealed overall positive findings for the use of electrical stimulation as a treatment technique. To further analyze the strength of these findings, the studies were evaluated for methodological limitations with regards to participant selection, treatment design, and outcome measure selection. This analysis revealed two main methodological limitations: 1) a lack of established treatment protocol which led to differences in how and with what other techniques electrical stimulation was used and 2) an absence of follow-up measures. While these factors do not appear to affect the applicability of the study findings, future research should focus developing a treatment protocol and investigating the long-term benefits of electrical stimulation treatment. / text

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.