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Search Results: 1 - 10 of 401695 matches for " Catriona M. Steele "
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Optimal Approaches for Measuring Tongue-Pressure Functional Reserve
Catriona M. Steele
Journal of Aging Research , 2013, DOI: 10.1155/2013/542909
Optimal Approaches for Measuring Tongue-Pressure Functional Reserve
Catriona M. Steele
Journal of Aging Research , 2013, DOI: 10.1155/2013/542909
Abstract: Tongue-palate pressure is a parameter of considerable interest in the field of dysphagia. Maximum isometric tongue-palate pressures (MIPs) decline in healthy aging and in dysphagia. Functional reserve (FR) is the difference between MIPs and swallowing pressures. Reduced FR is thought to constitute a risk for developing functional swallowing impairments. We compare different approaches for calculating FR and recommend an optimal approach. Tongue-palate pressure data were collected from 78 healthy adults ( ; ) during anterior and posterior MIPs, regular (RESS) and effortful (ESS) saliva swallows, and water swallows (4 repetitions per task). Six different measures of reserve were calculated using maximum anterior MIPs or ESS pressures at the top, and mean or maximum RESS or water swallow pressures at the bottom of the range. Correlations with age and MIPs were explored to confirm suitability for measuring FR. The impact of normalization to maximum MIP range was explored. We conclude that an optimal measure of FR involves the comparison of maximum MIP with mean saliva swallowing pressures. This parameter declines with age, but when normalized to an individual’s MIP range, the relationship is no longer evident. This suggests that FR does not necessarily decline in healthy aging. 1. Introduction The ability to generate tongue-palate pressure has emerged as a measure of considerable clinical and research interest in the field of dysphagia over the past two decades. Key to this interest is that tongue strength, measured during maximum isometric tongue-palate pressure tasks (MIPs), appears to decline in healthy aging [1–6]. This has been argued to resemble sarcopenia, a degenerative loss of skeletal muscle mass and strength seen in aging in the limb musculature. Reduced tongue strength has also been observed in adults with dysphagia [7–10]. These observations have prompted research into exercise-based methods for tongue strengthening in the hope that greater tongue strength and endurance will lead to improved swallowing function [9, 11, 12]. Functional reserve is the term coined to describe the difference in pressures generated in maximum isometric pressure (MIP) tasks compared to swallowing tasks. Robbins and colleagues were the first to point out that swallowing pressures appear to be preserved in healthy older adults, even in the presence of reduced MIPs. Reductions in functional reserve, due to reductions in MIPs, were argued to have important clinical implications and to place a person at greater risk of developing functional swallowing impairments,
A Method for Removal of Low Frequency Components Associated with Head Movements from Dual-Axis Swallowing Accelerometry Signals
Ervin Sejdi?, Catriona M. Steele, Tom Chau
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033464
Abstract: Head movements can greatly affect swallowing accelerometry signals. In this paper, we implement a spline-based approach to remove low frequency components associated with these motions. Our approach was tested using both synthetic and real data. Synthetic signals were used to perform a comparative analysis of the spline-based approach with other similar techniques. Real data, obtained data from 408 healthy participants during various swallowing tasks, was used to analyze the processing accuracy with and without the spline-based head motions removal scheme. Specifically, we analyzed the segmentation accuracy and the effects of the scheme on statistical properties of these signals, as measured by the scaling analysis. The results of the numerical analysis showed that the spline-based technique achieves a superior performance in comparison to other existing techniques. Additionally, when applied to real data, we improved the accuracy of the segmentation process by achieving a 27% drop in the number of false negatives and a 30% drop in the number of false positives. Furthermore, the anthropometric trends in the statistical properties of these signals remained unaltered as shown by the scaling analysis, but the strength of statistical persistence was significantly reduced. These results clearly indicate that any future medical devices based on swallowing accelerometry signals should remove head motions from these signals in order to increase segmentation accuracy.
The effects of head movement on dual-axis cervical accelerometry signals
Ervin Sejdi?, Catriona M Steele, Tom Chau
BMC Research Notes , 2010, DOI: 10.1186/1756-0500-3-269
Abstract: Data from 50 healthy adults were collected while participants performed five different head motions. Three different spectral features were extracted from each recording: peak frequency, spectral centroid and bandwidth. Statistical analyses showed that peak frequencies are independent of the type of head motion, participant gender and age. However, spectral centroids are statistically different between the anterior-posterior (A-P) and superior-inferior (S-I) directions and between different motion. Additionally, statistically different bandwidths are observed for head tilts down and back between the A-P and the S-I directions.These differences indicate that head motions induce additional non-dominant spectral components in dual-axis cervical recordings. The results presented here suggest that head motion ought to be considered in the development of medical devices based on dual-axis cervical accelerometery signals.Patients living with the effects of stroke and patients with neurodegenerative illnesses often have swallowing difficulties (dysphagia) [1]. The videofluoroscopic swallowing study (VFSS) is the current gold standard for the detection and management of dysphagia [2]. Nevertheless, excessive exposure to ionizing radiation, long waiting lists for the radiology suite at hospitals and the lack of appropriate equipment at every hospital render VFSS infeasible for ongoing patient monitoring [3,4]. In recent years, a technique involving the attachment of an accelerometer to the patient's neck conveniently termed cervical accelerometry emerged as a supplemental approach for the noninvasive assessment of swallowing disorders [5]. Traditionally, single-axis accelerometers were used [6]. However, recent studies have shown that dual-axis accelerometers yield more information and enhance analysis capabilities [7,8], likely due to the two-dimensional movement of the hyoid and the larynx during swallowing [[9]].Head movements, either voluntary or involuntary, can severely
Improvements in tongue strength and pressure-generation precision following a tongue-pressure training protocol in older individuals with dysphagia: Three case reports
Erin M Yeates,Sonja M Molfenter,Catriona M Steele
Clinical Interventions in Aging , 2008,
Abstract: Erin M Yeates1, Sonja M Molfenter1, Catriona M Steele1,2,3,41Toronto Rehabilitation Institute, Toronto, Canada; 2Department of Speech-Language Pathology, University of Toronto, Toronto, Canada; 3Canadian Institutes of Health Research New Investigator in Aging; 4Bloorview Kids Rehab, Toronto, CanadaAbstract: Dysphagia, or difficulty swallowing, often occurs secondary to conditions such as stroke, head injury or progressive disease, many of which increase in frequency with advancing age. Sarcopenia, the gradual loss of muscle bulk and strength, can place older individuals at greater risk for dysphagia. Data are reported for three older participants in a pilot trial of a tongue-pressure training therapy. During the experimental therapy protocol, participants performed isometric strength exercises for the tongue as well as tongue pressure accuracy tasks. Biofeedback was provided using the Iowa Oral Performance Instrument (IOPI), an instrument that measures tongue pressure. Treatment outcome measures show increased isometric tongue strength, improved tongue pressure generation accuracy, improved bolus control on videofluoroscopy, and improved functional dietary intake by mouth. These preliminary results indicate that, for these three adults with dysphagia, tongue-pressure training was beneficial for improving both instrumental and functional aspects of swallowing. The experimental treatment protocol holds promise as a rehabilitative tool for various dysphagia populations.Keywords: speech-language pathology, dysphagia, rehabilitation, aging, strength, accuracy
Automatic discrimination between safe and unsafe swallowing using a reputation-based classifier
Mohammad S Nikjoo, Catriona M Steele, Ervin Sejdi?, Tom Chau
BioMedical Engineering OnLine , 2011, DOI: 10.1186/1475-925x-10-100
Abstract: In this paper, a large corpus of dual-axis accelerometric signals were collected from 30 older adults (aged 65.47 ± 13.4 years, 15 male) referred to videofluoroscopic examination on the suspicion of dysphagia. We invoked a reputation-based classifier combination to automatically categorize the dual-axis accelerometric signals into safe and unsafe swallows, as labeled via videofluoroscopic review. From these participants, a total of 224 swallowing samples were obtained, 164 of which were labeled as unsafe swallows (swallows where the bolus entered the airway) and 60 as safe swallows. Three separate support vector machine (SVM) classifiers and eight different features were selected for classification.With selected time, frequency and information theoretic features, the reputation-based algorithm distinguished between safe and unsafe swallowing with promising accuracy (80.48 ± 5.0%), high sensitivity (97.1 ± 2%) and modest specificity (64 ± 8.8%). Interpretation of the most discriminatory features revealed that in general, unsafe swallows had lower mean vibration amplitude and faster autocorrelation decay, suggestive of decreased hyoid excursion and compromised coordination, respectively. Further, owing to its performance-based weighting of component classifiers, the static reputation-based algorithm outperformed the democratic majority voting algorithm on this clinical data set.Given its computational efficiency and high sensitivity, reputation-based classification of dual-axis accelerometry ought to be considered in future developments of a point-of-care swallow assessment where clinical informatics are desired.Dysphagia refers to any swallowing disorder [1] and may arise secondary to stroke, multiple sclerosis, and eosinophilic esophagitis, among many other conditions [2]. If unmanaged, dysphagia may lead to aspiration pneumonia in which food and liquid enter the airway and into lungs [3]. The video-fluoroscopic swallowing study (VFSS) is the gold standard method fo
Effects of liquid stimuli on dual-axis swallowing accelerometry signals in a healthy population
Joon Lee, Ervin Sejdi?, Catriona M Steele, Tom Chau
BioMedical Engineering OnLine , 2010, DOI: 10.1186/1475-925x-9-7
Abstract: Significant main stimulus effects were found on 6 out of 30 features for the discrete task and on 5 out of 30 features for the sequential task. Analysis of the features with significant stimulus effects suggested that the changes in the signals revealed slower and more pronounced swallowing patterns with increasing bolus viscosity.We conclude that stimulus type does affect specific characteristics of dual-axis swallowing accelerometry signals, suggesting that associated clinical screening protocols may need to be stimulus specific.Dysphagia refers in general to swallowing disorders [1], and is a common consequence of neurological conditions such as stroke, cerebral palsy, or Parkinson's disease [2]. Adverse effects of dysphagia include degraded psycho-social well-being [3], dehydration and malnutrition [4,5], and compromised immune system secondary to malnutrition [4]. Furthermore, dysphagia can jeopardize airway protection during pharyngeal swallowing, heightening the risk of entry of foreign material into the unprotected airway during swallowing (aspiration), which may lead to aspiration pneumonia [6]. Devastating outcomes of aspiration pneumonia range from hospitalization to death [7]. The current gold standard in dysphagia assessment is the videofluoroscopic swallowing study (VFSS) [1,8]. In this imaging technique, X-ray video of the pharyngeal region is recorded while the patient swallows food or liquid stimuli mixed with barium. The primary objectives of VFSS are to determine the nature and severity of dysphagia and to devise appropriate intervention techniques. Many smaller healthcare institutions are unable to provide VFSS, resulting in long wait times for patients with dysphagia [9]. In addition, VFSS is neither practical nor feasible for long-term or day-to-day monitoring of dysphagia.Recognizing the limitations of VFSS access, several alternative techniques have been investigated. Examples include pulse oximetry [10], cervical auscultation [11], and elect
Extraction of average neck flexion angle during swallowing in neutral and chin-tuck positions
Delbert Hung, Ervin Sejdi?, Catriona M Steele, Tom Chau
BioMedical Engineering OnLine , 2009, DOI: 10.1186/1475-925x-8-25
Abstract: To facilitate the study of chin tuck angle variations, we present a template tracking algorithm that automatically extracts neck angles from sagittal videos of individuals performing chin tuck swallows. Three yellow markers geometrically arranged on a pair of dark visors were used as tracking cues.The algorithm was applied to data collected from 178 healthy participants during neutral and chin tuck position swallows. Our analyses revealed no major influences of body mass index and age on neck flexion angles during swallowing, while gender influenced the average neck angle only during wet swallows in the neutral position. Chin tuck angles seem to be independent of anthropometry and gender in healthy adults, but deserve further study in pathological populations.The proposed neck flexion angle extraction algorithm may be useful in future studies where strict participant compliance to swallowing task protocol can be assured.Dysphagia is the umbrella term used to describe a large range of swallowing difficulties. Most of these difficulties arise from insults to motor or sensory pathways to the brain, which can be the result of congenital neurological conditions [1] or acute stroke [2]. In addition to neurogenic origins, dysphagia can also arise from anatomical abnormalities or physical damage to the structures involved in swallowing, for example, following tumor resectioning in the pharyngeal compartment [3].Dysphagia in symptomatic patients almost always involves impairment of swallowing during the oral or pharyngeal phases [4]. Patients with oral phase dysphagia often complain of difficulties handling the bolus in the oral cavity, indicative of neurological deficiencies in voluntary control of the tongue or jaw. However, these patients often succeed in swallows if the pharyngeal stage can be triggered using compensatory maneuvers. The symptoms and causes of pharyngeal dysphagia are more varied due to the high involvement of involuntary constrictor muscles in the proces
Pressure profile similarities between tongue resistance training tasks and liquid swallows
Catriona M. Steele, PhD,Gemma L. Bailey, MHSc,Sonja M. Molfenter, MHSc,Erin M. Yeates, MHSc
Journal of Rehabilitation Research and Development , 2010,
Abstract: Tongue-pressure resistance training is known to increase tongue strength in seniors and individuals with stroke-related dysphagia. However, evidence of associated functional improvements in swallowing is equivocal. We investigated similarities in pressure waveform profiles between swallowing and several tongue-palate pressure tasks to identify tasks that may be best suited for inclusion in tongue-pressure resistance training protocols for patients who are unable to safely perform real bolus swallows in treatment. Tongue-palate pressures were recorded in 20 healthy young adults. Participants performed water and nectar-thick juice swallows, effortful and noneffortful saliva swallows, and "half-maximum" tongue-palate partial-pressure tasks emphasizing either anterior or posterior tongue-palate contact at different speeds. Pressure slopes (amplitude change over time) during the pressure application (rise) and withdrawal (release) phases were analyzed. A subset of four tasks with the greatest similarity in slope characteristics to those seen in bolus swallows was identified: anterior-emphasis half-maximum tongue-palate presses, posterior-emphasis maximum isometric tongue-palate presses, posterior-emphasis half-maximum slow tongue-palate presses, and effortful saliva swallows. We propose that future research should explore the degree to which swallowing improvements are obtained from treatment protocols that emphasize these tasks.
Time-Frequency Analysis and Hermite Projection Method Applied to Swallowing Accelerometry Signals
Irena Orović,Srdjan Stanković,Tom Chau,Catriona M. Steele
EURASIP Journal on Advances in Signal Processing , 2010, DOI: 10.1155/2010/323125
Abstract: Fast Hermite projections have been often used in image-processing procedures such as image database retrieval, projection filtering, and texture analysis. In this paper, we propose an innovative approach for the analysis of one-dimensional biomedical signals that combines the Hermite projection method with time-frequency analysis. In particular, we propose a two-step approach to characterize vibrations of various origins in swallowing accelerometry signals. First, by using time-frequency analysis we obtain the energy distribution of signal frequency content in time. Second, by using fast Hermite projections we characterize whether the analyzed time-frequency regions are associated with swallowing or other phenomena (vocalization, noise, bursts, etc.). The numerical analysis of the proposed scheme clearly shows that by using a few Hermite functions, vibrations of various origins are distinguishable. These results will be the basis for further analysis of swallowing accelerometry to detect swallowing difficulties.
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