The patent's assignee is
News editors obtained the following quote from the background information supplied by the inventors: "Dysphagia is a serious component of many neurological diseases and injuries. The incidence of dysphagia following stroke has been reported to be 37-78% across studies, with aspiration incidence estimated at 43-54% in those with dysphagia. One systematic review has concluded that stroke patients who aspirate face 11.56 times the risk of developing pneumonia, compared to those without dysphagia. Patients who are aspirate, have been shown to be 10 times more likely (p
"Aspiration, generally understood as the entry of foreign contents into the upper airway, is a serious concern for individuals with swallowing difficulty (dysphagia), and can lead to pneumonia, for example. For instance, prandial aspiration, or the entry of foreign material into the upper airway during swallowing, is a serious component of dysphagia.
"Using known and particularly invasive techniques, such as videofluoroscopic swallowing examinations, aspiration severity may be sub-classified based on the observed depth of airway invasion. For example, transient entry of material into the laryngeal vestibule, above the vocal cords, is termed high penetration (or a score of 2 on the 8-point Penetration Aspiration Scale); scores of 3-5, termed penetration, apply when material enters the laryngeal vestibule without subsequent clearance, and aspiration is the term used when material crosses the vocal cords and enters the trachea (scores of 6-8). A major dilemma for the detection of aspiration is the fact that overt clinical signs (e.g., cough or throat clearing) are reportedly absent up to 67% of the time; this is called 'silent aspiration'. The risk of developing pneumonia has been found to be 4, 10, and 13 times greater, respectively, in patients with penetration, aspiration, or silent aspiration on videofluoroscopy, compared to individuals with normal swallowing. Evidence-based best practice guidelines concur that screening protocols should be used to facilitate the prompt identification and management of aspiration risk in high-risk populations, such as stroke patients; however, currently implemented protocols to this end often fail to provide satisfactory results, or again, achieve reasonable results at the expense of requiring the application of relatively invasive procedures.
"In addition to aspiration, swallowing inefficiency is a major concern in individuals with dysphagia. Swallowing inefficiency is defined as the inability to swallow the contents of a single bolus (or mouthful) in a maximum of 2 swallows. This frequently leads to the presence of residual material being left behind in the throat (pharynx) after the swallow. The presence of this leftover material is, in turn, a risk for aspiration.
"The main goals of a swallow screening protocol are generally two-fold: 1) to identify risk of impaired swallowing safety, i.e. penetration (entry of material into the airway above the level of the vocal cords) and/or aspiration (entry of material into the airway below the level of the vocal cords); and 2) to identify risk of impaired swallowing efficiency, characterized either by the presence of residues in the pharynx after the swallow, and/or prolonged transit times for moving a bolus in entirety from the mouth into the esophagus. To date, the principal emphasis in health policy calls for swallow screening has been on the first of these goals, that is the identification of penetration and/or aspiration risk (henceforth, 'P-A risk'). When patients are identified to have either dysphagia or P-A risk through screening, they are generally referred for comprehensive swallowing assessment.
"Unfortunately, the clinical identification of impaired swallowing safety and efficiency related to dysphagia is not particularly straightforward. Under usual circumstances, healthy awake people will swallow reflexively when material penetrates the airway above the vocal cords, and will cough when this material is aspirated below the vocal cords. Current P-A risk screening tools rely heavily on the recognition of overt clinical signs that imply possible aspiration: coughing, throat clearing, changes in respiratory rate, and changes in voice quality. In those with neurologic injury, however, overt clinical signs are frequently absent or volume-dependent. As noted above, silent aspiration is reported to occur in 25%-67% of acute stroke patients, and in 28% of patients overall, according to some studies. The variable expression of overt clinical signs of impaired swallowing safety in patients with neurogenic dysphagia contributes to limited success in P-A risk detection through clinical screening, and means that screeners must be trained to be alert for signs that are subtle. Similarly, post-swallow residues, related to swallowing inefficiency, are not reliably detectable at the bedside based on the observation of clinical signs, or based on asking patients whether they feel material sticking in their throats.
"For example, current clinical approaches to non-invasive screening for aspiration typically involve the swallowing of water. The clinician notes signs of difficulty, including cough, post-swallow throat clearing, or voice changes that might imply the presence of liquid around the vocal cords. However, studies differ in their conclusions regarding the validity of abnormal clinical signs for revealing aspiration, compared to blinded ratings of instrumental assessments, and screening protocols involving sips of water tend to over-identify aspiration risk with false-positive rates as high as 72%.
"Furthermore, current approaches to screening frequently rely on nurses to administer/conduct screening protocols. One widely-promoted clinical screening protocol (the Tor-BSST) has an accompanying training package, which involves initial training of 8 hours for a lead clinician/champion/trainer who then delivers training of 4 hours for individuals who will administer the screening protocol. However, institutional barriers have been reported to prevent implementation of screening guidelines, even after such extensive training. Given the turnover of nursing staff, a strong institutional commitment to continuing skills training and credentialing is required on a long-term basis.
"Given the variable performance of swallow screenings for detecting aspiration, and the burden that this approach involves for training and competency-maintenance, a need exists for a valid non-invasive instrumental method to reliably detect impaired swallowing safety and efficiency, for example in a clinical setting or at the bedside. While the appraisal of swallowing sounds or vibrations has been proposed as a candidate method, available studies have heretofore been unsuccessful at attaining valid identification of aspiration. Accordingly, valid, reliable tools for detecting aspiration and other related swallowing impairments are needed that overcome the variable predictive utility of known clinical screening protocols and/or reduce the substantial burden on nursing staff imposed by the implementation of such protocols.
"Therefore, there remains a need for a method and device for swallowing impairment detection that overcomes some of the drawbacks of known techniques, or at least, provides a useful alternative.
"This background information is provided to reveal information believed by the applicant to be of possible relevance to the invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the invention."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An object of the invention is to provide a method and device for swallowing impairment detection. In accordance with one embodiment, there is provided a device for use in identifying a possible swallowing impairment in a candidate during execution of a swallowing event, the device comprising: a dual axis accelerometer to be positioned in a region of the candidate's throat and configured to acquire axis-specific vibrational data representative of the swallowing event; a processing module operatively coupled to said accelerometer for processing said axis-specific data to extract therefrom, for each axis, one or more features representative of the swallowing event, and classify said vibrational data as indicative of one of normal swallowing and possibly impaired swallowing based on said extracted features.
"In accordance with another embodiment of the invention, there is provided a method for classifying cervical dual-axis accelerometry data acquired in respect of a candidate swallowing event to identify a possible swallowing impairment, comprising: receiving as input axis-specific vibrational data representative of the swallowing event; extracting one or more preset features representative of the swallowing event for each axis of said axis-specific vibrational data; comparing said extracted features with preset classification criteria defined as a function of said preset features; and outputting, based on said comparing step, classification of said vibrational data as indicative of one of normal swallowing and possibly impaired swallowing.
"In accordance with another embodiment of the invention, there is provided a computer readable-medium having statements and instructions stored thereon for implementation by a processor to automatically implement the above method.
"In accordance with another embodiment of the invention, there is provided a method for identifying a possible swallowing impairment in a candidate via execution of one or more preset swallowing events, comprising: recording dual-axis vibrational data representative of said one or more swallowing events; extracting one or more swallowing-event specific features for each axis of said dual-axis vibrational data; and classifying said extracted features as indicative of one of normal swallowing and possibly impaired swallowing.
"Other aims, objects, advantages and features of the invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
"Several embodiments of the present disclosure will be provided, by way of examples only, with reference to the appended drawings, wherein:
"FIG. 1 is a schematic diagram of a swallowing impairment screening device in operation, in accordance with one embodiment of the invention;
"FIG. 2 is a schematic diagram of a swallowing impairment detection device, and components thereof, in accordance with one embodiment of the invention;
"FIG. 3 is a high level dual axis accelerometry data processing flow diagram for implementation by a swallowing impairment detection device, in accordance with one embodiment of the invention;
"FIG. 4 is an illustrative dual axis accelerometry data processing flow diagram, showing optional steps in dashed-line boxes, for implementation by a swallowing impairment detection device, in accordance with one embodiment of the invention;
"FIG. 5A is a detailed dual axis accelerometry data processing flow diagram for implementation by a swallowing impairment detection device, in accordance with one embodiment of the invention;
"FIG. 5B is a detailed dual axis accelerometry data processing flow diagram for implementation by a swallowing impairment detection device in screening for both swallowing safety and efficiency, in accordance with one embodiment of the invention;
"FIG. 6 is a flow chart of a candidate screening and testing protocol for implementation using a swallowing impairment screening device, in accordance with one embodiment of the invention;
"FIG. 7 is a table of performance results (detection of impaired swallowing safety and the combination of impaired swallowing safety with impaired swallowing efficiency) achieved in accordance with one embodiment of the invention;
"FIG. 8 is a table of further aspiration-detection performance results, in accordance with the embodiment of FIG. 7; and
"FIG. 9 is a graphical representation of a classification of a training data set, for use in subsequent classifications of test swallowing events as indicative of a healthy swallowing event vs. a possible aspiration event, in accordance with one embodiment of the invention."
For additional information on this patent application, see: Chau,
Keywords for this news article include: Legal Issues, Information Technology, Information and Data Processing,
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