Isaac Sia

Spontaneous Swallowing Frequency Has Potential to Identify Dysphagia in Acute Stroke

Background and Purpose— Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke. Methods— In a cohort of 63 acute stroke cases, swallow frequency rates (swallows per minute [SPM]) were compared with stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with versus without clinically significant dysphagia. Receiver operating characteristic curve analysis was used to identify the optimal threshold in SPM, which was compared with a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was used to identify the minimally adequate time period to complete spontaneous swallow frequency analysis. Results— SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. Receiver operating characteristic curve analysis yielded a threshold of SPM⩽0.40 that identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5- to 10-minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke. Conclusions— Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel.

Normalization of temporal aspects of swallowing physiology after the McNeill dysphagia therapy program.

Objectives We examined the timing of physiological swallowing events in patients before and after completion of an exercise-based dysphagia intervention (McNeill Dysphagia Therapy Program; MDTP) and compared their performance to that of healthy volunteers. Methods Eight adults (mean age, 57.5 years) with chronic dysphagia (mean, 45 months) completed 3 weeks of the MDTP. Before and after the MDTP we measured lingual-palatal and pharyngeal manometric pressures during swallows of thin liquid, thick liquid, and pudding material in 5-mL volumes. Using the pressure peak of the pharyngoesophageal segment clearing wave as the anchor point, we measured the relative timing of pressure peaks from the anterior, middle, and posterior parts of the tongue and the manometric peaks from the base of the tongue, the hypopharynx, and the nadir of the pharyngoesophageal segment. We compared these results to identical measures obtained from 34 healthy adults (mean age, 44.0 years). Results The timing of physiological events before the MDTP was significantly slower than that of the group of healthy volunteers. The timing data from after the MDTP were not significantly different from those of the healthy group. The magnitude change was greatest for thin liquid. Conclusions Dysphagia therapy with the MDTP improves the timing of physiological events during swallowing. Temporal coordination of swallowing components after therapy approximates that of healthy adults, suggesting a normalization of swallow timing after the MDTP.

The synergistic effect of functional status and comorbidity burden on mortality: a 16-year survival analysis.

Objectives The relationship between disability and comorbidity on mortality is widely perceived as additive in clinical models of frailty. Design National data were retrospectively extracted from medical records of community hospital. Data Sources There were of 12,804 acutely-disabled patients admitted for inpatient rehabilitation in Singapore rehabilitation community hospitals from 1996 through 2005 were followed up for death till 31 December 2011. Outcome Measure Cox proportional-hazards regression to assess the interaction of comorbidity and disability at discharge on all-cause mortality. Results During a median follow-up of 10.9 years, there were 8,565 deaths (66.9%). The mean age was 73.0 (standard deviation: 11.5) years. Independent risk factors of mortality were higher comorbidity (p<0.001), severity of disability at discharge (p<0.001), being widowed (adjusted hazard ratio [aHR]: 1.38, 95% confidence interval [CI]:1.25–1.53), low socioeconomic status (aHR:1.40, 95%CI:1.29–1.53), discharge to nursing home (aHR:1.14, 95%CI:1.05–1.22) and re-admission into acute care (aHR:1.54, 95%CI:1.45–1.65). In the main effects model, those with high comorbidity had an aHR = 2.41 (95%CI:2.13–2.72) whereas those with total disability had an aHR = 2.28 (95%CI:2.12–2.46). In the interaction model, synergistic interaction existed between comorbidity and disability (p<0.001) where those with high comorbidity and total disability had much higher aHR = 6.57 (95%CI:5.15–8.37). Conclusions Patients with greater comorbidity and disability at discharge, discharge to nursing home or re-admission into acute care, lower socioeconomic status and being widowed had higher mortality risk. Our results identified predictive variables of mortality that map well onto the frailty cascade model. Increasing comorbidity and disability interacted synergistically to increase mortality risk.

Immediate effects of transcutaneous electrical stimulation on physiological swallowing effort in older versus young adults

OBJECTIVE This study compared the immediate impact of different transcutaneous electrical stimulation (TES) amplitudes on physiological swallowing effort in healthy older adults versus young adults. BACKGROUND Swallowing physiology changes with age. Reduced physiological swallowing effort in older adults including lower lingua-palatal and pharyngeal pressures may increase risk for swallowing dysfunction (i.e. dysphagia). Transcutaneous electrical stimulation (TES) has been advocated as an adjunctive modality to enhance outcomes in exercise-based therapy for individuals with dysphagia. However, significant variation in how TES is applied during therapy remains and the physiological swallowing response to TES is poorly studied, especially in older adults. MATERIALS AND METHODS Physiological change in swallowing associated with no stimulation, sensory stimulation and motor stimulation was compared in 20 young adults versus 14 older adults. Lingua-palatal and pharyngeal manometric pressures assessed physiological swallowing effort. RESULTS Multivariate analyses identified interactions between age and stimulation amplitude on lingual and pharyngeal functions. Motor stimulation reduced anterior tongue pressure in both age groups but selectively reduced posterior lingua-palatal pressures in young adults only. Sensory stimulation increased base of tongue (BOT) pressures in older adults but decreased BOT pressures in young adults. Motor stimulation increased hypopharyngeal pressures in both groups. CONCLUSION Age and TES level interact in determining immediate physiological responses on swallow performance. A one-size-fit-all approach to TES in dysphagia rehabilitation may be misdirected.

Hyoid and laryngeal excursion kinematics - magnitude, duration and velocity - changes following successful exercise-based dysphagia rehabilitation: MDTP.

Variability in magnitude of deglutitional hyolaryngeal excursion in patients with dysphagia suggests that it does not adequately represent the kinematics of swallowing difficulties or recovery following rehabilitation. On the other hand, reduced hyolaryngeal excursion velocity has been reported in patients with dysphagia. While increased movement velocity often accompanies clinical and functional recovery in many diseases, velocity changes in swallowing-related movement following dysphagia therapy have not been well studied. This study evaluated changes in hyoid and laryngeal excursion (magnitude, duration and velocity) before and following successful dysphagia therapy to provide a more comprehensive representation of improvement to swallowing kinematics in patients who have experienced successful rehabilitation. A secondary analysis of case series data was completed. Eight patients with severe, chronic dysphagia completed a standard course of an exercise-based dysphagia treatment programme (McNeill dysphagia therapy program, MDTP). Pre- and post-treatment, kinematic aspects of swallowing were evaluated for thin liquid, thick liquid and pudding swallows. Maximum hyoid and laryngeal excursion magnitude and excursion duration were measured. Excursion velocities were calculated from excursion magnitude and duration measures. Successful treatment for dysphagia facilitated increased hyolaryngeal excursion magnitude, duration and velocity. These changes were most prominent for the hyoid and most often observed with thin liquids. By examining hyoid and laryngeal excursion velocity in patients who have experienced successful dysphagia rehabilitation, this study demonstrated the value of evaluating spatial and temporal aspects of swallowing kinematics in a single measure for a more comprehensive representation of positive changes underlying functional recovery.

Virtual Agent Constructionism: Experiences from Health Professions Students Creating Virtual Conversational Agent Representations of Patients

This paper reports on applying constructionism with virtual agents in an educational setting. We introduce a methodology - Virtual Agent Constructionism, which involves health professions students creating virtual conversational agent representations of patients as part of coursework. The proposed methodology was implemented as an exercise in an educational course for three consecutive academic years. The aim of this paper is threefold - (i) to demonstrate feasibility of health professions students creating virtual agents in an educational setting as part of coursework, (ii) to report feedback from the students about the experience of creating virtual agents, and (iii) to report on initial trends that suggest that creating virtual agents helps health professions students improve their interviewing and interpersonal skills. In addition to these three innovations, we also present the virtual agents created as educational artifacts that can be used to train future students with their interpersonal skills.

Exploring the Effects of Healthcare Students Creating Virtual Patients for Empathy Training

Intelligent virtual agents have been successfully used for interpersonal skills training of healthcare students by enabling simulated interactions between healthcare students and virtual patient agents. However, during these interactions, students do not get the opportunity to take the perspective of the patient. Taking the perspective of the patient is essential for healthcare students to learn critical interpersonal skills like empathy. We propose having healthcare students create virtual patient agents of a particular race to provide them the opportunity to take the perspective of patients from that race, leading to increased empathy during subsequent interactions with patients of that race. We conducted a semester-long user study with 24 healthcare students to explore the effects of having them create virtual patient agents. Results indicate that healthcare students who created and interviewed virtual patients of the same race were significantly more empathetic than students who created virtual patients with a race discordant to the one they interacted with.

Spontaneous Swallow Frequency Compared with Clinical Screening in the Identification of Dysphagia in Acute Stroke

BACKGROUND The aim of this study was to compare spontaneous swallow frequency analysis (SFA) with clinical screening protocols for identification of dysphagia in acute stroke. METHODS In all, 62 patients with acute stroke were evaluated for spontaneous swallow frequency rates using a validated acoustic analysis technique. Independent of SFA, these same patients received a routine nurse-administered clinical dysphagia screening as part of standard stroke care. Both screening tools were compared against a validated clinical assessment of dysphagia for acute stroke. In addition, psychometric properties of SFA were compared against published, validated clinical screening protocols. RESULTS Spontaneous SFA differentiates patients with versus without dysphagia after acute stroke. Using a previously identified cut point based on swallows per minute, spontaneous SFA demonstrated superior ability to identify dysphagia cases compared with a nurse-administered clinical screening tool. In addition, spontaneous SFA demonstrated equal or superior psychometric properties to 4 validated, published clinical dysphagia screening tools. CONCLUSIONS Spontaneous SFA has high potential to identify dysphagia in acute stroke with psychometric properties equal or superior to clinical screening protocols.

Derivation and measurement consistency of a novel biofluid dynamics measure of deglutitive bolus-driving function-pharyngeal swallowing power

The primary function of the pharyngeal swallowing mechanism is to drive ingested materials into the esophagus. Currently, a definitive measure of pharyngeal bolus‐driving function that accounts for bolus movement remains lacking. The primary objectives of this study were to describe the derivation of a novel biofluid dynamics measure of deglutition—that is, pharyngeal swallowing power (PSP)—and to demonstrate the consistency of PSP in normal swallowing.

Bolus volume and viscosity effects on pharyngeal swallowing power-How physiological bolus accommodation affects bolus dynamics

Pharyngeal swallowing power (PSP) is a novel measure of pharyngeal bolus‐driving function derived from fluid dynamics principles. This study examined the impact of bolus volume and viscosity on PSP to determine bolus effects on pharyngeal bolus dynamics. The impact of bolus accommodation and physical characteristics of boluses were also explored.