Slow-Stream Expiratory Muscle Strength Training for Veterans With Dysphagia Living in Long-term Care

Sunnybrook Veterans Centre (VC) is a long-term care (LTC) facility with many elderly residents living with swallowing disorders who are at high risk of developing pneumonia from aspirating food/liquid into their lungs. Expiratory muscle strength training (EMST) using a hand-held resistance device over a four week intensive program has been shown to have promising results in improving cough function and reducing aspiration during swallowing in older, community-dwelling adults. The purpose of this study is to explore whether a modified slow-stream protocol of EMST over eight weeks is an effective therapy for improving swallowing safety and lung clearance in elderly VC residents with swallowing disorders. Before and after the eight week therapy program, we will measure participants' cough under spirometry, swallowing under videofluoroscopy, and their swallowing-related quality of life and diet texture modification. A three month follow-up visit will measure swallowing-related quality of life again, as well as record incidence of respiratory tract infections requiring antibiotics in the last three months, to be compared with broader institutional data.

This study will take place in Sunnybrook Veterans Centre (VC), a long-term care facility (LTC) with many residents above the age of 85 years living with dysphagia. These residents with dysphagia are at high risk of respiratory tract infections from aspiration of food/liquid particles into the lungs, exacerbated by factors like increased dependence for feeding and oral care, decreased mobility, multiple medical comorbidities, polypharmacy, and increased frailty. Expiratory muscle strength training (EMST) applied within a four-week intensive program (25 sets/week) has had promising results in improving cough function and reducing laryngeal penetration/aspiration (P/A) during swallowing in community-dwelling adults above the age of 65 years. The EMST150 is a handheld device with adjustable resistance that trains respiratory muscles used in exhalation. One set is defined as five exhales through the device set at a resistance level of 75% of an individual's maximum load, with a one minute break between breaths. The intensive four week EMST program outlined in previous literature was appropriate for the active, community-dwelling population they were studying. However, it would not be appropriate for most of the residents in the VC due to the extreme age, multiple medical comorbidities, increased frailty, and decreased functional independence in this population. An important aim of this study is to promote success by creating a protocol that fits into the average resident's schedule in a feasible way, but also has a similar number of total breaths through the device, in order to achieve clinical results. Resident perspective was sought from the Residents' Council executive and meeting attendees, and the final protocol was approved in a Residents' Council meeting. Participants would continue doing their usual therapies and activities with the EMST protocol being an add-on to that. The purpose of this study is to explore whether a modified, slow-stream EMST protocol of 12 sets/week over eight weeks is an effective therapy for improving pulmonary clearance and swallowing safety in LTC residents above the age of 85 years who have dysphagia. Primary outcomes will be assessed through a pre-post analysis of voluntary cough strength measured using spirometry, as well as laryngeal P/A measured under videofluoroscopy. Secondary outcome of swallowing-related quality of life will be measured using Dysphagia Handicap Index - Emotional scale and the International Dysphagia Diet Standardization Initiative Functional Diet Scale pre and post intervention, as well as at a 3 month follow-up. Incidence of respiratory tract infections requiring antibiotics in the three months post-intervention will be measured and compared with broader institutional data.

EMST, RMST, Expiratory Muscle Strength Training, Respiratory Muscle Strength Training, Videofluoroscopy, Aspiration Pneumonia, Rehabilitation, Dysphagia, Cough, Geriatric, Aging, Older Adults

This study will use an exploratory, cross sectional study design for the pre-post analysis of voluntary cough, measured through spirometry, laryngeal penetration/aspiration during swallow with thin liquids, measured under videofluoroscopy, and dysphagia-related quality of life, measured via questionnaire and diet texture modification scale. There is no control group; all participants will receive the same slow-stream expiratory muscle strength training protocol.

The therapy protocol consists of 12 sets of five breaths through the EMST150 device per week, in sessions of three or four sets (15 or 20 breaths). A typical schedule might be one 15 breath session four days per week, or one 20 breath session three days per week.

All participants will receive an initial visit for training on the therapy protocol, use of a weekly therapy log to track breaths, and use and maintenance of the EMST device. This will constitute the first EMST session and will be included in the therapy log as Week 1, Day 1. Each participant will have a minimum of seven weekly check-in visits from the research assistant and/or a member of the research team, where the EMST150 resistance will be recorded and adjusted to maintain training at 75% of their maximum load, as measured using the EMST150 device instruction manual. During these check-in visits, participants will provide their completed weekly therapy log and receive a new log.

Change in maximum voluntary cough strength pre and post intervention as measured through airflow analysis of digital cough waveform. The digital waveform will provide measures of inspiratory phase duration (seconds), compression phase duration (seconds), expiratory rise time (seconds), and expiratory peak flow (Litres/second), and cough volume acceleration (Litres/second squared) will be calculated as expiratory peak flow/expiratory phase rise time, as in Pitts et al., 2019, to represent cough strength. The protocol will consist of three voluntary coughs into a spirometer using a nose-clip, with a brief rest of 30-60 seconds between attempts. The best effort will be used to generate a digital cough waveform to be analyzed separately by two trained raters consisting of members of the research team or research assistant. Any disagreements between raters will be resolved through consensus with a third rater.

Change in frequency of laryngeal penetration (PAS scores >2) and aspiration (PAS scores >5) on swallows of thin liquid pre and post intervention. Videofluoroscopy (VFSS) protocol of four 10 mL thin liquid consisting of 20% w/v concentration of barium (Polibar Plus) and water, performed by the speech-language pathologist (SLP). Video processing will include removing audio, splicing the recordings into deidentified bolus-length clips, and randomizing these for rating. These clips will be rated using the Penetration Aspiration Scale by three SLPs who will attend calibration training at the Swallowing Rehabilitation Research Laboratory at Toronto Rehabilitation Institute. Raters will be blinded to participant and time. All raters will overlap on the first 25 clips, from which inter-rater reliability measures will be taken, and with any disagreements being resolved through consensus. The remaining clips will be divided among the three raters.

Change in swallowing-related quality of life. The DysHI-E consists of seven questions answered using a 3-point scale of Never, Sometimes, and Always, and a 7-point severity scale ranging from 1-normal to 7-severe problem (Silbergleit et al., 2012). This will be converted into a visual analogue scale and responses will be measured in centimeters from left to right, with the far left end being Never or 0.00 cm, and the far right end being Always or 30.00 cm.

Change in the level of diet texture restriction secondary to dysphagia. The IDDSI-FDS measures the number of diet texture levels allowed from the International Dysphagia Diet Standardization Initiative Framework.

Incidence of respiratory tract infections requiring antibiotics over the three months following intervention, for comparison with broader institutional data.

Inclusion Criteria: Fluent in the English language Identified by their speech-language pathologist as at risk for laryngeal penetration/aspiration when drinking thin liquids A Penetration Aspiration Scale score of 3+ on at least one thin liquid bolus during pre-test videofluoroscopy, as rated live at the time of test by the speech-language pathologist conducting the videofluoroscopy. Cognitively and physically able to perform study tasks (spirometry, EMST). If assistance and/or cuing is required, the participant must have a support team who is agreeable to providing this for the duration of the study at time of consent. Support teams may consist of any combination of family, friends, private companions, and VC staff. Medical clearance by the participant's most responsible physician (MRP) Exclusion Criteria: At time of consent General medical exclusions: Any history of hernia, pneumothorax, perforated tympanic membrane, recent surgery, untreated gastroesophageal reflux disease or untreated hypertension. Other medical conditions where increased intrathoracic pressure would be contraindicated, on an individual basis, as per participant's MRP Cognitively and/or physically unable to perform study tasks, despite support Participants who do not consent to videofluoroscopy or for whom videofluoroscopy is contraindicated After time of consent Participants who score PAS < 3 on pre-test videofluoroscopy Inability to complete pre-post testing for at least one primary outcome Inability to complete minimum 50 breaths of the weekly protocol, and minimum 400 total breaths through the device over the 8 week program

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