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We swallow about 600 times a day, mostly without thinking about it. But swallowing involves dozens of muscles and nerves in the mouth, throat and esophagus, and for people who struggle with the process, the results can be devastating.

Malnutrition, dehydration and social isolation are common in people with swallowing trouble. So is depression and aspiration of food that leads to pneumonia. Occasionally, swallowing issues cause choking and sudden death. And a recent U.S. study of hospitalized patients with serious illnesses found that more than half said needing a feeding tube to live was a state equal to or worse than death.

Many conditions can cause swallowing problems: stroke, neurodegenerative diseases such as Parkinson’s, and congenital or developmental conditions such as cerebral palsy and cleft palate. People treated for head and neck cancer often develop problems, sometimes years later; and their numbers are growing as cancer survival rates improve. Estimates on the global prevalence of swallowing disorders, which collectively are known as dysphagia, are about eight per cent – almost 600 million people.

But there is good news. Before 1980, most patients with complex dysphagia got feeding tubes; today, clinicians can offer videofluoroscopy and other bedside tests to better assess swallowing problems, and less invasive therapies that emphasize exercise and posture.

And at the University of Toronto, scientists in the and related fields are starting to answer long-standing questions such as how best to give dysphagia screening tests, which interventions work well for specific conditions, and how to create global standards to talk about and address swallowing issues.

Through research, we may be entering a new era in dysphagia care.

Which approach is better?

More than two-thirds of head and neck cancer patients need a feeding tube for several months, after radiotherapy. They typically get therapy from a speech language pathologist before swallowing problems begin or once symptoms arise. Both methods provide benefits, but the extent of the benefits from each approach is unclear.

Professor Rosemary Martino and her colleagues just launched a study that will provide answers. The US$8.5 million   will enrol 1,000 patients over five years in Toronto and six other cities across North America.

“The stuation now is what we call clinical equipoise,” says Martino, a professor in the department of speech-language pathology who holds a Canada Research Chair in swallowing disorders. “Both treatment approaches work but we don’t know which is better, and so we can’t know where to invest the most resources. We also know the clinical community is mixed in what they offer patients; this study will hopefully resolve those uncertainties once and for all.”

The researchers will track patients who get both proactive and reactive therapy, then measure and compare their ability to eat and swallow along with other health outcomes up to one year after radiotherapy. They will also parse the effects of each approach in different groups of patients and compare the effectiveness of low- and high-intensity proactive interventions. (Low-intensity therapy is pragmatic, with a focus on exercising oral musculature during meal times and some snacks; high-intensity therapy includes additional exercises between meals.)

“Intensity is both a resource and patient burden issue,” says Martino, whose lab is based at ����TV and the in University Health Network. “We know patient adherence to exercise therapy is often low, so we need to make sure we don’t overprescribe and raise the risk that they do nothing. And with better evidence, we can let patients know exactly how much better their swallow will be if they comply.”

The study will engage patients and families, clinicians and policy makers at several points, toward ensuring that new findings are practical and available to patients right away. Study researchers will also use new health informatics and quantitative imaging technology to establish the first international database to compare the effectiveness of swallowing interventions relative to radiation targets and doses. The database, housed by Martino and her team at University Health Network, will support trials to further guide therapy and help preserve the swallowing ability of patients.

A quick and effective screening test

Almost 60 per cent of acute stroke patients have some swallowing impairment. Stroke patients with dysphagia are three times more likely to get pneumonia, and for those with severe dysphagia, the risk of pneumonia is 11 times higher.

Globally, there is a pressing need for a quick and reliable bedside screening tool that can tell clinicians if a stroke patient has dysphagia: Early identification of swallowing problems allows for earlier intervention, which reduces the risk for pneumonia, malnutrition and death while speeding patient recovery and limiting health-care costs.

In the early 2000s, Martino’s lab developed a screening test called the Toronto Bedside Swallowing Screening Test (TOR-BSST), a simple one-page tool that only takes 10 minutes to administer and that allows clinicians to determine if a patient has a swallowing problem. In 2009, they from a trial of more than 300 stroke patients that showed the test had an accuracy rate of over 90 per cent.

It was a practice-changing study.

The lab quickly set up an online training module and began to teach health professionals in Toronto and across Canada and the U.S. how to deliver the test. The tool has now been translated into six languages and is being adopted around the world, most recently in Japan and Brazil. “The TOR-BSST is really a Canadian success story, and we’re now validating this tool in critically ill cardiac patients who have been intubated for one day or more”, says Martino.

Almost 400 clinicians globally have used the TOR-BSST. Martino and her colleagues continue to study new ways of delivering the test and they expect further results later this year.

Why making food easy to swallow is hard

A key treatment for dysphagia is diet-texture modification. Many patients find that soft or liquified foods are easier to swallow, but the best consistency for each patient is highly variable. As well, there is no globally accepted way to name and describe texture-modified foods, which has led to poor communication among patients, caregivers and families, and undermined treatments.

In 2013, international experts from several health professions came together to develop a common terminology for texture-modified foods and instructions for simple methods to test food and drink consistency. The group – the (IDDSI) – published a framework in 2015, and soon after several countries made implementation plans.

New Zealand became the first country to adopt IDDSI in January, and Canada and the U.S. are on track to implement early next year.

“For people with swallowing issues, food and liquid are like medication, and they come with some of the same risks. Getting diet texture wrong can kill,” says Catriona Steele (pictured left), who is a professor in the department of speech-language pathology, an IDDSI board member and a senior scientist at the in University Health Network. “Inside the hospital, we don't treat the kitchen with the same reverence as the pharmacy.”

Steele says the IDDSI framework will bring much more attention to dysphagia diets, but that kitchens and food manufacturers that prepare food for dysphagia patients in Canada have a lot of work to do before roll-out. For example, labels on commercially available products need to change. Moreover, there are still major knowledge gaps regarding which consistencies are best for patients with different conditions.

“Liquid behaves one way in a person with an intact system but may not behave the same in someone with stroke or head and neck cancer,” says Steele, whose has studied the physiology of swallowing since 2003. “So clinically, people have been making educated guesses. We’ll collect data for IDDSI on particular measurements in specific conditions to guide clinicians down the road.”

In another project, Steele and colleagues at the University of Waterloo recently looked at nutrition in seniors at 32 long-term care facilities in Canada. The study, called , found that texture-modified foods contribute to malnourishment, in part because people eat less of them and puréeing changes nutrient density.

“People prescribe these liquids with good intentions in terms of safety, but they might be creating a negative cycle that leads to malnutrition,” says Steele, although she points out that researchers are trying to improve the nutrition of these foods through supplements.

Another challenge in seniors and others with dysphagia is the emotional aspect of food.

“We all love to eat, so dietary changes can be very threatening to people. And there are many possible reasons for negative emotions around food,” says Steele. “Early in my career, I worked with Holocaust survivors, for example, and modifying food texture had particularly negative associations for them. So we need to do this carefully and only when justified, and that's not the standard of care at present.”

A guide to treating the young

Children with swallowing problems can be especially hard to diagnose, in part because the potential reasons for feeding issues are many: feeding aversion secondary to gastrointestinal reflux, sensory issues in autism, problems with muscle weakness or co-ordination in the face or neck, cardiac or respiratory conditions, and lack of appetite from medications, to name a few.

Moreover, many strategies that clinicians use in adults will not work in the pediatric population for developmental reasons. For children with developmental difficulties, swallowing problems are very common and upsetting for families. Up to 80 per cent of these children have some kind of feeding or swallowing impairment.

Treatment for children with developmental challenges is complex, and often demands a team of health professionals that may include a physician, speech language pathologist, developmental paediatrician, occupational therapist, physical therapist, dietitian and nurse.

The clinical feeding and swallowing team at provides comprehensive expertise to patients with developmental challenges at the hospital. But they also share their knowledge with colleagues at community hospitals, clinics and individual community practitioners, who often face a knowledge gap when trying to address dysphagia in children with developmental issues.

To that end, the swallowing team at Holland Bloorview and the hospital’s group recently developed a handbook, The handbook provides a hierarchical and integrated approach to guide practice, and highlights key considerations clinicians might face.

“There was a lack of clear summaries of the scientific evidence available across disciplines that presented information in an accessible, efficient way for a broad group of community clinicians who may need to care for children with feeding and swallowing impairments,” says Deryk Beal, an assistant professor in ����TV’s department of speech-language pathology and clinician scientist at Bloorview Research Institute.

The guide has been a huge success. Viewers have downloaded it more than 4,600 times since it appeared online in June last year, in more than a dozen countries and every Canadian province. The University of Montreal made it required reading for a third-year occupational therapy course, and a survey by Holland Bloorview staff found many users praised the guide for its clarity and relevance to practice.

Clinicians say they use the guide in several ways – as a quick-reference tool when seeing patients, when sharing knowledge with colleagues, and for on-boarding new staff and teaching students. Many users like the guide’s interprofessional focus, which enables them to better understand the perspectives and treatment options that professionals in other fields can bring to cases.

“We know feeding and swallowing is a specialized area of medical care and a lot of people working in the community may not have received specific training in some elements of the care they’re providing,’’ says Andrea Hoffman, an assistant professor in the department of pediatrics and developmental pediatrician at Holland Bloorview. “This handbook helps give them a framework to gather information and determine the important elements of the assessment from a range of disciplines, so they can make the best recommendations and most appropriate referrals to provide optimal care.”

Hoffman and her colleagues recently published two quick-reference handouts based on the guide, and also plan to create client-centred resources for families.