Just thinking about swallowing makes it harder to do. Head and neck cancer, a stroke, brain tumor, brain injury or even a tracheostomy tube and mechanical ventilation needed to sustain life can make it impossible.
Dysphagia, or swallowing problems, can also result from aging and accompanying loss of muscle strength.
"We swallow a thousand times or more per day, just our own saliva, without even thinking about it," says Dr. Lori Burkhead, speech-language pathologist and clinical research scientist at the Medical College of Georgia Department of Otolaryngology , Head and Neck Surgery. "We swallow in our sleep. Babies do it in utero. It is something we do without giving it much thought, but it's actually a very complex act that involves an intricate coordination between the brain, muscles and respiratory system."
An estimated 18 million Americans have difficulty with this routine function that, at worst, can lead to aspiration pneumonia, malnutrition, dehydration and death.
Evidence suggests that the same exercise science principles that strengthen bodies can help restore this fundamental function using mouth and throat muscles. Because swallowing muscles are not easy to access, applying the usual principles of exercise is more difficult. "Physical therapists can put a weight in someone's hand and exercise them or they can give patients external assistance and get them to complete a movement," says Dr. Burkhead. "I can't put weights on throat muscles for strengthening and I can't get at those muscles to help patients finish the movements they cannot do on their own."
Theories about the amount of resistance needed to strengthen a muscle, the number of repetitions and specificity of exercise along with technology such as biofeedback may help speech-language pathologists put more science and success into helping patients regain the ability to swallow, according to a review article authored by Dr. Burkhead available online in the scientific journal Dysphagia at http://dx.doi.org/10.1007/s00455-006-9074-z.
"At present, there remain more questions than answers regarding how to most effectively and efficiently approach dysphagia rehabilitation," Dr. Burkhead and her co-authors write. Historically, research has focused on compensatory maneuvers such as changing body position or modifying the amount or consistency of food and liquid. Compensation is important, but the problem still remains unless it is addressed through rehabilitation efforts, they say.
Although exercise principles used in physical rehabilitation and sports training have been gaining attention in dysphagia rehabilitation, Dr. Burkhead proposes more emphasis on these theories and more studies to learn to optimize these principles.
Dr. Burkhead asserts that many of the treatment techniques used in physical rehabilitation or athletic training are applicable and beneficial in dysphagia rehabilitation. "Physical therapists won't just tell a stroke patient to get up and walk; they first work on strengthening muscles of interest and discrete movements until patients can stand and take a few steps. They start with the components of a movement and then ultimately train the movement of interest, which in this case would be walking. The same thing goes for swallowing therapy. We can start with tongue movement or lip closure, but then we must be very conscious of moving toward task-specific exercise and working our patients at more challenging levels of intensity, which is something that our field is now starting to pay more attention to," says Dr. Burkhead.
There also is heightened interest in using tools such as neuromuscular electrical stimulation and biofeedback to boost the effects of exercise. She already routinely incorporates biofeedback. "It provides concrete information for the therapist as well as the patient and empowers them to take a more active role in their recovery. We frequently ask patients to swallow with greater emphasis or to swallow in unusual ways as part of their exercise regimen. Biofeedback helps them know if they are doing it correctly and with the right amount of intensity."
Computer-aided biofeedback provides patients a graphic representation on a computer screen of what their muscles are doing. The therapist can challenge patients to reach for higher and higher goals, which challenges the muscles more and more. "This helps the patient understand what they are doing right and to do more of it," she says. "This empowers patients and helps them not only judge but then modify their own performance."
Dr Burkhead also is developing a strengthening technique that incorporates a creative way to access hard-to-reach muscles. Her technique incorporates the use of the Therabite, device, developed by Atos Medical in Sweden, to improve mouth opening. The device holds the jaw in position while the patient places his tongue at the roof of the mouth and swallows. The rationale is based on exercise principles known to work in other parts of the body. Her studies in healthy patients have shown that swallowing in this unusual position significantly increases activation of the swallowing muscles.
Despite advances in this field, many questions remain about how to best help patients resume safe swallowing. "We use the evidence available to us along with what we know about how the body works to design treatment plans that target the problems as best we can. Many patients have improved with traditional therapy techniques, but I think that more research will lead to better therapy and greater outcomes in a shorter amount of time."