Swallowing difficulties and reduced cough are a major, yet commonly overlooked, issue in patients with multiple sclerosis and other brain conditions, according to Dr. Don Bolser, a University of Florida (UF) professor.
Pharmaceutical companies haven’t recognized the importance of preventing bits of food and drink from getting into the lungs while breathing, Bolser said. More research is needed on this issue, he said in a UF News story.
Bolser, a neurologist and neuroscientist, is studying how cough is controlled by the nervous system. He said cough is tightly linked to swallowing — a reflex that healthy people do not pay attention to until they have something go down the wrong pipe.
During swallowing, muscles are coordinated so that the windpipe closes as food or drink is moved from the mouth to the esophagus. While a swallowing problem might intuitively be viewed as difficulty moving food from the mouth to the esophagus, lack of muscle coordination also puts millions of people with various brain conditions at risk of aspiration pneumonia.
Aspiration pneumonia occurs when pieces of food and drink enter the lungs. A weakened cough reflex — also commonly seen in patients with brain damage — prevents a patient from getting the food out of the lungs.
These tiny bits of food invariably bring with them bacteria that are not normally present in the lungs. If they settle there, a life-threatening condition can follow.
Bolster said studies report aspiration pneumonia death rates of over 60 percent. And aspiration pneumonia strikes in about half of long-term care residents. The treatment is expensive, Bolster added, with each hospital admission costing about $17,000.
Despite these discouraging statistics, Bolster said no pharmaceutical companies are developing drugs to restore weakened swallowing and cough.
The most accepted approach to dealing with impaired swallowing is a recommendation that patients eat thick foods. They are easier to swallow and less likely to enter the airways.
Bolster said some companies market devices that aim to improve swallowing by applying a weak electrical current to the neck. Such treatment has no impact on a weakened cough reflex, however. In fact, research shows they fail to provide enough benefits to the majority of patients.
Researchers from Japan have used another approach toward preventing aspiration pneumonia. They use strong-tasting compounds such as menthol and capsaicin — the chemical that makes peppers hot — to provide patients with a sensory stimulation. Their studies have shown impressive results in preventing aspiration pneumonia in elderly people with serious swallowing problems.
Bolster said another approach is training patients to strengthen their breathing muscles. The method, called “expiratory muscle strength training,” can improve swallowing and cough in patients with Parkinson’s disease and stroke, studies show. But it has yet to be determined whether the method prevents aspiration pneumonia.
Bolster argued that more research on the neurological mechanisms of coughing and swallowing could yield information that can be used to develop treatments for this under-recognized problem in people with brain diseases.
In addition to his National Institutes of Health-funded research on this issue at the University of Florida, Bolser owns shares in Respiratory Engineering Solutions, a startup focused on developing a device to improve swallowing.