We take a lot for granted, don’t we? Breathing in and out; chugging down that cool drink on a hot summer day; sitting down and enjoying a meal with family or friends. We give little thought to these seeming “auto pilot” activities, but when we experience trouble in our ability to perform them, we suddenly realize how important they are to us.
Though exact prevalence in unknown, impairment in swallowing ability, or dysphagia, has been estimated in epidemiologic studies to afflict up to 7-10% of people over the age of 50, a figure that increases with age. Most common amount that many causes of dysphagia are neurogenic disorders, including stroke, degenerative neurologic diseases, Alzheimer dementia and traumatic brain injury.
Swallowing is a highly complex action which involves the interplay of multiple body systems, including the respiratory, digestive, musculoskeletal and neurologic systems. Normal swallowing takes place in a rapid sequence and can be broken down into three phases:
Food or liquid is organized into a small cohesive mass (bolus) in the mouth. Food is mixed with enzymes in saliva, which help break down food fibers.
The bolus is then gathered atop the tongue, which elevates and sweeps the bolus backward against the roof of the mouth.
The swallow reflex triggers.
At that moment, the tongue pushes against the tail of the bolus and the entire larynx elevates and moves slightly forward.
The epiglottis (a flexible cartilage below the base of the tongue) flexes over to channel the bolus toward the esophagus and to cap over the top of the airway to prevent aspiration, or the entry of foreign material into the trachea.
At the top of the trachea, the vocal folds valve together, adding a second level of airway protection.
The bolus then reaches the the upper esophageal sphincter (UES) at the top of the esophagus. When a bolus arrives at its threshold, it relaxes to allow passage.
Sequential, top to bottom contractions of the esophagus begin moving the bolus down toward the stomach. The bolus moves into the stomach with the relaxation of the lower esophageal sphincter (LES).
Amazing right? Intricate, instantaneous and elegant. And the most astonishing thing of all is that most of the time it works beautifully, and for decades. But the neurogenic problems named earlier may interfere for some individuals. That’s when a speech pathologist may get involved in assisting with the diagnosis and treatment of the problems.
Neurogenic problems may cause disruptions of the motor and sensory aspects of swallowing especially in the first two stages. Muscular weakness or incoordination, either of sudden onset (as in a brain injury or stroke) or gradual (as in progressive diseases like Parkinson disease or ALS) can interfere with bolus management and organization in the oral phase. This can cause slowness, reduced ability to retain food or liquid in the mouth, and reduced ability to move the bolus from the front to the back of the mouth. In the pharyngeal phase, muscular weakness can cause disturbances in the ability to clear food or liquid residue from the pharynx. Disruptions in the timing of the swallow sequence can also lead to aspiration. Thin liquids, which are difficult to control due to their fluid, fast flowing nature, are often the most difficult to swallow safely under these circumstances. Impairments in sensory perception can complicate the process further by contributing to unperceived pharyngeal retention or even aspiration which fails to elicit the coughing reflex normally experienced when something goes “down the wrong pipe.” Speech pathologists are often consulted to identify these problems by means of examining the oral/pharyngeal mechanism; by radiologic assessment called a modified barium swallow; and sometimes by fiberoptic endoscopic evaluation of swallowing (FEES). Once the problems are identified, the speech pathologist can recommend appropriate treatment and diet consistency alterations or, if necessary, NPO (nothing by mouth) status in cases of dangerously impaired swallowing. Treatment usually consists of various oral and pharyngeal exercises, sometimes facilitated by neuromuscular electrical stimulation, a technique which assists pharyngeal muscular contractions. Additionally, the speech pathologist may instruct the person with dysphagia in strategies or postures to improve swallowing as well as airway protection techniques.
Signs and symptoms of dysphagia resulting from neurogenic problems may include:
If you or someone you know is experiencing any of these, a physician should be contacted. Detection, especially early detection of dysphagia may prevent serious health complications such as pneumonia and/or inadequate nutrition, both of which can lead to a cascade of other problems. Be aware, and be well!
Sheila Gilmore is a speech-language pathologist who has been practicing in Orange County, CA with over 30 years experience.
For more information on dysphagia, visit: http://www.asha.org/Research/