A sequence of actions that moves food and liquids from the mouth to the stomach. Movement of the muscles of the mouth, including the tongue, is voluntary. Parkinson’s disease often affects the function of these muscles, causing the same kinds of symptoms that affect the muscles of mobility such as bradykinEsia (slowed muscle response) and lack of coordination. Putting a bite of food into the mouth activates the swallowing sequence normally the lips close, the jaw muscles move the jaw up and down and side to side to allow the teeth to break the food into pieces small enough to swallow, and the tongue mixes the pieces with saliva to make them soft enough to swallow. The tongue then presses against the roof of the mouth to move the food to the back of the mouth and into the throat.
At this juncture a series of involuntary movements take over, propelling the food down the esophagus and into the stomach. The epiglottis, a small flap of tissue, closes over the opening to the trachea to keep the food out of the lungs, and a series of powerful, wavelike contractions (peristalsis) carry the food down the esophagus. The sphincter muscle at the opening to the stomach relaxes, and the food drops into the stomach. The force of this involuntary sequence is so powerful that it can move food from the throat to the stomach even when a person is upside-down.
A slowed response at any part of the voluntary sequence affects the rest of the movements. Uncoordinated jaw movements result in inadequate pressure and motion to chew the food. If the tongue does not move properly, the food remains dry, making it harder to swallow. Parkinson’s can cause problems with the involuntary sequence of swallowing as well, especially if the person is taking anticholinErgic medications to treat tremors, which have the effect of slowing the actions of involuntary muscles such as those in the esophagus and the rest of the digestive tract.
Swallowing problems, called dysphagia, affect the person’s ability to eat. The manifestations of dysphagia can be fairly minor, such as drooling or leaking of food from the mouth during the voluntary phase of swallowing. Although these conditions seldom have health consequences, they often are embarrassing to the person with Parkinson’s. Aspirating food or liquid into the lungs is a significant health risk that can cause choking (a piece of food blocks the airways) and aspiration pneumonia (food particles settle into the lungs and cause infection). Both of these conditions can be life-threatening; everyone living in the household should know how to perform the hEimlich maneuver, a method for dislodging food that becomes stuck in the airways.
Some people with Parkinson’s have less saliva than they need to chew safely and effectively, usually as a side effect of medications such as anti-cholinergics, which dry out mucous membranes such as the lining of the mouth. Sometimes doctors prescribe anticholinergics specifically for this purpose, when saliva accumulates in the mouth and drooling becomes a problem. Most people with Parkinson’s have adequate saliva but lack the muscle control to swallow it. It is important to make a conscious effort to swallow saliva regularly, to prevent it from pooling in the mouth. However, saliva can present as significant a choking or aspiration risk as food.
speech-language pathology can help a person improve control of the muscles involved in swallowing and learn new methods for coping with symptoms such as bradykinesia. Swallowing and speech use many of the same physical structures, including muscle sequences. Techniques to improve one invariably improve the other. If choking and aspirating become more frequent than not as a result of worsening Parkinson’s symptoms, using a feeding tube to bypass the swallowing process may be necessary. Although many people resist use of a feeding tube, perceiving it as a capitulation to the disease process or a means of artificially sustaining life, it can relieve discomfort with minimal intrusion. Sometimes the symptoms of Parkinson’s more significantly affect the structures of the mouth and throat, leaving other voluntary muscle functions less affected or even intact. In such situations the person with Parkinson’s is not at the end of life but cannot get enough nutrition to meet the body’s needs. A feeding tube can alleviate these problems.
Dehydration and malnutrition are risks for people who have swallowing difficulties, who may consciously choose not to eat or drink or not eat or drink because of their difficulty. It is important for the person with Parkinson’s to drink adequate fluids and eat foods that are nutritious. For a person who has swallowing problems, soft or pureed foods often are easier to manage.