Most people are well aware of the communication difficulties that occur with Parkinson’s disease, but many are surprised to learn that swallowing issues are common as well, especially in the later stages. Swallowing is one of those bodily processes that we often don’t give a second thought to… until it becomes a problem.

A speech language pathologist (SLP) is trained to evaluate and manage both communication and swallowing impairment in a variety of conditions, including Parkinson’s disease. Swallowing issues (medically referred to as dysphagia) became under the purview of SLPs because the process of swallowing involves much of the same anatomy and physiology involved in speaking. Speech pathologists have specialized training in head and neck anatomy and physiology. They also study voice, articulation, respiration, resonance and motor speech. Most SLPs who work with adults have extensive training in dysphagia and complete clinical practicums to manage all manners of swallowing disorders.

This leads us to the obvious question… Why do swallowing issues occur in Parkinson’s? What exactly is happening here?

Along with the hallmark feature of difficulty initiating movement, Parkinson’s is known for making movements smaller. It’s often referred to as the disease of low amplitude. We often think of these smaller movements as they refer to gross motor movements such as having a smaller shuffling gait pattern or reduced arm swing when walking.

Now think of it in terms of communication. Vocal projection becomes reduced resulting in a soft, difficult to hear voice. Articulation and facial movements become reduced resulting in less precise speech and masked facial expression. Even intonation and prosody in the voice can be affected, resulting in flat robotic sounding speech.

With respect to swallowing function: jaw, lip, tongue and throat movements can become reduced in range resulting in difficulty chewing food, controlling liquid in the mouth and triggering a strong, timely swallow.

But it’s not simply an issue of direct muscle weakness, for example like what may occur in a stroke. There is a two-fold effect happening. The dopamine deficiency in Parkinson’s disease results in a perceptual impairment, a “faulty feedback loop” if you will. Your brain gives you incorrect information about the SIZE of the movements you are making. You may think that you are speaking loudly or smiling widely because your brain tells you that you have put sufficient effort into these movements. But this is often false information! Your voice may in fact be too quiet and your smile minimal. Because of this perceptual issue, you don’t adjust the movement to make it bigger. And as the old saying goes… if you don’t use it, you lose it. Over time, reduced movement and range results in further weakening of those muscles and systems.

The Three Phases of the Swallow

It’s also important to know that there are three distinct phases of the swallow. Any or all of these swallowing phases can be impacted in Parkinson’s disease.

The Mouth Phase

During the mouth or oral phase of the swallow, food or liquid must be prepared, controlled and transferred to the back of the mouth. This part of the swallow is completely under your volitional control. For example you can choose to hold a sip of water in your mouth for several seconds or chew a tough piece of steak extensively before swallowing, if needed.

The Throat Phase

The second phase of the swallow is the throat or pharyngeal phase of the swallow. This is where the brain takes over and completes a complex set of movements to safely transport the food or liquid into the food tube. An important part of the pharyngeal phase is ensuring that the airway is sufficiently closed to prevent food or liquid from “going down the wrong pipe”. When something goes down the wrong way it’s called aspiration. Aspiration events can lead to aspiration pneumonia which can be deadly if left untreated.

The Food Tube Phase

The third phase of the swallow is the food tube or esophageal phase where the food is transported to the stomach. Speech pathologists primarily manage the first two phases of the swallow as this last phase is largely treated and managed with medication and/or surgical intervention.

Common Swallowing Difficulties in Parkinson’s Disease

So what are some of the typical swallowing difficulties that can occur with Parkinson’s disease?

1. Spillage of food/liquid from the lips or prematurely into the throat due to difficulty with mouth control
2. Trouble initiating the transfer of food from the front to the back of the mouth
3. Trouble triggering a timely throat (pharyngeal) phase of the swallow
4. Reduced range of movement of the throat’s laryngeal structure resulting in reduced closure of the airway during the swallow
5. Food residue in the throat after the swallow (especially with dense food like bread or a thick pudding)
6. Reduced sensation of food/liquid entering the airway (aspiration!) resulting in an absent or ineffective cough response to clear

People with Parkinson’s disease have a higher risk of silent aspiration (not sensing/responding to things going down the wrong way) which puts them at a significantly higher risk of developing aspiration type pneumonia. There are ways to significantly reduce your risk of developing aspiration pneumonia in Parkinson’s disease, including ensuring that you have a thorough oral care routine.

If you have Parkinson’s disease and have started to experiencing any swallowing difficulty it’s essential to seek out a clinical swallowing assessment with a trained speech language pathologist near you.