Parkinson’s disease is a chronic neurodegenerative disorder occurring in the elderly patients characterized by the loss of dopaminergic neurons in the part of brain called as nigrostriatum. Dopamine is predominantly involved in the muscular control and coordination of the body. Due to the progressive loss of muscle control – both voluntary and involuntary – many other symptoms can develop in a patient suffering from Parkinson’s disease besides the typical symptoms of tremor and rigidity. Dysphagia is one such symptom. Dysphagia or difficulty in swallowing is a common problem in people with Parkinson’s disease which can have far-reaching consequences. It affects about 40% to 90% patients of the Parkinson’s disease.
Swallowing difficulties can occur at any stage of Parkinson’s disease. Dysphagia can lead to shorter survival time in a patient with Parkinson’s disease, not only because the affected muscles of the throat may make swallowing difficult – hence less food intake and increased chances of under-nutrition of the patient – but also because it increases the possibility of aspiration pneumonia. Aspiration pneumonia is the leading cause of death in Parkinson’s disease.
How does dysphagia occur?
Dysphagia is defined as inefficient or unsafe transfer of the food, liquid or saliva from the mouth into the stomach
The act of swallowing can be divided into 3 phases – oral, pharyngeal and esophageal. Parkinson’s disease patients usually have problems with the first 2 stages of swallowing, which means that their dysphagia is of the oropharyngeal type.
- Oral stage deficits occur most frequently in the parkinson’s disease patients and are mostly the first indication of dysphagia. Due to the limited excursion of the mandible, there is an increase in the time for oral preparation and chewing. Also, the “tongue pumping”, which is a repetitive backward and forward rocking motion of the tongue, prevents the food material to leave the oral cavity. Along with that, the weak tongue or cheek muscles make moving food around in the mouth difficult and can hamper chewing. Along with that, the weak throat muscles cannot sufficiently move the food towards the esophagus.
- Pharyngeal stage deficits: Occur due to the delay in triggering of the pharyngeal swallow. However, the delay is usually mild, still, any delay in triggering the pharyngeal swallow, usually carries the risk of aspiration. Cognitive impairment, upper extremity impairment, and impulsive feeding behavior exhibited by the patients with advanced Parkinson’s, contribute to the exacerbation of oropharyngeal dysphagia.
Signs and symptoms
Dysphagia in Parkinson’s disease is associated with increased morbidity and mortality. Signs and symptoms can range from mild to severe and include:
- Presence of food particle residues in the oral cavity, long after swallowing.
- Difficulty in swallowing drinks and food.
- Frequent coughing during and after eating or drinking, with a feeling as if something is stuck in the throat.
- Abnormal bolus formation, multiple tongue elevations, delayed swallowing reflex, increased time taken by the food bolus to pass through the pharynx.
- Drooling of saliva
- With the advancement of disease, swallowing might get severely compromised and can lead to aspiration.
Causes of Dysphagia in Parkinson’s Disease
A number of factors may contribute to swallowing problems in Parkinson’s disease.
- Motor impairment of the throat muscles as a result of Parkinson’s disease.
- Dysphagia can be made worse by lack of saliva or dry mouth. This is common in Parkinson’s disease patients, frequently related to anticholinergics medication. Refer to Parkinson’s Disease Drugs.
- Since Parkinson’s disease is more common in the elderly, associated features such as poor dentition can play a role.
Diagnosis of dysphagia in Parkinson’s Disease
When a person with Parkinson’s disease has problems with swallowing, a proper history and examination of the patient will help to determine the severity of dysphagia and evaluate the risk of aspiration. This is usually done by the doctor as well as a speech-language pathologist. A physical examination of head and neck is usually done along with trials with the food/liquid. A modified water test to assess the maximum swallowing volume is recommended to diagnose the oropharyngeal dysphagia.
If indicated, certain tests may also be done. These instrumental methods allow a reliable detection of aspiration events.
- Video-fluoroscopy: It is an instrumental examination with a moving X-ray. It is also commonly known as modified barium swallow study.
- Endoscopy: The throat is visualized with the help of an endoscope.
- Barium swallow.
Complications of dysphagia in Parkinson’s Disease
- Food and saliva which cannot be swallowed may collect in the mouth or back of the throat and cause choking, coughing or drooling.
- Aspiration pneumonia – due to food or liquids being inhaled into the lungs.
- Weight loss – this can be an indicator of the severity and duration of dysphagia.
- Shorter survival time in a patient with Parkinson’s disease.
- Dysphagia also complicates the medicine intake, which further complicates the situation.
- Apart from the physical problems faced due to dysphagia, certain psychosocial problems may also occur. Difficulty in swallowing can make patients dread meal times. The fear of choking is very real in some people. There is less enjoyment of food, especially due to the adjustments needed regarding the type of food that can be easily swallowed. Social adjustments, such as avoiding guests during meal times or going out to dinner can take its toll, both on the patient as well as the care-giver. Overall, it reduces the quality of life.
Treatment of dysphagia in Parkinson’s Disease
It is crucial to monitor the weight and provide necessary counseling about the signs and symptoms of swallowing difficulties, even to the patients who have not reported any swallowing difficulties as yet. Evaluation and treatment of swallowing disorders are done by a speech language pathologist.
- Behavioral treatments for dysphagia remain the mainstay of management as the pharmacological and surgical options for Parkinson’s disease are known to have more positive effects on the motor symptoms as compared to the non motor symptoms related to swallowing.
- Intensive swallowing therapy by a speech-language pathologist can help to overcome the weakness in the swallowing apparatus by strengthening exercises or compensatory maneuvers. Swallowing hard, holding breath while swallowing, tucking the chin to chest while swallowing are some compensatory maneuvers to help easy feeding.
- Sitting up straight and keeping the head slightly forward while eating may help.
- Modifications in diet, such as eating soft and pureed food can help.
- A fluctuating dysphagia during the ‘off-phase’ must be managed by optimizing dopaminergic medication.
- Gastric feeding tube in end stages of the disease may become necessary.
- Feeders who feed the patients, must be trained to monitor the safety of each swallow, and smaller bites at a slower rate must be encouraged.
- A percutaneous enteral gastrotomy is done for the enteral feeding, which improves the quality of life by providing nutritional support.