Dysphagia, or impaired swallowing of food, is a common problem in people who have suffered neurological damage and can have serious consequences. In this article we will explain why dysphagia occurs, how it is rehabilitated and what recommendations the affected person should follow in order to eat safely.
What is dysphagia?
Dysphagia is a disorder in the swallowing of food or saliva. It manifests itself with various signs, such as coughing, choking, respiratory infection or weight loss, among others. Dysphagia is due to a neurological disease or injury, such as stroke, traumatic brain injury, neurodegenerative diseases and high spinal cord injury, among others. Dysphagia can also be caused by head and neck cancer, although in this article we will refer to dysphagia associated with neurological disorders acquired in adulthood. Dysphagia can have serious medical consequences such as aspiration pneumonia or malnutrition. It also has psychosocial consequences, since feeding is an activity with a social and pleasurable dimension that has a significant impact on quality of life.
The approach to dysphagia is an interdisciplinary team task made up of physicians, speech therapists, nurses and other professionals, depending on each case.
However, together with the team, the role of the patient himself or his caregiver is of vital importance, who must know, understand and strictly follow the guidelines for safe feeding and the exercises recommended in each case.
Among the new treatment techniques, the incorporation of electrostimulation applied to dysphagia now makes it possible to intensify rehabilitation and significantly improve its results.
How does normal swallowing work?
To understand swallowing disorders, we must first understand how swallowing works under normal conditions. Swallowing is a vital function essential for survival, as it allows us to hydrate and nourish ourselves. However, the same structures that are used for feeding, i.e. the mouth and pharynx (throat), are also used for breathing and speech. Simply put, the pharynx is divided downward into two pathways: in front is the trachea, with the larynx at its upper end, which is the airway to the lungs; just behind the trachea is the esophagus, usually closed, which leads to the stomach and is the digestive tract. Thus, the mouth and throat are continuously used for different functions: breathing, speaking and swallowing, which requires a high degree of coordination.
Swallowing occurs in several phases. When the person is going to eat, first of all, anticipation occurs, which consists of recognizing that it is time to eat and correctly perceiving the type of food that is presented and its size, in order to take it with the appropriate movements, different for water, soup, a puree or a piece of meat. For example, some people with dementia or severe cognitive impairment do not realize that it is time to eat, or do not recognize the food presented to them.
Anticipation aside, swallowing occurs in four highly coordinated phases. In the oral preparatory phase, the food is collected in the mouth, palpated, chewed and formed into a bolus. This requires coordination of the jaw, facial muscles and tongue, as well as the sensitivity to chew without biting the cheeks or tongue.
In the oral propulsive phase (or oral transit phase), the tongue propels the bolus into the throat. When the throat senses the bolus, the pharyngeal phase is triggered. The pharyngeal phase (“swallowing reflex”) is a complex set of movements of the tongue, pharynx and larynx, which drive the food towards the esophagus, without it falling into the larynx and trachea. That is to say, momentarily the respiratory tract closes and the digestive tract opens to receive the food.
The pharyngeal phase is perceived externally, if we palpate the nut (larynx) while swallowing: we notice how it rises and falls in the neck.
The esophageal phase consists of the movement of the food through the esophagus to the stomach, thanks to the contractions of the esophageal muscles.
The oral preparatory and oral propulsive phases can be controlled voluntarily, as they allow us to take large or small spoonfuls, to chew slowly or quickly, to drink water in one gulp or in small sips. In contrast, the pharyngeal and esophageal phases are reflexive and cannot be controlled voluntarily.
What problems can occur in dysphagia?
Since swallowing is a complex process, different disturbances may occur, which can be summarized in two types:
- Inability to feed sufficiently due to weakness or clumsiness of the tongue and other muscles of the mouth. The consequence is weight loss, malnutrition and dehydration.
- Aspiration, i.e. passage of food into the airway. The cause may be tongue weakness, or various possible failures of the pharyngeal reflex. One possible consequence is respiratory infection, which may lead to aspiration pneumonia. Another consequence may be choking or suffocation, such as when a large piece of solid food is aspirated.
When a healthy person aspires food (“it goes down the other side”), a strong cough is immediately triggered, which usually serves to expel the food from the airway. However, some severe neurological patients have lost the cough reflex, so they may suffer from silent aspiration, even though they appear to eat normally.
The cognitive-behavioral state of the patient is important. An agitated patient has a higher risk of aspiration, so, in principle, he/she should not eat by mouth. A person with impulsive eating (eating quickly and in large bites) also has a higher risk of aspiration.
Signs of possible dysphagia
- Coughing during or after meals.
- Sensation of difficulty swallowing.
- Weight loss.
- Voice and speech changes.
- Sluggishness during meals.
- Changes in diet: foods that have been left out.
How is dysphagia detected and diagnosed?
In people with a known neurological injury, such as a stroke or traumatic brain injury, the physician will detect if there are swallowing problems and perform the necessary tests. In people with neurodegenerative diseases, dysphagia may present slowly and may even be the first symptom of an as yet undiagnosed disease. Signs such as coughing, weight loss and slowed eating suggest dysphagia, and a physician should be consulted.
For the diagnosis of dysphagia, several tests are performed, mainly:
- Functional examination of the movements and sensitivity of the face, mouth, throat and voice.
- Swallowing test with food. Different volumes and consistencies are tested in a regulated manner. It is a test that does not reliably detect if there is aspiration.
- Videofluoroscopy. It is a radiological test that is performed in certain cases, which allows to observe in a safe way if the food passes into the respiratory tract (aspiration). For example, a patient can safely take a food of a consistency such as yogurt, in a volume of up to 5 ml, but aspirate with higher volumes and with water.
- Esophageal manometry. It is performed in some cases, to explore the pressures during swallowing, and especially to determine if there are problems in the opening of the upper end of the esophagus at the time of swallowing.
What is the treatment of dysphagia?
Each patient is different and requires specific measures. The treatment of dysphagia depends on several factors: the type of dysphagia, the patient’s general state of health, and other factors such as the patient’s cognitive-behavioral state and the support he/she has from his/her family or caregiver. Dysphagia rehabilitation can be summarized in three aspects: the feeding route, the necessary adaptations in case of feeding by mouth and the exercise plan.
When feeding by mouth is not safe, other routes are generally used on a temporary basis: nasogastric tube (NGT), gastrostomy tube (GTP).
SNG consists of a thin tube that is inserted through the nose into the stomach. This route is used for short periods of time. When a longer period of non-oral feeding is anticipated, PEG is used, which consists of a tube inserted through the abdominal wall into the stomach. PEG is more comfortable and generally does not present complications in its management. The feeding route can be mixed: for example, general feeding by PEG and ingestion of some safe foods by mouth.
Does dysphagia improve?
In most cases dysphagia improves and resolves, so that the person gets to eat normally or with some restrictions. In patients with neurodegenerative diseases, the best way of feeding is oriented according to the progression. In severely affected individuals, improvement may be slow. Some patients will need to maintain PEG for feeding. There are very few cases in which the patient cannot eat by mouth again. Even in cases of severe alteration, we try to get the person to eat some food by mouth, in a properly controlled manner. The ideal objective will be that the person can eat in the best possible way, safely, and recover eating in its social and pleasurable dimension.