Dysphagia caused by neurological diseases

Swallowing disorders can be caused by various neurological diseases, such as stroke, Parkinson's disease, myasthenia gravis and muscle disorders. These disorders can lead to serious complications such as pneumonia or malnutrition and severely affect the quality of life of those affected and their families.

Swallowing disorders can occur at any age and in connection with various diseases. They can cause both structural and neurological problems and interfere with different phases of swallowing. For example, up to 80% of people who have had a stroke, 30% of people who have had a traumatic brain injury, and up to 80% of people with advanced dementia have swallowing disorders.

Swallowing disorders can have serious consequences, especially in neurological diseases. Malnutrition, dehydration and pneumonia can lead to an increased burden of disease and mortality. For example, the risk of pneumonia is three times higher in stroke patients and the mortality rate in intensive care patients with swallowing disorders is 10% higher. Severe consequences of the swallowing disorder also lengthen the stay in hospital. Another important aspect is the difficulty in taking medication due to the swallowing disorder, which can lead to problems with the effectiveness of the medication and irritation of the mucous membrane.

Swallowing disorders are often noticed late or not at all by those affected, since they develop insidiously or can also be attributed to sensitivity deficits. In many cases, there are already consequences that worsen the state of health without being noticed.

Due to demographic changes and medical advances, the incidence of neurogenic swallowing disorders is expected to continue to increase. There is a growing need for appropriate and targeted diagnostics Therapy. Below we provide a practical overview of the diagnosis and treatment of neurogenic swallowing disorders.

Physiology of Swallowing
The act of swallowing requires a complex interaction of 25 muscle groups that need to work together and be coordinated. It does this with the help of various cranial nerves and swallowing centers in the brain. In order to be able to swallow different consistencies and quantities without problems, these processes must work precisely.

The act of swallowing is initiated consciously and then continued automatically. It consists of five phases:

1. In the preoral phase, food intake is influenced by sensory stimuli and thoughts Essen stimulated.
2. The oral preparation phase begins with touching the lips. Here the food bolus is broken up, mixed with saliva and shaped.
3. In the oral transport phase, the bolus moves into the pharynx using the tongue, cheeks and lips.
4. Touching sensitive points on the roof of the mouth and tongue triggers the swallowing reflex. This initiates the pharyngeal phase. The bolus is pushed down the throat with a quick, backward movement of the base of the tongue. At the same time, the larynx, epiglottis, and vocal cords close to protect the airway. The bolus enters the esophagus while the neck and upper esophageal sphincter open. Due to the resulting negative pressure, the bolus is sucked further into the esophagus. Contractions in the throat help clear debris.
5. In the final esophageal phase, the bolus is transported into the stomach by undulating muscle movements.

There are several causes of dysphagia, classified according to the nature and location of the underlying problems. This includes structural disorders that can be caused by tumors, operations, inflammation, injuries, diseases or malformations of the organs involved in swallowing. Neurogenic disorders are caused by damage or diseases of the brain, such as strokes, Parkinson's disease or congenital brain damage. Psychogenic dysphagia can be caused by fear or aversion to certain food textures. In older people, age-related changes can lead to swallowing problems, this is known as primary presbyphagia.

Diagnostics

The aim of diagnostics is to precisely assess the act of swallowing and its disorders in order to derive an individually tailored therapy based on this. In order to cover the increasing demand for examinations of swallowing disorders despite limited resources, an efficient concept and optimal cooperation between different disciplines is required.

There are essentially two types of examination procedures available: screening procedures and apparatus-based procedures. The former serve to identify endangered patients and to select them for further technical examinations. A step-by-step diagnosis can be established through the use of screening instruments, clinical swallowing examinations and technical procedures.

During the systematic anamnesis by the attending physician, swallowing problems are rarely spontaneously mentioned by patients. Therefore, it is important that they specifically ask about specific symptoms. A structured anamnesis interview enables an initial assessment of the patient's state of health. Aspects such as attention, cognitive skills, communication skills and the expected willingness to cooperate are taken into account. This information is essential for further examinations and planning of therapy.

In addition to the anamnesis, questionnaires can be used to record swallowing difficulties. These require little time and can be used with different patient groups.

The clinical swallowing function examination (KSU) makes it possible to obtain information about the function of the organs and cranial nerves involved in swallowing. Sensory and motor functions are checked and the patient's ability to cooperate is assessed. Depending on the patient's condition, a swallow test with test boluses follows. The focus is on clinical signs of swallowing disorders such as repeated swallowing or signs of aspiration such as coughing.

Therapy for swallowing disorders

In the treatment of swallowing disorders (dysphagia), the following main goals are in the foreground:

• Avoidance of aspirations and other complications
• Ensuring oral nutrition
• Maintaining or restoring independence from feeding tubes
• Decanulation of tracheotomy patients.

In principle, the same therapeutic principles apply to all causes of swallowing disorders, although the focus of individual exercises can vary from case to case.

Conservative therapy includes restorative, compensatory and adaptive procedures. Depending on the need, measures to deal with secretions and/or to strengthen the cough reflex can also be important components of the therapy. The focus is increasingly on technology-supported therapy methods such as biofeedback methods or neuromuscular electrical stimulation, which are regarded as an effective supplement to conventional dysphagia therapy.

Reconstructive procedures involve exercises that target the muscles and structures involved in swallowing. For example, tongue resistance exercises can improve tongue strength and decrease throat debris. Ideally, these exercises are done with biofeedback to monitor their correct execution.

Compensatory procedures are used when neurological or structural deficits have to be compensated. This includes changes in head posture and adapted swallowing techniques, such as the supraglottic and super-supraglottic swallowing maneuver. During these maneuvers, the patient is instructed to hold their breath (supraglottic swallow) or strain (super-supraglottic swallow) before swallowing to protect the airway from possible aspiration during the swallow. During the super-supraglottic maneuver, an even better shielding of the entrance to the larynx is achieved through additional pressure build-up. These maneuvers require good patient compliance.

Adaptive procedures aim to adapt external factors to the sensory and motor disorders. These adjustments are intended to reduce the demands on the act of swallowing in the case of existing swallowing disorders. This includes adjusting the consistency of food, the use of aids and individual strategies for food intake.

In summary, neurogenic dysphagia is the most common cause of dysphagia, especially oropharyngeal dysphagia as a threatening complication of many neurological diseases. Those affected often do not perceive the swallowing disorder themselves, so an accurate diagnosis is of crucial importance in order to enable targeted therapy.

Studies have shown that the introduction of standardized FEES diagnostics in the stroke unit has halved the rate of pneumonia.

The ultimate goal of any therapy is to avoid aspiration. Conservative and instrument-based methods are available for this.

Future developments in diagnostics and therapy will make it possible to identify impaired functions even better and to treat them more individually. The research approaches in medicine and therapeutic science are increasingly complementing each other in order to achieve this goal.

This is supplemented by an informative webcast by the Parkinson Foundation