Dysphagia After Stroke - Predicting Risks

The WHO (World Health Organization) is expecting 20 million people to be struck by a stroke on a yearly base. More women than men will in the future have the risk on having a stroke.
Although stroke is seen in every age, 70% of the people having a stroke is older than 65. Dysphagia resulting from stroke is concerning scientists because of the risk for possible death, extra costs for special care and quality of life after the stroke. If not identified and managed well, it can lead to poor nutrition, pneumonia and increased disability, increased numbers for mortality. The possibility to predict a consisting and remaining dysphagia after a stroke is the focus of research nowadays.

Dysphagia occurs when there is a problem with any part of the swallowing process. When we see dysphagia after a stroke, problems include: not being able to start the swallowing reflex (because of the stroke or nervous system disorder. People with these problems are unable to begin the muscle movements that allow food to move from the mouth to the stomach.

Aspiration is a common problem for people with dysphagia and occurs when material a person is swallowing enters their airway and lungs, and pneumonia may develop. When the throat muscles are too weak they may not be able to prevent fluids or food from entering the airway or lungs. Aspiration causes choking, pneumonia and even death from asphyxiation.
Normally, aspiration would cause a violent cough, but a stroke can reduce sensation. After a stroke, food or liquid could enter the airway/lungs without someone being aware of it, called silent aspiration.

After a stroke many people have dysphagia. Dysphagia can affect up to 65 percent of stroke survivors, and is a serious problem that can cause potentially life threatening complications. That is an amount that needs consideration.
Dysphagia is influencing the quality of life and may lead to aspiration (causing pneumonia), malnutrition or dehydration, specifically in older patients. Mortality rates will rise when not recognizing dysphagia in time. Therefore it is necessary to focus on predictors of possible presence of dysphagia after stroke and the period this problem could stay.

In normal swallowing the pharynx has to be prepared on the volume of the coming bolus and, as said, gets information about sense and viscosity. Impulses will go to the Brainstem.
Patients with stroke located in the Brainstem will show a high risk of lacking the swallowing reflex. Size and exact location of the lesion are directly related to the prognosis for remaining dysphagia.
Having neurological damage caused by stroke, aspiration is a unexpected risk, as well as delayed first swallowing reflex, less control over the tongue muscles and control. A swallowing apraxia caused by stroke will show incorrect motor functions. When having a hemi-paralysis of the pharynx, there will also be high risk caused by unnoticed remaining residue after swallowing (Logemann, 2000).

In more recent research the relations between clinical variables and consequences for screening and treatment are considered. For example, Terré and Mearin (2006) show us that here are clear relations between clinical variables being age, intubation, velopharyngeal disorders and a cough when swallowing, changes in quality of voice, etiology and location of the lesion. Their study shows us that a clear correlation is proved between location of the lesion (posterior vascular area) and the changes in quality of the voice after the swallowing and aspiration. A disturbed vomiting reflex, coughing when swallowing as a reflex and also changes in quality of the voice really are the predictors of the high risk of aspiration, because the safety in the whole process has been lost.

The Royal Adelaide Prognostic Index for Dysphagic Stroke (RAPIDS) (Broadley S. et al., 2005) is the most recent index based on clinical and X-ray findings, that claims to be predictive about dysphagia and aspiration after stroke and also combines prediction with the grade of possible risk (Barthel index).

So there are possible predictors in the field of giving a prognoses for dysphagia and aspiration or prolonged dysphagia after stroke. An important issue for the patient as well as the medical staff and caregivers, insurance companies and revalidation therapists. Unfortunately, international guidelines in this field have not been developed yet.
No validated screening is used yet in the acute phase after stroke to give exact predictions about the recovery or risks after a stroke in the area of dysphagia and the life threatening extra risk of aspiration. Research is needed for confirming the best possible combination of tests and assessment leading to better screening in predicting consequences of stroke in the field of swallowing difficulties. Also, the best therapy and aimed evidence-based revalidation can be evaluated and formulated and linked to the screening procedure when available.

Written by M. Coppens