The swallowing reflex is a multi-step patterned response that is based on learning and experience.
While its main function is the intake of food and liquid, its second most important function is the protection of the airway. As breathing and swallowing occur in the same place, these two functions need to be highly coordinated in order to both maintain ventilation during intake of food and to prevent aspiration, which can be fatal. Aspiration occurs if food or liquid enters the larynx below the level of the vocal folds instead of down the pharynx to the stomach. Prevention of aspiration is highly dependent on a correct breathing-swallow pattern.
Prevention of aspiration is highly dependent on a correct breathing-swallow pattern.
Swallowing can be divided into several phases. It starts with the anticipatory phase, during which the food or liquid is assessed visually, and a motor plan is created in the brain on how it will be taken in and swallowed with a clear expectation on consistency and taste. During the next phase, the mouth analyzes the food or liquid, confirming or updating the visual expectation, purees it and moves it to the back. During the pharyngeal phase, the food or liquid is moved past the larynx and into the esophagus.
Aspiration occurs if that process is disturbed and food or liquid gets into the larynx and enters the airway. In healthy individuals, aspiration triggers the cough reflex, and the food or liquid gets expelled again. In the case of swallow dysfunction however, aspiration occurs, often in combination with impaired cough function. This inefficient airway hygiene can lead not only to the development of pneumonia, but also to malnutrition, as patients learn to avoid food that leads to aspiration. Swallow dysfunction is often seen with neurological or neuromuscular disorders, such as Parkinson’s and MS, and after stroke, but is also highly prevalent in otherwise healthy elderly people.
So where does breathing come in? Swallowing takes place in a specific pattern after inhalation, during early or mid-exhalation. The body automatically permits the swallow at the right lung volume. In many patients with dysphagia, this pattern is disturbed, and swallowing occurs, for example, during inhalation.
Swallow dysfunction is often seen with neurological or neuromuscular disorders, such as Parkinson’s and MS, and after stroke
Aspiration can be prevented by re-establishing the correct breathing and swallowing pattern. Patients will train to inhale, exhale a little bit, and then swallow. These retrained patterns, together with pulmonary hygiene and good cough function, can effectively reduce aspiration and pneumonia.
Strengthening the respiratory system supports swallow function by improving laryngeal function to ensure airway protection, prevent aspiration, and reduce pneumonia risk. This is done by increasing ribcage flexibility to improve lung volume and ease of inhalation before swallowing as well as by improving cough function to strengthen the cough reflex to promote good pulmonary hygiene, airway clearance and to prevent aspiration. In addition, respiratory muscle training can lay the foundation for conscious re-training of a correct breathing-swallow pattern.
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