Three types of positive and negative pressure variations impact the bolus and control of the swallow. These include
Swallowing occurs in three stages. In the first stage, oral transit, (here defined as including oral prep) the tongue cups to position the food/fluid/saliva for swallowing, and the front of the tongue elevates, followed by elevation of the back of the tongue. The food is propelled into the pharyngeal esophageal (P-E) segment, which is the beginning of the second stage of swallowing, pharyngeal transit. The epiglottis comes down to protect the trachea as the hyoid bone elevates (carrying the thyroid cartilage and larynx upward) and then immediately returns to the pre-swallow position. The third stage, esophageal transit, then begins, with a peristaltic wave that propels the bolus down the esophagus into the stomach. Dysphagia - is defined as difficulty in swallowing or the inability to swallow. This may be due to pressure imbalances, structural changes or abnormality in innervation of the pharyngeal or esophageal muscles. The ability to swallow may also be affected by more readily remediated oral mechanical problems. Dysphagia due to innervation problems or structural deviations at the second and third stages of swallowing should be differentiated from difficulty in the first stage (oral), which may be favorable improved through positioning, handling techniques, and techniques to control the flow and placement of food and fluids.
As the above descriptions indicate, swallowing difficulties may lead to short-term problems, such as coughing, and long-term problems, such as aspiration, pneumonia and scarring of the lungs. Knowledge of a client's swallowing abilities will assist in determining strategies for controlling positioning and the flow and placement of food and fluids to encourage more efficient swallowing.
Normal swallowing includes primitive and mature patterns.
Abnormal swallowing patterns include: