Explanation
The eating and swallowing process is generally considered to comprise of 5 phases: the pre-preparatory phase, the preparatory phase, the oral phase, the pharyngeal phase, and the esophageal phase. However, we acquire eating and swallowing functions through learning in the developmental period, so when helping patients who are still in the developmental period, we must pay attention to the 8 stages in the development of eating and swallowing functions.
Explanation
There are 8 stages in the normal development of eating and swallow functions in children (Mukai, 2000). Characteristic movements are acquired through development of swallowing function, then eating function, and finally finger function.
Explanation
Sucking movement (reflexes) is the function that we are born with, while purposive functions develop through repeated reception of appropriate external sensory stimulation.
Explanation
There are many factors that interfere with the development of eating and swallow functions throughout our lifetime. Acquiring principle functions can be delayed or halted if problems occur during the process of functional development.
Explanation
The preparatory period for oral eating is characterized by sucking of milk mainly through reflexive movements. Infants learn sensations through active sucking and mouthing their fingers and toys in this period.
Explanation
After the preparatory period for oral eating, in which reflexive movements predominate, the first function to be acquired is swallowing. Inward rolling of the lower lip is a characteristic observation in this period. Because tongue movements are restricted to backward and forward, the only forms of foods that can be processed further are liquids and smooth puree.
Explanation
The mouth does not have to be closed while sucking milk. However, in this stage, the lips are voluntarily closed when food is placed and processed in the mouth. Because jaw movements have not yet been stabilized, non-viscous liquids can't be processed.
Explanation
The lips are now closed and this means that the tongue can't protrude but moves upward and downward to crush soft foods. The jaws simply move upward and downward, observed as symmetrical pulling of the corners of the mouth when food is crushed strongly.
Explanation
Once the tongue becomes able to process reasonably hard food, we can increase the texture of the food to food that can't be crushed only with tongue movements. By experience, infants place food on the area where their molars will erupt and crush it with their maxilla and mandible. Acquiring this function requires oral sensory experiences through mouthing fingers or toys. Their development can be assessed easily by observing asymmetric movements of the corners of the mouth.
Explanation
The focus of development until this point has been on oral function. Now, however, movements that need hand-mouth coordination start through play using the fingers. This stage is called the preparatory stage for self-feeding.
Explanation
In this stage, infants acquire the function that enables them to transfer food to the mouth using their fingers. As the trunk becomes more stable, infants become able to use their hands more freely away from the trunk and then move food from the front of the body to the center of the lips.
Explanation
This function requires a high degree of coordination and allows food to be transferred with eating utensils such as spoons, forks, and chopsticks. In the normal developmental process, the movements for using chopsticks will be learnt by 6 years of age.
Explanation
Dysphagia in the developmental period has various causes. In addition to underlying diseases, notable adverse factors include disturbance in the mealtime environment and insufficient sensory experience.
Explanation
Here we see the characteristics of the 5 developmental stages in the normal development of eating and swallow functions and the symptoms that can occur with problems in each developmental stage. There are specific symptoms at each of the 5 stages of functional development, similar to problems occurring specific to the each of the 5 eating and swallowing phases. Because hand and finger functions are often not mature in pediatric patients with dysphagia, the first 5 developmental stages (up to the development of oral function) are shown here.
Explanation
Early approaches need to be implemented soon after birth. Naturally, the earliest possible intervention is preferable, but intervention at the later stage can still facilitate functional development. Because physical development influences functional development, changes attributed to children's age need to be taken into consideration. Also, close cooperation is needed with parents and guardians and with other health professionals in, for example, public health, medical care, treatment, and education over the long time until patients reach adulthood.
