46.Indirect Training for the Preparatory and Oral Stages

Explanation

In this module, we first cover what happens during the preparatory and oral stages, signs of impairment in these stages, and what causes the impairment. We then look at the general significance of indirect training and specific methods of indirect training particularly for the preparatory and oral stages.

Explanation

During the preparatory and oral stages, food or liquid is taken into the mouth, masticated, and mixed with saliva to adjust its properties to make it suitable for swallowing. Then a food bolus is formed in the mouth using the dorsum of the tongue. The tip of the tongue pushes the bolus against the anterior aspect of the hard palate, the center of the tongue cups into a spoon-like shape, and from there the tongue transports the bolus into the pharynx. At that point, the root of the tongue moves frontward and downward, the hypopharynx opens to create a slope, and pressure decreases. These changes move the bolus into the pharynx.

For someone to perform these tasks smoothly when eating, they must be conscious and alert, cognitively sound, be able to pay attention to taking of food and fluids into the mouth, mastication, and swallowing, and also be able to sustain that attention.

Explanation

These are some signs of impairment in the preparatory and oral stages:

Cannot easily take food into the mouth

Food often spills out of the mouth

Can take food into the mouth but cannot masticate it well

Cannot form a food bolus while masticating food

Cannot transport the food bolus toward the pharynx and propel it downward

Explanation

Here are some causes of impairment in the preparatory and oral stages:

Cannot close the lips due to motor paralysis or sensory impairment

Cannot masticate sufficiently due to missing teeth or poorly fitting dentures

Weakness in the muscles of mastication, specifically the masseter muscle, temporal muscle, and medial and lateral pterygoid muscle, as well as impaired coordination between those muscles, can also cause poor mastication

Also, motor or sensory impairment of the tongue can impede mastication and other steps in food bolus formation, which impedes the transport of food toward the pharynx. As mentioned in Slide 2, people with reduced attentiveness or a reduced attention span due to conditions such as disorder of consciousness or dementia can have difficulty eating.

Explanation

The general purpose of indirect training is to improve the function and coordination of the structures involved in eating and swallowing by engaging these structures individually or collectively without using food. Indirect training generally has a low risk of choking and aspiration because it does not use food.

This training can be performed with a wide range of patients with dysphagia of various causes. It's sometimes also used even with patients who received indirect training immediately after developing dysphagia and already started to eat orally.

Explanation

Specific methods used in indirect training are as follows:

1. If the lips are hypotonic, we can increase tone by vibratory stimulation or tapping the lips. Place a tongue depressor between the lips and instruct patients to forcefully close their mouth and work to keep the tongue depressor from being pulled out. In another exercise, apply resistance against the upper and lower lips in the upward and downward directions, and instruct patients to maintain effort against resistance for a few seconds.
2. If the cheek muscles are weak, instruct patients to tightly purse their lips while keeping them closed and then pull the corner of their lips to the side. This is also held for a few seconds per repetition.

Explanation

If the tongue muscles are loose, we can increase muscle tone by vibratory stimulation or tapping. If they are tense, we can improve muscle tone by massage or stretching.

3. In training for lifting the tip of the tongue, instruct patients to open their mouth and strongly push the tip of their tongue against the maxillary anterior teeth for a few seconds. If the mandible moves to assist movement of the tip of the tongue, use a bite block to maintain the mandible stretched open during the exercise. We can also use pronunciation exercises using sounds that require movement of the tip of the tongue (ie, "t," "d," and "n" sounds). Give patients feedback about whether movement of the tip of the tongue is sufficiently strong and pronunciation is correct.

Explanation

In training for lifting the dorsum of the tongue, apply light pressure to the dorsum of the tongue using a tongue depressor, spoon, or your rubber-gloved fingers. Instruct patients to lift their tongue against that resistance and maintain that effort for several seconds. Using our finger helps us to directly sense the degree of force applied to the dorsum of the tongue. It has recently become possible to use a tongue pressure measurement device to measure parameters such as the specific degree of force applied to the tip or dorsum of the tongue, duration of effort, and effects of exercise.

Explanation

4. When performing mouth-opening and mouth-closing training, be mindful of patients' seated posture and positioning before starting the training in order to prevent excessive strain of the head and neck, including clenching of the teeth. If patients have pain due to temporomandibular joint contracture or dislocation and may not be able to open or close their mouth, don't force them to do the exercises. Instead, consult a dentist or oral surgeon, particularly one with expertise in arthrosis of the temporomandibular joint.

Explanation

First, muscle tension is relieved by massaging the masseter muscle or temporal muscle. Then, patients are instructed to slowly open and close the mouth, then protrude and retract the mandible, and then move it left and right. If they cannot execute these movements well, we can use our hands to gradually increase the range of motion. If they can't close their mouth well, they should place both their thumbs at the mandibular molars and apply resistance as they gently close their mouth with their own strength. If they can't exert enough force, we can use our hands to help them close their mouth.

Explanation

5. The first step in training for mastication and propulsion is to have patients slowly mimic mastication movements with nothing in their mouth. Once they can achieve some degree of rhythmic movement, they can bite down on gauze or a tongue depressor placed at the molars. Next, to prevent accidental swallowing, use gum or a similar substance wrapped in gauze for chewing. Place it at the left or right molars and move the gum or a similar substance wrapped in gauze to make mastication movements on each side. Once patients can make spontaneous tongue movements, instruct them gradually to move the substance for chewing from left to right in the mouth to practice mastication.

Explanation

In training for bolus transport as well, have patients to simulate movements that transport a bolus, by instructing them to place the tip of their tongue against the maxillary anterior teeth, create a cup in the center of the tongue, gradually move the tongue backward following the hard palate, and swallow air. We can also use lollipops to practice this movement, by having the patient lick the candy. However, putting sweet food into the mouth causes large amounts of saliva to be secreted, so we must look out for drooling and particularly aspiration when using this approach.

References & Recommended reading

1. Saitoh E & Mukai Y eds:Dysphagia Rehabilitation, 2^nd edition, Ihiyaku Publishers 2007
2. The Society of Japanese Clinical Dysphagia Research eds: Rehabilitation for Dysphagia 2^nd edition, Ishiyaku Publishers
3. Seirei Mikatahara General Hospital Swallowing Team eds: Pocket Manual of Dysphagia 2^nd edition, Ishiyaku Publishers, 2003