The Oral Motor System and The Gustatory System

The gustatory system is better known as our sense of taste. As mentioned, it works very closely with the olfactory system (smell). But what’s also very important for children with autism, and sensory processing challenges is the oral motor system.

The oral motor system is not one of the senses. Actually, it’s about the way the senses are interconnected and work together inside the mouth. This system enables us to not only taste but to chew, swallow, and communicate.

It’s also the system that tells the brain if something is hot or cold, chewy or mushy, etc.

These textures and temperature, along with the actual flavor detected by the gustatory system, and the smell, combined play a huge role in how people respond to different foods.

Disclaimer: This post contains affiliate links,

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This post is part of a 10 part series on the sensory systems. Each part will contain a table of contents to help you easily navigate through the entire series.

Table of Contents:

1. Introduction – The Sensory Spectrum
2. The Tactile System
3. The Auditory System
4. The Visual System
5. Proprioception
6. Vestibular System
7. Interoception
8. The Olfactory System
9. The Oral-Motor System
10. Bilateral Coordination

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How Does The Gustatory System Work?

First, we’ll look at how the gustatory system works, then examine how all of the senses work together inside the mouth as the oral motor system.

Your tongue is porous. These pores are called papillae.  If you look at your tongue in the mirror, you will actually see the papillae. And all of your taste buds are located inside of these papillae.

Actually, each papilla has anywhere from 5 to 1000 taste buds inside of it.

Your taste buds are composed of gustatory receptors. These are the sensory receptors that detect flavors, then relay sensory information to the brain.

There can be anywhere from 10 to 50 gustatory receptors per taste bud (and 5 to 1000 taste buds per pore). If you did the math, that’s a lot of sensory receptors.

Those aren’t all of the sensory receptors on the tongue though. Tactile receptors surround them and detect pain and temperature.

Basically, whenever something enters our mouth (mainly foods, but other items can activate receptors, too), the gustatory receptors are activated.

The chemical structure of flavor cells determines which gustatory receptors are activated. Next, activated receptors initiate a nerve impulse, sending the message through the neural pathway, to the brain.

Because the different types of these receptors respond to different substances you don’t taste chocolate with the same taste buds/receptors that you use to taste a hot pepper. 

When Taste Signals Reach The Brain

While examining the other senses you may have noticed that neural signals typically go straight to their sensory cortex where they are interpreted by the brain and then a response is generated.

The gustatory system is a little different. Signals from this system make a pit stop at the brainstem first before arriving at the gustatory cortex.

The brainstem determines what unconscious reaction to taste you’ll have. For example, if the taste is unpleasant, your brain stem may trigger nausea or cause gagging as an automatic reaction. That can happen before you actually taste the food (although the whole thing happens so quickly you won’t be able to tell).

It’s not until the signal reaches the gustatory cortex that we taste the flavor of something. Here, all taste information gets sorted and is how you actually perceive the taste of your food.

Signals from the olfactory system also go to the gustatory cortex because smell plays a large role in taste. For example, think about how having nasal congestion affects the way your food tastes.

The Oral Motor System

The oral motor system involves all of the senses inside the mouth and it’s what creates the entire experience of any oral input.

• The need to chew, bite and suck comes from the proprioceptive input that we receive from pressure and movement in our jaws. 
• How things taste come from both the gustatory and olfactory systems. 
• The tactile system detects the texture, consistency, and temperature or food.
• Oral sensory processing doesn’t only effect eating. It also affects the way we move our mouth, control saliva, and produce sounds for speech.
• How the sensory systems work together affects all sensory processing issues within the oral motor system.

Sensory Processing Challenges Related to the Oral Motor System

As I mentioned multiple sensory systems and how they work together impacts processing issues inside the mouth. Here are some examples:

• Food aversions may be from hypersensitivity to tactile input. This can make certain textures unbearable. If this is the case, your child might avoid certain foods. Or, they may refuse to eat foods that have more than one texture. For example, eating cereal with milk, because the cereal is crunchy and the milk is a smooth liquid.
• If your child has a hyper-sensitive proprioceptive system they may prefer soft foods. If their system is hypo-sensitive they may prefer foods that are crunchy or chewy, and enjoy thick drinks like smoothies and milkshakes through a straw.
• Some people naturally have more taste buds, which makes them experience taste more strongly. For example, they may be highly sensitive to certain flavors – or all flavors – and they may prefer to eat a very bland diet.
• Having more taste buds also means there are more pain receptors on the tongue so they may be particularly sensitive to hot foods as well as spicy flavors.

Signs of Oral Processing Hyper-Sensitivity (Over Responsive)

• Gags or chokes often while eating
• Has trouble using a straw
• Picky eater
• Won’t try new foods
• Avoids “mushy” foods or crunchy foods
• Avoids foods with more than one texture
• Problems with chewing or swallowing
• Drools a lot
• Dislikes brushing teeth
• May have strong emotional reactions (meltdowns, running away, etc) to requests of eating, tooth brushing, etc.

Signs of Oral Processing Hypo-Sensitivity (Under Responsive)

• Frequently mouths non-food items, past infancy, and toddler-hood (for young children this is a normal part of development)
• Chews on items such as clothing, pencils, furniture, toys, etc 
• Bites self or others
• Enjoys, or is insensitive to, spicy foods
• Enjoys crunchy and chewy food
• Makes noises with their mouth that are irritating to others
• Verbal stims
• Grinds teeth or bites lips, or cheeks

Strategies for Managing Oral Motor Challenges

For Over-Responsiveness 

• Blow bubbles, play with whistles.
• Using a three-sided toothbrush so teeth can be cleaned in less time.
• Offer drinks in a water bottle that has a bite valve
• Provide snacks that are soft, or bland, depending on the child’s preferences
• When cooking use smaller amounts (or none) of seasoning/spices because they may be able to taste these more strongly than you can. 
• Use a sticker chart for trying new foods
  
• Sucking on ice just prior to mealtime may help with some kids who are extremely sensitive to flavors by numbing the taste buds slightly. 

For Under-Responsiveness

• Crunchy snacks like raw vegetables, pretzels, crackers, etc.
• Use an electric toothbrush
• Imitate faces in the mirror
• Offer toys for chewing. For example, chewlery, or chewy wristbands for kids who like to chew on their clothing.
• Offer foods with strong flavors. For example, sour candies, or spicy foods
• Offer gum or chewy candy as an alternative to teeth grinding and biting
• Give them a straw to drink applesauce, thick smoothies, milkshakes, or other thick sancks/beverages

Speech-Language Pathology

Speech-language pathologists can do a lot more than just help with speech problems like stuttering and pronunciation.

They can actually help with most oral motor challenges, such as:

• Feeding and swallowing challenges
• cognitive communication including social skills and executive functions
• voice and resonance issues
• motor speech planning
• auditory processing

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