Reader inquiry on sensory integration and speech delay, August 28, 2008

My son has a speech delay and has some mild sensory integration issues. He is a picky eater and prefers certain textures, i.e. crunchy, hard vs. soft foods. The occupational therapist who evaluated him said that many times when you resolve the sensory issues, the child's speech progresses. How are the two related? What sense is involved with the speech process? If the sensory integration affects speech, what activities help with the speech process?

Whole body connected--take a look

I heard a story once about an American man who suffered from frequent migraines. He tried over-the-counter and prescription medications and went to a whole string of specialists, but nothing helped. When a friend suggested acupuncture, he was skeptical, but desperate enough to try anything, so he made an appointment with a Chinese doctor who came highly recommended. At his first appointment, the doctor had him lie down and began to examine his feet. Wondering if perhaps the doctor hadn't understood his English, he timidly ventured to say, "Excuse me, but I'm here because of migraines. You know, headaches." The doctor continued palpating his feet; "Yeah, yeah, headache. Migraine. I know," he said without looking up. Perplexed, the patient asked, "Is there some sort of connection between the feet and the head?" Impatiently, the acupuncturist replied, "Whole body connected--take a look."

Whole nervous system connected

Like the rest of the body, the nervous system is all one unit. To be sure, the nervous system has many parts, but really there is no part of the human nervous system that is not connected to every other part, so really all the senses are involved one way or another.

The "five" senses

Perhaps the most obviously relevant sense is hearing (sign language excepted, of course). Auditory input from other speakers affects our pronunciation, and auditory feedback from our own speech allows us to monitor the accuracy of our speech.

Sight is also relevant. Although blind people can develop superb speaking skills, and even sighted people routinely carry on conversations by telephone, we use visual information when it is available. In addition to facial expressions and gestures, we often reinforce our listening by watching the speaker's lips. Most of us cannot lip-read very accurately, but watching the speaker's lips does contribute to our perception of what is being said. A nice illustration of this is what is called the "McGurk effect." If you watch a video of a person saying "Bah" with the syllable "Gah" dubbed over it, so that you are seeing "Bah" and hearing "Gah", you will perceive neither "Bah" nor "Gah", but "Dah". The same thing will happen if you see "Gah" and hear "Bah"--you will perceive "Dah". Numerous demonstrations of the McGurk Effect are available on YouTube.

It's harder to make a case for taste and smell, but our sense of touch (tactile sense) contributes to speech because of the contact that occurs between the articulators (e.g. the upper and lower lips for /p/ an /b/; the back of the tongue and the soft palate for /k/ and /g/). The tactile sense also helps us monitor the flow of breath through our oral and nasal passages, as well as vibration in the larynx and the resonance chambers of the pharynx, nose, and mouth.

The sixth and seventh senses

Although we often refer to "the five senses," we actually have seven. The two that get left out are the vestibular sense (the sense of balance) and the proprioceptive sense (the sense of the body's position and motion). Both are important for speech.

Proprioception is the sense of the body's position in relation to itself, and movement of the body's parts. This is the sense that tells you which joints are bent or extended, which muscles are contracting and which are relaxing. Nerve endings embedded in the muscle fibers fire messages to the brain to tell it when the fibers are stretched. These messages are crucial for reflexes like the "knee jerk", when your doctor hits the tendon just below your knee cap and your foot kicks outward. They also help regulate muscle tone. Proprioception is crucial to fine motor coordination. The proprioceptive and tactile systems work together to allow us to grip an egg firmly enough not to drop it but gently enough not to crush it.

The vestibular system controls what we often think of as our sense of balance. Messages from the semicircular canals in the inner ear relay information to the brain about motion and any changes of our position in space. Because the semicircular canals are in the inner ear, the messages they send are carried along the same nerve, Cranial nerve VIII, as auditory signals travelling from the ears. Therefore, difficulties with vestibular processing often co-occur with hearing and auditory processing deficits. The vestibular system works with the visual system to enable us to keep our eyes focused on an object while we are in motion. This is why the entire world doesn't appear to be shaking when we are running or riding a horse. When you hear a noise and turn toward it, that's the vestibular and auditory systems working together. When the makers of IMAX films use camerawork and surroud sound to make you feel like you're in motion even when you are sitting still in a theater, they are manipulating the visual and auditory systems to "trick" the vestibular system.

Sensory integration and speech

Speech is a fine motor activity. Every time we talk, dozens of muscles from the abdomen, chest, neck, larynx, pharynx, jaw, tongue, face, and lips work together with precise coordination and sequencing. The brain coordinates and controls all of these, while at the same time doing all the cognitive processing involved in formulating the message, choosing the appropriate words, grammatical structures, facial expressions and gestures, plus paying attention to the listener's visual and auditory feedback (facial expressions, 'body language,' nods, grunts, sighs, etc.). The process is so complex it's a wonder anyone can do it!

Sensory integration disorders are usually treated by occupational therapists, but they often co-occur with speech and language impairments, so speech-language pathologists are frequently involved in treating children with sensory integration issues, and may incorporate sensory integration activities into their treatment when appropriate.

Since I have not met your son, I can't really determine what specific activities would be beneficial for him. My advice is to follow your OT's advice and recommendations, and make sure that both his speech therapist and is OT are aware of each other's goals. Hopefully they have both given you a home program to work on. Work both programs every day if your son can handle it.

The Out of Sync Child by Carol Stock Kranowitz is a book with lots of great information on sensory integration. The Out of Sync Child Has Funby the same author is full of sensory integration activities that you can do at home, including a number of respiratory and oral-motor activities.

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