New vocabulary word: dissociation-- to remove from association; separate.
With regards to human body, this describes the ability to use various sets of muscles independent of one another--to use them separately. When a baby is newborn, she has no head control. If you unwrap her from her swaddling, her body will all flail about. She has no ability to control her muscles individually, so everything moves at once.
Gradually, over the course of months, she starts to get head control. This is the beginning of muscular dissociation. Head-body dissociation is the first accomplishment.
Next on the dissociative oral motor menu comes jaw-from-head. Being able to move the jaw requires control of the head. If the head isn't stable (strong head/neck control), the jaw cannot work independently from the head (just like a baby can use her arms to bat at the mobile, but she cannot use her fingers to grasp until she has fine-tuned her arms; she cannot dissociate her fingers from her arms).
The smaller muscle group is dependent on the strength and stability of the larger muscle group.
Now, let's throw low tone into the mix. It takes a lot longer to get head control. And much much longer to get jaw strength and stability.
Here's a simple exercise for you to do to understand the importance of stability. (courtesy of SRJ)
Sit straight in your chair--back and bottom straight against the back of the chair, with your feet on the floor (or close to it if your legs don't reach), arms in your lap. Your body should be in 90 degree angles at the ankle, knees and hips. Now straighten your legs in front of you. Move your legs together towards the left. Then the right. Point your toes downward. Now point them up.
(Yes, you need to actually do this, not just read it--this is an interactive blog post! And I know you are actually sitting while you are reading this, so it's not like you have at actually move very much!)
You can feel your abdominal muscles working to make the leg muscles behave.
Now, scoot to the front of your chair, with your bottom on the edge of the seat. Your back is not supported. Sit straight up, with your body again at 90 degree angles. Do the same movements--legs straightened out, move side to side, then pointing toes.
Was it easier or harder to move your legs this time?
Yes, much harder. It's because you didn't have stability in your core. The back of the chair provided the stability you needed to perform the muscle task. Your torso and arms, even head and neck were working overtime to try to support your legs. (Try it again and notice which muscles got tight.) Without stability, the leg muscles had to work much harder, and the movements were not as refined as the first time seated appropriately. (If you did this in a computer chair with wheels, you might try it on a regular kitchen chair as well.)
Okay, so stability is important for muscles to work optimally.
Appropriate seating is REALLY important. If your baby/child does not have a firm surface on which to rest her feet, her body will not be able to work optimally. This goes for fine motor skills-doing puzzles, pencil grasp, finger feeding, etc, as well as jaw control. Without a solid footing (literally!), the body spends lots of energy trying to find stability.
The way most people try to compensate for lack of stability is to wrap their feet around the legs of the chair. It's not the best, but it will do in a pinch in the short term. Of course, kids don't always have that option--their legs are too short. So they end up leaning against the high chair tray or desk, or use other forms of bad posture to create stability. Do you have an active child (NDA or with Ds) (NDA=not diagnosed with anything) who can't sit still? Dropping pencils, wiggling in their seat? Frequently adding foot support will help diminish this behavior. Also, having some cushion on the seat helps as well. An actual chair cushion is fine, as long as it doesn't wiggle around, or you could use some dycem to help her bottom stick to the chair. (Dycem= a non-slip rubbery sheet that's a little bit tacky/sticky. It's great stuff--you can cut it to size, it really grips, and can be re-used over and over or permanently glued onto a surface. It's good to use to keep plates and cups in place on a high chair tray. Or cut out shapes to match block shapes and make your own puzzles--tons of things to do with it!)
Last week, when I had Baby K. here, I needed to use Dycem on her booster seat. I didn't have appropriate seating for her (I always end up giving away stuff Hannah has outgrown)--just a booster seat attached to a kitchen chair. Her feet were sticking out straight, and her bottom kept sliding forward. Of course, the lap belt held her in place for safety, but her hips weren't at 90 degrees. So I stuck a piece of Dycem on the seat. You wouldn't think that something to anchor her tush could improve her ability to drink from a straw cup and use her pincer grasp, but it did. She had more stability so she could dissociate more of her muscles.
Back to the jaw...
In my opinion, the missing piece in the Beckman exercises is the lack of specific attention to the jaw. With that technique there is no straightforward way to increase both strength and stability of the jaw. Granted, we didn't get very far in the Beckman program, but it seemed rather passive to me--with the therapist doing the work and the client just allowing her mouth to be massaged, pulled and pushed. It seemed more sensory based rather than strength building. (Disclaimer--I could be way off, and I'm not trying to bash the Beckman protocol--it just didn't make that much sense to me.)
Guess what happens if you don't have stability and strength in the jaw? The tongue and lips cannot dissociate. The larger muscle group (jaw) needs to provide stability for the smaller muscle group (tongue, and then later, lips).
I've seen several blogs recently post Sara Rosenfeld-Johnson's 1997 article The Oral-Motor Myths of Down Syndrome. (Yes! Please print it out and read it until you understand it. It might not be applicable to your child, but it is important that you know and can share this information. Bottle or breast feeding--keep the baby's ear higher than the mouth.) Down Syndrome New Mama posted a link back in February, and it is interesting to read the comments readers left.
I certainly thought Hannah had great oral motor skills before I learned more about oral motor skills. We waited to start puree foods until Hannah could sit relatively well. She was about 9 months old when she could sit well in a high chair (Dycem, where were you when I needed you?). Have you ever tried to eat and swallow while semi-reclined? Isn't it difficult? And the mouth is usually even with the height of the ears if the body is semi-reclined. Our kids with low-set small ears also have low tone in the sphincter at the base of the Eustacian tube. This sphincter's job is to open and close to regulate air pressure in the ear. Of course, frequently in the Ds population, the sphincter is weak, so milk or liquid food (purees) can easily slip in to the Eustacian tube, eventually causing ear infections. Not a good plan. I'm all for delaying solids until a baby can sit.
Back to the jaw, again.
Hannah could and would eat just about anything as a toddler. None of my kids liked meat as toddlers, so it wasn't a surprise that she didn't care for it. She could eat a bagel, so I figured she could chew "tough" foods. She didn't "stuff"-putting too much food in her mouth. She didn't have sensory issues in her mouth--textures weren't a problem, she didn't avoid any foods.
So it came as a surprise to me when her first official oral motor evaluation indicated that Hannah had a weak jaw. Besides a weak jaw, she had unbalanced weakness--her left side was significantly weaker than her right. I never noticed that she chewed primarily on the right side. I didn't ever really look in to see if she was using her tongue to move food from one side of her mouth to another. I was surprised that SRJ could practically pinpoint when the imbalance started--she had me bring a series of pictures from birth to age 3+ so she could see Hannah's smile. I never would have noticed that the left side of her smile was slightly lower than her right. When she pointed it out I could see it. Even a frown showed the imbalance. See that pout?
You can see that her right side has more defined musculature. The little "frown line" goes much further downward on the right. Her left cheek is a little puffier (though she is off kilter a bit anyhow).
I woulda used a new picture if I wasn't so lazy...sorry about that. I'm sure I've got one that would be a better example, but I'd have to hunt through a decade of photos (Eight years ago an inquisitive 4 year old redhead who will remain nameless shuffled a decade's worth of pictures, never to be organized again).
Jaw. How to fix that? How to give the tongue the support it needs to make all the moves it needs?
