I had a friend who used to wear different earrings in each ear because she loved to create a different visual experience when she turned her head. She finally convinced me to see the value of asymmetry in visual art but in motor development, it’s not such a great thing. Don’t get me wrong, between 2 and 3 months of age it is typical for babies to display movement and posture that is opposite on one side of the body from the other.
But after that, babies move towards symmetrical posture, bring their head and hands in to the middle and begin using both hands together. It’s as if they need to experience the extremes of range individually and then they can discover the middle.
The development of symmetry comes from a balanced activation of the extensors on the back of the trunk and flexors on the front, as you can see in the child in the second photo. Activation of the flexors is extremely important not only for motor skills but also to help the eyeswork together as a team, which impacts depth perception and eye-hand coordination.
Things go awry when children can’t make it to the middle; they begin to use the asymmetry for stability. The child in the first photo can turn his head and look at toys but if he needs to stabilize his b
ody in this position, he will have trouble picking them up or bringing them to his mouth or to his other hand to play with them. This will interfere with fine motor and cognitive skills.
Many of my clients have been born with low tone in their trunk. This low tone allows them to fall into gravity, which allows activation of their extensors but is a challenge when it comes to activating the flexors. And without that flexion, a child remains in asymmetrical postures. Unfortunately, this asymmetry interferes with visual skills as well as movement and fine motor skills.
Asymmetry can result from any number of issues. I’ve already mentioned low tone. As well, many children with motor and sensory challenges learn to rely on asymmetry for stability. Children with torticollis (shortening of a neck muscle on one side) also experience asymmetry, as do many children with medical issues (e.g. G-tubes, heart surgery). Prolonged asymmetry can result in difficulties with balance, vision, eye-hand coordination and perceptual skills.
So when you are playing with your child promote symmetry whenever you can, beginning with the head and eyes, because it can support such a variety of skills.
Shelley Mannell PT
HeartSpace Physical Therapy for Children www.heartspacept.com
@heartspacept on Twitter or HeartSpacePT on Facebook
Photo credit: www.ehow.c
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