With thanks to Nancy O’Dell and Patricia Cook, who wrote the book: Stopping ADHD.
The Symmetrical Tonic Neck Reflex (STNR) is one of the primitive, reflexive movements made by all human babies. The STNR is an automatic movement that makes the top half of the body work in opposition to the bottom half. This means that when the top half of the body is straight, the bottom half bends, and vice versa. It also makes it possible for the right and left sides of the body to work together. The reflex is activated by a change in the position of the neck, which produces a change in the muscular tension (tonic).
The reflex makes it possible for a baby to crawl and then after a good long period of crawling – about six months – the child should have crawled enough to be in control of his body rather than having the STNR in control. If something goes wrong along the developmental path, the child may not be able to crawl easily and so find the attempted movement so frustrating that they simply get up and walk early. This allows the STNR to remain past it’s due date!
Early on, the interference of the STNR may not be noticeable because young children are allowed lots of freedom to sit as they like and move more. They are seldom required to remain at a desk to complete tasks and listen to the teacher for long periods.
If his body is controlled by the STNR, a child will feel more comfortable if his arms are straight when sitting with knees and hips bent, or sitting with straight legs when the arms are bending in order to write. If the STNR caused a child’s arms to actually shoot straight out in front of them when their legs are bent, adults would realise a problem. But the reflex is not so obvious. We are talking about normal children who are still experiencing the ‘pull’ of the reflex, rather than being totally under its control. This means that they may be able to sit normally for a while but they cannot sit comfortably and they cannot sit still for long periods of time.
What you might see.
Children start to move in ways that help to relieve the physical tension they feel when required to sit still. They may reach their arms across the desk to try and maintain straight arms; they may sit on one or both legs under them; they may try to ‘lock’ their bodies into their chairs by wrapping their feet around the chair legs; they may prefer to lie on the floor; they may slouch in their chairs, keeping their arms and legs stretched in front on them; they may prefer to stand at their desks; they may try to write with their head on one of their arms.
And the STNR doesn’t only affect sitting but also impacts on other aspects of learning. For this reason, it is important to check that a retained STNR is not part or whole of your child’s ‘disruptive’ behaviours and school difficulties.