Abnormal Muscle Tone Common in Children with Brain-Based Disorder
Children with brain-based disorder, such as ASD, Sensory Processing Disorder and learning disability often have abnormal muscle tone, being either too high (hypertonus) or too low (hypotonus). Muscle tone is determined by messages sent via neural tracts in the central nervous system to the musculoskeletal system. One of the common causes of having abnormal tonus is having had a trauma to the brain, such as a stroke, head injury or being born with structural damage such as Down syndrome. So why do many children with brain-based disorder, without any structural brain damage experience abnormal muscle tone?
Abnormal processing of sensory information between the inner ear, the spinal cord and the stretch receptors in the muscles and supporting ligaments of bones and skin throughout the body is one common cause. This sense, called proprioception, provides awareness of relationships between our different body parts and gives our muscles functional tone. Poor connectivity between these structures can affect the numbers of neural messages being transmitted, the quality of the relay and processing of messages.
In my experience more children with brain-based disorder have hypotonus. These children have difficulty activating postural and core muscles fully, getting into the right position to get the job done and maintaining positions. Lack of normal muscle tone effects balance, especially the ability to stand on one foot, coordinated movement, ability to make smooth, fine adjustment of the eyes and their hand tends to fatigue quickly during handwriting. Some children with hypotonus have speech articulation difficulties, but typically not enough to qualify for formal speech therapy. Auditory processing deficits can result. Others have difficulty with eliminating their bowel and experience chronic constipation or fear of elimination.
To increase the child’s muscle tone and improve proprioception there needs to be experiences available to increase the number of transmissions sent from the inner ear and strengthen the connectivity between the neural tracts in the brain leading to the musculoskeletal system. The most effective way to do this is through regular, consistent activity that will provide the most input or energy to the inner ear. Spinning, jumping, swinging, heavy work with weighted balls, pushing and pulling weighted objects, balancing and holding poses are the best activities with spinning being at the top of the list. Listening to therapeutic sound or music also stimulates the inner ear to send more messages and strengthen connectivity. Combining more than one activity at a time...even better! For instance, sitting with legs crossed holding a weighted ball at chest height or overhead while spinning on a rotation board and listening to therapeutic sound. As a rule, I don’t use spinning with children unless they have hypotonus, because many children get dysregulated and over-stimulated with this type of sensory input.