Why Crossing the Midline Matters for Individuals with Autism

Everyday activities – writing, reading, walking, running, or buttoning a shirt – often feel automatic. Coordinating both hands to slip the button on a shirt through its loophole goes without a second thought. Alternating between each arm and leg when going for a morning jog doesn’t require a conscious effort. That ease comes from bilateral coordination, the brain’s ability to let the left and right sides of the body work together in a controlled, coordinated way. Crossing that imaginary center line on the body, however, can be challenging for many individuals with autism spectrum disorder (ASD). Contributing factors include sensory processing difficulties and retained primitive reflexes – early-life movement patterns that should integrate as the nervous system matures.

A 2020 study of 117 children with autism found that 63% demonstrated impairments in bilateral coordination. Retained primitive reflexes – reported in roughly 80% of individuals with autism, can make crossing the visual midline difficult, particularly when the asymmetrical tonic neck reflex (ATNR) remains active. Similarly, 90-95% of individuals with autism experience sensory processing difficulties. Yet effective midline crossing depends on accurate input from the vestibular and proprioceptive sensory systems – both commonly dysregulated in ASD. 

Encouraging midline crossing in autism

Primitive movement training and rhythmic movement training (RMT) directly work to encourage bilateral integration by introducing movements that target retained primitive reflexes, sensory dysfunction, and midline crossing. 

By practicing movements that mirror the ATNR pattern as it appears in early development, neural pathways can gradually be re-patterned to allow for more voluntary control. For example, turning the head to the right while the right arm extends and the left arm flexes – then repeating on the other side – recreates the infant reflex in which limbs on the turned side extend and the opposite limbs flex. With purposeful primitive movement training, reflexes like the ATNR can integrate over time, helping with related challenges such as reduced visual–motor control and difficulty crossing the midline.

Primitive movement training offers a comprehensive approach to address barriers to midline crossing when paired with rhythmic movement training. RMT integrates cross-body and sensory informed movement to build bilateral coordination and support communication across the corpus callosum – the bundle of nerve fibers that allows the brain’s hemispheres to work together. 

Movements such as rhythmically shifting gaze up and down while standing on one foot challenge the vestibular system by combining head motion with balance control, while wall pushes provide strong proprioceptive input through sustained pressure and resistance. Providing purposeful, targeted sensory input to these systems helps the body develop a more regulated response to stimuli and organize feedback more effectively – building a clearer sense of where body parts are in space and in relation to one another.

Primitive movement training and rhythmic movement training together target barriers to bilateral coordination and stimulate both hemispheres of the brain. Improving bilateral coordination makes everyday tasks easier and increases motor control. Research also suggests that even brief, regular bilateral physical activity can significantly improve children’s processing speed, focused attention, concentration, and attention span.

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