The Importance of Crossing Midline and Sensory Processing Disorders

The following is an excerpt adapted from: From Flapping to Function: A Parent's guide to Autism and Hand Skills

Typically developing children naturally cross midline  (CML) during play and functional activities. This is not a skill that parents usually teach, which is why you have probably never heard of this term. Children with dyspraxia or other types of Sensory Processing Disorders (SPD) may avoid crossing midline. Related red flags that a child has SPD include:

  1. Avoiding stabilizing toys with one hand while manipulating them
  2. Switching hands frequently so that one hand does not develop skill for complex tasks such as cutting on a line
  3. Low muscle tone and/or hand strength; and
  4. Poor motor control

What is Midline?

MIDLINE: is an imaginary vertical line running from the top of the head to the toes, that divides the body into left and right sides. 

Seven-year-old Pedro reached for markers using whichever hand was closest to them, and then used that hand to color. He didn't attempt to stabilize the paper with his opposite hand. Observing this, the teacher, consulted with the school occupational therapist, Leila.

Leila recommended that he practice forming large circles on a whiteboard. She offered him a marker positioned directly in front of him at, midline. He grasped it with his left hand, suggesting this hand might be dominant. Leila gently held his right arm at his side while he drew large circles on the board. Next, Leila placed her hand on top of his to guide his movements. With this help Pedro was able to trace over large diagonal crosses and horizontal figure-eights without switching hands. Leila encouraged Pedro to use the same hand to reach for materials such as puzzle pieces and pictures during sorting tasks.

Activities to Strengthen Hands

Leila also recommended activities to help Pedro strengthen his hands, especially his fingers, so that he didn't switch the marker from hand to hand due to fatigue. His teacher tried the 1-2-3 PULL activity shown in the video below and realized that Pedro's left hand had better control than his right when pulling the rings. This observation reinforced the idea that he was left-hand  dominant. 

Here are a few activities that help to develop strong hands:

  1. Ripping apart paper, fabric or Velcro
  2. Play dough and clay
  3. Squeeze toys such as balls that squeak
  4. Squeeze pins 
  5. Using tools such as scissors, hole punchers, staplers or tongs that require force.
  6. Push peg boards
  7. Lego bricks, Tinker Toys and other construction toys

Crossing Midline Throughout the Day

Occupational therapists love to set up materials to require CML! The girl on the horse is shown using her right hand to remove clips attached to the mane to insert into the basket on her left. Set-up may be as simple as asking for a high five without letting the person switch hands to avoid CML. Here are a few simple adaptations:

  1. Play Twister, Simon Says or Copy Me as you CML. The girl in the photo crosses midline with her left hand to touch the vibrating cushion to her right side.

2) As the child to place stickers on the opposite arm or leg.

3. Swat at a suspended ball, taking turns using right and left hand for 5-10 swats. The child will end up, at times, CML as the ball moves.

Finally, the last video demonstrates an activity that uses either Scrabble tiles or alphabet blocks. This works on many visual and fine-motor skills as I alternate hands to place the letters alphabetically. Consider adding challenging by listing spelling words on a wall board to then spell out with the tiles on the table. This adaptation will work on visual skills as the child looks back and forth from wall (in vertical plane) to tiles ( in horizontal plane), as well as helping to ace the upcoming spelling quiz!

Source: Crossing Midline Alphabet Sequencing for Children with Sensory Processing Disorders by RecyclingOT


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