By moving an object that makes a mark, such as a pencil, back and forth, a line is drawn. The line is a concrete representation of the effects of their actions. Drawing a line is an elementary form of organizing and seeing the effects of the actions of the hand. Writing and drawing are based on understanding this cause and effect relationship, which can be done with a stick in the dirt or petroglyphs on rocks.
Most back and forth motions are done with the right hand in the horizontal plane. Somewhere around 90% of all the people in the world are right handed, which is unique to humans and thought to be related to the fact that a similar percentage of people have their speech centers located in the left hemisphere.
All three possible anomalies to being right hand dominate and left hemisphere speech dominate do, in fact occur. Because we all know someone who is left-handed, moving back and forth with the left hand is not surprising. Speech hemisphere dominance is unknown for most people. These irregularities probably explain many of the differences observed with cerebral vascular accidents and right versus left hemiplegia.
Using both hands to move a bilateral sander or exercise equipment in a vertical plane might escape your consideration, but it can qualify as an equivalent task because the same people are able to move up and down, bilaterally within ACL 3.2.
Independent turning of the pages in a book usually enters the scale within ACL 3.2, with the repetitive back and forth motion. They may pay more attention to the motion of turning of the pages than looking at the pictures. That becomes apparent when they hold the book upside down. If turning the pages is what interests them and sustains their attention, there is no reason to turn the book right side up. If they are happy, leave them be.
Dropping and tossing balls requires attention to releasing the ball. Familiar, light weight balls are less apt to be turned into a weapon. Ping pong balls may be the best size for those people who have a tentative grasp.
The back and forth motion can be engaged in using bath mitts and sponges. The action is usually independent and located in one spot. The cute animals are prolific in dollar stores now, and they do help capture their attention. While they are busy "washing" in one spot, the caregiver can clean other essential areas. And or, their use can be during scheduled activities at a different time of day.
All of these scrub brushes tend to have procedural memories associated with a back and forth or circular motion. The motion will probably be restricted to the spot in front of them and the adequacy of cleaning is not the point. Women are especially prone to have an activity history of feeling useful while cleaning. Some ladies have been known to do it too long.
People who have no history of using scrub brushes can imitate the back and forth motion and do enjoy this activity. When scrubbing is out of character, friends and family can be reassured by their taking pleasure in doing a repetitive motion.
Planning ahead for wet and soapy storage prevents aggravation in the long run. This container is made of metal and covered in plastic, and came from the dollar store.
