In part, because the fingers are situated away from the center of the body, and they require more brain power to access, coordinated improvement of finger patterns are among the latest to develop during childhood.
Infants are born with grasp pattern reflexes that allow them to hold objects early in development. However, integrated patterns of touch sensations followed by motor expression begin to take a while to develop.
The ability to use both hands together emerge as a feature of early learning.
However, skilled use of the hands and fingers are typically delayed for children who have sensory processing dysfunction. This means that the ability to manipulate objects tends to be delayed for children with SPD. Their ability to impact their environment is compromised. In a similar manner, their opportunity to learn about the three dimensional world in which they live in is constricted.
Toys that allow for manipulation of medium sized construction elements are helpful. Since these type of toys typically move when they are not held properly, they inherently provide the type of feedback needed to teach about using both hands together.
Use of a visual model to be copied from is also an essential ingredient needed. Since these children typically lack the ability to integrate visual perceptual feedback efficiently with their motor output, having an image to compare their product with helps the learning process.
Finger function skills, from holding a pencil or crayon properly, to buttoning a shirt as well as shoe lace tying require separated use of the fingers. Different sides of the hand should begin to develop into dedicated motor patterns as the growth process continues.
In practical daily living activities, the ability to separate both sides of the hand results in the ability to carry more than one thing in each hand at one time on a semi-automatic basis. For example, automaticity in being able to separate out the key for the car ignition switch, while holding the other keys away so that you can insert the ignition key and turn on the motor is useful. We use the skill of separated hand function in everyday living tasks on a semi-automatic basis.