Here’s how dysgraphia symptoms may also be explained by retained primitive reflexes and incomplete lower brain development.
Illegible writing can be a sign of one or more retained primitive reflexes. For example, if the Palmar Grasp Reflex is still active, such people are still “wired” to clutch whatever they are holding. So they will not naturally develop the tripod pincer grip, and the latter is what we use to hold a pencil correctly. These people then either spend a great deal of effort trying to override the Palmar Grasp Reflex (and then what is left to remember how to write the letters?), or they will attempt to write without a proper grip. Both scenarios often result in illegible writing.
A retained Asymmetrical Tonic Neck Reflex (ATNR) and Symmetrical Tonic Neck Reflex (STNR) interfere with writing in a different way. When these reflexes are still active, head movement causes the arms and legs to bend and straighten involuntarily. For example, a person with a retained ATNR will want to straighten his arm every time that he looks at the pencil. But every time that he looks away, his arm will want to bend. Such back-and-forth movement affects the motor control of the wrist and fingers and results in poor penmanship and fatigue when writing.
Until the ATNR is inhibited, it’s almost as though there is a “wall” between the left and right brain hemispheres. When such people cannot get across the wall, they may not be able to retrieve information that was stored in the opposite hemisphere. This, then, may explain why some people are inconsistent in recalling how to write letters.
Writing letters also requires the ability to see details that differentiate letters from each other. Being able to see details is acquired when the midbrain develops.