According to the NIMH, no one knows for sure what causes learning disabilities. Some possible causes are genetic factors, parental alcohol, tobacco and other drug use, problems during pregnancy or delivery, toxins in the child’s environment, and chemotherapy or radiation exposure at a young age. New scientific evidence seems to show that learning disabilities do not stem from a single area of the brain; the difficulties arise when information from the various levels of the brain needs to come together. Studies from the NIMH have found, “New research indicates that there may be variations in the brain structure called the planum temporale, a language-related area found in both sides of the brain.” For example, in a person with dyslexia, the two structures are equal in size. In a person without dyslexia, the left planum temporale is noticeably larger.

LD’s can be divided into three broad categories: developmental speech and language disorders, academic skills disorders, and other—anything not covered by the first two. Development speech and language disorders include development articulation disorder, or the trouble controlling the rate of speech; developmental expressive language disorder; and developmental receptive language disorder, where the brain seems to be set to a different frequency and perception is poor. Developmental receptive language disorder often goes hand-in-hand with a developmental language expressive disorder. Academic skills disorders include developmental reading disorders, developmental writing disorders and developmental arithmetic disorders. The other learning disabilities category encompasses motor skills disorders and anything else.

Obviously, the types of learning disabilities are varied and affect people in different ways. The NIMH says, “LD is a broad term that covers a pool of possible causes, symptoms, treatments and outcomes.” The most common learning disabilities include attention deficit and attention deficit hyperactivity disorder (ADD), dyslexia and hyperlexia. Other, rare forms of learning disabilities include dyscalculia (a math disability caused by an organic condition of the brain in which a person has a difficult time solving math problems and grasping math concepts), dysgraphia (a writing disability where letters are hard to form and hard to write in a defined space which is caused by brain damage) and dyspraxia (the impairment of the ability to perform coordinated movements).