According to Burns, ADD, dyslexia, and auditory processing disorder share a fundamental problem: difficulty in understanding and processing speech.
Essentially, in all three of these disorders, the parts of the brain that handle sensory input develop earlier than those responsible for focus and attention. This causes the overlapping symptoms that can easily confuse medical professionals. For example, what looks like a child with ADD simply not paying attention may, in fact, be a child who simply cannot understand what is being said. If they are misdiagnosed, treatment will certainly be ineffective.