What is the definition or description of: learning disorders?

LD's often present: as ADHD, which is an undifferentiated, attention-based learning disability all by itself. LD's usually come in two main varieties, although there are thousands of subtypes. Visual LD's involve a disturbance/limitation in encoding, organizing and decoding visual information, usually seen in reading. Auditory LD's are the same ony with information taken in with the ears. People can have both