rception, unusual sensory discrimination such as enhanced sense of touch & smell, and perfect appreciation passing time without knowledge of a clock face. The most common savant skill is musical ability. A regularly re-occurring triad of musical genius, blindness and autism is particularly striking in the world literature on this topic. Premature birth history is commonly reported in persons with Savant Syndrome. In some cases of Savant Syndrome a single special skill exists; in others there are several skills co-existing simultaneously. The skills tend to be right hemisphere in type--nonsymbolic, artistic, concrete, directly perceived--in contrast to left hemisphere type that tend to be more sequential, logical, and symbolic including language specialization. Whatever the special skills, they are always linked with phenomenal memory. That memory, however, is a special type--very narrow but exceedingly deep--within its narrow confines. Such memory is a type of "unconscious reckoning"--habit or procedural memory--which relies on more primitive circuitry (cortico-striatal) than higher level (cortico-limbic) cognitive or associative memory used more commonly and regularly in normal persons. Approximately 10% of persons with Autistic Disorder have some savant abilities; that percentage is much greater than in other developmental disabilities where in an institutionalized population that figure may be as low as 1:2000. Since other developmental disabilities are much more common than autism, however, the actual percent of persons with Savant Syndrome turns out to be approximately half Autistic Disorder and half other Developmental Disabilities. Theories to explain Savant Syndrome include eidetic imagery, inherited skills, concrete thinking and inability to think abstractly, compensation & reinforcement, and left brain injury with right brain compensation. Newer findings on cerebral lateralization, and some imaging and other studies that do sh...
