Savantism

http://www.autismtoday.com/articles/SavantSyndrome.htm
By Darold A. Treffert, M.D.

Savant Syndrome is a rare, but spectacular, condition in which persons with various developmental disabilities, including Autistic Disorder, have astonishing islands of ability or brilliance that stand in stark, markedly incongruous contrast to the over-all handicap.
The term idiot savant (French for"learned idiot" or "knowledgeable idiot") was first used to describe the condition in 1887 by John Langdon Down, who is known for his description of Down Syndrome. The term "idiot savant" was later described as a misnomer because not all reported cases fit the definition of idiot, originally used for a person with a very severe mental retardation. The term autistic savant was also used as a diagnosis forthis disorder. Like idiot savant, the term autistic savant also became looked at as a misnomer because only one-half of those who were diagnosed at the time with savant syndrome had autism. Upon realization of the need for accuracy of diagnosis and dignity towards the individual, the term savant syndrome became widely accepted terminology.[3][9]
In some, savant skills are remarkable simply incontrast to the handicap (talented savants). In others, with a much rarer form of the condition, the ability or brilliance is not only spectacular in contrast to the handicap, but would be spectacular even if viewed in a normal person (prodigious savant). There are fewer than 100 reported cases of prodigious savants in the world literature. The condition was first named Idiot Savant in 1887 by Dr. J.Langdon Down (better known for having named Down's Syndrome). He chose that term because the word "idiot" at that time was an accepted classification level of mental retardation (IQ below 25) and the word "savant" meant knowledgeable person derived from the french word savoir, meaning "to know". The term idiot savant has been largely discarded now, appropriately, because of its colloquial,pejorative connotation and has been replaced by Savant Syndrome. Actually Idiot Savant was a misnomer since almost all of the reported cases have occurred in persons with IQs of 40 or above. The condition can be congenital or acquired in an otherwise normal individual following CNS injury or disease. It occurs in males more frequently than in females in an approximate 6:1 ratio. 
  
Savant skills occurwithin a narrow but constant range of human mental functions, generally in six areas: calendar calculating; lightening calculating & mathematical ability; art (drawing or sculpting); music (usually piano with perfect pitch); mechanical abilities; and spatial skills. In some instances unusual language abilities have been reported but those are rare. Other skills much less frequently reportedinclude map memorizing, visual measurement, extrasensory perception, 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 symbolicincluding 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)...