Savant syndrome is a condition in which a person with mental retardation exhibits exceptional skill or brilliance in some limited field.^[1] People with savant syndrome may have neurodevelopmental disorders, notably autism spectrum disorders and/or brain injuries, demonstrate profound and prodigious capacities and/or abilities far in excess of what would be considered normal. In spite of the name syndrome, it is not recognized as a mental disorder, or as a part of mental disorder, in any of the medical manuals, such as the ICD-10^[2] or the DSM-IV.^[3]

According to psychiatrist Darold Treffert, almost all savants have special, prodigious memory, which he describes as "very deep, but exceedingly narrow". It is narrow in the sense that they can have exceptional memory but some of them have difficulty putting it to use. Savant skills are usually found in one or more of five major areas: art, musical abilities, calendar calculation, mathematics and spatial skills.^[4]

Savant syndrome is poorly understood. No widely accepted cognitive theory explains savants' combination of talent and deficit.^[5] It has been suggested that individuals with autism are biased towards detail-focused processing and that this cognitive style predisposes both individuals with and without autism to savant talents.^[6] Another hypothesis is that savants hyper-systemize, predisposing them to show talent. Hyper-systemizing is an extreme state in the empathizing–systemizing theory that classifies people based on their skills in empathizing with others versus systemizing facts about the external world.^[7] Also, the attention to detail shown by many savants is a consequence of enhanced perception or sensory hypersensitivity in these unique individuals.^[7][8] It has also been confirmed that some of these savants operate by directly accessing low-level, less-processed information that exists in all human brains but is normally unavailable to conscious awareness.^[9]

• There is no agreement about how many people have savant skills. The estimates range from "exceedingly rare"^[10] to one in ten people with autism having savant skills in varying degrees.^[4]
• 50% of savants have autism; the other 50% often have psychological disorders or mental illnesses.^[4]
• Some prodigious savants have very significant disorder and disability. Examples include Richard Wawro, Henriett Seth F., and Jonathan Lerman.

A 2009 British study of 137 parents of autistic children found that 28% believe their offspring met the criteria for a savant skill, defined as a skill or power "at a level that would be unusual even for normal people".^[11]

• As many as 50 cases of Sudden or Acquired Savant Syndrome are currently profiled.^[12]

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 for this 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.^[4][10]

The 1988 fictional film Rain Man was loosely based on the savant Kim Peek, among others.^[13]

A prodigious savant is someone with a skill level equivalent to or greater than that of a prodigy, regardless of any cognitive disability. The most common trait of prodigious savants is their seemingly limitless mnemonic skills, with many having eidetic or photographic memories. Prodigious savants are extremely rare, with fewer than one hundred noted in more than a century of literature on the subject. Treffert estimates that fewer than fifty or so such individuals are alive today.

The following are well-known people with savant syndrome, noted for their talent in their identified fields:

• Asperger syndrome
• Ideasthesia
• Creativity and mental illness

• The Wisconsin Medical Society lists 29 savant profiles.