Savant syndrome

Savant syndrome is a condition in which a person demonstrates one or more profound and prodigious capacities or abilities far in excess of what would be considered normal, yet often also has significant deficits in other areas of brain processing.^[1][2][3] People with savant syndrome may have neurodevelopmental disorders, notably autism spectrum disorders (in which case they are often referred to as autistic savants), or brain injuries. The most dramatic examples of savant syndrome occur in individuals who score very low on IQ tests, while demonstrating exceptional skills or brilliance in specific areas, such as rapid calculation (hypercalculia), art, memory, or musical ability.^[4][5][6][7] Although termed a syndrome, it is not recognized as a mental disorder nor as part of a mental disorder in medical manuals such as the ICD-10^[8] or the DSM-5.^[9]

Another form of savant syndrome is acquired savant syndrome, in which a person acquires prodigious capabilities or skills following dementia, a head injury or concussion, epilepsy, or other brain disturbances. This syndrome is more rare, with a study by Darold Treffert in 2010 showing that in a registry of 319 known savants, only 32 had acquired savant syndrome.^[10]

Signs and symptoms

Savant skills are usually found in one or more of five major areas: art, memory, arithmetic, musical abilities, and spatial skills.^[1] The most common kind of savants are calendrical savants,^[11][12] "human calendars" who can calculate the day of the week for any given date with speed and accuracy, or recall personal memories from any given date. Advanced memory is the key "superpower" in savant abilities.^[11]

Approximately half of savants are autistic; the other half often have some form of central nervous system injury or disease.^[1] It is estimated that 10% of those with autism have some form of savant abilities.^[1][13][14]

Mechanism

Psychological

No widely accepted cognitive theory explains savants' combination of talent and deficit.^[15] It has been suggested that individuals with autism are biased towards detail-focused processing and that this cognitive style predisposes individuals either with or without autism to savant talents.^[16] Another hypothesis is that savants hyper-systemize, thereby giving an impression of 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.^[17] Also, the attention to detail of savants is a consequence of enhanced perception or sensory hypersensitivity in these unique individuals.^[17][18] It has also been confirmed that some savants operate by directly accessing low-level, less-processed information that exists in all human brains that is not normally available to conscious awareness.^[19]

Neurological

Savant syndrome results from damage to the left anterior temporal lobe, an area of the brain key in processing sensory input, recognizing objects and forming visual memories. Savant syndrome has been artificially replicated using transcranial magnetic stimulation to temporarily disable this area of the brain.^[20]

Epidemiology

There are no objectively definitive statistics about how many people have savant skills. The estimates range from "exceedingly rare"^[21] to one in ten people with autism having savant skills in varying degrees.^[1] A 2009 British study of 137 parents of autistic children found that 28% believe their children met the criteria for a savant skill, defined as a skill or power "at a level that would be unusual even for 'normal' people".^[22] As many as 50 cases of sudden or acquired savant syndrome have been reported.^[23][24]

Males with savant syndrome outnumber females by roughly 6:1,^[25] slightly higher than the sex ratio disparity for autism spectrum disorders of 4.3:1.^[26]

History

The term idiot savant (French for "learned 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 intellectual disability. The term autistic savant was also used as a description for the disorder. Like idiot savant, the term came to be considered a misnomer because only half of those who were diagnosed with savant syndrome were autistic. Upon realization of the need for accuracy of diagnosis and dignity towards the individual, the term savant syndrome became widely accepted terminology.^[1][21]

Notable cases

• Temple Grandin^[27]
• Derek Amato^[28]
• Anthony Cicoria
• Alonzo Clemons
• Jodi DiPiazza
• Tommy McHugh
• Jason Padgett^[29]
• Kim Peek
• Jon Sarkin
• Orlando Serrell
• Daniel Tammet
• Tom Wiggins, blind American pianist and composer^[30]
• Kodi Lee^[31]
• Brian "Fred Worm" MacGregor^[32]

Case studies

Calendrical savants

A calendrical savant (or calendar savant) is someone who—though mentally disabled—can name the day of the week of a date, or vice versa^[33] in a few seconds or even a tenth of a second, on a limited range of decades or certain millennia.^[12] These savants are mostly autistic. The rarity of human calendar calculators is possibly due to the lack of motivation to develop such skills among the general population.^[34] Calendrical savants, on the other hand, may not be prone to invest in socially engaging skills.^[34]

See also

• Asperger syndrome
• Ideasthesia
• Creativity and mental illness
• Hyperthymesia
• Child prodigy

References

External links