Savant syndrome—sometimes abbreviated as savantism—is not a recognized medical diagnosis, but researcher Darold Treffert defines it as a rare condition in which persons with developmental disorders (including autism spectrum disorders) have one or more areas of expertise, ability or brilliance that are in contrast with the individual's overall limitations.^[1] Treffert says the condition can be genetic, but can also be acquired,^[1] and coexists with other developmental disabilities "such as mental retardation or brain injury or disease that occurs before (pre-natal) during (peri-natal) or after birth (post-natal), or even later in childhood or adult life."^[1]

Individuals with the syndrome are often simply called savants. This can be a source of confusion since savant can also mean a person of learning, especially one of great knowledge in a particular subject. The terms idiot savant or autistic savant are also used. "Idiot" was used by the medical profession in the late 19th and early 20th century to refer to a person whose IQ was less than 20, although that usage has now given way to "profound mental retardation"; the term idiot savant is no longer regarded as a valid medical term.^[1]

According to Treffert, about half of persons with savant syndrome have autistic disorder, while the other half have another developmental disability, mental retardation, brain injury or disease. He says, "...  not all savants are autistic, and not all autistic persons are savants."^[1] Other researchers state that autistic traits and savant skills may be linked,^[2] or have challenged some earlier conclusions about savant syndrome as "hearsay, uncorroborated by independent scrutiny".^[3]

According to Treffert, something that almost all savants have in common is a remarkable memory:^[1] a memory that he describes as "exceedingly deep but very, very narrow".^[1]

Savant-like skills may be latent in everyone.^[4] Allan Snyder attempted to simulate savant impairment in normal controls by "directing low-frequency magnetic pulses into the left fronto-temporal lobe" of the brain. Differences were observed in four of 11 subjects.^[4]

An autistic savant (historically described as an idiot savant) is a person with both autism and savant skills. Autistic savants may have mental abilities called splinter skills.^[1] Why autistic savants are capable of these astonishing feats is not quite clear. Some savants have obvious neurological abnormalities (such as the lack of corpus callosum in Kim Peek's brain). Many savants are known to have abnormalities in the left hemisphere of the brain.^[5]

The Savant Syndrome is poorly understood. There is no cognitive theory that explains the combination of talent and deficit found in savants ^[6]

Savant syndrome is four to six times more frequent in males than females, and this delta is not entirely explained by the preponderance of males in the autistic population ^[1]. This has led to suggestions ^[1] that the Geschwind-Galaburda Hypothesis applies to savant syndrome where both the brain injury and savantism appear to be congenital.

According to Treffert:^[1]

• 10% of people on the autistic spectrum have savant skills
• Less than 1% of persons with other developmental disabilities have savant skills
• 50% of savants are autistic; the other 50% have different disabilities, mental retardation, brain injury or a brain disease
• Male savants outnumber female savants by four to six times.

Between 0.5 and 1% of people on the autistic spectrum have savant skills according to the UK National Autistic Society.^[7]

According to Treffert, the term idiot savant was first used to describe the condition in 1887 by Dr. John Langdon Down, who is known for his description of Down Syndrome.^[1]

Kim Peek was the basis for the 1988 fictional film Rain Man,^[8][9] although his diagnosis is no longer autism.^[10]

There are only about 100 recognized prodigious savants in the world.^[11]

• Alonzo Clemons, American clay sculptor.^[12]
• Tony DeBlois, blind American musician.^[13]
• Leslie Lemke, blind American musician.^[8]
• Jonathan Lerman, American artist.^[14]
• Thristan Mendoza, Filipino marimba prodigy.^[15]
• Derek Paravicini, blind British musician.^[16]
• James Henry Pullen, gifted British carpenter.^[17]
• Matt Savage, U.S. autistic jazz prodigy.^[18]
• Henriett Seth-F., Hungarian autistic savant, poet, writer and artist.^[19]
• Daniel Tammet, British high-functioning autistic savant (mathematical synesthaesia, language absorbtion, and memory).^[20]
• Stephen Wiltshire, British architectural artist.^[21]
• Richard Wawro, Scottish artist.^[8]

• Heaton P, Wallace GL (2004). "Annotation: The savant syndrome." Journal of Child Psychology & Psychiatry (journal)|Journal of Child Psychology & Psychiatry 45 (5): 899–911. PMID PMID 15225334 doi:10.1111/j.1469-7610.2004.t01-1-00284.x
• Hou C, Miller BL, Cummings JL; et al. (2000). "Artistic savants". Neuropsychiatry Neuropsychol Behav Neurol. 13 (1): 29–38. PMID 10645734. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
• Miller LK (1998). "Defining the Savant Syndrome". Journal of Developmental and Physical Disabilities. 10 (1): 73–85. doi:10.1023/A:1022813601762.
• Miller LK (1999). "The savant syndrome: intellectual impairment and exceptional skill". Psychol Bull. 125 (1): 31–46. doi:10.1037/0033-2909.125.1.31. PMID 9990844. {{cite journal}}: Unknown parameter |month= ignored (help)
• Nettelbeck T, Young R (1996). "Intelligence and savant syndrome: Is the whole greater than the sum of the fragments?". Intelligence. 22 (1): 49–68. doi:10.1016/S0160-2896(96)90020-3.
• Ockelford A, Pring L (2005). "Learning and creativity in a prodigious musical savant". Int Congr Ser. 1282: 903–7. doi:10.1016/j.ics.2005.05.051.
• O'Connor N, Cowan R, Samella K (2000). "Calendric Calculation and Intelligence." Intelligence 28, 31–48.
• Pearce JC (1992). Evolution's End: Claiming the Potential of Our Intelligence, HarperSanFrancisco, San Francisco.
• Pring L (2005). "Savant talent". Dev Med Child Neurol. 47 (7): 500–3. doi:10.1017/S0012162205000976. PMID 15991873.
• Saloviita T, Ruusila L, Ruusila U (2000). "Incidence of savant syndrome in Finland". Percept Mot Skills. 91 (1): 120–2. doi:10.2466/PMS.91.5.120-122. PMID 11011882.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Snyder AW, Mulcahy E, Taylor JL, Mitchell DJ, Sachdev P, Gandevia SC (2003). "Savant-like skills exposed in normal people by suppressing the left fronto-temporal lobe". J. Integr. Neurosci. 2 (2): 149–58. doi:10.1142/S0219635203000287. PMID 15011267.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Snyder AW (2001) "Paradox of the savant mind." Nature 413, 251–252.
• Snyder AW, Mitchell DJ (1999). "Is integer arithmetic fundamental to mental processing?: the mind's secret arithmetic". Proc. Biol. Sci. 266 (1419): 587–92. doi:10.1098/rspb.1999.0676. PMID 10212449.
• Tammet Daniel (2006). Born On A Blue Day, Hodder & Stoughton, London.
• Treffert DA, Christensen DD (2005). "Inside the mind of a savant". Sci Am. 293 (6): 108–13. PMID 16323698.
• Treffert DA (2000). Extraordinary People, Bantam Press, London. ISBN 0593016734
• Treffert DA (1988). "The idiot savant: a review of the syndrome". Am J Psychiatry. 145 (5): 563–72. PMID 3282450.
• Treffert DA. "Savant Syndrome: Recent Research, Results and Resources (1999)". Wisconsin Medical Society. Retrieved 2008-03-27.
• Young R (2005). "Neurobiology of savant syndrome". In Stough C (ed.) (ed.). Neurobiology of Exceptionality. doi:10.1007/0-306-48649-0_8. ISBN 978-0-306-48476-6. {{cite book}}: |editor= has generic name (help)

• Wisconsin Medical Society: Savant Syndrome