Savant Syndrome: Clinical and Neuropsychological Features

Abstract

Savant syndrome defines the people who have severe developmental and mental disabilities but also have extraordinary mental skills which are missing in many people. Although general mental capacity is under average mental level, savant has excessive knowledge about one or more domains. It is accepted that as many as one in 10 persons with autistic disorder have such remarkable abilities in varying degrees, although savant syndrome occurs in other developmental disabilities or in other types of central nervous system injury or disease as well. Males outnumber females by an approximate 6 : 1 ratio in savant syndrome. Savant skills are limited to five general categories. These are music, art, calender calculating, mathematics and mechanical or spatial skills. Savant skills can also be divided into three as savants who have splinter skills, talented savants and prodigious savants. A remarkable memory welds to the special abilities determined in savant syndrome. Savant syndrome can be congenital or it can be acquired. Most often savant skills emerge in childhood, superimposed on some underlying developmental disability present at birth. However, acquired savant skills can also appear, when none were previously present, in neurotypical individuals following brain injury or disease later in infancy, childhood or adult life. Savant skills don't depend on only rote memory. It is approved that an enhanced or spared ability to represent and manipulate highly organised domain-specific information. Various theoretic models were defined to explain the neuropsychological profile in savant syndrome. Interest in savants has a long history, stretching back to the early 18th century; nevertheless, the savant syndrome remains as much a mystery now as it did when it was first described. Given that many questions about the existence and nature of savant talent remain unanswered, it seems likely that research efforts will continue unabated.

Keywords

• Savant, Autism, Memory, Talent, Savant Syndrome

Savant Sendromu: Klinik ve Nöropsikolojik Özellikleri

Öz

Savant sendromu, ağır düzeyde gelişimsel ya da zihinsel yetersizliklerin yanında çoğu insanda bulunmayan sıra dışı zihinsel becerileri olan kişileri tanımlamaktadır. Kişinin genel zeka düzeyi ortalamanın altında olmasına karşın bir ya da birden fazla alanda aşırı düzeyde bilgi sahibidir. Savant sendromu olgularının yaklaşık yarısının otistik bozukluğa bağlı, kalan yarısının da diğer tip gelişimsel bozukluklar, zeka geriliği veya merkezi sinir sistemi hastalıkları ya da yaralanmalarına bağlı olduğu kabul edilmektedir. Erkeklerde kızlara oranla altı kat daha sık görülür. Savant becerileri genellikle beş genel kategori ile sınırlıdır. Bunlar müzik becerileri, sanat becerileri; takvim hesaplama becerisi; matematik becerisi ve mekanik ya da mekansal becerilerdir. Savant olguları parçalı becerileri olan savantlar, yetenekli savantlar ve olağanüstü savantlar olarak üçe ayrılabilir. Savant sendromunda saptanan özgül becerilere hemen her zaman olağanüstü bir bellek eşlik eder. Savant sendromu konjenital ya da edinsel olabilir. Birçok savant becerisi doğumda var olan bazı gelişimsel güçlüklerin üzerine eklenerek çocuklukta ortaya çıkmaktadır. Edinsel savant becerileri sağlıklı gelişim gösteren bireylerde bebeklik, çocukluk ya da erişkinlikte geçirilen kafa travması ya da merkezi sinir sistemi travması sonrası gelişebilir. Savant becerilerinin zaman içinde kaybolması kural olmaktan ziyade istisnadır. Savantların becerileri sadece ezber belleğine dayanmamaktadır. Oldukça organize, alana özgü bilginin temsil edilme ve düzenleme becerisinin gelişmiş olduğu bilinmektedir. Savant sendromundaki nöropsikolojik profili açıklamak için birçok teorik model ortaya konmuştur. Savant olgularına olan ilgi 18. yüzyılda başlamış olmasına karşın halen ilk tanımlandığı dönemdeki gibi gizemini korumaktadır. Savant'a özgü yeteneklerin varlığı ve doğası ile ilgili birçok soru halen yanıtsız olduğundan bu konu ile ilgili araştırmalar artarak devam edecek gibi gözükmektedir.

Anahtar Kelimeler

• Savant, Otizm, Bellek, Yetenek, Savant Sendromu

Kaynakça

1. Treffert DA. The savant syndrome: an extraordinary condition. A synopsis: past, present, future. Philos Trans R Soc Lond B Biol Sci 2009; 364(1522):1351-1357.
2. Down J. On Some of The Mental Affections of Childhood and Youth. London, Churc- hill, 1887.
3. Charness N, Clifton J, MacDonald L. Case study of a musical ‘mono-savant’: A cognitive psychological focus. In The Exceptional Brain: Neuropsychology of Talent and Special Abilities (Eds LK Obler, D Fein): 277-293. New York, Guilford, 1988.
4. Treffert D. Extraordinary People: Understanding ‘Idiot Savants’. New York, Harper and Row, 1989.
5. Heaton P, Wallace GL. Annotation: the savant syndrome. J Child Psychol Psychiatry 2004; 45:899-911.
6. Hill AL. Idiot savants: Rate of incidence. Percept Mot Skills 1977; 44:161–162.
7. Rimland, B. Savant capabilities of autistic children and their cognitive implications. In Cognitive Defects in the Development of Mental Illness (Ed G Serban): 43-65. New York, Brunner-Mazel, 1978.
8. Hermelin B. Bright Splinters of the Mind: A Personal Story of Research with Autistic Savants. London, Kingsley, 2001.

9. Saloviita T, Ruusila L, Ruusila U. Incidence of savant skills in Finland. Percept Mot Skills 2000; 91:120–122.
10. Hill AL. Savants: Mentally retarded individuals with special skills. In International Review of Research in Mental Retardation Vol.9 (Ed NR Ellis). New York, Academic Press, 1978.
11. Geschwind N, Galaburda AM. Cerebral Lateralization: Biological Mechanisms, Associations and Pathology. Cambridge, MA, MIT Press, 1987.
12. Peek F. The Real Rain Man. Salt Lake City, Utah, Harkness Publishers, 1996.
13. Treffert D, Wallace G. Islands of genius. Sci Am 2002; 286:76-85.
14. Rimland B, Fein DA. Special talents of autistic savants. In The Exceptional Brain: Neuropsychology of Talent and Special Abilities (Eds LK Obler, DA Fine): 474-492. New York, NY, Guilford Press, 1988.
15. Munoz-Yunta J, Ortiz-Alonso T. Savant or Idiot Savant Syndrome. Rev Neurol. 2003; 36(suppl 1):157-161.
16. Nettelbeck T, Young R. Intelligence and savant syndrome: Is the whole greater than the sum of the fragments? Intelligence 1996; 22:49–67.
17. Bender MB, Feldman M, Sobin AJ. Palinopsia. Brain 1968; 91:321–338.
18. Giray EF, Barclay AG. Eidetic imagery; Longitudinal results in brain-damaged children. Am J Ment Defic 1977; 82:311–314.
19. Young R, Nettelbeck T. The abilities of a musical savant and his family. J Autism Dev Disord 1995; 25:229–245.
20. Critchley M. The Divine Banquet of the Brain. New York, Raven Press, 1979.
21. Tredgold, AF. Mental Deficiency. New York, NY, William Wood, 1914.
22. Barr MW. Some notes on echolalia, with the report of an extraordinary case. J Nerv Ment Dis 1898; 25:20–30.
23. Mishkin M, Malamut B, Bachevalier J. Memories and habits: two neural systems. In Neurobiology of Learning and Memory (Eds G Lynch, JL MacGaugh, NM Weinberger): 65-77. New York, NY, Guilford Press, 1984.
24. Lythgoe M, Pollak T, Kalmas M, de Hann M, Chong WK. Obsessive, prolific artistic output following subarachnoid hemorrhage. Neurology 2005; 64:397–398.
25. Treffert DA. Extraordinary People: Understanding Savant Syndrome. Omaha, NE, iUniverse Inc, 2006.
26. Miller BL, Cummings J, Mishkin F, Boone K, Prince F, Ponton M et al. Emergence of artistic talent in fronto-temporal dementia. Neurology 1998; 51:978–982.
27. Hou C, Miller B, Cummings J, Goldberg M, Mychack P, Bottino V et al. Artistic savants. Neuropsychiatry Neuropsychol Behav Neurol 2000; 13:29–38.
28. Duckett, J. Idiot-savants: superspecialization in mentally retarded persons (Doctoral thesis). Texas, Department of Special Education, University of Texas in Austin, 1976.
29. LaFontaine L. Divergent abilities in the idiot savant (Doctoral thesis). Boston, School of Education, Boston University, 1974.
30. Smith SB. The Great Mental Calculators. New York, Columbia University Press, 1983.
31. Southall G. The Continuing Enslavement of Blind Tom, The Pianist Composer (1868– 1887). Minneapolis, MN, Challenge Productions, 1983.
32. Hindermann F. Katzen. Zurich, Switzerland, Manesse Verlag, 1982.
33. Heaton P, Allen R, Williams K, Cummins O, Happé F. Do social and cognitive deficits curtail musical understanding? Evidence from autism and Down syndrome. Br J Dev Psychol 2008; 26:171-182.
34. Brown WA, Cammuso K, Sachs H, Winklosky B, Mullane J, Bernier R et al. Autism- related language, personality and cognition in people with absolute pitch: Results of a preliminary study. J Autism Dev Disord 2003; 33:163–167.
35. DeLong GR, Aldershof AL. An association of special abilities with juvenile manic- depressive illness. In The Exceptional Brain: Neuropsychology of Talent and Special Abilities (Eds LK Obler, DA Fine): 387-395. New York, NY, Guilford Press, 1988.
36. Hill AL. Savants: Mentally retarded individuals with special skills. In International Review of Research in Mental Retardation (Ed N Ellis): 277-298. New York, Academic Press, 1978.
37. Anderson M, O’Connor N, Hermelin B. A specific calculating ability. Intelligence 1999; 26:383–403.
38. Kelly SJ, Macaruso P, Sokol SM. Mental calculation in an autistic savant: A case study. J Clin Exp Neuropsychol 1997; 19:172–184.
39. Mottron L, Belleville S. Perspective production in a savant autistic draughtsman. Psychol Med 1995; 25:639–648.
40. Happe´ F. Autism: Cognitive deficit or cognitive style? Trends Cogn Sci 1999; 3:216– 222.
41. Howe M. Fragments of Genius: The Strange Feats of Idiot Savants. London, Routledge, 1989.
42. Ellis NR, Palmer RL, Reeves CL. Developmental and intellectual differences in frequency processing. Dev Psychol 1988; 24:38–45.
43. Ellis NR, Woodley-Zanthos P, Dulaney CL. Memory for spatial location in children, adults, and mentally retarded persons. Am J Ment Retard 1989; 93:521–526.
44. Sloboda J. The Musical Mind: The Cognitive Psychology of Music. Oxford, Oxford University Press, 1985.
45. Roberts DA. Case history of a so-called idiot savant. J Genet Psychol 1945; 66:259- 265.
46. Horwitz WA, Ketsenbaum C, Person E, Jarvik L. Identical twin-“idiot savants”-calendar calculators. Am J Psychiatry 1965; 121:1075-1079.
47. Sacks O.The Twins. New York, Review of Books, 1985.
48. Rife DC, Snyder LH. Studies in human inheritance, VI: a genetic refutation of the principles of behavioralistic psychology. Hum Biol 1931; 3:547-559.
49. Jones HE. Phenomenal memorizing as a special ability. J Appl Psychol 1920; 4:202- 206.
50. Brill AA. Some peculiar manifestations of memory with special reference to ligthning calculators. J Nerv Ment Dis 1940; 92:709-726.
51. Treffert DA. The idiot savant: A review of the syndrome. Am J Psychiatry 1988; 145:563-572.
52. Wiscott DS. A musical idiot savant. Psychiatry 1969; 32:494-515.
53. Seguin E. Idiocy and its Treatment by the Psychological Method, 1866. New York, Kelley, 1971.
54. Nurcombe MD, Parker N. The idiot savant. J Am Acad Child Psychiatry 1964; 3:469- 487.
55. Steel JG, Gorman R, Flexman JE. Neuropsychiatric testing in an autistic mathematical idiot-savant: evidence for nonverbal abstract capacity. J Am Acad Child Psychiatry 1984; 6:704-707.
56. Simonton DK. The psychology of high abilities by Howe, M.J.A. Contemporary Psychology – APA Review of Books 2001; 2:176–179.
57. Heaton P, Hermelin B, Pring L. Autism and pitch processing: A precursor for savant musical ability. Music Perception 1998; 15:291–305.
58. Heavey L, Pring L, Hermelin B. A date to remember: The nature of memory in savant calendrical calculators. Psychol Med 1999; 29:145–160.
59. Plaisted KC, O’Riordan M, Baron-Cohen S. Enhanced discrimination of novel, highly similar stimuli by adults with autism during a perceptual learning task. J Child Psychol Psychiatry 1998; 39:765–775.
60. Heaton P, Hermelin B, Pring, L. Can children with autistic spectrum disorders perceive affect in music? An experimental investigation. Psychol Med 1999; 29:1405– 1410.
61. Miller L. Musical Savants: Exceptional Skill in the Mentally Retarded. Hillsdale, NJ, Lawrence Erlbaum Associates, 1989.
62. Waterhouse L. Speculations on the neuroanatomical substrate of special talents. In In The Exceptional Brain: Neuropsychology of Talent and Special Abilities (Eds LK Obler, DA Fine): 493-512. New York, NY, Guilford Press, 1988.
63. Mottron L, Burack, JA. Enhanced perceptual functioning in the development of autism. In The Development of Autism (Eds JA Burack, T Charman, N Yirmiya, PR Zelazo): 131-148. Mahwah, NJ, Lawrence Erlbaum Associates, 2001.
64. Phillips A. Talented imbeciles. Psychol Clin 1930; 18:246-255.
65. Clark T. The application of savant and splinter skills in theautistic population through curriculum design: a longitudinal multiple-replication study (Doctoral thesis). UK, School of Education Studies, University of South Wales,1930.