Overview of experimental study and survey
| Number | Study | Participants | Purpose | Measure | Results |
|---|---|---|---|---|---|
| 1 | Dubischar-Krivec et al. [48] (2009) | Savant calendar calculators with autism, n=3, age 9-36 yr Healthy calendar calculators, n=3 Non-savant subjects with autism, n=6 healthy calendar calculator layman, n=18 |
Identify the cognitive processes that distinguish calendar calculation in savant individuals from healthy calendar calculators. | Calculated dates of the present (current month), calculated dates of the past and future 50 years | • Savant calendar calculators with autism (ACC) showed shorter reaction times and fewer errors than healthy calendar calculators (HCC) and non-savant subjects with autism, and significantly fewer errors than healthy calendar calculator laymen when calculating dates of the present. • ACC performed faster and more accurate than HCC regarding past dates. However, no differences between ACC and HCC were detected for future date calculation • Distinct calendar calculation strategies in ACC and HCC, with HCC relying on calendar regularities for all types of dates and an involvement of (rote) memory in ACC. |
| 2 | Howlin et al. [6] (2009) | n=137 (average age 24 yr) | To investigate the nature and frequency of savant skills in a large sample of individuals with autism | Diagnostic and cognitive assessments Savant skills: parent report (n=23) |
• Thirty-nine participants (28.5%) met criteria for either a savant skill or an exceptional cognitive skill. • One-third of males showed some form of outstanding ability compared with 19 per cent of females. • No individual with a non-verbal intelligence quotient (IQ) below 50 met criteria for a savant skill. |
| 3 | Vital et al. [13] (2009) | 6426 8-year-olds with and without parent-reported special abilities | To investigate the association between special abilities and autism spectrum disorder (ASD)-like traits | A screening questionnaire for ASD-like traits IQ, sex, and socioeconomic status (SES) |
• The association between special abilities and ASD-like traits and expand it to traits in the general population. • The type of nonsocial traits most strongly associated with special abilities suggests a link to a featural information processing style, or ‘weak central coherence.’ |
| 4 | Pring et al. [17] (2010) | ASD savant artist, n=9, age 23-43 yr ASD adult, n= 9, age 22-42 yr Mild/moderate learning difficulties (MLD), n=9, age 16-18 yr Art students, n=9, age 17-20 yr Psychology students, n=9, age 17-20 yr |
Explore the nature of local and global processing in savant artists with ASD | Block Design & embedded figures test (EFT) | • There were no significant differences between the meaningful and abstract versions of the EFT, in any of the groups. • The savant artists performed above the level of the ASD and MLD groups on the block-design test, but not the EFT. • Although an enhanced local processing style is an important aspect of savant artistic talent, motor control also appears to be a necessary skill. |
| 5 | Soulières et al. [47] (2010) | ASD savants, n=2, nonsavant ASD, n=6 | Understanding the Superior estimation abilities through a case study | Computerized and noncomputerized tasks | • Certain autistic spectrum individuals may develop superior and highly specialized abilities in estimation. • These findings in relation to the role of “veridical mapping” in the development of special ability. |
| 6 | Bölte et al. [46] (2011) | High functioning ASD, males, n= 35 High functioning ASD females, n= 21 Unaffected sibling controls (23 males and 35 females) |
• To identify gender differences and clinical correlations in the cognitive domain • Functional comparison of visual attention to detail and executive function |
Autism Diagnostic Observation Schedule (ADOS), intelligence tests, Child Behavior Checklist (CBCL)/Young Adult Behavior Checklist (YABCL), Autism Diagnostic Interview-Revised (ADI-R), visual attention to detail (ATTD) & selected executive functions (EF) | • Females with ASD outperformed males on EF as assessed by the Trail Making Test B-A. Males with ASD showed superior performance for ATTD as measured by the Block Design Test (BD) clinically meaningful cognitive sex differences in ASD. • Particularly an association between EF and stereotypic behaviours and interests. • ATTD as a potential basis for specific cognitive strengths (e.g., scientific/savant skills) might be more pronounced in males with ASD. |
| 7 | Crane et al. [15] (2011) | Savant group, n=9, age 23-43 Autism, n=5 Asperger syndrome, n= 3 Atypical autism, n=1 Control group Non savant ASD, n=9 Mild Learning Disabilities, n=8 |
To assess executive abilities (specifically, fluency, perseveration and monitoring) in savant artists with ASD, relative to non-talented individuals with ASD or MLD | Three facets of executive ability (fluency, perseveration and monitoring) assessed. | • The savant artists performed better than the ASD comparison group on the fluency and monitoring, but not perseveration, aspects of the design fluency task. • No significant differences were observed between the savant, ASD and MLD groups on the card sort task. • In the domain of their talent, savant artists have enhanced executive abilities, relative to their non-talented counterparts. |
| 8 | Kim et al. [8] (2011) | Savant autism, n=60 Nonsavant autism, n= 81 | Relationship between Savant Skills and Autistic Symptoms in Korean Patients with Autism Spectrum Disorder | The domain scores and total scores of the Korean version ADI-R, Korean versions of Asperger Syndrome Diagnostic Scale (K-ASDS), and Korean translated versions of Social Responsiveness Scale (K-SRS) | • Memory (n=47) was the most prevalent savant skill in the savant ASD group (n=60). • The savant ASD group had a statistically higher mean age and IQ score than did the nonsavant ASD group. • The savant ASD group showed high IQ profile, a higher RRB and higher language and cognitive scores than did the nonsavant ASD group. |
| 9 | Bennett and Heaton [42] (2012) | Study 1. Parents of 125 children, adolescents and young adults with autism spectrum disorders Study 2. Three individuals with exceptional skills for music, art and mathematic |
1. To develop and pilot a new screening questionnaire 2. Validating the screening instrument |
Special Skills in Autism Questionnaire+case study | • 42% of respondents had children with one or more skills that were outstanding given their child’s functional skills. • Special skills are associated with superior working memory and highly focused attention that is not associated with increased obsessesionality. • Although intellectual impairment and a local bias have been widely associated with special skills in the savant literature, neither the screening nor case studies provided strong evidence for such associations. |
| 10 | Pring et al. [40] (2012) | Savant artists with ASD, n=9 Non-artistically talented individuals with ASD n=9 Mild/moderate learning difficulties (MLD), n=9 Talented art students, n=9 |
To explore savant artists with autism and their creativity | 1) TTCT (Torrance Test of Creative Thinking) Task 2) Figural synthesis task (FST) |
• The savants did produce more elaborative responses than the ASD and MLD groups, no differences were observed on the other indices of creativity. • Elaboration is a key skill in savant artistic talent. • On the non-drawing construction task, the savant group produced more original (but not more fluent) outputs. |
| 11 | Bouvet et al. [45] (2014) | Savant autism (n=1, age 21 yr): several savant abilities: absolute pitch and synesthesia-like associations | To examine the relationship of enhanced perception, veridical mapping, and savant ability | Case study (developmental history, self-report, test) | • The co-occurrence of abilities, which share the same structure, suggest the importance of veridical mapping in the atypical range and nature of abilities displayed by autistic people. |
| 12 | Dubischar-Krivec et al. [49] (2014) | Savant calendar calculators with autism, n=3 Typically developing calendar calculators, n=3 |
Neural mechanisms of savant calendar calculating in autism Neural mechanisms of savant calendar calculating in autism |
126 calendar tasks with dates of the present, past, and future | • ASD people perform better in accurate responses. • In terms of speed, it was not. • During calendar calculation, calendar calculators with ASD and typically developing calendar calculators both showed maxima at frontal and left superior temporal sites as well as bilateral insulae. • This is in accordance with verbal fact retrieval and working memory as well as monitoring and coordination processes. |
| 13 | Finocchiaro et al. [44] (2015) | A child with savant and ASD (age 7 yr) | A case study of a child with ASD and savant abilities | A protocol of academic skills: Measures of cognitive, academic, adaptive skills, Calculation skills | • Performances in number elaboration showed an adequate access to semantic and verbal number information. • In the written and mental calculation task and in fact retrieval, implicating calculation strategies and information retrieval, processes were automatized. |
| 14 | Treffert and Rebedew [41] (2015) | Savnant autism, n=319 | To identify the demographic characteristics of Savant Syndrome | Subjects were chosen based upon existing mail and e-mail | • 79% male, 21% female. • 90% are congenital savants, 10% are acquired savants. • Among the individuals with congenital savant syndrome, the most common underlying disability was ASD (75%); in the other 25%. • Fifty-five percent possessed a single special skill, while 45% had multiple skills. • Music was the most frequent principal skill followed by art, memory, mathematics, calendar calculating, language, visual-spatial/mechanical, athletic, computer, extrasensory perception, and other skill. |
| 15 | De Marco et al. [16] (2016) | 24-year-old male (asperger syndrome) | Observation of special ability | Calendar calculation skills, priming effect, The “Easter Test” Investigation of autobiographical memories |
• Responded with 98.2 % accuracy to 492 day-date correspondences covering a period of 40 years. • Such accurate performance on future-date trials relies on knowledge and use of calendrical regularities. |
| 16 | Bennett and Heaton [43] (2017) | Savant ASD group, n=17 (age 8-13 yr) Nonsavant autism group, n=19 (age 8-13 yr) Typically developing, n=17, (age 8-13 yr) |
To compare clinical and cognitive profiles of child savants and non-savants with ASD | 1. Skill validation assessment 2. Clinical assessement: symptom severity (Social Communication Questionnaire, ADOS, short sensory profile), Obsessionality 3. Cognitive ability Assessments |
• Striking differences between savant and non-savant groups emerged on measures of cognitive ability. • Children with savant skills exhibited highly superior working memory and their scores on tests of analytic skills were also superior to those of non-savants. |
| 17 | Hughes et al. [12] (2018) | Savant and ASD, n=44 Nonsavant ASD, n= 36 Typical control, n=31 |
Investigate a psychological profile in autism and savant syndrome | Investigated the cognitive and behavioural profiles. Investigate a novel savant skill— calendar calculation |
• Heightened sensory sensitivity, obsessional behaviours, technical/spatial abilities, and systemising were all key aspects in defining the savant profile distinct from autism alone, along with a different approach to task learning. • A unique cognitive and behavioural profile in autistic adults with savant syndrome that is distinct from autistic adults without a savant skill. |
| 18 | Daniel and Menashe [11] (2020) | Savant, n=712 Nonsavant, n=2032 |
Exploring the familial role of social responsiveness differences between savant and non-savant children with autism | • Demographic features and primary ASD diagnosis measures • Compare the SRS scores between the savant and non-savant groups. |
• Savant children had significantly lower SRS scores (less deficiencies) compared to non-savant children (p<0.05). • Intra-familial analyses revealed weak pairwise-correlations between SRS scores of parents and their children. • The less severe autistic traits among savant children with ASD compared to other people with ASD is not likely to be a familial trait. |
| 19 | Park [1] (2021) | 9 mothers of ASD and savant syndrome | Explore the parenting experience of mothers who has young adult child with ASD and savant syndrome | In depth interview | • Parents have been confused with their child’s abilities. • There are still many difficulties that those parents encounter, therefore, they expect more systematic support. • Parents were hoped to their child to live as healthy members of the society. |
| 20 | Bal et al. [52] (2022) | n=1470 | Examining the relationship between parent-reported talents and strengths and performance on standardized cognitive tests | Parent report ADI-R, Differential Ability Scales, 2nd edition | • Almost half (46%) had at least one parentreported talent and an additional 23% without extraordinary talents had at least one personal strength. • Children with these parent-reported skills had different patterns of performance on these standardized tests than children without skills in that area (i.e., visuospatial, drawing, computation, reading, and memory). • These results emphasize the importance of considering strengths separately by area. |