Calendar Calculation Savant Syndrome in Autism Spectrum Disorder: Cognitive Function Measured by the Wechsler Intelligence Scale

This study addressed gaps in prior research on savant syndrome (SS) by restricting participation to individuals with diagnosed autism spectrum disorder (ASD), where SS frequently co-occurs, and focusing on a specific subtype: savant syndrome in calendar calculation (SSC). The primary objectives were to determine the prevalence, intellectual profile, and developmental trajectory of SSC and compare these characteristics with those in savant syndrome in art (SSA), savant syndrome in music (SSM), and non-savant individuals (NSS) with ASD. SSC was identified using broad classification criteria. Intellectual functioning and Wechsler Intelligence Scale indices were compared across the four groups (SSC, SSA, and SSM, and NSS). For SSC, accuracy rates and reaction times on a calendar calculation task were assessed in relation to Full-Scale Intelligence Quotient (FSIQ) and subtest scores. SSC was most frequently observed among individuals with mild intellectual disability. Some participants lost calendar calculation skills over time. Wechsler test findings showed significantly lower FSIQ in SSC than in NSS. By subtest, SSC scored highest on Digit Span, SSA and SSM on Block Design, and NSS on Similarities. All SS groups scored lowest on Comprehension, whereas NSS scored lowest on Coding. In the calendar calculation task, accuracy correlated with Digit Span scores and the discrepancy between Digit Span and Comprehension, while reaction time correlated inversely with FSIQ. Exceptional calendar calculation abilities in ASD were linked to a cognitive profile marked by superior memory (auditory working memory and long term memory) but weak Comprehension.