Neuropsychological analysis of an idiot savant: A case study

Although biological etiologies and diffuse anatomical changes have been provided as plausible explanations for the unusual behaviors observed in idiot savants, no neuropsychological case studies or explanations for these behaviors are found in the literature. We present a case in which the "diagnosis" of idiot savant was based on historical, clinical, and test data. To assess his calendar abilities, this individual was subsequently tested over a period of six months on his ability to determine the day of the week across approximately 1,000 years. For a period of approximately 100 years he was 100% accurate. The neuropsychological tests revealed marked deficits in all areas with performance generally in the lower 1-5th percentile of the population (e.g., Full Scale Intelligence Quotient [FSIQ] = 54). Tests of attention yielded the best scores although still deficient. General learning, coding, and executive function tests proved to be challenging. In contrast, tests of visuo-motor abilities were only of moderate difficulty for the individual. These findings are considered within the theoretical framework of Rimland (autism) and Squyres (memory).