Intradimensional / Extradimensional Shift Test correlate with repetitive Set-shifting in children with autism spectrum disorders : Reversal shifting deficits

A D D R E S S Correspondence should be addressed to: B E N JA M I N E . Y E RYS ,Children’s Research Institute–Neuroscience, Children’s National Medical Center, 111 Michigan Ave NW, Washington, DC 20009, USA. e-mail: byerys@cnmc.org autism © 2009 SAGE Publications and The National Autistic Society Vol 13(5) 523–538; 335716 1362-3613(2009) Copyright © The Author(s), 2009. Reprints and permissions: http://www.sagepub. co.uk/journalspermissions.nav DOI: 10.1177/1362361309335716 K E Y W O R D S attention; autism; ID/ED shift task; set-shifting at University of Newcastle on March 15, 2014 aut.sagepub. com Downloaded from Individuals with autism spectrum disorders (ASDs) struggle to shift their attention during daily activities (Gioia et al., 2002) and on laboratory measures (see Hill, 2004 and Pennington and Ozonoff, 1996 for comprehensive reviews). Set-shifting in laboratory tasks requires successful switching between two tasks or sorting the same stimulus by different features. Setshifting is one of several cognitive components that fall within the executive function (EF) domain, which enables individuals to achieve goals efficiently (Pennington and Ozonoff, 1996). The present study examines: (1) set-shifting in 6to 13-year-old children with and without highfunctioning ASDs using the Intradimensional/Extradimensional (ID/ED) Shift Test from the Cambridge Neuropsychological Test Automated Battery, and (2) the relationship between set-shifting performance and core repetitive behavior/restricted interest symptoms in the ASD group. Set-shifting is one cognitive process that holds promise as an intermediate phenotype in ASDs. Intermediate phenotypes include cognitive processes that serve as a link between the observed behavioral symptoms of neurodevelopmental and psychiatric disorders and their brain and/or genetic bases (Gottesman and Gould, 2003). This connection requires establishing an association between the cognitive process and core symptoms as well as brain and genetic indices. Several independent investigations report a positive relationship between set-shifting deficits and restricted interest/ repetitive behavior symptoms in autism (Lopez et al., 2005; South et al., 2007). Furthermore, in a recent functional neuroimaging investigation of set-shifting in adults with ASDs, the activation patterns of anterior cingulate cortex and left intraparietal sulcus correlated negatively with the restricted interest/repetitive behaviors index from the Autism Diagnostic Interview– Revised (ADI–R: Shafritz et al., 2008). This finding connects brain function during a set-shifting task with core symptoms of ASDs. Taken together, these findings suggest set-shifting as a potentially valuable intermediary between ASD symptoms and neurobiological functioning. To investigate this possibility further, a reliable measure of set-shifting with as few extraneous (cognitive and motor) demands as possible and with an established link to brain function is needed. Investigations of setshifting in ASD have typically relied on two measures of flexibility: the Wisconsin Card Sorting Test and the ID/ED Test. The former is criticized for its lack of specificity to flexibility (Hill, 2004), social administration (Ozonoff, 1995), and language demands (Liss et al., 2001). In contrast, the ID/ED Test measures flexibility in a systematic fashion that allows for controlled increases in shifting demands (Cambridge Cognition, 1996). It consists of nine stages, which encompass three types of tasks: simple object discrimination; shifting within a single dimension (e.g. shape: intradimensional (ID) shift); and shifting attention from one dimension to A U T I S M 13(5)