The paradox of cognitive flexibility in autism

In the paper

“So far, none of the other prominent cognitive autism theories gives an explanation for the observed inflexibility in autism.”

In the paper

“If we calculate this ratio (autism groups 2.0 [15,16] or 2.1 [8], schizophrenia groups >3 [16]), none of the studies actually showed evidence for difficulties with cognitive flexibility in autism.”

What the sources say

• Not checked yetcites [15] Goldstein, 2001, Attentional processes in autism, J. Autism Dev. Disord. source
• Not checked yetcites [16] Goldstein, 2002, High-functioning autism and schizophrenia - A comparison of an early and late onset neurodevelopmental disorder, Arch. Clin. Neuropsychol. source
• Not checked yetcites [8] Hill, 2006, Executive processes in Asperger syndrome: patterns of performance in a multiple case series, Neuropsychologia source

In the paper

“By contrast, Landa and colleagues [7] reported that children with high functioning autism had difficulties with ID-shifts, but outperformed typically developing children on ED-shifts.”

What the sources say

• Not checked yetcites [7] Landa, 2005, Language, social, and executive functions in high functioning Autism: a continuum of performance, J. Autism Dev. Disord. source

In the paper

“One study of adults with autism reported no cognitive flexibility deficits [9], but another study including children with autism reported deficits [29].”

What the sources say

• Not checked yetcites [9] Lopez, 2005, Examining the relationship between executive functions and restricted, repetitive symptoms of Autistic disorder, J. Autism Dev. Disord. source
• Not checked yetcites [29] Corbett, B.A. et al. Examining executive functioning in children with autism spectrum disorder, attention deficit hyperactivity disorder, and typical development. Psychiatry Res. (in press)

In the paper

“However, the discrepancies in cognitive flexibility findings might not be so straight forward because ADHD children seem to be primarily challenged on switch paradigms [70,71] but not on the ID/ED task [29,32,34,35].”

What the sources say

• Not checked yetcites [70] Cepeda, 2000, Task switching and attention deficit hyperactivity disorder, J. Abnorm. Child Psychol. source
• Not checked yetcites [71] Smith, 2006, Task-specific hypoactivation in prefrontal and temporoparietal brain regions during motor inhibition and task switching in medication-naive children and adolescents with attention deficit hyperactivity disorder, Am. J. Psychiatry source
• Not checked yetcites [29] Corbett, B.A. et al. Examining executive functioning in children with autism spectrum disorder, attention deficit hyperactivity disorder, and typical development. Psychiatry Res. (in press)
• Not checked yetcites [32] Happé, 2006, Executive function deficits in autism spectrum disorders and attention-deficit/hyperactivity disorder: examining profiles across domains and ages, Brain Cogn. source
• Not checked yetcites [34] Goldberg, 2005, Subtle executive impairment in children with Autism and children with ADHD, J. Autism Dev. Disord. source
• Not checked yetcites [35] Sinzig, 2008, Inhibition, flexibility, working memory and planning in autism spectrum disorders with and without comorbid ADHD-symptoms, Child Adolesc. Psychiatry Ment. Health source

In the paper

“In these studies, neither the children with autism nor the children with ADHD failed the task (see also Box 2).”

In the paper

“Task-related activation for individuals with ASD was limited to the ventrolateral PFC when a response shift or shift in cognitive set was required, whereas many other areas including dorsolateral PFC, anterior cingulate cortex, premotor cortex and the basal ganglia were activated in the TYP group.”

What the sources say

• Not checked yetcites [41] Shafritz, 2008, The neural circuitry mediating shifts in behavioral response and cognitive set in autism, Biol. Psychiatry source

In the paper

“ADHD children showed difficulties with the WCST in two studies [20,68], but not in two other studies [14,69].”

What the sources say

• Not checked yetcites [20] Tsuchiya, 2005, Computerized version of the Wisconsin card sorting test in children with high-functioning autistic disorder or attention-deficit/hyperactivity disorder, Brain Dev. source
• Not checked yetcites [68] Nyden, 1999, Executive function/attention deficits in boys with Asperger syndrome, attention disorder and reading/writing disorder, Autism source
• Not checked yetcites [14] Geurts, 2004, How specific are executive functioning deficits in Attention Deficit Hyperactivity Disorder and autism?, J. Child Psychol. Psychiatry Allied Discip. source
• Not checked yetcites [69] Ozonoff, 1999, Brief report: specific executive function profiles in three neurodevelopmental disorders, J. Autism Dev. Disord. source

In the paper

“There were no differences between the groups in behavioral performance for switching, but there was reduced activation in frontal, striatal and parietal regions in the ASD group.”

What the sources say

• Not checked yetcites [41] Shafritz, 2008, The neural circuitry mediating shifts in behavioral response and cognitive set in autism, Biol. Psychiatry source

In the paper

“However, Ozonoff and colleagues [36] reported difficulties with ED-shifts and not with ID-shifts in the largest autism study to date, which included a very well-characterized national sample of children with high functioning autism and Asperger syndrome.”

What the sources say

• Not checked yetcites [36] Ozonoff, 2004, Performance on Cambridge neuropsychological test automated battery subtests sensitive to frontal lobe function in people with autistic disorder: evidence from the collaborative programs of excellence in autism network, J. Autism Dev. Disord. source

In the paper

“The findings of Sinzig and colleagues [35] suggest that children with autism with comorbid ADHD show difficulties with the task, whereas children with autism without any comorbid ADHD do not.”

What the sources say

• Not checked yetcites [35] Sinzig, 2008, Inhibition, flexibility, working memory and planning in autism spectrum disorders with and without comorbid ADHD-symptoms, Child Adolesc. Psychiatry Ment. Health source

In the paper

“In summary, with respect to clinical neuropsychological measures, only studies using the WCST clearly report deficits (i.e. has high discriminating power), whereas the findings of studies using other measures are inconsistent, but generally do not support these findings.”

In the paper

“In a relatively small study with a wide age range, Schmitz and colleagues [40] reported that adults with ASD, who performed behavioral tasks comparably to typically developing (TYP) adults, showed increased activation in the right inferior and parietal areas associated with performance on a task-switching paradigm in ASD.”

What the sources say

• Not checked yetcites [40] Schmitz, 2006, Neural correlates of executive function in autistic spectrum disorders, Biol. Psychiatry source

In the paper

“To our knowledge, only four studies have investigated task-switching in people with autism and none of them reported performance deficits [40–43].”

What the sources say

• Not checked yetcites [40] Schmitz, 2006, Neural correlates of executive function in autistic spectrum disorders, Biol. Psychiatry source
• Not checked yetcites [41] Shafritz, 2008, The neural circuitry mediating shifts in behavioral response and cognitive set in autism, Biol. Psychiatry source
• Not checked yetcites [42] Stahl, 2002, Joint attention and set-shifting in young children with autism, Autism source
• Not checked yetcites [43] Whitehouse, 2006, Inner speech impairments in autism, J. Child Psychol. Psychiatry Allied Discip. source

In the paper

“This qualitative literature overview shows that the findings regarding cognitive flexibility deficits in individuals with autism as assessed by either clinical neuropsychology (other than the WCST) or experimental cognitive psychology paradigms, are rather inconsistent, despite exhibiting behavioral inflexibility in many respects.”

In the paper

“The field lacks clear mechanistic hypotheses about the autism related deficits that can be tested and validated.”

In the paper

“However, we question that failure on these measures is indeed because of cognitive inflexibility because performance on these measures draws upon a broad range of cognitive processes.”

In the paper

“Failure on the Wisconsin Card Sorting Task can be because of deficits in various cognitive processes including learning from feedback, keeping the goal of the task in mind, noticing that a change in strategy is necessary, inhibiting a previous motor response, switching to another response and sustaining responding over time.”

What the sources say

• Not checked yetcites [24] Barcelo, 1999, Role of dorsolateral prefrontal cortex in attentional set shifting: parsing the cognitive significance of WCST errors with event-related potentials, Psychophysiology
• Not checked yetcites [25] Ozonoff, 1995, Reliability and validity of the Wisconsin card sorting test in studies of autism, Neuropsychology source
• Not checked yetcites [26] Sergeant, 2002, How specific is a deficit of executive functioning for attention-deficit/hyperactivity disorder?, Behav. Brain Res. source

In the paper

“The MCST includes a warning that the sorting rule needs to be changed, however this does not ensure the participants can do so or ascertain the new sorting rule [28].”

What the sources say

• Not checked yetcites [28] Zelazo, 1996, An age-related dissociation between knowing rules and using them, Cogn. Dev. source

In the paper

“Arbuthnott and Frank [30] showed that a ratio score of the first part of the task in relation to the second part that is higher than three is indicative of cognitive flexibility difficulties.”

What the sources say

• Not checked yetcites [30] Arbuthnott, 2000, Trail making test, part B as a measure of executive control: validation using a set-switching paradigm, J. Clin. Exp. Neuropsychol. source

In the paper

“Nonetheless, there are two potential confounds in this task. First, participants failing to reach the final stages of the task are automatically given the highest error score, which might obscure findings (Box 1). Sustaining attention difficulties, as opposed to cognitive flexibility, can decrease performance on this task, which is the second potential confound.”

In the paper

“This very brief overview of recent neuroimaging findings indicates that more studies based on mechanistically plausible hypotheses using well-controlled experimental paradigms, including large samples of children with ASD, will be required before it is possible to draw conclusions about cognitive flexibility from imaging studies.”

In the paper

“Hence, both ASD and ADHD have been associated with cognitive control difficulties, but ostensibly diverge when we focus on cognitive flexibility.”

In the paper

“First, as described in the previous paragraph, there are serious issues with the WCST that makes it impossible to conclude that failure is indeed because of cognitive inflexibility, although failure might be because of generalized performance deficits (i.e. executive functioning deficits).”

In the paper

“Stated simply, success on the ID/ED task does not predict success on a task-switch paradigm because other factors, such as the level of attention shifting (i.e. feature versus dimension) probably have a role in determining performance (Box 1).”

In the paper

“Thus, it remains unclear whether comorbidity of ADHD in autism is a valid explanation for mixed findings (Box 3).”

In the paper

“Because Happé [32] only included children with ADHD of the combined subtype, differences related to subtype do not provide a sufficient explanation for these mixed findings.”

What the sources say

• Not checked yetcites [32] Happé, 2006, Executive function deficits in autism spectrum disorders and attention-deficit/hyperactivity disorder: examining profiles across domains and ages, Brain Cogn. source

In the paper

“Some argue that attention difficulties are central to autism [37], and there is a striking co-occurrence of autism with attention deficit hyperactivity disorder (ADHD) [38,39].”

What the sources say

• Not checked yetcites [38] Gadow, 2005, Comparison of DSM-IV symptoms in elementary school-age children with PDD versus clinic and community samples, Autism source
• Not checked yetcites [39] Gadow, 2006, ADHD symptom subtypes in children with pervasive developmental disorder, J. Autism Dev. Disord. source

In the paper

“It is well established that people with ADHD encounter various severe cognitive control difficulties [57], but cognitive flexibility does not seem to be a key deficit [4,12,26,57,67].”

What the sources say

• Not checked yetcites [57] Nigg, 2005, An integrative theory of attention-deficit/hyperactivity disorder based on the cognitive and affective neurosciences, Dev. Psychopathol. source
• Not checked yetcites [4] Pennington, 1996, Executive functions and developmental psychopathology, J. Child Psychol. Psychiatry Allied Discip. source
• Not checked yetcites [12] Willcutt, 2008, Recent developments in neuropsychological models of childhood psychiatric disorders, Adv. Biol. Psychiatry source
• Not checked yetcites [26] Sergeant, 2002, How specific is a deficit of executive functioning for attention-deficit/hyperactivity disorder?, Behav. Brain Res. source
• Not checked yetcites [67] Willcutt, 2005, Validity of the executive function theory of attention-deficit/hyperactivity disorder: a meta-analytic review, Biol. Psychiatry source

In the paper

“Second, to our knowledge the sequence of trial types involved in the ID/ED is not based on a validated neural network model of cognitive control.”

In the paper

“For example, Wager and colleagues [48] reported that in typically developing adults, good and poor performance on a cognitive flexibility task were associated with activation of different neural circuits (ventral medial prefrontal cortex [MPFC] and rostral anterior cingulate cortex [ACC], and dorsolateral PFC [DLPFC], MPFC and parietal cortex, respectively).”

What the sources say

• Not checked yetcites [48] Wager, 2005, Towards a taxonomy of attention shifting: individual differences in fMRI during multiple shift types, Cogn. Affect. Behav. Neurosci. source

In the paper

“Therefore, the correlations obtained in the given examples [8–10] might be because of a general executive functioning deficit”

In the paper

“Other top down factors and/or mediating variables (bottom up) might better explain inflexibility than the measures discussed so far.”

In the paper

“However, increasing ecological validity always comes at the cost of reducing the mechanistic purity of the task.”

In the paper

“Hence, these comparisons between clinical groups might help us to unravel the etiology of each of these disorders and will provide insight into the differences and similarities among various neurodevelopmental disorders [44].”

What the sources say

• Not checked yetcites [44] Casey, 2001, Evidence for a mechanistic model of cognitive control, Clin. Neurosci. Res. source

In the paper

“However, there is considerable evidence that ADHD characteristics need to be carefully considered when studying autism (Box 2)”

In the paper

“For example, failure on the WCST might be because of social-motivational factors [25,26]”

What the sources say

• Not checked yetcites [25] Ozonoff, 1995, Reliability and validity of the Wisconsin card sorting test in studies of autism, Neuropsychology source
• Not checked yetcites [26] Sergeant, 2002, How specific is a deficit of executive functioning for attention-deficit/hyperactivity disorder?, Behav. Brain Res. source

In the paper

“or uncertainty regarding the expectations of the task which might evoke stress.”

In the paper

“In the current diagnostic statistical manual (DSM)-IV-text revision [1], both diagnoses cannot be given simultaneously.”

What the sources say

• Not checked yetcites [1] American Psychiatric Association (2000) Diagnostic and Statistical Manual of Mental Disorders (4th ed., TR) American Psychiatric Association

In the paper

“Ravizza and Carter [49] have argued that all switches are not created equal”

What the sources say

• Not checked yetcites [49] Ravizza, 2008, Shifting set about task switching: behavioral and neural evidence for distinct forms of cognitive flexibility, Neuropsychologia source

In the paper

“It is well-established that a certain level of arousal and/or stress is conducive for optimal performance”

What the sources say

• Not checked yetcites [53] Yerkes, 1908, The relation of strength of stimulus to rapidity of habit-formation, J. Comp. Neurol. Psychol. source

In the paper

“Although unstudied, over or under arousal might provide a plausible connection between psychobiological factors and performance on cognitive flexibility tasks in autism.”

In the paper

“One benefit of task-switching paradigms is that they have been extensively studied in typical development, providing a context for use in atypically developing populations.”

In the paper

“To go directly from the mechanistic tasks to observable behavior might be too large a gap to bridge.”