Executive processes in Asperger syndrome: Patterns of performance in a multiple case series

Performance on these measures correlated with autistic symptomatology.

“Moreover, performance on these measures correlated with autistic symptomatology.”

After accounting for slower initiation (Hayling time 1 as covariate), no group differences remained in the latency to respond in the second part of the Hayling test [F(1,40) = 0.07, p = 0.79].

“Once slower initiation had been accounted for in this way, no group differences remained in the latency to respond in the second part of the test [ F (1,40) = 0.07, p = 0.79].”

In terms of the classic tests of executive function adopted in the study, only performance on the Trailmaking test distinguished between the two participant groups.

“In terms of the classic tests of executive function adopted in the study, only performance on the Trailmaking test distinguished between the two participant groups.”

Outliers are seen in some of the classic tests of executive function, as well as in the newer tests.

“Here, outliers are seen in some of the classic tests of executive function, as well as in the newer tests.”

In a pilot study of 35 adults with ASD, large and significant difficulties in areas of daily living associated with executive dysfunction were identified.

“In a pilot studyweused theDEXin a sample of 35 adults with ASD. Large and significant difficulties in areas of daily living associated with executive dysfunction were identified.”

The number of AS outliers on the Six Elements test longest time was 13 (61.90% of the AS group).

“| Six Elements test: longest time | 21 | 13 (61.90) |”

Performance on the Trailmaking test of psychomotor speed (part A) showed a greater difference than performance on the test thought to tap cognitive flexibility (part B).

“although performance on the test of psychomotor speed (part A) showed a greater difference than performance on the test thought to tap cognitive flexibility (part B).”

Overall 11 of 22 comparisons showed a significant group difference in performance.

“Overall 11 of 22 comparisons showed a significant group difference in performance, and it is these measures that formed the focus of the remaining investigation.”

There was a clear group difference in overall score on the Hayling test.

“However, there was a clear group difference in overall score on the Hayling test”

There were no differences between the groups on all classical tests of executive function.

“There were no differences between the groups on all 'classical' tests of executive function.”

Many of the tests showed no impairment in the performance of the AS group.

“However, many of the tests showed no impairment in the performance of the AS group.”

The number of AS outliers on the Trail-making part A was 13 (59.09% of the AS group).

“| Trail-making part A | 22 | 13 (59.09) |”

After accounting for slower psychomotor skill (Trailmaking part A as covariate), no group differences remained in the speed of performance on Trailmaking part B [F(1,41) = 0.01, p = 0.92].

“Once slower psychomotor skill had been accounted for in this way, no group differences remained in the speed of performance on part B [ F (1,41) = 0.01, p = 0.92].”

The number of AS outliers on the Hayling overall total was 8 (38.09% of the AS group).

“| Hayling overall total | 21 | 8 (38.09) |”

The significant correlations were seen only between the measures of autistic symptomatology and parts of the newer tests of executive function, specifically the action program and six elements subtasks of the BADS and the Hayling test.

“The significant correlations were seen only between the measures of autistic symptomatology and parts of the newer tests of executive function, specifically the action program and six elements subtasks of the BADS and the Hayling test.”

On the temporal judgement subtest of the BADS, the group of adults with Asperger syndrome was significantly better able to estimate the time required for four commonplace activities than the control group.

“However, on the temporal judgement subtest of the BADS, the group of adults with Asperger syndrome was significantly better able to estimate the time required for four commonplace activities than the control group.”

The findings show mixed performance on tests of executive functions in a group of able adults with Asperger syndrome.

“these findings show mixed performance on tests of executive functions in a group of able adults with Asperger syndrome.”

On the tests that discriminated the groups, all of the ASD individuals except one were identified as significantly impaired (below the 5th percentile of the control mean) on at least one executive measure.

“On the tests that discriminated the groups, all of the ASD individuals except one were identified as significantly impaired (i.e. below the 5th percentile of the control mean) on at least one executive measure.”

There was no difference in the errors produced by the two participant groups on the Hayling test.

“While there was no difference in the errors produced by the two participant groups”

There was a significant correlation between Hayling overall score and performance on the Stroop test in the AS group only [AS, r(19) = 0.45, p < 0.05; controls, r(19) = 0.19, p = 0.42].

“as well as a significant correlation between this measure and performance on the Stroop test (another test of inhibition) in the AS group only [AS, r (19) = 0.45, p < 0.05; controls, r (19) = 0.19, p = 0.42].”

The number of AS outliers on the AQ was 18 (81.82% of the AS group).

“| AQ | 22 | 18 (81.82) |”

The number of AS outliers on the Communication Checklist was 14 (63.64% of the AS group).

“| Communication Checklist | 22 | 14 (63.64) |”

Only one individual with AS was unimpaired on all three measures (SET longest time, AQ, Communication Checklist).

“and only one was unimpaired on all three measures.”

These behaviours were not seen in any of the control participants.

“These behaviours were not seen in any of the control participants.”

The total score on the Hayling test alone does not account for any of the AS outliers.

“it is clear that the total score on the Hayling test alone does not account for any of the AS outliers”

Combinations of the SET longest time, the AQ and the Communication Checklist account well for the AS outliers.

“It is clear that combinations of these three measures account well for the AS outliers.”

All those with AS who were identified as outliers on the Hayling overall total measure were also identified as outliers on the Communication Checklist.

“all those with AS who were identified as outliers on the Hayling overall total measure were also identified as outliers on the Communication Checklist.”

In adults with Asperger syndrome compared with matched controls, there were no differences on all 'classical' tests of executive function once difficulties in psychomotor processing and visual search had been accounted for.

“Overall, there were no differences between those with and without AS on all 'classical' tests of executive function, once difficulties in psychomotor processing and visual search had been accounted for (cf. group difference on trails A and B).”

• Also stated in: § 3. Discussion · p. 17 · plain

  “Interestingly, no significant group differences were found on any of the tests that are considered to be 'classical' executive tests, after controlling for psychomotor speed (the MCST, Stroop test, Trail-making test and verbal fluency).”

Only one individual with AS was an outlier on each measure alone.

“Only one individual with AS was an outlier on each measure alone”

The qualitative performance of the AS group was distinguished from that of their peers in some cases: those with AS were more likely to get engrossed in one particular subtask at the expense of the other five subtests.

“The qualitative performance of the AS group was also distinguished from that of their peers in some cases: as the SET longest time difference shows, those with AS were more likely to get engrossed in one particular subtask at the expense of the other five subtests.”

In adults with Asperger syndrome compared with matched controls, large differences were found on newer tests of executive function, particularly the Six Elements task of the BADS and the Hayling test.

“However, surprisingly large differences were found on other, newer tests of executive function, in particular on the Six Elements task of the BADS and on the Hayling test.”

• Also stated in: § 3. Discussion · p. 17 · plain

  “Nevertheless, significant group differences were found on certain newer tests, particularly the Six Elements and Hayling tests.”

The Six Elements and Hayling tests correlated with measures of autistic behaviours.

“These tests were sensitive not only at a group level but also on a case-by-case basis and they correlated with measures of autistic behaviours.”

• Also stated in: § 3. Discussion · p. 17 · plain

  “These tests also correlated with autistic symptomatology and a high proportion of the AS group performed below the 5th percentile with reference to the controls.”

• AssumptionRests on an assumption: The Communication Checklist validly measures autistic symptomatology.

A 16-year-old male (id170) spent a very short period of time on each of the six SET subtests and then settled now to complete one subtest in detail, knowing that he had fulfilled the rule 'complete something from all tests'.

“or that of a 16-year-old male who spent a very short period of time on each of the six SET subtests and then settled now to complete one subtest in detail, knowing that he had ful- filled the rule 'complete something from all tests' (id170).”

A high proportion of the AS group performed below the 5th percentile with reference to the controls on the Six Elements and Hayling tests.

“These tests also correlated with autistic symptomatology and a high proportion of the AS group performed below the 5th percentile with reference to the controls.”

The multiple case analyses revealed executive dysfunction on some performance measures of classical tests in a minority of AS individuals.

“The multiple case analyses did reveal executive dysfunction on some performance measures of these tests in a minority of AS individuals.”

Focusing on adults avoids issues concerning late maturation of the frontal lobes that may cloud the picture in studies of children and adolescents.

“By focusing on this group, we can avoid issues concerning the late maturation of the frontal lobes (Mesulam, 2002) that may cloud the picture in studies of children and adolescents as we are tapping into an apparently mature executive system.”

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The Trailmaking group difference reflects difficulties in psychomotor processing and visual search rather than in executive dysfunction.

“Thus, while this was the only one of the traditional tests of executive function to show a group difference, this difference reflects difficulties in psychomotor processing and visual search rather than in executive dysfunction.”

The widespread difficulties identified in the pilot study highlighted the impact of a hypothesised executive dysfunction in the day-to-day life of such individuals.

“Such widespread difficulties highlighted the impact of a hypothesised executive dysfunction in the day-to-day life of such individuals.”

Difficulties in planning, mental flexibility and generativity have been documented in autism spectrum disorders.

“Systematic reviews of the literature reveal mixed evidence for executive dysfunction in ASD, although difficulties in planning, mental flexibility and generativity have been documented (see Pennington, & Ozonoff, 1996, for review).”

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Evidence for executive dysfunction in autism spectrum disorders is mixed.

“Mixed evidence exists for executive dysfunction in autism spectrum disorders (ASD).”

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  “Systematic reviews of the literature reveal mixed evidence for executive dysfunction in ASD, although difficulties in planning, mental flexibility and generativity have been documented (see Pennington, & Ozonoff, 1996, for review).”

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Carefully selecting an IQ-matched control group moves away from complications in interpreting results in the light of ability level.

“Third, by carefully selecting an IQmatched control group we move away from complications in interpreting results in the light of ability level, since the interpretation of performance of a clinical group can be influenced strongly by selection of controls.”

• Also stated in: § 3. Discussion · p. 17 · plain

  “Third, by carefully selecting an IQ-matched control group we again move away from complications in interpreting results in the light of ability level.”

Performance on the Hayling test is a useful test of inhibition in an AS sample.

“This suggests that performance on the Hayling test is a useful test of inhibition in an AS sample.”

This study provides evidence for significant executive dysfunction in Asperger syndrome.

“This study provides evidence for significant executive dysfunction in Asperger syndrome.”

The Hayling latency difference appears to reflect difficulties in initiation per se, rather than in inhibition or strategy formation.

“Thus, this difference appears to reflect difficulties in initiation per se, rather than in inhibition or strategy formation.”

In studies with large numbers of individuals, significant differences at the group level may be largely meaningless in terms of the degree of executive dysfunction exhibited by individuals within the group if there is a large degree of overlap between the groups.

“Conversely, in studies with large numbers of individuals, 'significant' differences in performance at the group level may be largely meaningless in terms of the degree of executive dysfunction exhibited by the individuals within the group if there is a large degree of overlap between the groups.”

Studies with children with ASD have shown dissociations between performance on classic tests of executive function.

“Studies with children with ASD have shown plenty of dissociations between performance on these tests (see Hill, 2004a).”

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The findings of the group and correlational analyses in two groups well matched for sex, age and intellectual ability provide some evidence for a deficit in executive functions in Asperger syndrome.

“In summary, the findings of the group and correlational analyses in two groups well matched for sex, age and intellectual ability, provides some evidence for a deficit in executive functions in Asperger syndrome.”

Greatest dysfunction appeared in response initiation and intentionality at the highest level-the ability to engage and disengage actions in the service of overarching goals.

“Greatest dysfunction appeared in response initiation and intentionality at the highest level-the ability to engage and disengage actions in the service of overarching goals.”

Any deficits causally related to autistic symptomatology should be found in their most pure forms in high-functioning individuals with ASD, i.e. those with Asperger syndrome.

“Therefore, any deficits that are related causally to autistic symptomatology should be found in their most pure forms in high-functioning individuals with ASD, i.e. those with Asperger syndrome.”

Non-significant group differences are not indicative of fully intact performance in all participants.

“Consequently non-significant group differences are not indicative of fully intact performance in all participants.”

Mixed findings on executive dysfunction in ASD may arise from the nature of the tasks administered and the nature of the autism and/or control samples used.

“This may be because of the nature of the tasks used, the heterogeneity of participants, and difficulties with recruiting appropriate control groups.”

• Also stated in: § Abstract · p. 2 · hedged

  “Mixed findings may arise from a number of issues, including the nature of the tasks administered as well as the nature of the autism and/or control samples used.”

Only a handful of previous studies of executive function in adults with ASD have been published.

“Second, we report data from a group of adults, rather than children, for which only a handful of previous studies have been published (see Table 1).”

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The difficulties identified in the pilot study were reminiscent of the executive dysfunction seen in those with acquired dysexecutive syndrome.

“These difficulties were reminiscent of the executive dysfunction seen in those with acquired dysexecutive syndrome.”

It seems likely that differing profiles of executive dysfunction can be identified in those with different developmental disorders.

“It seems likely, however, that differing profiles of executive dysfunction can be identified in those with different developmental disorders.”

Our data support prior reports of deficits in executive function in the autism spectrum.

“Our data support those reported by a number of other researchers who have shown deficits in executive function in the autism spectrum (see Table 1 and Hill, 2004a,b).”

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The findings of the current study suggest that greatest dysfunction appeared in response initiation and intentionality-the ability to engage and disengage actions in the service of overarching goals.

“Overall, then, the findings of the current study suggest that greatest dysfunction appeared in response initiation and intentionality-the ability to engage and disengage actions in the service of overarching goals.”

Asperger syndrome might be considered the purest form of autism because it is unimpeded by the effects of learning difficulty.

“First, Asperger syndrome might be considered to be the purest form of autism in the sense that it is unimpeded by the effects of learning dif- ficulty, for example (Frith, 2004).”

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Response initiation and intentionality, in particular the ability to engage and disengage actions in the service of overarching goals, are impaired in adults with Asperger syndrome.

“Specifically, response initiation and intentionality, in particular the ability to engage and disengage actions in the service of overarching goals, are impaired.”

Combining the three analyses provides stronger evidence than is obtained purely from the executive function data or from any one of the three analyses alone.

“This provides stronger evidence than is obtained purely from the executive function data, or from the use of any one of the three analyses alone.”

The performance of the AS sample appears to mirror a number of findings reported in the literature.

“While we must be wary of drawing parallels between acquired and developmental disorders, the performance of our AS sample appears to mirror a number of findings reported in the literature.”

In adults with ASD, a model of executive strengths (working memory and response inhibition) and weaknesses (planning and cognitive flexibility) best predicted the severity of restricted, repetitive behaviours.

“In this study, a model of executive strengths (working memory and response inhibition) and weaknesses (planning and cognitive flexibility) best predicted the severity of restricted, repetitive behaviours reported in a group of adults with ASD (Lopez et al., 2005).”

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The population assessed in the present study provides a particularly good test of the theory that executive function is central to ASD.

“There are three main reasons why the population assessed in the present study provides a particularly good test of the theory that executive function is central to ASD.”

In ASD, normal brain activations are not seen when completing tasks on which behavioural performance falls in the normal range.

“To date, it seems that this is not the case (e.g. Boucher et al., 2005; Schmitz et al., 2005).”

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The study has provided support for the existence of deficits in specific aspects of executive function in Asperger syndrome.

“By showing this, our study has provided support for the existence of deficits in specific aspects of executive function in Asperger syndrome.”

The Six Elements task is crucially related to planning, organisation and action monitoring.

“For example, Burgess (1997) confirmed that this task is crucially related to planning, organisation and action monitoring.”

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The data presented are indicative of specific difficulty in at least two aspects of executive function-response initiation and intentionality.

“While the data that we have presented are indicative of specific difficulty in at least two aspects of executive function - what has been termed response initiation and intentionality by Burgess et al. (1998) - the possibility remains that we have identified a general dysexecutive syndrome rather than specific deficits.”

Goal/subgoal coordination is a critical component of the Six Elements test.

“Goal/subgoal coordination is a critical component of the Six Elements test.”

In a comparison of children with ASD, ADHD and Tourette syndrome, Ozonoff and Jensen (1999) reported differential performance between the groups on tests of planning, cognitive flexibility and inhibition.

“Specifically, in a comparison of children with ASD, ADHD and Tourette syndrome, Ozonoff and Jensen (1999) reported differential performance between the groups on a test of planning, cognitive flexibility and inhibition.”

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The AS participants in the study can be expected to experience a degree of executive dysfunction in their everyday living.

“Thus, we can expect that the AS participants in our study will experience a degree of executive dysfunction in their everyday living.”

The deficits might also be seen as a difficulty in goal/sub-goal coordination.

“This might also be seen as a difficulty in goal/sub-goal coordination such as that described by Ward and Allport (1997).”

The Six Elements and Hayling tests are apparently highly sensitive to AS.

“both tests which are apparently highly sensitive to AS”

Assessing adults avoids issues concerning late maturation of the frontal lobes that may cloud the picture in studies of children and adolescents.

“Second, by assessing adults we avoid issues concerning the late maturation of the frontal lobes that may cloud the picture in studies of children and adolescents (especially when these groups are compared with their typically developing peers).”