The Tower of London(DX): a standardized approach to assessing executive functioning in children.

In the current study, the Tower of London (Shallice, 1982) was modified to enhance its clinical utility as a measure of childhood executive functioning. The Tower of London-Drexel (TOL(DX)) was administered to normal control (NC; N = 56) and attention-deficit hyperactivity disorder (ADHD; N = 99) children (ages 7 to 12) to determine whether age-related changes in performance were evident, to gather normative data, and to evaluate the test-retest reliability and criterion-validity of the measure. The results revealed age-related changes in score performance, age-group normative data, an acceptable level of reliability and significant differences in performance of NC and ADHD subjects. Further, discriminant analysis classification rates determined that the TOL(DX) was sensitive and highly specific to ADHD. Implications and limitations of the study are discussed.     

Tower of London test performance in children with poor arithmetic skills

The Tower of London (TOL) has been used to assess executive functions in both children and adults with documented brain dysfunction. Like many other measures of executive function, it has not been widely used in the assessment of learning disabilities in children. However, if performance on the TOL discriminated among groups of children with different academic strengths and weaknesses, then it may be useful in identifying learning disability subtypes. The purpose of this study was to determine whether performance on the TOL would differ among 3 groups of children: those with arithmetic difficulties, those with reading difficulties, and those with no academic difficulties. The group with arithmetic difficulties exhibited significantly greater impairment on the TOL than either the group with reading difficulties or the group with no difficulties. The latter 2 groups performed similarly. The clinical utility of the TOL, as well as the relation between arithmetic deficits and executive functions, are discussed.     

Tower of London Test Performance in Children With Poor Arithmetic Skills

The Tower of London (TOL) has been used to assess executive functions in both children and adults with documented brain dysfunction. Like many other measures of executive function, it has not been widely used in the assessment of learning disabilities in children. However, if performance on the TOL discriminated among groups of children with different academic strengths and weaknesses, then it may be useful in identifying learning disability subtypes. The purpose of this study was to determine whether performance on the TOL would differ among 3 groups of children: those with arithmetic difficulties, those with reading difficulties, and those with no academic difficulties. The group with arithmetic difficulties exhibited significantly greater impairment on the TOL than either the group with reading difficulties or the group with no difficulties. The latter 2 groups performed similarly. The clinical utility of the TOL, as well as the relation between arithmetic deficits and executive functions, are discussed.     

Construct validity of the auditory continuous performance test for preschoolers

Development of diagnostic instruments directed toward neuropsychological assessment of preschoolers lags significantly behind those available for school-age children (DeWolfe, Byrne, & Bawden, 2000). This is particularly true for measures of executive function (EF). The Auditory Continuous Performance Test for Preschoolers (ACPT--P; Mahone, Pillion, & Hiemenz, 2001) is a computerized, Go-No-go test developed to measure selected EF skills in preschoolers. First, to determine whether performance on the ACPT--P is associated with hearing impairment, we compared performance of children with mild hearing loss (MHL) to controls on the ACPT--P, and measures of spatial working memory (SWM) and motor persistence (MP). There were no differences between performance of the MHL group and controls on any of these measures. Second, to examine the construct validity of the ACPT--P, we compared performance of 40 preschoolers with ADHD to 40 age- and sex-matched controls, using the ACPT--P to measure response preparation, sustained attention, and inhibitory control. We also compared these groups on measures of SWM and MP. The group with attention deficit hyperactivity disorder (ADHD) performed significantly worse than controls on the ACPT--P (omissions, mean response time, variability) and MP. The ACPT--P was correlated with the MP, but not with the SWM measure. Both the ACPT--P and the MP measures showed low to moderate correlations with parent ratings of behavior associated with ADHD. These findings support the use of performance-based assessment of executive control skills in preschoolers suspected of having ADHD. In this age group, the ACPT--P may be particularly useful in assessing sustained attention and response preparation and may complement behavior rating scales.     

Executive function profile of children with attention deficit hyperactivity disorder

We explored the neuropsychological profile for executive functions of children with attention deficit hyperactivity disorder (ADHD) to assess whether problems associated with the two most cited relevant processes-inhibition and attentional problems-were the core of any executive function difficulty. A battery of executive function tests was administered to 31 children with a clinical diagnosis of ADHD and to 33 normal control participants, all aged between 7 and 12. The executive function battery encompassed a number of tasks, selected because each had multiple measures: a sustained attention reaction time task, a related vigilance task, an adaptation of the Hayling Sentence Completion Test, an adaptation of the Brixton Spatial Rule Attainment Test, a Letter Fluency task, a number Stroop task, and an “n-back” working memory task. The overall pattern of the results fit well with those obtained in previous studies as far as abnormalities of the ADHD group in the domain of inhibitory processes, attentional functions, and executive functions. The children with ADHD, although performing well on baseline tasks, performed more poorly than the controls on all the experimental tasks with one borderline exception: Letter Fluency, where the children with ADHD showed a very different pattern than most adult frontal lobe subgroups. However, there was no specific impairment on measures of inhibitory processes. In addition, strategy generation and use were severely affected in the ADHD group. Particular findings fitted well with disorders of a high-level effort system and of a monitoring system.     

Executive Function Profile of Children With Attention Deficit Hyperactivity Disorder

We explored the neuropsychological profile for executive functions of children with attention deficit hyperactivity disorder (ADHD) to assess whether problems associated with the two most cited relevant processes-inhibition and attentional problems-were the core of any executive function difficulty. A battery of executive function tests was administered to 31 children with a clinical diagnosis of ADHD and to 33 normal control participants, all aged between 7 and 12. The executive function battery encompassed a number of tasks, selected because each had multiple measures: a sustained attention reaction time task, a related vigilance task, an adaptation of the Hayling Sentence Completion Test, an adaptation of the Brixton Spatial Rule Attainment Test, a Letter Fluency task, a number Stroop task, and an "n-back" working memory task. The overall pattern of the results fit well with those obtained in previous studies as far as abnormalities of the ADHD group in the domain of inhibitory processes, attentional functions, and executive functions. The children with ADHD, although performing well on baseline tasks, performed more poorly than the controls on all the experimental tasks with one borderline exception: Letter Fluency, where the children with ADHD showed a very different pattern than most adult frontal lobe subgroups. However, there was no specific impairment on measures of inhibitory processes. In addition, strategy generation and use were severely affected in the ADHD group. Particular findings fitted well with disorders of a high-level effort system and of a monitoring system.     

Tower of London Performance in Healthy Adolescents: The Development of Planning Skills and Associations With Self-Reported Inattention and Impulsivity

Studies have investigated planning skill development using the Tower of London (TOL). Reports conflict regarding maturational trajectories and associations with IQ, other executive functions, and impulsivity. A convenience sample of 9- to 20-year-olds completed the TOL and other measures. TOL accuracy improved until ages 15–17. Digit span backwards (DSB), response inhibition, and IQ were correlated with TOL performance. DSB contributed to TOL accuracy above and beyond age and IQ. Inhibitory control and DSB both contributed to the modulation of planning times across problems. Self-reported inattention and hyperactivity were associated with low performance. Task approaches reflecting planning and psychometric issues are discussed.     

Wisconsin Card Sorting Test with children: a meta-analytic study of sensitivity and specificity

More and more frequently the presence of executive function deficits appears in the research literature in conjunction with disabilities that affect children. Research has been most directed at the extent to which executive function deficits may be implicated in specific disorders such as attention deficit hyperactivity disorder (ADHD); however, deficits in executive function have been found to be typical of developmental disorders in general. The focus of this paper is to examine the extent to which one frequently used measure of executive function, the Wisconsin Card Sorting Test (WCST), demonstrates sensitivity and specificity for the identification of those executive function deficits associated with ADHD as well as its use with other developmental disorders through meta-analytic methods. Evidence of sensitivity of the WCST to dysfunction of the central nervous system is reviewed. Effect sizes calculated for all studies compared groups of children on differing variables of the WCST. The results of this meta-analysis suggest that across all of the studies, individuals with ADHD fairly consistently exhibit poorer performance as compared to individuals without clinical diagnoses on the WCST as measured by Percent Correct, Number of Categories, Total Errors, and Perseverative Errors. Notably, other various clinical groups performed more poorly than the ADHD groups in a number of studies. Thus, while impaired performance on the WCST may be indicative of an underlying neurological disorder, most likely related to frontal lobe function, poor performance is not sufficient for a diagnosis of ADHD. Implications for further research are presented.     

An empirical analysis of the BASC Frontal Lobe/Executive Control scale with a clinical sample.

Data from a clinical sample of children and adolescents were used to examine the characteristics of the Frontal Lobe/Executive Control (FLEC) scale of the Behavior Assessment System for Children Parent Rating Scales, including preliminary evidence of the scale's clinical utility and relationship to other behavioral measures of executive function and characteristics of Attention Deficit Hyperactivity Disorder (ADHD). Results indicate that participants in the ADHD and other clinical groups received very similar scores on the FLEC scale, and both groups were rated significantly higher in behaviors associated with executive dysfunction than were participants in the no diagnosis group. Correlational results indicate that scores on the FLEC scale were significantly correlated with scores on the Behavior Rating Inventory of Executive Function-Parent Form and Conners' Parent Rating Scales Revised-Short Form. Based on our results, the FLEC scale appears to be a useful behavioral rating tool in the assessment of executive function that may serve as a supplement to more traditional measures.     

Impact of gender and age on executive functioning: do girls and boys with and without attention deficit hyperactivity disorder differ neuropsychologically in preteen and teenage years?

ADHD is known to have neuropsychological correlates, characterized mainly by executive function (EF) deficits. However, most available data are based on studies of boys through age 12. Our goal was to assess whether girls with ADHD express neuropsychological features similar to those found in boys, and whether these impairments are found in both preteen and teen samples. Participants were 101 girls and 103 boys with DSM--III--R ADHD, and 109 comparison girls and 70 boys without ADHD, ages 9 to 17 years. Information on neuropsychological performance was obtained in a standardized manner blind to clinical status. Primary regression analyses controlled for age, socioeconomic status, learning disability, and psychiatric comorbidity. Girls and boys with ADHD were significantly more impaired on some measures of EFs than healthy comparisons but did not differ significantly from each other. With the exception of 1 test score there were no significant Sex × Diagnosis interactions. Moreover, there were no more significant interactions among age, gender, and diagnosis than would be expected by chance. Neuropsychological measures of EFs were comparably impaired in girls compared to boys with ADHD, and these impairments are found at ages 9 to 12 and ages 13 to 17. These findings suggest that executive dysfunctions are correlates of ADHD regardless of gender and age, at least through the late teen years.     

Comparative efficiency of a discrepancy analysis for the classification of Attention-Deficit/Hyperactivity Disorder in adults.

The present study evaluated an alternative method of neuropsychological test interpretation for the classification of Attention-Deficit/Hyperactivity Disorder (ADHD) in adults. Specifically, an intra-individual discrepancy analysis was implemented in which differences between intellectual functioning and performance on a battery of six frontal/executive tests were examined within a homogeneous group of ADHD adults and matched normal controls. Significant group differences were identified between the ADHD adults and control sample on each of the dependent measures, with moderate diagnostic efficiency rates for the individual measures and a Discrepancy Impairment Index (DII). The discrepancy analysis approach generated significantly greater sensitivity in detecting the presence of ADHD as compared to a level of performance interpretive approach. Overall, these results provide support for the consideration of discrepancies between intellectual ability and frontal/executive functioning for the assessment of adult ADHD.     

Executive functioning and olfactory identification in young adults with attention deficit-hyperactivity disorder

Young adults with attention deficit-hyperactivity disorder (ADHD; N = 105) were compared with a control group (N = 64) on 14 measures of executive function and olfactory identification using a 2 (group) X 2 (sex) design. The ADHD group performed significantly worse on 11 measures. No Group X Sex interaction was found on any measures. No differences were found in the ADHD group as a function of ADHD subtype or comorbid oppositional defiant disorder. Comorbid depression influenced the results of only 1 test (Digit Symbol). After IQ was controlled for, some group differences in verbal working memory, attention, and odor identification were no longer significant, whereas those in inhibition, interference control, nonverbal working memory, and other facets of attention remained so. Executive function deficits found in childhood ADHD exist in young adults with ADHD and are largely not influenced by comorbidity but may be partly a function of low intelligence.     

Prediction of ADHD in boys and girls using the D-KEFS

To examine patterns of executive dysfunction associated with ADHD, 123 children (54 ADHD, 69 controls) of ages 8–16 years were administered selected subtests from the Delis–Kaplan Executive Function System (D-KEFS). Children with ADHD performed significantly worse than controls on measures of both basic (less executive demand) skills and those with more executive demand from the Color–Word Interference and Tower subtests; however, no group differences were noted on any of the D-KEFS contrast scores. Most subtype comparisons yielded no differences; however, children with the Combined subtype outperformed children with the Inattentive subtype on measures of both basic and executive skills from the Trail Making Test. Children with ADHD demonstrate executive dysfunction that is identified by D-KEFS summary, but not contrast scores. In this carefully screened sample of children with ADHD, few significant differences were found between groups suggesting limited sensitivity or specificity of the D-KEFS for classifying children with ADHD.     

Learning disabilities and executive dysfunction in boys with attention-deficit/hyperactivity disorder

The effect of comorbid reading or arithmetic learning disabilities (LDs) on neuropsychological function in attention-deficit/hyperactivity disorder (ADHD) was studied. Participants were young males diagnosed with ADHD, with and without LD, and non-ADHD, non-LD male controls of similar age. LD was defined by combined regression-based and low-achievement classifications. Analyses adjusted for the effect of psychiatric comorbidity, age, and socioeconomic status on neuropsychological function. Children who had both ADHD and LD were significantly more impaired on both executive and nonexecutive functions than ADHD children without LD. Neuropsychological performance was most impaired in ADHD with combined arithmetic and reading disability. These data indicate that comorbid LD, especially arithmetic disability, significantly increases the severity of executive function impairment in ADHD.     

Neuropsychological correlates of ADHD symptoms in preschoolers

The authors examined the neuropsychological status of 22 preschoolers at risk for attention-deficit/hyperactivity disorder (ADHD) and 50 matched control children, using measures of nonverbal working memory, perceptual and motor inhibition, and memory for relative time. All tasks included paired control conditions, which allowed for the isolation of discrete executive function constructs. Group differences were evident on several measures of neuropsychological functioning; however, after accounting for nonexecutive abilities, no deficits could be attributed to specific functions targeted by the tasks. Performance on executive measures was not related to objective indices of activity level or ratings of ADHD symptoms. Yet, the fact that at-risk preschoolers were highly symptomatic casts doubt on whether executive function deficits and/or frontostriatal networks contribute etiologically to early behavioral manifestations of ADHD.     

Family-genetic study of executive functioning in attention-deficit/hyperactivity disorder: Evidence for an endophenotype?

This study examined familiality of attentional control and mental flexibility in multiplex attention-deficit/hyperactivity disorder (ADHD) families. The authors hypothesized that siblings of ADHD probands, although not behaviorally expressing ADHD, have deficits in these executive functions and that the performance of probands, unaffected siblings, and control participants are on a continuum. Participants (aged 6 to 17) were 25 ADHD probands with a family history of ADHD, their 25 unaffected siblings, and 48 control participants. The unaffected siblings did not differ from the ADHD probands on attentional control or on some measures of mental flexibility. Linear changes in performance across the groups reflected an intermediate position of the unaffected siblings between the probands and control participants. These results suggest that these executive functions may be suitable endophenotypes of ADHD.     

Executive function and attention deficit hyperactivity disorder: stimulant medication and better executive function performance in children.

BACKGROUND: Executive function deficits have been reported repeatedly in children with Attention Deficit Hyperactivity Disorder (ADHD). Stimulant medication has been shown to be effective in improving cognitive performance on most executive function tasks, but neuropsychological tests of executive function in this population have yielded inconsistent results. Methodological limitations may explain these inconsistencies. This study aimed to measure executive function in medicated and non-medicated children with ADHD by using a computerized battery, the Cambridge Neuropsychological Test Automated Battery (CANTAB), which is sensitive to executive function deficits in older patients with frontostriatal neurological impairments. METHODS: Executive function was assessed in 30 children with ADHD: 15 were stimulant medication naive and 15 were treated with stimulant medication. These two groups were compared to 15 age, sex and IQ matched controls. RESULTS: The unmedicated children with ADHD displayed specific cognitive impairments on executive function tasks of spatial short-term memory, spatial working memory, set-shifting ability and planning ability. Impairments were also seen on spatial recognition memory and delayed matching to sample, while pattern recognition memory remained intact. The medicated children with ADHD were not impaired on any of the above executive function tasks except for deficits in spatial recognition memory. CONCLUSIONS: ADHD is associated with deficits in executive function. Stimulant medication is associated with better executive function performance. Prospective follow-up studies are required to examine these effects.     

Executive functioning in children with attention-deficit/hyperactivity disorder: combined type with and without a stimulant medication history

Behavioral and neuropsychological functioning in unmedicated children with attention-deficit/hyperactivity disorder (ADHD) who have a history of medication treatment (Rx) versus those who are treatment na?ve (TN) has, to our knowledge, not been previously studied. Ninety-four children in four groups (ADHD/Rx, ADHD/TN, learning disabilities [LD], and controls) were evaluated, while unmedicated, on measures of achievement, neuropsychological functioning, and behavior. The ADHD/Rx group performed significantly better than the TN group on writing, Stroop interference, and measures of attention, and performed as well as the control group on executive functioning, verbal working memory, and academics. Behaviorally, the ADHD groups showed more difficulty with mood and externalizing behaviors compared with the LD and control groups, with the ADHD/TN performing the most poorly. Findings suggest that the ADHD/Rx group shows better executive and academic functioning even when unmedicated.     

A meta-analysis of the sensitivity and specificity of the Stroop Color and Word Test with children.

The purpose of this paper is to examine the extent to which the Stroop Color-Word Test demonstrates sensitivity and specificity for the identification of executive function deficits in children and adolescents. Meta-analytic methods were used to identify executive function deficits associated with attention deficit hyperactivity disorder (ADHD) and other developmental disorders. Weighted effect sizes were calculated for all studies found that compared groups of children on the Stroop task. Results indicated that across studies, children and adolescents with ADHD fairly consistently exhibited poorer performance when compared to individuals without clinical diagnoses on the Stroop task as measured by the weighted Word, Color, Color-Word, and Interference scores. The Stroop task did not discriminate ADHD groups from other clinical groups consistently across studies. In conclusion, while impaired performance of the Stroop task may be indicative of an underlying neurological disorder related to frontal lobe dysfunction, poor performance is not sufficient for a diagnosis of ADHD.     

成人ADHD患者静息脑电及其与生态执行功能的相关性

目的:探究成人注意缺陷多动障碍(ADHD)患者的脑电特征及其与生态执行功能的关系。方法:选取成人ADHD患者33例及正常对照30例,用执行功能行为评定量表成人版(BRIEF-A)评估生态执行功能,并记录静息态脑电,分析不同频段脑电的绝对功率,探讨其与执行功能缺陷的相关性。结果:与正常对照相比,ADHD患者BRIEF-A各因子得分及其全脑θ波及中央区β绝对功率均高于对照组(均P<0.01);ADHD患者的工作记忆评分与其双侧额叶θ波绝对功率呈正相关(r=0.43、0.49,均P<0.05),情感控制评分与双侧中央区β波绝对功率呈正相关(r=0.43、0.49,均P<0.05)。结论:成人ADHD患者生态执行功能存在缺陷,其额叶θ波及中央区-顶叶β波功率增高可能分别参与其工作记忆缺陷及情感控制不良的神经病理学机制。