Long-Term Follow-Up of Children with Mental Retardation/Borderline Intellectual Functioning and ADHD

Fifty-two children (ages 7 to 14 years) with moderate mental retardation to borderline intellectual functioning were recontacted 12 to 65 months following participation in a double-blind, placebo-controlled trial of methylphenidate (MPH). Sixty-nine percent of subjects continued to be prescribed medication for behavior control at follow-up. While 72% of the sample evidenced improvement, over two-thirds continued to be rated at or above the 98th percentile on the Hyperactivity Index of the Parent Conners. In fact, 22% of subjects had received inpatient psychiatric treatment between the time of the initial MPH trial and follow-up. Finally, subjects with high initial ratings on the Parent Conners Conduct Problems scale were more likely to be suspended from school or receive inpatient psychiatric treatment than subjects with low initial ratings. The results suggested that children with ADHD and mental retardation or borderline intellectual functioning continued to exhibit significant symptoms associated with attention deficit hyperactivity disorder (ADHD) at follow-up and that early conduct problems were predictive of continuing behavioral difficulties.     

Conners’ continuous performance test (CCPT-II) in children with ADHD,ODD, or a combined ADHD/ODD diagnosis

The current study investigated if results on the Conners’ Continuous Performance Test (CCPT-II) could discriminate between children with ADHD (n = 59), ODD (n = 10), ADHD+ODD (n = 15), and normal controls (n =160), and how the results are associated with and explained by the intellectual function of the child. The sample was derived from the Bergen Child Study (BCS), a longitudinal, ongoing, population-based study of children’s development and mental health. CCPT-II performance did not differentiate between the three diagnostic groups (i.e., ADHD, ODD, and ADHD+ODD). Children with ODD (with or without comorbid ADHD) did not differ from children in the control group on any CCPT-II parameters. Children with ADHD made statistically significant more errors of omissions and showed a more variable response time to targets than the control group. The correlations between CCPT-II measures and IQ were mild to moderate, and there was a statistically significant group difference in IQ: Children with ADHD, and children with ADHD+ODD, obtained lower IQ scores than normal controls. A hierarchical multiple regression analysis showed that IQ, but not diagnostic group status, was significant predictors of CCPT-II performance. CCPT-II performance should be interpreted with caution when assessing ADHD and/or ODD in children.     

Basic number processing deficits in ADHD: a broad examination of elementary and complex number processing skills in 9- to 12-year-old children with ADHD-C

ADHD (attention-deficit hyperactivity disorder) and academic difficulties are frequently associated, but to date this link is poorly understood. In order to explore which components of number processing and calculation skills may be disturbed in children with ADHD we presented a series of respective tasks to 9- to 12-year-old children with ADHD-combined type and matched children without ADHD (of any type) without concomitant dyscalculia and/or dyslexia. Overall, group differences were not significant regarding overlearned and explicitly trained simple and complex calculation skills. More basic number processing skills are - for instance - the ability to compare one-digit numbers according to their magnitude (so-called magnitude comparison), to count or to transcode numbers, i.e. to write down an Arabic number '21' in verbal dictation. Significant differences favouring control children in basic number processing skills were obtained in a number comparison task and in a dot enumeration task. Importantly, our results cannot be explained by group differences regarding specific working memory and executive function components. Thus, number processing skills and in particular the processing of numerical magnitude should be investigated in children diagnosed with ADHD even when no comorbid learning disabilities are reported.     

Academic Underachievement and Attention-Deficit/Hyperactivity Disorder: The Negative Impact of Symptom Severity on School Performance

Many children with Attention-Deficit/Hyperactivity Disorder (ADHD) achieve academically at a lower level than would be predicted given their intellectual abilities. However, the extent to which this is due to behavioral problems versus cognitive deficits associated with the disorder is unclear. In the present study, a group of children with ADHD (with average intellectual abilities) performed significantly below prediction in reading, writing, and mathematics skills and demonstrated a greater discrepancy between actual and predicted achievement than did a group of non-ADHD children. Even when controlling for performance on a measure of executive functioning, severity of ADHD symptoms, based on parent report, significantly predicted academic underachievement in reading, writing, and mathematics. These results indicate that the more severe the behavioral symptomatology of children with ADHD is, the more negatively impacted their school performance may be. Results are discussed in terms of diagnostic and intervention implications.     

Behavioral Characteristics of DSM-IV ADHD Subtypes in a School-Based Population

From an ethnically diverse sample of 2,744 school children, 221 attention deficit hyperactivity disorder (ADHD) [123 (4.5%) predominantly inattentive (IA), 47 (1.7%) predominantly hyperactive/impulsive (HI), and 51 (1.9%) combined type (C)] were identified using teacher ratings on a Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV) symptom checklist. Subjects were compared to 221 controls on teacher ratings of behavioral, academic, and social functioning. The results revealed relatively independent areas of impairment for each diagnostic group. The IA children were impaired in all areas, but were rated as displaying more appropriate behavior and fewer externalizing problems than HI or C children. The HI group displayed externalizing and social problems, but was rated as no different than controls in learning or internalizing problems. The C group demonstrated severe and pervasive difficulties across domains. These findings support the validity of the DSM-IV ADHD subtypes; all ADHD groups demonstrated impairment relative to controls, but show different patterns of behavioral characteristics.     

A critical appraisal of the role of neuropsychological deficits in preschool ADHD

The present study aimed at improving our understanding of the role of neuropsychological deficits in preschool Attention Deficit Hyperactivity Disorder (ADHD). The study included 52 children in the ADHD group and 72 controls (age 4–6 years). Both laboratory measures and teacher reports of executive deficits (i.e., working memory, inhibition, and shifting), delay-related behaviors (i.e., the preference for minimizing delay), and emotional functions (i.e., emotion recognition and regulation) were included. Variable-oriented analyses were complemented with person-oriented analyses (i.e., identifying the proportion of patients considered impaired). Results showed that the ADHD group differed from controls with regard to all measures of executive functioning and most measures of delay-related behaviors, but few differences were found for emotional functioning. A substantial subgroup (23%) of children with ADHD did not have a neuropsychological deficit in any domain. There were subgroups with executive or delay-related deficits only, but no pure emotional subgroup. The overlap between different neuropsychological deficits was much larger when teacher reports were used as opposed to laboratory measures. Regarding functional impairments, large mean differences were found between the ADHD group and controls. However, neuropsychological deficits were not able to explain individual variations in daily life functioning among children with ADHD. In conclusion, the present study identified some important methodological and theoretical issues regarding the role of neuropsychological functioning in preschool ADHD.     

Frontal lobe functioning in adolescents with attention deficit hyperactivity disorder

A prominent hypothesis regarding the etiology of attention deficit hyperactivity disorder (ADHD) is that its presence and magnitude reflect frontal lobe dysfunction. Past tests of this hypothesis have been inconsistent. The present study examined frontal lobe functioning in adolescents with ADHD. A sample of 10 ADHD adolescents and 10 controls between the ages of 12 and 17 served as participants for the study. The control group was matched on age (within six months) and gender. This study aided in clarifying past contradictory studies by using clearly defined criteria to determine ADHD, a representative age range of participants, carefully selected tests, and a control task. The two measures that were administered to assess frontal lobe functioning were the Wisconsin Card Sorting Test and the Stroop Color and Word Test. The Purdue Pegboard was used as a control measure that did not assess frontal lobe functioning. The findings indicate that the ADHD group performed significantly worse on the following: color score, color/word score, and interference score of the Stroop Color and Word Test; percent of perseverative responses, percent of perseverative errors, and number of completed categories of the Wisconsin Card Sorting Test. No differences were found on the Purdue Pegboard task.     

Spatial reversal as a measure of executive functioning in children with autism

The purpose of this experiment was to compare the executive functioning performance of children with autism with chronological- and verbal-matched controls in a spatial-reversal task. Three groups of children participated in this experiment. One group was identified as having autism (7 boys), the 2nd group contained 7 typically developing children (6 boys, 1 girl) who were matched to the 1st group based on their verbal performance, and the 3rd group contained 7 typically functioning children (6 boys, 1 girl) matched to the 1st group based on chronological age. Each group was given a spatial-reversal task containing 2 problems. In the 1st problem, children selected a toy on a particular side in a pair. In the 2nd problem, the contingencies were reversed such that children were to choose the toy on the opposite side. Children with autism generally performed worse than comparison groups as indicated by their overall higher rate of errors. However, these results must be qualified by considering the performance for each problem: Errors for the children with autism were infrequent during the 1st problem but increased in the 2nd, whereas errors for comparison children showed the opposite pattern. When these results from the spatial-reversal task were interpreted from the perspective of hypothesis-testing theory, the executive functioning deficiency of children with autism was found to involve the selection and testing of stereotypic response sets that were not likely to be revised or changed flexibly according to feedback from the environment or the demands of the task.     

Inhibition,Reinforcement Sensitivity and Temporal Information Processing in ADHD and ADHD+ODD: Evidence of a Separate Entity?

This study compared children with ADHD-only, ADHD+ODD and normal controls (age 8–12) on three key neurocognitive functions: response inhibition, reinforcement sensitivity, and temporal information processing. The goal was twofold: (a) to investigate neurocognitive impairments in children with ADHD-only and children with ADHD+ODD, and (b) to test whether ADHD+ODD is a more severe from of ADHD in terms of neurocognitive performance. In Experiment 1, inhibition abilities were measured using the Stop Task. In Experiment 2, reinforcement sensitivity and temporal information processing abilities were measured using a Timing Task with both a reward and penalty condition. Compared to controls, children with ADHD-only demonstrated impaired inhibitory control, showed more time underestimations, and showed performance deterioration in the face of reward and penalty. Children with ADHD+ODD performed in-between children with ADHD-only and controls in terms of inhibitory controls and the tendency to underestimate time, but were more impaired than controls and children with ADHD-only in terms of timing variability. In the face of reward and penalty children with ADHD+ODD improved their performance compared to a neutral condition, in contrast to children with ADHD-only. In the face of reward, the performance improvement in the ADHD+ODD group was disproportionally larger than that of controls. Taken together the findings suggest that, in terms of neurocognitive functioning, comorbid ADHD+ODD is a substantial different entity than ADHD-only.     

Spatial Reversal as a Measure of Executive Functioning in Children With Autism

The purpose of this experiment was to compare the executive functioning performance of children with autism with chronological- and verbal-matched controls in a spatial-reversal task. Three groups of children participated in this experiment. One group was identified as having autism (7 boys), the 2nd group contained 7 typically developing children (6 boys, 1 girl) who were matched to the 1st group based on their verbal performance, and the 3rd group contained 7 typically functioning children (6 boys, 1 girl) matched to the 1st group based on chronological age. Each group was given a spatial-reversal task containing 2 problems. In the 1st problem, children selected a toy on a particular side in a pair. In the 2nd problem, the contingencies were reversed such that children were to choose the toy on the opposite side. Children with autism generally performed worse than comparison groups as indicated by their overall higher rate of errors. However, these results must be qualified by considering the performance for each problem: Errors for the children with autism were infrequent during the 1st problem but increased in the 2nd, whereas errors for comparison children showed the opposite pattern. When these results from the spatial-reversal task were intérpreted from the perspective of hypothesis-testing theory, the executive functioning deficiency of children with autism was found to involve the selection and testing of stereotypic response sets that were not likely to be revised or changed flexibly according to feedback from the environment or the demands of the task.     

Children with ADHD and depression: a multisource, multimethod assessment of clinical, social, and academic functioning

Although ADHD and depression are common comorbidities in youth, few studies have examined this particular clinical presentation. To address method bias limitations of previous research, this study uses multiple informants to compare the academic, social, and clinical functioning of children with ADHD, children with ADHD and depression, and children without ADHD, all derived from a large community sample. High levels of comorbid depression are found in children with ADHD. Children withADHDand depression are more depressed and anxious than their non-depressed ADHDcounterparts but do not have more extreme levels of ADHD or aggression. The association between depression and ADHD does not appear to be epiphenomenal, that is, related to a shared association with anxiety or externalizing symptoms. Finally, children with ADHD and depression display more impairment in social and academic functioning compared to controls. Although social impairment is greater in children with ADHD and depression than in children with only ADHD, conduct problems are not.     

Event rate and reaction time performance in ADHD: Testing predictions from the state regulation deficit hypothesis using an ex-Gaussian model

According to the state regulation deficit (SRD) account, ADHD is associated with a problem using effort to maintain an optimal activation state under demanding task settings such as very fast or very slow event rates. This leads to a prediction of disrupted performance at event rate extremes reflected in higher Gaussian response variability that is a putative marker of activation during motor preparation. In the current study, we tested this hypothesis using ex-Gaussian modeling, which distinguishes Gaussian from non-Gaussian variability. Twenty-five children with ADHD and 29 typically developing controls performed a simple Go/No-Go task under four different event-rate conditions. There was an accentuated quadratic relationship between event rate and Gaussian variability in the ADHD group compared to the controls. The children with ADHD had greater Gaussian variability at very fast and very slow event rates but not at moderate event rates. The results provide evidence for the SRD account of ADHD. However, given that this effect did not explain all group differences (some of which were independent of event rate) other cognitive and/or motivational processes are also likely implicated in ADHD performance deficits.     

Inhibition of return in children with Tourette's syndrome and comorbid forms: a preliminary study.

BACKGROUND: This study investigated the nature and functioning of the visual-spatial inhibition of return (IOR) phenomenon in children with "pure" Tourette's syndrome (TS), and those with comorbid forms of TS. METHOD: Children with TS-only and "TS + comorbid" (TS + ADHD +/- OCD) and matched controls performed the inhibition of return (IOR) task, which involved responding to left and right visual targets appearing on a computer screen that were preceded by congruent or incongruent exogenous visual cues. RESULTS: The TS-only group performed similarly on the IOR task to the controls. When the TS-only group was subdivided into children with mild and severe TS symptoms, a post hoc comparison between the controls and severe TS symptom children revealed that these TS children had a reduced magnitude of IOR for targets appearing in the right visual field. The comparison between the TS + comorbid and controls revealed an atypical IOR pattern for the TS + comorbid group. They displayed a loss of normal facilitatory and inhibitory effects for right visual field targets. CONCLUSIONS: The findings suggest abnormalities in attentional "disengage" and "move" mechanisms in TS when directing attention to the right visual field, which may reflect left posterior parietal, superior colliculus, and midbrain pathology.     

Age of Onset of ADHD in a Sample of Elementary School Students

Examined the age of onset of ADHD symptoms and subtypes using parent ratings of a large sample of elementary school students. Results showed: (1) in children with ADHD-combined type, hyperactive-impulsive symptoms emerged at younger ages than inattention symptoms; (2) about one-fifth of children who met symptom count and impairment criteria for ADHD did not meet the age of onset criterion; (3) Children who did not meet the age of onset criterion consisted primarily of children with inattention problems; and (4) children who did not meet the age of onset criterion had more impaired parent-child relationships, self-esteem, family functioning, and higher overall impairment ratings than children who did meet the criterion. These results raise questions about the validity of the age of onset criterion for ADHD as formulated in DSM-IV.     

Sluggish cognitive tempo in children and adolescents with higher functioning autism spectrum disorders: Social impairments and internalizing symptoms

Sluggish cognitive tempo (SCT) was introduced in 1980s in the field of attention deficit hyperactivity disorder (ADHD). Studies indicate that symptoms of SCT are separate from symptoms of ADHD and independently associated with multiple domains of functioning in clinical groups and in typical development. We assessed whether similar pattern would apply to higher functioning autism spectrum disorders (ASD). Children with higher functioning ASD (N = 55; 5?15 years) were divided into the ASD+High SCT (n = 17), the ASD+Medium SCT (n = 18) and the ASD+Low SCT (n = 20) groups based on parent‐rated daydreaming and slowness on the Five to Fifteen questionnaire (FTF). The groups were compared on SCT‐related impairments found in previous studies: social skills, academic functioning, psychiatric symptoms, and processing speed. Assessment methods were the FTF, the Development and Well‐Being Assessment, and the Coding subtest of the WISC‐III. The ADHD symptoms were statistically controlled due to the overlap between SCT and ADHD. The ASD+High SCT and ASD+Medium SCT groups were significantly more likely to have the most pronounced social impairments, and the ASD+High SCT group had significantly higher rate of internalizing disorders compared to the ASD+Low SCT group. Our results suggest that children with higher functioning ASD and high or medium levels of SCT symptoms could be at higher risk for psychosocial impairments than children with higher functioning ASD with low levels of SCT symptoms. Co‐occurring ADHD symptoms do not explain the finding. Recognizing SCT symptoms in higher functioning ASD would be important to targeting preventive support.     

Association between Hyperemesis Gravidarum in pregnancy on postnatal ability of infants to attend to a play task with their mother

Research indicates a higher prevalence of attention deficits in children exposed to HG in utero compared to controls with some claiming that the deficit is due to prenatal effects of malnutrition in HG mothers and others that it is due to maternal mental health after birth. The current study examines the effect of hyperemesis gravidarum (HG) diagnosis during pregnancy on infant attention controlling for maternal stress, depression anxiety and attachment. Thirty-eight infants mean age 4 months were videotaped with their mothers (19 mothers with a hyperemesis diagnosis and 19 controls) during play with a soft toy and looking at a picture book. Infant attention was operationalized as gaze direction towards the play activity, mother, and ‘distracted’ (indicated by looking away from play or mother). Mothers completed stress, depression, anxiety, and attachment questionnaires. HG exposed infants attended for significantly less time during play with a book or soft toy compared to controls. Maternal stress, depression, anxiety, and attachment did not differ in HG mothers and controls. Infant ability to attend to the toy, book, mother or being distracted did not relate to maternal postnatal attachment, or mental health. These results suggest that the prenatal environment, especially exposure to HG might be associated with reduced infant attention abilities independent of maternal postnatal health.     

Priming Sentence Production in Adolescents and Adults with Attention-Deficit/Hyper-Activity Disorder

Theoretical accounts of attention-deficit/hyperactivity disorder (ADHD) posit a prominent role for problems in response inhibition (Nigg 2006). A key avenue for impulsivity in children with ADHD is inappropriate language expression. In this study, we sought to determine whether poor inhibitory control affects language production in adolescents and adults with ADHD. One hundred and ninety-five participants (13–35 years old; 65% male) were presented with two pictures and a verb, and their task was to form a sentence. If deficits in response inhibition affect language production, then participants with ADHD should be more likely than non-ADHD controls to begin speaking before having formulated a plan that will allow a grammatical continuation. The results showed that the ADHD-combined subtype, in particular, was more likely to produce an ungrammatical sequence. Effects were not moderated by age or gender. These data suggest that response suppression deficits in ADHD adversely affect the basic processes of sentence formation.     

Does a Positive Bias Relate to Social Behavior in Children With ADHD?

This study examines whether positively biased self-perceptions relate to social behaviors in children with attention-deficit/hyperactivity disorder (ADHD) as compared to control children. The social behaviors of children with ADHD (n = 87) were examined relative to control children (CTL; n = 38) during a laboratory-based dyadic social interaction task. Children with ADHD were subgrouped into those with a positive illusory bias (PIB) in their self-perceptions (ADHD + PIB) versus those without such a bias (ADHD – PIB). Using a behavioral coding system adapted for this study, ADHD + PIB, ADHD – PIB, and CTL participants were compared on objectively coded social behaviors occurring within the context of the social interaction task. Whereas both ADHD groups displayed more disruptive behavior than controls, only the ADHD + PIB group displayed less prosocial behavior and less effortful behavior. This study breaks new ground by examining positively biased self-perceptions as they relate to social behavior in children with ADHD and provides promising new insight into the social problems experienced by these children.