Changing a response set in normal development and in ADHD children with and without tics

Which Factors Influence Attentional Functions? Attention Assessed by KiTAP in 105 6-to-10-Year-Old Children

This research revealed the children with difficulties in attentional functions among healthy children attending primary school and aimed to identify the possible sociodemographic factors, such as the child’s age, gender, and school grade, that could influence attentive performance. The participants were 105 children aged 6–10 years (M age = 8.6; SD = 1.04), attending primary schools. Family economic condition was mostly at a medium level (63.5%), and parents most frequently had 13 years of schooling. The computerized test KiTAP was administered to children to assess their attentional functions. Results showed a higher frequency of omissions and false alarms and a reduced speed in alertness, go/no-go, and sustained attention tasks compared to Italian norms. Hierarchical regression analyses were run with school grade, gender, and current age as independent variables and mean reaction times (and standard deviation), number of omissions, and false alarms as dependent ones. The results showed that male gender and attending a lower grade impacted on lower attentional performance in several subtests. Girls showed the best performances in tests of distractibility and impulsive reaction tendencies, while higher school grade positively influenced divided and sustained attention. These results could be useful to identify children with major attentional difficulties, and some recommendations for future studies and the implementation of attention empowerment programmes are proposed.

Cognitive potential of children with attention deficit and hyperactivity disorder

The literature has described comorbidities among the symptoms of children with Attention Deficit and Hyperactivity Disorder (ADHD) and the auditory processing changes, and these symptoms have been overlooked in the assessment, and consequently, on the rehabilitation of these individuals.

OBJECTIVE

To compare the findings of the long latency auditory evoked potentials in children with and without ADHD.

METHOD

This is a historical cohort cross-sectional case-control study, in which we enrolled 30 children with and without ADHD, aged 8-12 years. We performed the long-latency auditory evoked potential test in two scanning procedures through passive and active tasks differing in frequency and duration (MMNf and MMNd) (P300f and P300D).

RESULTS

When comparing the performance of children with and without ADHD in the electrophysiological test assessment of hearing, we found significant differences concerning the P2 amplitude in the LE - which was higher for the ADHD group; and concerning the N2 amplitude and latency - which were abnormal in the ADHD group.

CONCLUSION

This study provided a greater understanding of the central auditory pathways of children with and without ADHD when evaluated from electrophysiological tests.

Effects of speed and accuracy instructions on performance in a visual search task by children with good or poor attention

Children rated by teachers as having good or poor attention ability carried out a visual search task in which they were required to find a series of targets in a complex display. Different groups were told to concentrate on either speed or accuracy. Previous studies using this task have consistently shown that children rated as having poor attention make more errors (false alarms to non-targets in the display), but do not differ in the time to make a correct response; this result was replicated. Though the instructions produced wide differences in speed and error rates in the expected directions, these differences were similar in both attention groups and the differences in error rates between the two groups remained unchanged. It is suggested that these findings are not compatible with the view that children with poor attention make errors primarily due to fast impulsive responding, nor with an explanation in terms of slower processing of the input by such children. An alternative explanation of the high error rates in such children is offered in terms of weak executive function resulting in poor ability to inhibit false alarms to non-targets.

Transtorno do déficit de atenção e hiperatividade em crianças: uma revisão interdisciplinar

O presente artigo revisa criticamente o amplo escopo da literatura relacionada aos critérios diagnósticos, bases etiológicas e tratamentos farmacológico e comportamental do transtorno do déficit de atenção e hiperatividade (TDAH) em crianças. Foram consultadas as bases eletrônicas MedLine, Lilacs, PsycINFO e PubMed nas últimas três décadas. Os resultados dessa revisão apontam para uma predominância do critério diagnóstico baseado no Manual Diagnóstico e Estatístico das Doenças Mentais, bem como a necessidade de uma maior interação entre variáveis biológicas e comportamentais na compreensão das bases etiológicas e de tratamento deste transtorno. Sugestões para maximizar a eficácia desta interação são apresentadas e discutidas.

Perceptual and motor inhibition in adolescents/young adults with childhood-diagnosed ADHD

OBJECTIVE

This study examined perceptual and motor inhibition in a longitudinal sample of adolescents/young adults who were diagnosed with ADHD in childhood, and as a function of the relative persistence of ADHD.

METHOD

Ninety-eight participants diagnosed with ADHD in childhood were reevaluated approximately 10 years later. Eighty-five never-ADHD controls similar in age, IQ, sociodemographic background, and gender distribution served as a comparison group. Participants were administered a psychiatric interview and the Stimulus and Response Conflict Tasks (Nassauer & Halperin, 2003).

RESULTS

Participants with childhood ADHD demonstrated slower and less accurate responses to both control and conflict conditions relative to the comparison group, as well as more variable responses in both conditions of the motor inhibition task; there was no specific effect of childhood ADHD on perceptual or motor inhibition. ADHD persisters and partial remitters did not differ in overall accuracy, speed or variability in responding, but relative to partial remitters, persisters demonstrated greater slowing in response to perceptual conflict.

CONCLUSIONS

These findings are consistent with theories positing state regulation, but not inhibitory control deficits in the etiology of ADHD, and suggest that improved perceptual inhibition may be associated with better outcome for ADHD.

Computerspiele im Kindes- und Jugendalter unter besonderer Betrachtung von Suchtverhalten, ADHS und Aggressivität

Einleitung: Computerspiele gehören mittlerweile zu den beliebtesten Freizeitbeschäftigungen von Kindern und Jugendlichen und ersetzen in zunehmendem Maß traditionelle Spiel-und Interaktionsaktivitäten. Gesamt betrachtet sind mit dieser Entwicklung nicht nur emotionale oder soziale Entwicklungsrisiken verbunden und im pädagogisch-therapeutischen Bereich können sich mit der Nutzung von Computerspielen auch durchaus Förder- oder sogar therapeutische Möglichkeiten verbinden. Anderseits mehren sich Belege, dass die exzessive Nutzung von Computerspielen mit einem signifikant erhöhten Risiko zu nicht-stoffgebundenem Suchtverhalten einhergeht und die Prävalenzen hierfür altersübergreifend besorgniserregend hoch sind mit tendenzieller Zunahme. Zielsetzung: Der vorliegende Beitrag basiert auf einer Medlinerecherche. Die Zielsetzung besteht darin, zunächst motivationale und entwicklungspsychologische Besonderheiten von Computerspielen herauszuarbeiten, Prävalenzen und Risiken für eine Suchtentwicklung darzustellen und Verbindungen sowie Auswirkungen zu ausgewählten psychischen Störungen, nämlich Aufmerksamkeitsdefizitstörungen und aggressiven Verhaltensweisen darzustellen. Ergebnisse: Die vorliegenden Ergebnisse weisen aus, dass speziell von einer ADHS betroffene Kinder und Jugendliche aufgrund der neuropsychologischen Gegebenheiten dieses Störungsbildes vulnerabel sind für die Entwicklung einer Computerspielsucht. Zum anderen kann der exzessive Konsum gewalthaltiger Computerspiele ein wichtiges Bindeglied für das Zustandekommen vermehrt aggressiver Verhaltensweisen bedeuten bei Vorliegen von bereits vorbestehenden aggressiven Kognitionen und Verhaltensskripten. Schlussfolgerung: Angesichts der zunehmenden klinischen Relevanz von Suchtverhalten bei Computerspielen besteht dringend die Notwendigkeit zur Erarbeitung diagnostischer und therapeutischer Standards, wobei der Vernetzung mit ebenfalls mit der Materie befassten Fach- bzw. Arbeitsbereichen eine wichtige Bedeutung zukommt.

Reduced activation in right lateral prefrontal cortex and anterior cingulate gyrus in medication-naïve adolescents with attention deficit hyperactivity disorder during time discrimination

BACKGROUND

Patients with attention deficit hyperactivity disorder (ADHD) under-perform when discriminating between durations differing by several hundred milliseconds. This function involves right prefrontal and anterior cingulate (AC) brain regions, which are structurally and functionally compromised in this patient group during executive tasks. We investigated the neuro-anatomical substrates mediating fine temporal discrimination in adolescents with ADHD compared with controls, using functional magnetic resonance imaging (fMRI).

METHODS

Twenty-one male medication-naïve adolescents aged 10-15 years with a DSM-IV diagnosis of ADHD (combined subtype) and without comorbid Axis I disorders (except conduct disorder) were compared to a group of 17 age- and IQ-matched healthy adolescents. Using fMRI on a 1.5T scanner, we compared brain activation and performance between adolescents with ADHD and controls during a time discrimination task contrasted with a temporal order task.

RESULTS

Despite comparable performance, patients with ADHD showed decreased activation in right dorsolateral and inferior prefrontal cortex and AC during time discrimination compared with controls.

CONCLUSIONS

Right hemispheric fronto-cingulate abnormalities in ADHD, previously observed during inhibitory and executive functions, are also associated with temporal perception. Furthermore, recruitment of medication-naïve patients precludes the possibility that deficits are attributable to stimulant exposure.

Increased event-related theta activity as a psychophysiological marker of comorbidity in children with tics and attention-deficit/hyperactivity disorders

OBJECTIVE

The question as to whether coexisting tic disorder (TD) and attention-deficit/hyperactivity disorder (ADHD) in children represent a combination of two independent pathologies, a separate nosologic entity manifested by both tics and hyperactivity or a phenotype subgroup of one of the two major clinical forms has received increasing attention. The aim of the present study was to classify the TD+ADHD comorbidity in the neurocognitive domain and to elucidate the neurophysiological background of TD+ADHD coexistence by analyzing event-related electroencephalographic (EEG) oscillations in the theta (3-7.5 Hz) frequency band.

METHODS

Event-related potentials were recorded at 10 electrodes in 53 children (9-13 years old) from four groups (healthy controls, TD-only, ADHD-only, and combined TD+ADHD patients), while they performed an auditory selective attention task requiring a button press to a predefined target. Event-related theta oscillations were analyzed by means of time-frequency decomposition (wavelet analysis) in two latency ranges-early (0-200 ms) and late (200-450 ms). The effects of psychopathology factors (TD and ADHD) and task variables (attended channel and stimulus task relevance) on early (ETR) and late (LTR) theta responses were evaluated statistically. Theta response measures were further correlated with psychopathology scores and spontaneous theta EEG activity.

RESULTS

(1) The ETR was enhanced only in comorbid children and did not differ between the control, TD-only, and ADHD-only groups. (2) The LTR was larger in children with ADHD (ADHD-only and comorbid), but this effect was mediated by the spontaneous theta EEG activity. (3) The ETR was larger to attended stimuli at frontal-central electrodes contralateral to the side of attention, to the target stimulus type at frontal locations, and at the hemisphere contralateral to the side of the response. The functional reactivity and scalp distribution of ETRs were modulated by psychopathological factors.

CONCLUSIONS

In the neurocognitive domain, the TD+ADHD comorbidity can be identified as a unique nosologic entity. Both the spontaneous theta activity and late event-related theta oscillations appear as neurophysiological markers of the ADHD condition. In children, the early event-related theta oscillations may be associated with representations of relevant target features in working memory.

SIGNIFICANCE

(1) A new model is proposed according to which TD+ADHD comorbidity can be classified at different levels (from neurobiological to cognitive). (2) The functional significance of stimulus-synchronized theta oscillations in children is described for the first time.

Are endophenotypes based on measures of executive functions useful for molecular genetic studies of ADHD?

BACKGROUND

Behavioral genetic studies provide strong evidence that attention-deficit/hyperactivity disorder (ADHD) has a substantial genetic component. Yet, due to the complexity of the ADHD phenotype, questions remain as to the specific genes that contribute to this condition as well as the pathways from genes to behavior. Endophenotypes, or phenotypes that are more closely linked to the neurobiological substrate of a disorder, offer the potential to address these two issues simultaneously (Freedman, Adler, & Leonard, 1999). Thus far, potential endophenotypes for ADHD have not been systematically studied.

METHOD

The current paper reviews evidence supporting the use of deficits on neurocognitive measures of executive functions for this purpose.

RESULTS

Such deficits are a correlate of ADHD and show preliminary evidence of heritability and association with relevant candidate genes. Nonetheless, studies that have assessed the familial and genetic overlap of neurocognitive impairments with ADHD have yielded inconsistent results.

CONCLUSIONS

In order for executive function deficits to be used as an endophenotype for ADHD, we recommend greater attention to the neurocognitive heterogeneity of this disorder and to the precision of measurement of the neuropsychological tests employed. We also discuss empirical strategies that may be necessary to allow such research to progress prior to full resolution of the pathophysiological basis of ADHD.

Inhibition, ADHD, and computer games: the inhibitory performance of children with ADHD on computerized tasks and games

Contrary to empirical reports of inhibitory dysfunction in ADHD, parental reports suggest that when playing computer games, the inhibitory abilities of children with ADHD are unimpaired. This small-scale preliminary investigation into this phenomenon looks at inhibition of an ongoing response and activity exhibited by children with ADHD between 6 and 14 years old on two commercially available games, on the Conners's Continuous Performance Test II (CPT II), and on a more game-like version of the same task that incorporates characteristics commonly found in commercially available computer games. The performance of participants with ADHD on commercially available games is equivalent to that of typically developing participants and is significantly better on the more game-like version of the CPT II.

Prenatal alcohol exposure causes attention deficits in male rats

Children with fetal alcohol spectrum disorder (FASD) are often diagnosed with attention-deficit/ hyperactivity disorder (ADHD). These children show increases in reaction time (RT) variability and false alarms on choice reaction time (CRT) tasks. In this study, adult rats prenatally exposed to ethanol were trained to perform a CRT task. An analysis of the distribution of RTs obtained from the CRT task found that rats with a history of prenatal ethanol exposure had more variable RT distributions, possibly because of lapses of attention. In addition, it was found that, similar to children with FASD, the ethanol-exposed rats had more false alarms. Thus, rats with prenatal ethanol exposure show attention deficits that are similar to those of children with FASD and ADHD.

Effects of event probability and sequence on children with attention-deficit/hyperactivity, reading, and math disorder

BACKGROUND

We investigated the impact of stimulus probability and sequence on performance and event-related potentials of 310 children classified into 12 combinations of attention-deficit/hyperactivity disorder (Not-attention-deficit/hyperactivity disorder, Inattentive and Combined subtypes) with presence/absence of reading disorder and math disorder.

METHODS

Subjects pressed buttons to displays of the letters O and X, which were presented with probabilities of either .17/.83 or .50/.50. Greater response selection was required in the .17/.83 condition.

RESULTS

Stimulus probability had comparable effects on all diagnostic groups. The extent of mismatch between a stimulus and preceding events elicited less systematic increases in errors, P3b latency, and P3b amplitude among both attention-deficit/hyperactivity disorder subtypes than controls. Mismatch with preceding trials more greatly reduced math disorder and reading disorder + math disorder children's speed in the Rare task and accuracy in both conditions. Math disorder and reading disorder + math disorder subjects also registered less the effects of alternations of the infrequent O on N2 amplitude and on P3b latency.

CONCLUSIONS

Math disorder and reading disorder + math disorder youngsters' lower sensitivity to sequence irregularity in their event-related potentials along with greater disruption of performance suggest working memory deficits that adversely affected response selection. Comorbidity of attention-deficit/hyperactivity disorder and reading disorder did not affect the results.

Motor control and state regulation in children with ADHD: a cardiac response study

The goal of the current study was to investigate whether poor motor control in children with Attention-Deficit Hyperactivity Disorder (ADHD) was associated with a state regulation deficit. For this purpose, 28 ADHD and 22 healthy children carried out two Go No-Go tests: one with a fast stimulus presentation rate, and the other with a slow stimulus presentation rate. Groups were compared on RT performance and on specific cardiac measures, reflecting arousal, motor activation/inhibition, and effort allocation. No group difference in the arousal measure (mean heart rate) was found. Further, groups did not differ with respect to response inhibition: in both the fast and slow condition, ADHD children made comparable numbers of errors of commission to the control group, and the groups did not differ with respect to the heart rate deceleration after the onset of the No-Go signal, reflecting motor inhibition. Group differences were found with respect to motor activation and effort allocation in the condition with a slow presentation rate. In this condition: (1) ADHD children reacted more slowly to Go signals than control children, suggesting poor motor activation; (2) the heart rate deceleration before the onset of Go signals, which is believed to reflect motor preparation, was less pronounced in the ADHD children; (3) after Go signals, where a response was given, the cardiac shift from deceleration to acceleration, indicating response initiation, was delayed in ADHD children; and (4) ADHD children had greater heart rate variability (0.10 Hz component) than the control group, indicating that less effort was allocated. No group differences in motor activation and effort allocation were found in the condition with a fast presentation rate of stimuli. We conclude, therefore, that a slow presentation rate of stimuli brings the ADHD child in a non-optimal activation state.

Methylphenidate does not modify the impact of response frequency or stimulus sequence on performance and event-related potentials of children with attention deficit hyperactivity disorder

Twenty-six children with attention deficit/hyperactivity disorder (ADHD) participated in a double-blind trial consisting of 2 consecutive weeks each of placebo and methylphenidate (M = 26.92 mg/day = 0.78 mg/kg/day). As expected, stimulant therapy resulted in moderate weight loss, increased somatic complaints, and teacher and parent reports of reduced inattentiveness, aggression, and oppositionality. In both phases of the trial, patients were tested in a choice reaction time task assessing two aspects of the task that presumably affect response selection: response frequency (ratio of targets/nontargets = 25/75 vs. 50/50) and stimulus sequence (alternations vs. repetitions). Both manipulations yielded expected results on performance and event-related potentials (ERPs). Stimulant treatment increased accuracy and speed among younger children and curtailed variability of reaction time for the sample as a whole. However, methylphenidate did not affect ERPs. In combination, the results imply that the enhancement of performance by methylphenidate does not involve the demands of response selection examined in this study.