Rosa van Mourik

When distraction is not distracting: A behavioral and ERP study on distraction in ADHD.

OBJECTIVE Although an increased distractibility is one of the behavioral criteria of Attention Deficit Hyperactivity Disorder (ADHD), there is little empirical evidence that children with ADHD are in fact more distractible than their normal peers. METHODS We recorded event-related potentials (ERPs) to distracting novel sounds (novels) and standard sounds, (standards) while children performed a visual two-choice reaction time task. Twenty-five children with ADHD were compared with eighteen normal controls (aged 8-12 years). RESULTS Children with ADHD showed a larger early P3a (150-250 ms), both in response to the standard and in response to the novel. The late phase of the P3a had a larger amplitude in the ADHD group in the 250-300 ms window compared to the control group, which was only present in response to the novel. Interestingly, the novel reduced the errors of omission in the ADHD group to a greater extent than in the normal control group. CONCLUSIONS Although children with ADHD show an increased orienting response to novels, this distracting information can enhance their performance temporarily, possibly by increasing their arousal to an optimal level, as indicated by the reduced omission rate. SIGNIFICANCE These data indicate that distraction is not always distracting in children with ADHD and that distraction can also have beneficial effects.

Neurocognitive consequences of a paediatric brain tumour and its treatment: a meta-analysis.

Aim  This meta‐analysis provides a systematic review of studies into intellectual and attentional functioning of paediatric brain tumour survivors (PBTS) as assessed by two widely used measures: the Wechsler Intelligence Scale for Children (3rd edition; WISC‐III) and the Conners’ Continuous Performance Test (CPT).

Interference control in children with attention deficit/hyperactivity disorder

The view that Attention Deficit/Hyperactivity Disorder (ADHD) is associated with a diminished ability to control interfference is controversial and based exclusively on results of (verbal)-visual interference tasks, primarily the Stroop Color Word task. The present study compares medication-naïve children with ADHD (n = 35 and n = 51 in Experiments 1 and 2, respectively) with normal controls (n = 26 and n = 32, respectively) on two interference tasks to assess interference control in both the auditory and the visual modality: an Auditory Stroop task and a Simon task. Both groups showed reliable but equal degrees of interference on both tasks, suggesting that children with ADHD do not differ from normal controls in their ability to control interference in either modality.

Neural correlates of response inhibition in children with attention-deficit/hyperactivity disorder: A controlled version of the stop-signal task

The stop-signal task has been used extensively to investigate the neural correlates of inhibition deficits in children with ADHD. However, previous findings of atypical brain activation during the stop-signal task in children with ADHD may be confounded with attentional processes, precluding strong conclusions on the nature of these deficits. In addition, there are recent concerns on the construct validity of the SSRT metric. The aim of this study was to control for confounding factors and improve the specificity of the stop-signal task to investigate inhibition mechanisms in children with ADHD. FMRI was used to measure inhibition related brain activation in 17 typically developing children (TD) and 21 children with ADHD, using a highly controlled version of the stop-signal task. Successful inhibition trials were contrasted with control trials that were comparable in frequency, visual presentation and absence of motor response. We found reduced brain activation in children with ADHD in key inhibition areas, including the right inferior frontal gyrus/insula, and anterior cingulate/dorsal medial prefrontal cortex. Using a more stringent controlled design, this study replicated and specified previous findings of atypical brain activation in ADHD during motor response inhibition.

Alterations in the ventral attention network during the stop-signal task in children with ADHD: an event-related potential source imaging study

Objective: Deficits in response inhibition figure prominently in models of ADHD; however, attentional deficiencies may better explain previous findings of impaired response inhibition in ADHD. We tested this hypothesis at the neurophysiological level. Method: Dense array ERPs (event-related potentials) were obtained for 46 children with ADHD and 51 controls using the stop-signal task (SST). Early and late components were compared between groups. N2 and P3 components were localized with LAURA distributed linear inverse solution. Results: A success-related N1 modulation was only apparent in the ADHD group. N2 and P3 amplitudes were reduced in ADHD. During the successful inhibition N2, the ADHD group showed reduced activation in right inferior frontal gyrus (rIFG), supplementary motor area (SMA), and right temporoparietal junction (rTPJ), and during failed inhibition in the rIFG. During the successful inhibition P3, reduced activation was found in anterior cingulate cortex (ACC) and SMA. Conclusion: Impairments in the ventral attention network contribute to the psychopathology of ADHD and challenge the dominant view that ADHD is underpinned by impaired inhibitory control.

Behavioral Effects of Neurofeedback Compared to Stimulants and Physical Activity in Attention-Deficit/Hyperactivity Disorder: A Randomized Controlled Trial

OBJECTIVE The efficacy of neurofeedback as a treatment for attention-deficit/hyperactivity disorder (ADHD), and whether neurofeedback is a viable alternative for stimulant medication, is still an intensely debated subject. The current randomized controlled trial compared neurofeedback to (1) optimally titrated methylphenidate and (2) a semi-active control intervention, physical activity, to account for nonspecific effects. METHODS A multicenter 3-way parallel-group study with balanced randomization was conducted. Children with a DSM-IV-TR diagnosis of ADHD, aged 7-13 years, were randomly allocated to receive neurofeedback (n = 39), methylphenidate (n = 36), or physical activity (n = 37) over a period of 10-12 weeks. Neurofeedback comprised theta/beta training on the vertex (Cz). Physical activity consisted of moderate to vigorous intensity exercises. Neurofeedback and physical activity were balanced in terms of number (~30) and duration of sessions. A double-blind pseudorandomized placebo-controlled crossover titration procedure was used to determine an optimal dose in the methylphenidate intervention. Parent and teacher ratings on the Strengths and Difficulties Questionnaire (SDQ) and Strengths and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN) were used to assess intervention outcomes. Data collection took place between September 2010 and March 2014. RESULTS Intention-to-treat analyses revealed an improvement in parent-reported behavior on the SDQ and the SWAN Hyperactivity/Impulsivity scale, irrespective of received intervention (ηp² = 0.21-0.22, P ≤ .001), whereas the SWAN Inattention scale revealed more improvement in children who received methylphenidate than neurofeedback and physical activity (ηp² = 0.13, P ≤ .001). Teachers reported a decrease of ADHD symptoms on all measures for methylphenidate, but not for neurofeedback or physical activity (range of ηp² = 0.14-0.29, P < .001). CONCLUSIONS The current study found that optimally titrated methylphenidate is superior to neurofeedback and physical activity in decreasing ADHD symptoms in children with ADHD. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT01363544.

Neurofeedback to improve neurocognitive functioning of children treated for a brain tumor: design of a randomized controlled double-blind trial

BackgroundNeurotoxicity caused by treatment for a brain tumor is a major cause of neurocognitive decline in survivors. Studies have shown that neurofeedback may enhance neurocognitive functioning. This paper describes the protocol of the PRISMA study, a randomized controlled trial to investigate the efficacy of neurofeedback to improve neurocognitive functioning in children treated for a brain tumor.Methods/DesignEfficacy of neurofeedback will be compared to placebo training in a randomized controlled double-blind trial. A total of 70 brain tumor survivors in the age range of 8 to 18 years will be recruited. Inclusion also requires caregiver-reported neurocognitive problems and being off treatment for more than two years. A group of 35 healthy siblings will be included as the control group. On the basis of a qEEG patients will be assigned to one of three treatment protocols. Thereafter patients will be randomized to receive either neurofeedback training (n=35) or placebo training (n=35). Neurocognitive tests, and questionnaires administered to the patient, caregivers, and teacher, will be used to evaluate pre- and post-intervention functioning, as well as at 6-month follow-up. Siblings will be administered the same tests and questionnaires once.DiscussionIf neurofeedback proves to be effective for pediatric brain tumor survivors, this can be a valuable addition to the scarce interventions available to improve neurocognitive and psychosocial functioning.Trial registrationClinicalTrials.gov NCT00961922.

Auditory Conflict Processing in ADHD.

BACKGROUND Impaired cognitive control has been implicated as an important developmental pathway to attention deficit/hyperactivity disorder (ADHD). Cognitive control is crucial to suppress interference resulting from conflicting information and can be measured by Stroop-like tasks. This study was conducted to gain insight into conflict processing in children with ADHD. METHODS Event-related potentials (ERPs) were recorded in an auditory Stroop task. Twenty-four children with ADHD were compared with 24 control children (aged 8-12 years). RESULTS No deficit in interference control was found on the auditory Stroop task in children with ADHD. Children with ADHD responded more slowly, less accurately and more variably compared to controls. No differences between the groups occurred in the early conflict-related ERPs. However, the difference between the congruent and the incongruent condition in the 450-550 ms time window was absent in the ADHD group compared to controls. In addition, the conflict sustained potential was found frontally in the ADHD group but parietally in the control group. CONCLUSIONS These ERP findings suggest that children with ADHD evaluate conflict to a lesser extent and differ in the way their brains select appropriate responses during conflict compared with controls.

Timed performance weaknesses on computerized tasks in pediatric brain tumor survivors: A comparison with sibling controls.

ABSTRACT With more children surviving a brain tumor, insight into the late effects of the disease and treatment is of high importance. This study focused on profiling the neurocognitive functions that might be affected after treatment for a pediatric brain tumor, using a broad battery of computerized tests. Predictors that may influence neurocognitive functioning were also investigated. A total of 82 pediatric brain tumor survivors (PBTSs) aged 8–18 years (M = 13.85, SD = 3.15, 49% males) with parent-reported neurocognitive complaints were compared to a control group of 43 siblings (age M = 14.27, SD = 2.44, 40% males) using linear mixed models. Neurocognitive performance was assessed using measures of attention, processing speed, memory, executive functioning, visuomotor integration (VMI), and intelligence. Tumor type, treatment, tumor location, hydrocephalus, gender, age at diagnosis, and time since diagnosis were entered into regression analyzes as predictors for neurocognitive functioning. The PBTSs showed slower processing speeds and lower intelligence (range effect sizes .71–.82, p < .001), as well as deficits in executive attention, short-term memory, executive functioning, and VMI (range effect sizes .40–.57, p < .05). Older age at assessment was associated with better neurocognitive functioning (B = .450, p < .001) and younger age at diagnosis was associated with lower intelligence (B = .328, p < .05). Medical risk factors, e.g., hydrocephalus, did not show an association with neurocognitive functioning. Late effects in PBTSs include a broad range of neurocognitive deficits. The results suggest that even PBTSs that were traditionally viewed as low risk for neurocognitive problems (e.g., surgery only, no hydrocephalus) may suffer from decreased neurocognitive functioning.

Stimulus-preceding negativity in ADHD.

Children with ADHD often show disrupted response preparation as indicated by attenuated stimulus-preceding negativity (SPN). This study examined response preparation in a relatively short cue–stimulus interval. No differences in SPN occurred between children with ADHD and their normal peers. A strong positive relationship was found between SPN and mean reaction time in both groups. Children with ADHD are able to mentally prepare themselves for upcoming events in short cue–stimulus intervals.