[Show abstract][Hide abstract] ABSTRACT: Emotional dysregulation in daily life is very common in children with attention deficit hyperactivity disorder (ADHD). It is however not clear whether this reflects a specific deficit or that it may be the result of generic executive function (EF) deficits. The current study addresses this question by means of an emotional working memory (WM) task with 2 memory load conditions and four possible backgrounds (blank screen, neutral, positive or negative picture), which was administered to 38 typically developing children and 29 children with ADHD. Children responded slower on trials when negative pictures were presented at the background versus when neutral pictures were presented, indicating an emotional interference effect; however crucially, groups did not differ in this respect. Reaction times were also slower on trials with a neutral picture as background versus trials without a picture, with children with ADHD showing an enhanced interference effect. There was a main effect of WM load on performance, but it did not interact with interference or group effects. To summarize, the findings indicate a generic interference control deficit in the children with ADHD in the current sample, while they could not provide support for an emotional interference deficit.
No preview · Article · Dec 2015 · Research in developmental disabilities
[Show abstract][Hide abstract] ABSTRACT: Error awareness has been argued to depend on sensory feedback and interoceptive awareness (IA) (Ullsperger et al., 2010). We recorded EEG while participants performed a speeded Go/No-Go task in which they signaled error commission. Visibility of the effector was manipulated, while IA was measured with a heartbeat perception task. The late Pe was larger for aware than unaware errors. The ERN was also found to be modulated by error awareness, but only when the hand was visible, suggesting that its sensitivity to error awareness depends on the availability of visual sensory feedback. Only when the response hand was visible, the late Pe amplitude to aware errors correlated with IA, suggesting that sensory feedback and IA synergistically contribute to the emergence of error awareness. These findings underscore the idea that several sources of information accumulate in time following action execution in order to enable errors to break through and reach awareness.
No preview · Article · Dec 2015 · Biological psychology
[Show abstract][Hide abstract] ABSTRACT: Prior studies demonstrate altered organisation of functional brain networks in attentiondeficit/hyperactivity
disorder (ADHD). However, the structural underpinnings of these
functional disturbances are poorly understood. In the current study, we applied a graphtheoretic
approach to whole-brain diffusion magnetic resonance imaging data to investigate
the organisation of structural brain networks in adults with ADHD and unaffected controls
using deterministic fibre tractography. Groups did not differ in terms of global network
metrics - small-worldness, global efficiency and clustering coefficient. However, there were
widespread ADHD-related effects at the nodal level in relation to local efficiency and
clustering. The affected nodes included superior occipital, supramarginal, superior temporal,
inferior parietal, angular and inferior frontal gyri, as well as putamen, thalamus and posterior
cerebellum. Lower local efficiency of left superior temporal and supramarginal gyri was
associated with higher ADHD symptom scores. Also greater local clustering of right putamen
and lower local clustering of left supramarginal gyrus correlated with ADHD symptom
severity. Overall, the findings indicate preserved global but altered local network organisation
in adult ADHD implicating regions underpinning putative ADHD-related neuropsychological
Preview · Article · Oct 2015 · Clinical neuroimaging
[Show abstract][Hide abstract] ABSTRACT: Background:
Individuals with attention deficit hyperactivity disorder (ADHD) display excess levels of default mode network (DMN) activity during goal-directed tasks, which are associated with attentional disturbances and performance decrements. One hypothesis is that this is due to attenuated down-regulation of this network during rest-to-task switching. A second related hypothesis is that it may be associated with right anterior insula (rAI) dysfunction - a region thought to control the actual state-switching process.
These hypotheses were tested in the current fMRI study in which 19 adults with ADHD and 21 typically developing controls undertook a novel state-to-state switching paradigm. Advance cues signalled upcoming switches between rest and task periods and switch-related anticipatory modulation of DMN and rAI was measured. To examine whether rest-to-task switching impairments may be a specific example of a more general state regulation deficit, activity upon task-to-rest cues was also analysed.
Against our hypotheses, we found that the process of down-regulating the DMN when preparing to switch from rest to task was unimpaired in ADHD and that there was no switch-specific deficit in rAI modulation. However, individuals with ADHD showed difficulties up-regulating the DMN when switching from task to rest.
Rest-to-task DMN attenuation seems to be intact in adults with ADHD and thus appears unrelated to excess DMN activity observed during tasks. Instead, individuals with ADHD exhibit attenuated up-regulation of the DMN, hence suggesting disturbed re-initiation of a rest state.
No preview · Article · Oct 2015 · Psychological Medicine
[Show abstract][Hide abstract] ABSTRACT: Theory of mind (ToM) research has shown that adults with high functioning autism (HFA) demonstrate typical performance on tasks that require explicit belief reasoning, despite clear social difficulties in everyday life situations. In the current study, we used implicit belief manipulations that are task-irrelevant and therefore less susceptible to strategies. In a ball detection task, it was shown that neurotypical individuals detect a ball faster if an agent believed the ball was present. We predicted that adults with high functioning autism (HFA) would not show this effect. While we found a numerical difference in the hypothesized direction, we did not find a reliable group. Interestingly, the implicit ToM-index showed a strong negative correlation with both self-reported and observational measures of social difficulties in the HFA group. This suggests that the relationship between implicit ToM reasoning and the symptomatology of HFA might be subtler than assumed.
No preview · Article · Sep 2015 · Cognitive neuroscience
[Show abstract][Hide abstract] ABSTRACT: For statistical analysis of event related potentials (ERPs), there are convincing arguments against averaging across stimuli or subjects. Multivariate filters can be used to isolate an ERP component of interest without the averaging procedure. However, we would like to have certainty that the output of the filter accurately represents the component.
We extended the linearly constrained minimum variance (LCMV) beamformer, which is traditionally used as a spatial filter for source localization, to be a flexible spatio-temporal filter for estimating the amplitude of ERP components in sensor space. In a comparison study on both simulated and real data, we demonstrated the strengths and weaknesses of the beamformer as well as a range of supervised learning approaches.
In the context of measuring the amplitude of a specific ERP component on a single trial basis, we found that the spatiotemporal LCMV beamformer is a filter that accurately captures the component of interest, even in the presence of both structured noise (e.g., other overlapping ERP components) and unstructured noise (e.g., ongoing brain activity and sensor noise).
The spatio-temporal LCMV beamformer method provides an accurate and intuitive way to conduct analysis of a known ERP component, without averaging across trials or subjects.
Eliminating averaging allows us to test more detailed hypotheses and apply more powerful statistical models. For example, it allows the usage of multi-level regression models that can incorporate between subject/stimulus variation as random effects, test multiple effects simultaneously and control confounding effects by partial regression.
Full-text · Article · Aug 2015 · IEEE transactions on bio-medical engineering
[Show abstract][Hide abstract] ABSTRACT: Deficits in task-related attentional engagement in attention-deficit/hyperactivity disorder (ADHD) have been hypothesised to be due to altered interrelationships between attention, default mode and salience networks. We examined the intrinsic connectivity during rest within and between these networks. Six-minute resting-state scans were obtained. Using a network-based approach, connectivity within and between the dorsal and ventral attention, the default mode and the salience networks was compared between the ADHD and control group. The ADHD group displayed hyperconnectivity between the two attention networks and within the default mode and ventral attention network. The salience network was hypoconnected to the dorsal attention network. There were trends towards hyperconnectivity within the dorsal attention network and between the salience and ventral attention network in ADHD. Connectivity within and between other networks was unrelated to ADHD. Our findings highlight the altered connectivity within and between attention networks, and between them and the salience network in ADHD. One hypothesis to be tested in future studies is that individuals with ADHD are affected by an imbalance between ventral and dorsal attention systems with the former playing a dominant role during task engagement, making individuals with ADHD highly susceptible to distraction by salient task-irrelevant stimuli.
No preview · Article · Aug 2015 · European Archives of Psychiatry and Clinical Neuroscience
[Show abstract][Hide abstract] ABSTRACT: The present study is the first to examine predictors and consequences of nonsuicidal self-injury (NSSI) in adolescence using parent-reported data in a longitudinal design. Across three time points, we examined the reciprocal effects of parent-reported parenting behaviors as they are related to adolescents' NSSI.
The present study is a three-wave prospective study in a large sample of community adolescents and their parents. At time 1 (age 12), the sample consisted of 1396 adolescent reports and 1438 parent reports. Time 2 (age 13) included 827 adolescent and 936 parent reports. At time 3 (age 14), 754 adolescent and 790 parent reports were obtained. Engagement in NSSI (adolescent report) was determined by an affirmative response to the item 'Have you intentionally injured yourself (e.g., cut, burn, scratch) this year, without the intent to die?'. Parental awareness of NSSI at age 13 and 14 was examined using a single-item screening question. Parenting behaviors were examined by the parent versions of the Parental Behavior Scale.
Results showed that although NSSI was reported by 10 % of the adolescents, only 3 % of the parents were aware of the NSSI behaviors of their children. Cross-lagged analyses showed a reciprocal relationship between NSSI and parenting behaviors over time. We found a significant effect of both positive parenting and controlling parenting on the presence of NSSI at time 2. But vice versa NSSI also has an effect on parenting behaviors over time. Results showed that NSSI at time 1 has an impact on controlling parenting behaviors, namely punishment at time 2. NSSI at time 2 showed an impact on parent's perception of positive parenting, parental rule setting, punishment and harsh punishment.
The present study examined predictors and consequences of NSSI in a longitudinal design, and emphasized the importance of examining reciprocal interactions between NSSI and parenting behaviors. Furthermore, it is the first study to examine parent-reported data in a longitudinal design and gives insight into parents' perspectives.
Full-text · Article · Jul 2015 · Child and Adolescent Psychiatry and Mental Health
[Show abstract][Hide abstract] ABSTRACT: In the current EEG-study, we investigated whether individuals with autism spectrum disorder (ASD) effectively use their own sense of touch to understand tactile experiences that accompany other people’s actions (action-based touch). We tested the action-based somatosensory congruency paradigm (Deschrijver, Wiersema, & Brass, submitted) in a group of adults with high-functioning autism (HFA) and a group with matched controls. In this paradigm, participants observe a finger tap movement of a human or wooden hand, combined with a tactile sensation that is spatially either congruent or incongruent to the tactile consequence of the observed movement. We predicted that individuals with HFA would show altered neuronal processing in response to the congruency of observed action-based human touch at early stages of own somatosensory processing (in the P50, N100 and N140 SEPs) and at later stages of higher-order cognitive self-related processing (P3). First, the data yielded evidence for altered somatosensory processing in the P50 and the N100 (but not in the N140). Second, while the control group showed a congruency effect for human hand trials only in the P3, this effect diminished in the HFA group and reliably correlated with social symptomatology and sensory hypersensitivity/avoidance scales. This suggests that individuals with HFA do not signal to the same extent when simulated action-based touch does not match own touch. We argue that compromised self-other distinction abilities centered on somatosensory processing might denote a crucial theoretical link between sensory and social impairments in the autism spectrum.
[Show abstract][Hide abstract] ABSTRACT: 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.
Full-text · Article · Dec 2014 · Child Neuropsychology
[Show abstract][Hide abstract] ABSTRACT: Numerous studies have detected elevated electroencephalographic (EEG) theta/beta ratio (TBR) or theta power in children with attention deficit/hyperactivity disorder (ADHD) and therefore TBR has been suggested to be a promising biomarker of ADHD. At the same time, recent theoretical models have emphasized the heterogeneity of ADHD and the notion that cognitive deficits in ADHD are not fixed but fluctuate according to contextual and state factors. Surprisingly, so far the context- or state-dependency of EEG abnormalities in ADHD has hardly been addressed. Therefore, in the current study, 3 minutes eyes closed resting EEG before and after execution of 3 n-back tasks were compared between 21 children with ADHD and 22 typically developing children. No difference between groups was found for TBR or theta power (or other frequency bands), neither before nor after task execution, indicating that enhanced TBR or theta power is not to be considered universal for the disorder. Hence, cautiousness is warranted in using these indices for diagnostic purposes in ADHD. Across groups, posterior theta power, as well as central and posterior beta power was attenuated after task execution, which was interpreted as the children experiencing a more alert state after cognitive effort. Yet, this EEG modulation was similar in both groups, providing no support for a context-or state-dependency of EEG abnormalities in ADHD. However, in light of the absence of any group differences in EEG parameters, further research is warranted.
No preview · Article · Oct 2014 · Clinical EEG and neuroscience: official journal of the EEG and Clinical Neuroscience Society (ENCS)
[Show abstract][Hide abstract] ABSTRACT: The state regulation deficit model posits that individuals with attention-deficit/hyperactivity disorder (ADHD) have difficulty applying mental effort effectively under suboptimal conditions such as very fast and very slow event rates (ERs). ADHD is also associated with diminished suppression of default mode network (DMN) activity and related performance deficits on tasks requiring effortful engagement. The current study builds on these 2 literatures to test the hypothesis that failure to modulate DMN activity in ADHD might be especially pronounced at ER extremes. Nineteen adults with ADHD and 20 individuals without any neuropsychiatric condition successfully completed a simple target detection task under 3 ER conditions (2-, 4-, and 8-s interstimulus intervals) inside the scanner. Task-related DMN deactivations were compared between 2 groups. There was a differential effect of ER on DMN activity for individuals with ADHD compared to controls. Individuals with ADHD displayed excessive DMN activity at the fast and slow, but not at the moderate ER. The results indicate that DMN attenuation in ADHD is disrupted in suboptimal energetic states where additional effort is required to optimize task engagement. DMN dysregulation may be an important element of the neurobiological underpinnings of state regulation deficits in ADHD. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
Full-text · Article · Oct 2014 · Journal of Abnormal Psychology
[Show abstract][Hide abstract] ABSTRACT: Objective:
This study aimed to provide more insight into the functional significance of electroencephalographic (EEG) deviances in attention-deficit/hyperactivity disorder (ADHD) by evaluating quantitative EEG during performance on a task with a low activation level and a task tapping top-down executive control.
Behavioral performance and EEG activity were compared between 24 adults with ADHD and 20 typically developing adults during a simple slow-paced 2-choice reaction time (2-CRT) task and a moderately paced flanker task.
During the slow 2-CRT task, adults with ADHD responded slower, more variably, and tended to make more errors of commission. Although being slower, adults with ADHD showed equally large congruency effects during flanker task performance, indicating intact interference inhibition. In the slow 2-CRT task, (midline) theta and beta power were higher in the ADHD group than in the control group, whereas no significant EEG group differences were observed in the flanker task. A moderate positive correlation between theta power and errors of commission was found in the 2-CRT task for adults with ADHD.
Adults with ADHD performed worse on a task inducing a low activation level but showed intact interference inhibition. The EEG findings are in accord with this, showing an abnormal EEG pattern in ADHD only when a low activation level was induced, not when top-down executive control load was high. Time-on-task effects could not explain the group deviances. The findings indicate that EEG deviances in ADHD are task-dependent and may be related to a suboptimal energetic state, rather than impaired top-down executive control.
[Show abstract][Hide abstract] ABSTRACT: Objective
The present study investigates whether either adolescents' psychological distress and/or perceived parenting predicted the occurrence of NSSI. Furthermore, the consequences of NSSI are examined in a three-wave longitudinal study.
The sample at time 1 (age 12) consisted of 1396 adolescent reports and 1438 parent reports. At time 2 (age 13), 827 adolescent reports and 936 parent reports were obtained. Time 3 (age 14) included 754 adolescent reports and 790 parent reports. Psychological distress of adolescents was measured using the Strengths and Difficulties Questionnaire. Perceived parenting behaviors were examined by the Parental Behavior Scale and the Psychological Control Scale.
A total of 10% of the adolescents engaged in NSSI at least once before age 15. Higher psychological distress of adolescents at time 1 was associated with the presence of NSSI at time 2 or 3. The association between psychological distress at time 1 and perception of decreased parental rule setting at time 3 was mediated by the presence of NSSI at time 2.
The present study showed that psychological distress at age 12 predicts NSSI over time and that parental awareness of NSSI changes the perception of parenting behaviors.
Full-text · Article · Aug 2014 · Journal of Adolescence
[Show abstract][Hide abstract] ABSTRACT: Introduction:
This study adds to the knowledge on somatization in adolescents by exploring its relation with parenting behavior and the mediating/moderating role of physiological responses in adolescents to parenting behavior.
Eighteen adolescents with high and 18 adolescents with low somatization scores and their mothers completed a discussion task, from which observed parenting behavior scores were derived. Skin conductance in adolescents was measured before and during the discussion.
For adolescents with high levels of physiological responses, unadaptive parenting was related to a higher chance of high somatization scores. For low physiologically responsive adolescents, the relation between parenting behavior and somatization was not significant.
Parenting behavior is not univocally related to somatization in adolescents, but the association depends on physiological responses in adolescents.
Full-text · Article · May 2014 · International journal of psychophysiology: official journal of the International Organization of Psychophysiology