Jan R Wiersema

Ghent University, Gand, Flanders, Belgium

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Publications (52)117.68 Total impact

  • [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.
    Child neuropsychology : a journal on normal and abnormal development in childhood and adolescence. 12/2014;
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    ABSTRACT: Effortful control (EC), the self-regulation component of temperament, is traditionally measured using questionnaires. Through the years, several neuropsychological measures originating from the cognitive psychology and the executive function (EF) literature have been introduced in the domain of temperament research to tap EC. Although this is not particularly surprising, given the conceptual overlap between EC and EF, it remains unclear whether EC questionnaires and neuropsychological EF tasks can really be used interchangeably when measuring EC. The current study addressed two important aspects in evaluating the interchangeability of both types of measures, that is: (a) do they measure the same construct? and (b) do they give the same results when comparing clinical populations? Three EC questionnaires, two inhibitory control tasks, and two attentional control tasks were administered in 148 typically developing children, 30 children with attention-deficit/hyperactivity disorder (ADHD), and 31 children with autism spectrum disorder (ASD). All children were between 10 and 15 years of age and had a full scale IQ of 80 or higher. Confirmatory factor analyses revealed that the questionnaires and EF tasks do not capture the same underlying latent variable(s). Groups could not be differentiated from each other based on their performance on EF tasks, whereas significant group differences were found for all EC-reports. Overall, our findings show more differences than commonalities between the EC questionnaires and EF tasks and, consequently, suggest that both types of measures should not be used interchangeably. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Research in developmental disabilities. 11/2014; 36C:587-599.
  • Inez Buyck, Jan R Wiersema
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    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.
    Clinical EEG and neuroscience. 10/2014;
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    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).
    Journal of abnormal psychology. 10/2014;
  • Inez Buyck, Jan R Wiersema
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    ABSTRACT: This study investigated the stability and state-related characteristics of electroencephalographic (EEG) deviances in attention-deficit/hyperactivity disorder (ADHD). Three minutes resting EEG with eyes closed and eyes open were compared between 21 children with ADHD and 29 typically developing children. Across resting conditions, children with ADHD exhibited divergent topographic distribution for theta, alpha and beta power compared to typically developing children. In addition, less alpha and theta suppression to eye opening was found in children with ADHD, but only in those without comorbid ODD/CD. Findings of the present study refer to a consistent divergence in topographic distribution in ADHD across resting state conditions, yet demonstrate that state-related factors and comorbidity may also contribute to resting EEG deviances in ADHD. The state-related findings are in accord with several theoretical accounts emphasizing the role of contextual and state factors defining deficits in ADHD.
    Research in developmental disabilities. 08/2014; 35(12):3217-3225.
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    ABSTRACT: This study adds to knowledge on somatisation in adolescents by exploring its relation with parenting behaviour and the mediating/moderating role of physiological responses in adolescents to parenting behaviour.
    International journal of psychophysiology: official journal of the International Organization of Psychophysiology 05/2014; · 3.05 Impact Factor
  • A. Nijhof, R. Raymaekers, J. R. Wiersema
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    ABSTRACT: Background: There is a growing body of evidence indicating that individuals with autism spectrum disorder (ASD) show abnormal patterns of gamma (> 30 Hz) oscillations in their EEG. These abnormalities have been observed during perceptual and cognitive processing but more recently also during resting state conditions. Excessive power in the gamma frequency band has been argued to reflect abnormally high excitability of cortical structures and/or a temporal binding deficit. Resting state EEG studies on gamma power in children with ASD are however still scarce. Objectives: To investigate resting state EEG gamma power in children with high-functioning autism (HFA). Methods: A group of children (9 to 13 years) with HFA were compared with a group of age-matched typically developing peers. Eyes-closed resting EEG was measured for three minutes, using a 128-channel EEG system. Power in the gamma frequency band was extracted from the EEG signal and compared between groups. Results: As hypothesized, children with ASD showed higher power in the gamma band. Importantly, this increase of gamma activity was found at electrode positions that are distant from potential sources of myogenic artefacts. Conclusions: Excessive resting state EEG gamma power in children with ASD seems to represent a robust phenomenon, which may have important implications for diagnostics and interventions. However future studies are needed to investigate the specificity of the findings by directly comparing clinical groups and to elucidate the functional meaning of enhanced gamma in ASD.
    2014 International Meeting for Autism Research; 05/2014
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    ABSTRACT: The default mode network (DMN) is the core brain system supporting internally oriented cognition. The ability to attenuate the DMN when switching to externally oriented processing is a prerequisite for effective performance and adaptive self-regulation. Right anterior insula (rAI), a core hub of the salience network (SN), has been proposed to control the switching from DMN to task-relevant brain networks. Little is currently known about the extent of anticipatory processes subserved by DMN and SN during switching. We investigated anticipatory DMN and SN modulation using a novel cued-switching task of between-state (rest-to-task/task-to-rest) and within-state (task-to-task) transitions. Twenty healthy adults performed the task implemented in an event-related functional magnetic resonance imaging (fMRI) design. Increases in activity were observed in the DMN regions in response to cues signalling upcoming rest. DMN attenuation was observed for rest-to-task switch cues. Obversely, DMN was up-regulated by task-to-rest cues. The strongest rAI response was observed to rest-to-task switch cues. Task-to-task switch cues elicited smaller rAI activation, whereas no significant rAI activation occurred for task-to-rest switches. Our data provide the first evidence that DMN modulation occurs rapidly and can be elicited by short duration cues signalling rest- and task-related state switches. The role of rAI appears to be limited to certain switch types - those implicating transition from a resting state and to tasks involving active cognitive engagement.
    NeuroImage 05/2014; · 6.25 Impact Factor
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    ABSTRACT: Investigating the underlying neural mechanisms of autism spectrum disorder (ASD) has recently been influenced by the discovery of mirror neurons. These neurons, active during both observation and execution of actions, are thought to play a crucial role in imitation and other social-communicative skills that are often impaired in ASD. In the current electroencephalographic study, we investigated mu suppression, indicating neural mirroring in children with ASD between the ages of 24 and 48 months and age-matched typically developing children, during observation of goal-directed actions and non-goal-directed mimicked hand movements, as well as during action execution. Results revealed no significant group differences with significant central mu suppression in the ASD children and control children during both execution and observation of goal-directed actions and during observation of hand movements. Furthermore, no significant correlations between mu suppression on one hand and quality of imitation, age, and social communication questionnaire scores on the other hand were found. These findings challenge the "broken mirror" hypothesis of ASD, suggesting that impaired neural mirroring is not a distinctive feature of ASD. Autism Res 2014, ●●: ●●- ●●. © 2014 International Society for Autism Research, Wiley Periodicals, Inc.
    Autism Research 02/2014; · 3.99 Impact Factor
  • Inez Buyck, Jan Roelf Wiersema
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    ABSTRACT: This study investigated EEG activity and its developmental course in ADHD throughout the lifespan, as well as the accuracy of EEG parameters in distinguishing ADHD patients from typically developing individuals. Three minutes eyes closed resting EEG was compared between 62 individuals with ADHD (36 children, 26 adults) and 55 typically developing individuals (30 children, 25 adults). EEG activity and maturation did not differ between individuals with ADHD and typically developing individuals. However, despite comparable developmental course between clinical groups, persistent elevated theta/beta ratio and reduced relative beta power were observed in the ADHD inattentive subtype compared to the ADHD combined subtype and controls across the lifespan. Therefore, a maturational deviation rather than a maturational delay may underlie a subgroup of ADHD. EEG based classification failed for ADHD but proved successful for age. These findings emphasize heterogeneity in ADHD throughout the lifespan and question clinical utility of conventional EEG approaches for diagnostic purposes in ADHD.
    Psychiatry Research. 01/2014;
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    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. Design 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. Results 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. Conclusions 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.
    Journal of Adolescence. 01/2014; 37(6):817–826.
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    ABSTRACT: This study examines the influence of a button response task on the event-related potential (ERP) in a semantic priming experiment. Of particular interest is the N400 component. In many semantic priming studies, subjects are asked to respond to a stimulus as fast and accurately as possible by pressing a button. Response time (RT) is recorded in parallel with an electroencephalogram (EEG) for ERP analysis. In this case, the response occurs in the time window used for ERP analysis and response-related components may overlap with stimulus-locked ones such as the N400. This has led to a recommendation against such a design, although the issue has not been explored in depth. Since studies keep being published that disregard this issue, a more detailed examination of influence of response-related potentials on the ERP is needed. Two experiments were performed in which subjects pressed one of two buttons with their dominant hand in response to word-pairs with varying association strength (AS), indicating a personal judgement of association between the two words. In the first experiment, subjects were instructed to respond as fast and accurately as possible. In the second experiment, subjects delayed their button response to enforce a one second interval between the onset of the target word and the button response. Results show that in the first experiment a P3 component and motor-related potentials (MRPs) overlap with the N400 component, which can cause a misinterpretation of the latter. In order to study the N400 component, the button response should be delayed to avoid contamination of the ERP with response-related components.
    PLoS ONE 01/2014; 9(2):e87650. · 3.53 Impact Factor
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    ABSTRACT: Executive attention and its relationship with effortful control (EC) were investigated in children with ADHD (n = 24), autism spectrum disorder (ASD; n = 20), and controls (n = 21). Executive attention measures included flanker-performance and event-related potentials (N2, P3, and ERN). EC was assessed using questionnaires. Only the ERN was found to be robustly related to EC across groups. N2 did not differ between groups and only children with ADHD + ODD showed diminished executive attention as expressed in RT and P3. In ADHD, monitoring of incorrect (ERN) and correct (CRN) responses was diminished. Overall, the link between EC and executive attention was less strong as expected and varied depending on group and measure considered. All groups were able to detect conflict (N2) and all but ADHD + ODD were able to allocate extra attention in order to respond correctly (P3). Findings indicate a general reduced response monitoring in ADHD.
    Biological psychology 01/2014; · 4.36 Impact Factor
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    ABSTRACT: Introduction This study adds to knowledge on somatisation in adolescents by exploring its relation with parenting behaviour and the mediating/moderating role of physiological responses in adolescents to parenting behaviour. Method Eighteen adolescents with high and eighteen adolescents with low somatisation scores and their mothers completed a discussion task, from which observed parenting behaviour scores were derived. Skin conductance in adolescents was measured before and during the discussion. Results For adolescents with high levels of physiological responses, unadaptive parenting was related to a higher chance of high somatisation scores. For low physiologically responsive adolescents, the relation between parenting behaviour and somatisation was not significant. Conclusion Parenting behaviour is not univocally related to somatisation in adolescents, but the association depends on physiological responses in adolescents.
    International Journal of Psychophysiology. 01/2014;
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    ABSTRACT: Attention Deficit/Hyperactivity Disorder (ADHD) is a pathophysiologically complex and heterogeneous condition with both cognitive and motivational components. We propose a novel computational hypothesis of motivational deficits in ADHD, drawing together recent evidence on the role of anterior cingulate cortex (ACC) and associated mesolimbic dopamine circuits in both reinforcement learning and ADHD. Based on findings of dopamine dysregulation and ACC involvement in ADHD we simulated a lesion in a previously validated computational model of ACC (Reward Value and Prediction Model, RVPM). We explored the effects of the lesion on the processing of reinforcement signals. We tested specific behavioral predictions about the profile of reinforcement-related deficits in ADHD in three experimental contexts; probability tracking task, partial and continuous reward schedules, and immediate versus delayed rewards. In addition, predictions were made at the neurophysiological level. Behavioral and neurophysiological predictions from the RVPM-based lesion-model of motivational dysfunction in ADHD were confirmed by data from previously published studies. RVPM represents a promising model of ADHD reinforcement learning suggesting that ACC dysregulation might play a role in the pathogenesis of motivational deficits in ADHD. However, more behavioral and neurophysiological studies are required to test core predictions of the model. In addition, the interaction with different brain networks underpinning other aspects of ADHD neuropathology (i.e., executive function) needs to be better understood.
    Neural networks: the official journal of the International Neural Network Society 05/2013; 46C:199-209. · 1.88 Impact Factor
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    ABSTRACT: OBJECTIVE: Previous infant studies investigated neural mirroring during the observation of live or video actions. However, both methods have their (dis)advantages and studies using one of these methods are not always directly comparable. Therefore, the present study directly compared neural mirroring activity in a video setting with a live setting in infants between 18 and 36months old. METHODS: Central mu rhythm suppression was measured through EEG recordings during the observation and imitation of the same goal-directed and mimicked actions presented either on video or live. RESULTS: Results revealed significant mu suppression during action imitation in both settings but stronger mu suppression was observed in the live setting during this condition. Significant mu suppression during the observation of goal-directed actions and mimicked actions was only observed in the live setting. CONCLUSION: This study revealed a different influence of video and live actions on neural mirroring activity in infants. SIGNIFICANCE: It is recommended to use live actions to investigate neural mirroring in young children.
    Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 05/2013; · 3.12 Impact Factor
  • J. R. Wiersema, L. De Coster, M. Brass
    2013 International Meeting for Autism Research; 05/2013
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    ABSTRACT: Objective: The preference for sooner smaller over larger later rewards is a prominent manifestation of impulsivity in ADHD. According to the State Regulation Deficit (SRD) model, this impulsive choice is the result of impaired regulation of arousal level and can be alleviated by adding environmental stimulation to increase levels of arousal. Method: To test this prediction, we studied the effects of adding background "pink noise" on impulsive choice using a classical and new adjusting choice delay task in a sample of 25 children with ADHD and 28 controls. Results: Children with ADHD made more impulsive choices than controls. Adding noise did not reduce impulsive choice in ADHD. Conclusion: The findings add to the existing evidence on impulsive choice in ADHD, but no evidence is found for the SRD model's explanation of this behavioral style. Alternative explanations for impulsive choice in ADHD are discussed. (J. of Att. Dis. 2013; XX(X) 1-XX).
    Journal of Attention Disorders 03/2013; · 2.16 Impact Factor
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    ABSTRACT: Since their discovery in the early 1990s, mirror neurons have been proposed to be related to many social-communicative abilities, such as imitation. However, research into the early manifestations of the putative neural mirroring system and its role in early social development is still inconclusive. In the current EEG study, mu suppression, generally thought to reflect activity in neural mirroring systems was investigated in 18- to 30-month-olds during the observation of object manipulations as well as mimicked actions. EEG power data recorded from frontal, central, and parietal electrodes were analysed. As predicted, based on previous research, mu wave suppression was found over central electrodes during action observation and execution. In addition, a similar suppression was found during the observation of intransitive, mimicked hand movements. To a lesser extent, the results also showed mu suppression at parietal electrode sites, over all three conditions. Mu wave suppression during the observation of hand movements and during the execution of actions was significantly correlated with quality of imitation, but not with age or language level.
    Developmental Science 03/2013; 16(2):173-85. · 3.89 Impact Factor
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    ABSTRACT: Objective: Attention-deficit/hyperactivity disorder (ADHD) is associated with performance deficits across a broad range of tasks. Although individual tasks are designed to tap specific cognitive functions (e.g., memory, inhibition, planning, etc.), these deficits could also reflect general effects related to either inefficient or impulsive information processing or both. These two components cannot be isolated from each other on the basis of classical analysis in which mean reaction time (RT) and mean accuracy are handled separately. Method: Seventy children with a diagnosis of combined type ADHD and 50 healthy controls (between 6 and 17 years) performed two tasks: a simple two-choice RT (2-CRT) task and a conflict control task (CCT) that required higher levels of executive control. RT and errors were analyzed using the Ratcliff diffusion model, which divides decisional time into separate estimates of information processing efficiency (called "drift rate") and speed-accuracy tradeoff (SATO, called "boundary"). The model also provides an estimate of general nondecisional time. Results: Results were the same for both tasks independent of executive load. ADHD was associated with lower drift rate and less nondecisional time. The groups did not differ in terms of boundary parameter estimates. Conclusion: RT and accuracy performance in ADHD appears to reflect inefficient rather than impulsive information processing, an effect independent of executive function load. The results are consistent with models in which basic information processing deficits make an important contribution to the ADHD cognitive phenotype. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
    Neuropsychology 03/2013; 27(2):193-200. · 3.58 Impact Factor

Publication Stats

504 Citations
117.68 Total Impact Points

Institutions

  • 2005–2014
    • Ghent University
      • Department of Experimental Clinical and Health Psychology
      Gand, Flanders, Belgium
  • 2009
    • University of Southampton
      • Department of Psychology
      Southampton, ENG, United Kingdom
    • University of Groningen
      • Department of Psychology
      Groningen, Province of Groningen, Netherlands