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. © 2013 Springer-Verlag Wien

Snappy App: a mobile continuous performance test with physical activity measurement for assessing Attention Deficit Hyperactivity Disorder

A Continuous Performance Test (CPT) was incorporated into a smartphone application (App) to measure three symptom domains associated with Attention Deficit Hyperactivity Disorder (ADHD); attention, impulsivity and hyperactivity. The App was pilot tested on 11 healthy adults over three test-ing sessions. No differences in performance were found between testing ses-sions suggesting good test consistency. A decrement in performance over time was only found for one measure of attention and on one testing session. The CPT showed some sensitivity to ADHD-related symptoms where self-reported impulsive behaviour was related to the CPT measures of impulsivity and activi-ty. User acceptability was good although some design improvements were sug-gested. Further pilot testing of the App in a clinical population is needed

ADHD and EEG-neurofeedback: a double-blind randomized placebo-controlled feasibility study

Electroencephalography (EEG)-neurofeedback has been shown to offer therapeutic benefits to patients with attention-deficit/hyperactivity disorder (ADHD) in several, mostly uncontrolled studies. This pilot study is designed to test the feasibility and safety of using a double-blind placebo feedback-controlled design and to explore the initial efficacy of individualized EEG-neurofeedback training in children with ADHD. Fourteen children (8–15 years) with ADHD defined according to the DSM-IV-TR criteria were randomly allocated to 30 sessions of EEG-neurofeedback (n = 8) or placebo feedback (n = 6). Safety measures (adverse events and sleep problems), ADHD symptoms and global improvement were monitored. With respect to feasibility, all children completed the study and attended all study visits and training sessions. No significant adverse effects or sleep problems were reported. Regarding the expectancy, 75% of children and their parent(s) in the active neurofeedback group and 50% of children and their parent(s) in the placebo feedback group thought they received placebo feedback training. Analyses revealed significant improvements of ADHD symptoms over time, but changes were similar for both groups. This pilot study shows that it is feasible to conduct a rigorous placebo-controlled trial to investigate the efficacy of neurofeedback training in children with ADHD. However, a double-blind design may not be feasible since using automatic adjusted reward thresholds may not work as effective as manually adjusted reward thresholds. Additionally, implementation of active learning strategies may be an important factor for the efficacy of EEG-neurofeedback training. Based on the results of this pilot study, changes are made in the design of the ongoing study

Influence of Stimulant Medication and Response Speed on Lateralization of Movement-Related Potentials in Attention-Deficit/Hyperactivity Disorder

Hyperactivity is one of the core symptoms in attention deficit hyperactivity disorder (ADHD). However, it remains unclear in which way the motor system itself and its development are affected by the disorder. Movement-related potentials (MRP) can separate different stages of movement execution, from the programming of a movement to motor post-processing and memory traces. Pre-movement MRP are absent or positive during early childhood and display a developmental increase of negativity. We examined the influences of response-speed, an indicator of the level of attention, and stimulant medication on lateralized MRP in 16 children with combined type ADHD compared to 20 matched healthy controls. We detected a significantly diminished lateralisation of MRP over the pre-motor and primary motor cortex during movement execution (initial motor potential peak, iMP) in patients with ADHD. Fast reactions (indicating increased visuo-motor attention) led to increased lateralized negativity during movement execution only in healthy controls, while in children with ADHD faster reaction times were associated with more positive amplitudes. Even though stimulant medication had some effect on attenuating group differences in lateralized MRP, this effect was insufficient to normalize lateralized iMP amplitudes.A reduced focal (lateralized) motor cortex activation during the command to muscle contraction points towards an immature motor system and a maturation delay of the (pre-) motor cortex in children with ADHD. A delayed maturation of the neuronal circuitry, which involves primary motor cortex, may contribute to ADHD pathophysiology

Mapping attention-deficit/hyperactivity disorder from childhood to adolescence - no neurophysiologic evidence for a developmental lag of attention but some for inhibition

BACKGROUND: The role of a developmental lag for deficits of higher brain functions in attention-deficit/hyperactivity disorder (ADHD) has not yet been tested in longitudinal studies. We examined the development of neurophysiological markers of attention (Cue P300; contingent negative variation [CNV]) and inhibition (NoGo P300) in ADHD and control groups from childhood to adolescence for support of the developmental lag hypothesis of ADHD. METHODS: ADHD (n = 28/3 girls) and control (n = 22/5 girls) subjects were assessed at baseline (Time 1; ADHD age 10.8 +/- 1.8 years, controls 10.4 +/- 1.1 years) and at two follow-up examinations (Time 2 after 1.2 years, Time 3 after 2.5 years). Event-related potential maps were recorded during a cued Continuous Performance Test (CPT) at all assessments and analyzed using scalp and source (sLORETA) measures. RESULTS: CPT performance showed common effects of ADHD and younger age, consistent with (but not specific to) developmental lag. The NoGo P300 developed earlier and became stronger in control subjects than in the ADHD group, again consistent with an initial developmental lag. In contrast, the attenuation of the Cue P300 and the CNV with ADHD at all assessments was opposite to the enhancement with younger age and thus inconsistent with developmental lag. The sLORETA source localization also differed between ADHD and developmental effects. CONCLUSIONS: These results provide strong evidence for multiple and persistent neural processing deficits in ADHD. They do not support the developmental lag hypothesis for attentional dysfunction in ADHD despite partial evidence that developmental lag contributes to inhibitory brain dysfunction during early adolescence

Differences in neurophysiological markers of inhibitory and temporal processing deficits in children and adults with ADHD

We compared ADHD-related temporal processing and response inhibition deficits in children and adults using event-related potentials (ERPs) during cued continuous performance tasks (CPT, O-X-version, plus a more demanding flanker version). ERP markers of temporal processing (Cue CNV) and inhibition (NoGo P300) were obtained in matched groups of children (32 with ADHD, mean age 11.2 years, and 31 controls, mean age 11.1 years) and adults (22 ADHD, mean age 42.7 years, and 22 controls, mean age 44.0 years). ERP markers and performance reflected both age and ADHD status. Performance was poorer, and Cue CNV and NoGo P300 were weaker in ADHD children and adults compared to their matched controls. ADHD-related ERP differences in children were more prominent at posterior scalp sites but more pronounced at anterior scalp sites in adults, paralleling the prominent topographic changes of both ERP markers with development. The fact that differences in the same test and the same processing period appear in both children and adults, but that they present in different aspects of performance and different scalp topographies, leads to the conclusion that some ADHD-related deficits persist into adulthood despite alterations of their qualitative aspects

Countering posttraumatic LHPA activation in refugee mothers and their infants

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Behavioral and neurophysiological study of attentional and inhibitory processes in ADHD-combined and control children.

This study compares behavioral and electrophysiological (P300) responses recorded in a cued continuous performance task (CPT-AX) performed by children with attention deficit hyperactivity disorder-combined subtype (ADHD-com) and age-matched healthy controls. P300 cognitive-evoked potentials and behavioral data were recorded in eight children with ADHD (without comorbidity) and nine control children aged 8-12 years while performing a CPT-AX task. Such task enables to examine several kinds of false alarms and three different kinds of P300 responses: the "Cue P300", the "Go P300" and the "NoGo P300", respectively, associated with preparatory processing/attentional orienting, motor/response execution and motor/response inhibition. Whereas hit rates were about 95% in each group, ADHD children made significantly more false alarm responses (inattention- and inhibition-related) than control children. ADHD children had a marginally smaller Cue P300 than the control children. Behavioral and electrophysiological findings both highlighted inhibition and attention deficits in ADHD-com children in the CPT-AX task. A rarely studied kind of false alarm, the "Other" FA, seems to be a sensitive FA to take into account, even if its interpretation remains unclear.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe