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Attention shifts and anticipatory mechanisms in hyperactive children: an ERP study using the Posner paradigm
C Perchet1, O Revol, P Fourneret
1Clinical Neurophysiology Laboratory, Research Unit EA1880, (University Claude Bernard), Lyon, France.
Insights
Children with attention-deficit/hyperactivity disorder (ADHD) exhibit motor impulsivity and impaired anticipatory mechanisms during attention shifting tasks. These findings suggest developmental delays in executive frontal functions and early attentional processing.
Area of Science:
- Neuroscience
- Developmental Psychology
- Cognitive Science
Background:
- Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting executive functions.
- Attention shifting paradigms are crucial for assessing cognitive processing in children.
Purpose of the Study:
- To investigate attentional, decisional, and motor processing in children with and without ADHD during an attention shifting task.
- To identify specific electrophysiological and behavioral markers associated with ADHD in this context.
Main Methods:
- Utilized a variant of the Posner paradigm with event-related potentials (ERPs) and performance measures.
- Recorded responses from 13 typically developing children and 24 children diagnosed with ADHD.
Main Results:
- ADHD children made more errors, particularly anticipatory ones, and exhibited faster reaction times.
- ADHD children showed a shortened N2-P3 to motor response interval and reduced P1 attentional priming.
- Absence of contingent negative variation/readiness potential in ADHD patients during uncued conditions.
Conclusions:
- ADHD is characterized by motor impulsivity and deficient anticipatory mechanisms in attention shifting, possibly due to frontal executive dysmaturation.
- Early attentional priming deficits were observed in ADHD, though without clear behavioral correlates.
- Combined electrophysiological and behavioral data reveal distinct response patterns in ADHD during attention shifting.
Background:
The aim of this study was to assess attentional, decisional, and motor processing stages during the performance of an attention shifting paradigm, both in normal children and children with attention-deficit/hyperactivity disorder (ADHD).
Methods:
We recorded event-related potentials (ERPs) and performance measures during a variant of the Posner paradigm in 13 control subjects and 24 ADHD children. Subjects responded with a spatially concordant motor response to left or right visual targets, which could be either preceded by a spatial cue ("valid" = same side; "invalid" = opposite side) or presented uncued.
Results:
Patients made significantly more errors than control subjects, with predominance of the anticipatory type. As compared to control subjects, ADHD children had faster reaction times, as well as a shortened interval between the N2 and P3 ERPs and the motor response. Patients also showed a decreased attentional priming effect on early sensory responses (P1). Finally, the slow negativity (contingent negative variation/readiness potential) that preceded the target in the "no cue" condition was absent in ADHD patients.
Conclusions:
The combined analysis of electrophysiological and behavioral data suggest a characteristic mode of response of ADHD in attention shifting tasks, characterized by "motor impulsivity" with release of motor responses before stimulus processing is adequately completed, as well as a lack of strategic planning/anticipatory mechanisms in the absence of warning stimulus. These deficits may be partly attributed to dysmaturation of executive frontal functions. In addition, a minor deficit in early attentional priming was also observed in ERPs, with no apparent behavioral counterparts.