Differences in Ex-Gaussian Parameters from Response Time Distributions Between Individuals with and Without Attention Deficit/Hyperactivity Disorder: A Meta-analysis

Long-Term Neurodevelopmental Outcome of Children With Mild Traumatic Brain Injury

BACKGROUND

To investigate the long-term outcome of pediatric mild traumatic brain injury (mTBI) in terms of neurocognitive, behavioral, and school functioning and to identify clinical risk factors for adverse outcomes.

METHODS

This study describes the follow-up of a prospective multicenter sample of 89 children with mTBI 3.6 years postinjury and 89 neurologically healthy children matched for sex, age, and socioeconomic status. Neurodevelopmental outcomes were assessed using an intelligence test, behavioral questionnaires, computerized neurocognitive tests, and longitudinal (pre- and postinjury) standardized school performance data.

RESULTS

Children with mTBI exhibited intelligence in the average range but had more behavioral problems related to inattentiveness (P = 0.004, d = 0.47) and hyperactive impulsivity (P = 0.01, d = 0.40) and showed poorer neurocognitive performance in information processing stability (P = 0.003, d = -0.55) and Visual Working Memory (P = 0.04, d = -0.39) compared with matched peers. Longitudinal school performance data revealed poorer performance in Technical Reading up to two years postinjury (P = 0.005, d = -0.42) when compared with normative data. Clinical risk factors did not reveal predictive value for adverse outcomes in children with mTBI.

CONCLUSIONS

This study indicates that children with mTBI are at risk of long-term deficits in neurocognitive and behavioral functioning, with longitudinal evidence suggesting shortfalls in school performance up to two years postinjury. Clinical risk factors do not provide a solid basis for long-term neurodevelopmental prognosis. Findings emphasize the importance of, and challenges for, early identification of children at risk for adverse neurodevelopmental outcome after mTBI.

ADHD Adults Show Lower Interindividual Similarity in Ex-Gaussian Reaction Time Vectors for Congruent Stimuli Compared to Control Peers

OBJECTIVE

Interindividual similarity refers to how similarly individuals respond when receiving the same stimulus or intervention. In this study, we aimed to examine interindividual similarity in adults with ADHD.

METHOD

We used the cosine similarity index of ex-Gaussian reaction time (RT) vectors of mu, sigma, and tau parameters during a Stroop task.

RESULTS

Our results demonstrate that the ADHD group exhibits a reduced interindividual similarity index in their ex-Gaussian RT vectors for congruent stimuli compared to the healthy control group. Importantly, we did not find significant differences in the interindividual similarity index to incongruent stimuli between both groups, thus suggesting that this reduced index was selective for congruent stimuli.

CONCLUSION

Our findings highlight that ADHD adults exhibit more significant interindividual differences in cognitive functioning when processing congruent stimuli than healthy controls. These results provide new insights into the selective mechanisms underlying ADHD and may contribute to developing new targeted interventions for this disorder.

Assessment of ADHD Subtypes Using Motion Tracking Recognition Based on Stroop Color-Word Tests

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder known for its significant heterogeneity and varied symptom presentation. Describing the different subtypes as predominantly inattentive (ADHD-I), combined (ADHD-C), and hyperactive-impulsive (ADHD-H) relies primarily on clinical observations, which can be subjective. To address the need for more objective diagnostic methods, this pilot study implemented a Microsoft Kinect-based Stroop Color-Word Test (KSWCT) with the objective of investigating the potential differences in executive function and motor control between different subtypes in a group of children and adolescents with ADHD. A series of linear mixture modeling were used to encompass the performance accuracy, reaction times, and extraneous movements during the tests. Our findings suggested that age plays a critical role, and older subjects showed improvements in KSWCT performance; however, no significant divergence in activity level between the subtypes (ADHD-I and ADHD-H/C) was established. Patients with ADHD-H/C showed tendencies toward deficits in motor planning and executive control, exhibited by shorter reaction times for incorrect responses and more difficulty suppressing erroneous responses. This study provides preliminary evidence of unique executive characteristics among ADHD subtypes, advances our understanding of the heterogeneity of the disorder, and lays the foundation for the development of refined and objective diagnostic tools for ADHD.

Effects of auditory white noise stimulation on sustained attention and response time variability

Introduction

"The moderate brain arousal model" claims that white noise improves attention by optimizing brain arousal. We analyze Conners' Continuous Performance Test-3 (CCPT-3) performance, expecting to find reduced reaction time variability with noise mediated by decrease under long event-rates and in later parts of the test, indicating that noise reverse fall in phasic and tonic arousal.

Methods

Sixty-five children with high or lower ADHD-symptoms from a child psychiatric unit, succeeded to complete the CCPT-3 with and without white noise.

Results

Noise reduced overall variability, improved performance in later parts of the test, and reduced response variability under the longest event rate particularly in the high symptoms group. No overall change in omissions and commissions, but the high symptoms group made fewer omissions during noise compared the low symptom group.

Discussion

The study indicates an arousal effect of noise but should be replicated with other noise variants and amplitudes to improve effect and compliance.