Electrophysiological signatures of inhibitory control in children with Tourette syndrome and attention-deficit/hyperactivity disorder

Neural markers of methylphenidate response in children with attention deficit hyperactivity disorder and the impact on executive function

Background

Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity. A core cognitive deficit in ADHD is executive function (EF) impairment, which significantly impacts daily life. Methylphenidate (MPH) is a widely used first-line treatment for ADHD, but objective biomarkers to assess treatment response are lacking. The aim of this study was to investigate the effects of MPH on executive function and identify potential neural biomarkers of response in children with ADHD using electroencephalogram (EEG).

Methods

A total of 26 boys with ADHD (mean age 8.64 ± 1.30 years) participated in the study. All participants were treated with 18 mg/day of oral extended-release MPH in the morning for 8 weeks. Executive function was assessed using the BRIEF2 and Digit Span Test (DST), and event-related potentials (ERP) were measured at baseline and after 8 weeks of MPH treatment.

Results

After 8 weeks of MPH treatment, significant improvements were observed in several executive function domains. BRIEF2 scores, including inhibition, self-monitoring, shifting, emotional control, initiation, working memory, planning/organization, task monitoring, and material organization, were significantly reduced (P < 0.05). Behavioral performance in the Go/NoGo task also improved, with shorter correct response times and higher accuracy rates (P = 0.002, P = 0.009). EEG results revealed a reduction in Nogo-P300 latency at Fz, Cz and Pz compared to baseline (P<0.05).

Conclusions

The normalization of P300 latency following MPH treatment appears to be a reliable neural biomarker of positive treatment response in children with ADHD. MPH was associated with improvements in executive function, particularly in inhibitory control and working memory.

Role and related mechanisms of non-invasive brain stimulation in the treatment of Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by impaired or delayed functional development. Although the pathology of TS remains to be determined, the continuous development of science and technology has provided new perspectives to understand its pathological mechanism. Research into non-invasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation and direct current stimulation, have shown promising therapeutic potential in clinical studies. Furthermore, NIBS has been shown to affect the brain of patients with TS, including synaptic transmission, release of neurotransmitters, in addition to the activation of microglial cells and astrocytes. However, an exploration of the innate mechanisms is still lacking. This review aims to summarize the pathogenesis of TS and intervention with NIBS in clinical patients with TS. It aims to provide a theoretical basis for more in-depth investigations of innovative therapies for TS in the future.

Neurocognitive Functioning in Tourette Syndrome: From Research Findings to Clinical Implementation

Individuals living with Tourette syndrome (TS) may benefit from cognitive assessment, as it may elucidate specific difficulties for which someone could receive accommodation and highlight relative strengths to build upon. Eventually, cognitive assessment could help predicting symptom trajectory or treatment outcome. However, the literature on cognition in TS is often equivocal, which may be at least partly attributed to small samples, inconsistent consideration of co-occurring conditions, psychotropic medication, and developmental influence. Here, we aimed to provide a comprehensive overview of the literature on cognition in TS, to disentangle conflicting findings and make suggestions of how the findings can be applied to promote better outcomes.

Global research progress of electroencephalography applications in attention deficit hyperactivity disorder: Bibliometrics and visualized analysis

Attention deficit hyperactivity disorder (ADHD) is a profound neurodevelopmental disorder. Currently, the diagnosis of ADHD relies on clinical assessments and lacks objective testing. Research in electroencephalography (EEG) offers new hope for the diagnosis of ADHD, with researchers actively seeking objective EEG biomarkers. This study conducts a bibliometric analysis of the application of EEG in ADHD, aiming to provide a brief overview of the characteristics, main research areas, development paths, and trends in this field. The Web of Science Core Collection was queried on June 10, 2024, to gather relevant scholarly works from the period of 2004 to 2023. Analysis was conducted using CiteSpace, VOSviewer, and Microsoft Excel 2019. In the past 20 years, 1162 documents qualified, with a swift rise in annual publications. The USA, University of London, and Barry RJ led in productivity and impact, while the Clinical Neurophysiology topped in publication volume and citations. High-frequency terms include "ADHD," "EEG," "event-related potentials (ERP)," "children," and "neurofeedback." Clustering key terms such as "cognitive control," "theta waves," "epilepsy," "graph theory," "machine learning," and "neurofeedback" form the cornerstone of the current core research areas. At the same time, a series of emerging research frontiers are gradually emerging, including "theta/beta ratio (TBR)," "P300 wave," "neurofeedback," and "deep learning." Over the past 2 decades, research on the application of EEG in ADHD has been burgeoning, with themes becoming increasingly profound. These insights provide key guidance on current trends, development trajectories, and future challenges in the field.

Additive and Interactive Effects of Attention-Deficit/Hyperactivity Disorder and Tic Disorder on Brain Connectivity

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and persistent tic disorder (PTD) are two neurodevelopmental disorders that frequently co-occur. Contributions of each disorder to cognitive and behavioral deficits have been reported. In this paper, we tested 3 models of pathophysiology for the two disorders (additive, interactive, and phenotypic) using resting-state connectivity associated with each disorder separately and together.

METHODS

Participants were 148 children (55 with ADHD only, 33 with ADHD and PTD, 27 with PTD only, and 33 healthy control subjects) at ages 8 to 12 years. Following diagnostic interviews and behavioral assessment, participants underwent a 128-channel electroencephalography recording. Resting-state, cortical source-level effective connectivity was analyzed across the 4 groups using a 2 × 2 factorial design with factors of ADHD (with/without) and PTD (with/without).

RESULTS

ADHD diagnosis was the primary driver of cognitive and behavioral deficits, while deficits associated with PTD were primarily with thought problems and internalizing problems when compared with controls. Subadditive effects were observed in co-occurring ADHD+PTD for parent-rated behavioral problems and cognitive functions. Aberrant effective connectivity was primarily associated with ADHD, more specifically with lower posterior and occipital-frontal connectivity, while children with PTD exhibited greater left postcentral to precuneus connectivity. Weaker ADHD-related connectivity was associated with more severe behavioral problems, including internalizing behaviors, thought problems, and working memory deficits.

CONCLUSIONS

Similar to general behavioral deficits, aberrant resting-state neural connectivity in pediatric ADHD and PTD combines additively in co-occurring cases. The findings of this study support ADHD as a focus of treatment in comorbid cases, given the driving role of ADHD in both behavioral and neurophysiological deficits.

Impeded frontal-occipital communications during Go/Nogo tasks in humans owing to mental workload

Human brains rely on oscillatory coupling mechanisms for regulating access to prefrontal cognitive resources, dynamically communicating between the frontal and remote cortex. We worry that communications across cortical regions will be impeded when humans in extreme space environments travel with mental load work, affecting the successful completion of missions. Here, we monitored crews of workers performing a Go/Nogo task in space travel, accompanied by acquisitions of electroencephalography (EEG) signals. These data demonstrated that when the target stimulus suddenly changed to the non-target stimulus, an instantaneous communication mechanism between the frontal and occipital cortex was established by theta-gamma phase-amplitude coupling (PAC). However, this frontal-occipital communication was impeded because of the mental workload of space travel. 86 healthy volunteers who participated in the ground imitation further indicated that mental workload caused decoupled theta-gamma PAC during the Go/Nogo task, impeding frontal-occipital communications and behavioral performance. We also found that the degree of theta-gamma PAC coupling in space was significantly lower than on the ground, indicating that mental workload and other hazards worsen the impeded frontal-occipital communications of humans. These results could guide countermeasures for the inadaptability of humans working in spaceflight.

P3b Amplitude and Latency in Tic Disorders: A Meta-Analysis

P3b is an event-related potential (ERP) that may be abnormal in patients with tic disorders (TD), but evidence has been inconsistent. Given the possible association between P3b and TD and the need for biomarkers for TD, the primary objective of this meta-analysis was to characterize P3b in patients with TD in comparison to healthy controls (HCs).

METHODS

By searching PubMed, Embase, Web of Science, SCOPUS, Medline, and Google Scholar, we identified studies that compared P3b between TD patients and HCs. The amplitude and latency of P3b were then analyzed. Subgroup analyses were conducted to investigate the influence of different experimental factors on P3b indices.

RESULT

Overall, 19 articles involving 388 cases and 414 controls were evaluated. There were no significant abnormalities in P3b amplitude and latency in TD patients. The P3b amplitude of the TD patients was significantly decreased during the oddball task, and the P3b amplitude of the adult TD patients was also significantly decreased.

CONCLUSION

TD patients may have an abnormal P3b compared to HCs under specified conditions.