Increased cerebral blood flow in the right anterior cingulate cortex and fronto-orbital cortex during go/no-go task in children with ADHD.

OBJECTIVE: Arterial spin labeling (ASL) is a relatively new imaging modality in the field of the cognitive neuroscience. In the present study, we aimed to compare the dynamic regional cerebral blood flow alterations of children with ADHD and healthy controls during a neurocognitive task by using event-related ASL scanning. METHODS: The study comprised of 17 healthy controls and 20 children with ADHD. The study subjects were scanned on 3 Tesla MRI scanner to obtain ASL imaging data. Subjects performed go/no-go task during the ASL image acquisition. The image analyses were performed by FEAT (fMRI Expert Analysis Tool) Version 6. RESULTS: The mean age was 10.88 ± 1.45 and 11 ± 1.91 for the control and ADHD group, respectively (p = .112). The go/no-go task was utilized during the ASL scanning. The right anterior cingulate cortex (BA32) extending into the frontopolar and orbitofrontal cortices (BA10 and 11) displayed greater activation in ADHD children relative to the control counterparts (p < .001). With a lenient significance threshold, greater activation was revealed in the right-sided frontoparietal regions during the go session, and in the left precuneus during the no-go session. CONCLUSION: These results indicate that children with ADHD needed to over-activate frontopolar cortex, anterior cingulate as well as the dorsal and ventral attention networks to compensate for the attention demanded in a given cognitive task.

The neurocognitive nature of children with ADHD comorbid sluggish cognitive tempo: Might SCT be a disorder of vigilance?

Sluggish Cognitive Tempo (SCT) refers to a clinical construct including several symptoms such as sluggishness, absentmindedness, low energy. In the present study, we compared neurocognitive laboratory outcomes of ADHD children with or without SCT. METHOD: The CNS Vital Signs Battery was utilized to measure neurocognitive measure of the participants. The SCT+ADHD group comprised of 42 subjects, ADHD group was 41 subjects and control group was 24 subjects. RESULTS: The cognitive flexibility score was found to be more severely impaired in ADHD children with SCT in comparison to the ADHD-only. Additionally, greater deficits in the Shifting Attention Test (p = 0.014) and the Continuous Performance Test (reaction time score, p < 0.01) were found in the SCT+ADHD group relative to ADHD group. Processing speed, visual/auditory memory, psychomotor speed and reaction time were not found to more impaired in those comorbid with SCT. CONCLUSION: Impairments in the cognitive flexibility and more specifically shifting attention and continuous performance may be indicative of vigilance and orientation problems rather than executive functions for the SCT construct.

Attention-Deficit/Hyperactivity Disorder and Very Preterm/Very Low Birth Weight: A Meta-analysis.

CONTEXT: Although very preterm (VP), extremely preterm (EP), very low birth weight (VLBW), and extremely low birth weight (ELBW) newborns seem to have a higher risk of later attention-deficit/hyperactivity disorder (ADHD), the magnitude of the risk is not well-defined. OBJECTIVE: To systematically review and meta-analyze the risk of VP/VLBW and EP/ELBW individuals to develop a ADHD categorical diagnosis or dimensional symptomatology compared with controls with normal weight and/or birth age. DATA SOURCES: We used PsycINFO, Medline, Embase, and Cochrane databases. STUDY SELECTION: We selected cross-sectional, prospective, or retrospective studies with no time or language restriction. DATA EXTRACTION: Independent reviewers screened and extracted data using predefined standard procedures. RESULTS: In 12 studies (N = 1787), researchers relying on a categorical diagnosis showed that both VP/VLBW and EP/ELBW subjects have a higher ADHD risk (odds ratio [OR] = 3.04 higher than controls; 95% confidence interval [CI] 2.19 to 4.21). In subgroup analyses, we demonstrated that the more extreme the cases, the higher the ORs (VP/VLBW: OR = 2.25 [95% CI 1.56 to 3.26]; EP/ELBW: OR = 4.05 [95% CI 2.38 to 6.87]). We drew data from 29 studies (N = 3504) on ADHD symptomatology and found significant associations with inattention (standardized mean difference [SMD] = 1.31, 95% CI 0.66 to 1.96), hyperactivity and impulsivity (SMD = 0.74, 95% CI 0.35 to 1.13), and combined symptoms (SMD = 0.55, 95% CI 0.42 to 0.68) when compared with controls. LIMITATIONS: Heterogeneity was significantly high for all analyses involving the 3 ADHD dimensions. CONCLUSIONS: With our results, we provide evidence that VP/VLBW subjects have an increased risk of ADHD diagnosis and symptomatology compared with controls, and these findings are even stronger in the EP/ELBW group. Future researchers should address which risk factors related to prematurity or low birth weight lead to ADHD.