Clinical presentations of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents: comparison of neurocognitive performance

[Formula: see text] Neurocognition in children with cognitive disengagement syndrome: accurate but slow

Cognitive disengagement syndrome (CDS), previously termed sluggish cognitive tempo (SCT), is characterized by excessive daydreaming, mental confusion, and slowed behavior or thinking. Prior research has found inconsistent relations between CDS and neurocognition, though most studies have used small or ADHD-defined samples, non-optimal measures of CDS, and/or examined limited neurocognitive domains. Accordingly, this study examined the association of parent- and teacher-reported CDS symptoms using a comprehensive neurocognitive battery in a sample of 263 children (aged 8-12) selected with a range of CDS symptomatology. Parents and teachers provided ratings of CDS and ADHD inattentive (ADHD-IN) symptoms. Path analyses were conducted to examine CDS and ADHD-IN as unique predictors of neurocognitive functioning after covarying for age, sex, and family income. CDS symptoms were uniquely associated with slower performance across a range of cognitive domains, including verbal inhibition, rapid naming/reading, planning, divided attention, and set shifting. In contrast, ADHD-IN symptoms were uniquely associated with poorer performance on a Go/NoGo task (inhibition/distractibility), visual scanning and discrimination, and interference control. Findings from the current study, amongst the first to recruit children based on levels of CDS symptomatology, provide the strongest evidence to date that the neurocognitive phenotype of CDS is characterized by slowed cognitive processing, and add to its validity as a separate syndrome from ADHD. If replicated, these findings have implications for assessment, treatment, and school accommodations for CDS. Neuroimaging studies exploring the neurobiological basis of CDS are also needed.

Attention deficit hyperactivity disorder: Neuropsychological profile and study of its impact on executive functions and academic performance

INTRODUCTION

The aim of the study was to describe the neuropsychological profile of patients with attention deficit hyperactivity disorder (ADHD) and the impact of the disorder on executive functioning and academic performance.

PATIENTS AND METHODS

We conducted a retrospective observational and analytical study. The sample consisted of 24 children with a diagnosis of ADHD (aged 6-15 years) without pharmacological treatment and 24 controls without ADHD (aged 7-15 years). A comprehensive neuropsychological evaluation was carried out, encompassing major cognitive domains, in addition to assessment of executive functioning and psychopathological symptoms through the administration of questionnaires to parents and teachers.

RESULTS

The cognitive profile of the ADHD group was characterized by overall scores (including executive functions and academic abilities) in the normal range (z scores between -1 and 1), although significantly lower compared to the control group. Over half of the patients with ADHD (58%) had associated specific learning disorders. Furthermore, teachers tended to report executive function difficulties more frequently in male students.

CONCLUSIONS

In the study sample, the group of patients with ADHD exhibited cognitive performance within the normal range, although with lower scores compared to controls. Behavioural rating scales provide valuable information about functioning outside the clinic, but may yield biased results on account of the focus on externalising symptoms. The neuropsychological evaluation is a useful tool that can facilitate the diagnosis of ADHD and an effective response to the needs and characteristics of patients and families.

Is WISC-IV Working Memory Index associated with ADHD symptoms in 7-8-year-olds?

The Working Memory Index (WMI) in the Wechsler Intelligence Scale for Children (WISC) has been suggested to be associated with ADHD symptoms. The relationship between WMI and ADHD symptoms in the general population is not clear. The study aimed to examine the association between working memory (WM) and behavioral regulation (BR), and hyperactivity/inattention (HI) in a general population sample of 7-8-year-olds, and whether general intellectual functioning is associated with BR and HI. The study also examined if those with low WMI also fulfill elevated ADHD criteria. The study group (N = 865) was assessed with the WISC (Fourth edition), the Behavior Rating Inventory of Executive Function, the Strengths and Difficulties Questionnaire, and the Five to Fifteen Questionnaire, and divided into three groups based on WM function, and in relation to BR and/or HI problems. The associations between WM and BR, and WM and HI, including intellectual functioning as covariate, were examined. WM deficits were found in 22%, but the majority of those had no BR or HI problems. Four percent in the study group had WM deficits combined with BR and/or HI problems, and in about one third of those inattentive ADHD criteria were fulfilled. WM and prosocial behavior were associated with BR and HI. WM deficits measured with WISC WMI in 7-8-year-olds do not always signal BR and/or HI problems.

Neuroplasticity to autophagy cross-talk in a therapeutic effect of physical exercises and irisin in ADHD

Adaptive neuroplasticity is a pivotal mechanism for healthy brain development and maintenance, as well as its restoration in disease- and age-associated decline. Management of mental disorders such as attention deficit hyperactivity disorder (ADHD) needs interventions stimulating adaptive neuroplasticity, beyond conventional psychopharmacological treatments. Physical exercises are proposed for the management of ADHD, and also depression and aging because of evoked brain neuroplasticity. Recent progress in understanding the mechanisms of muscle-brain cross-talk pinpoints the role of the myokine irisin in the mediation of pro-cognitive and antidepressant activity of physical exercises. In this review, we discuss how irisin, which is released in the periphery as well as derived from brain cells, may interact with the mechanisms of cellular autophagy to provide protein recycling and regulation of brain-derived neurotrophic factor (BDNF) signaling via glia-mediated control of BDNF maturation, and, therefore, support neuroplasticity. We propose that the neuroplasticity associated with physical exercises is mediated in part by irisin-triggered autophagy. Since the recent findings give objectives to consider autophagy-stimulating intervention as a prerequisite for successful therapy of psychiatric disorders, irisin appears as a prototypic molecule that can activate autophagy with therapeutic goals.