Transcranial Direct Current Stimulation Improves Executive Dysfunctions in ADHD: Implications for Inhibitory Control, Interference Control, Working Memory, and Cognitive Flexibility

Objective: This study examined effects of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) on major executive functions (EFs), including response inhibition, executive control, working memory (WM), and cognitive flexibility/task switching in ADHD. Method: ADHD children received (a) left anodal/right cathodal DLPFC tDCS and (b) sham stimulation in Experiment 1 and (a) left anodal DLPFC/right cathodal OFC tDCS, (b) left cathodal DLPFC/right anodal OFC tDCS, and (c) sham stimulation in Experiment 2. The current intensity was 1 mA for 15 min with a 72-hr interval between sessions. Participants underwent Go/No-Go task, N-back test, Wisconsin Card Sorting Test (WCST), and Stroop task after each tDCS condition. Results: Anodal left DLPFC tDCS most clearly affected executive control functions (e.g., WM, interference inhibition), while cathodal left DLPFC tDCS improved inhibitory control. Cognitive flexibility/task switching benefited from combined DLPFC-OFC, but not DLPFC stimulation alone. Conclusion: Task-specific stimulation protocols can improve EFs in ADHD.

Prevalence of autism traits and attention-deficit hyperactivity disorder symptoms in a clinical sample of children and adolescents with chronic pain

Purpose

Recent research has suggested that autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) may be comorbid to pediatric chronic pain, but the empirical support is yet scarce. Therefore, the current study aimed to investigate the occurrence of traits and symptoms consistent with clinically significant ASD and ADHD in a group of children and adolescents with chronic debilitating pain and examine potential differences in pain and demographic variables between children with and without clinically significant traits and symptoms of ASD and ADHD.

Patients and methods

This cross-sectional study included 146 parent–child dyads (102 girls, 111 mothers, children 8–17 years) consecutively referred to a tertiary pain clinic. Parents completed the Social Responsiveness Scale to assess autistic traits, and Conners-3 to measure symptoms of ADHD in their children. Children completed the Lübeck Pain Questionnaire to evaluate experienced pain.

Results

Among children, 20 (13.7%) received scores consistent with clinically significant ASD and 29 (19.9%) received scores consistent with clinically significant ADHD, with a combined prevalence of clinically significant ASD/ADHD traits and symptoms of 26% of the total sample. Only 4.8% of children were previously diagnosed with either disorder. Among children with clinically significant ASD traits, girls were more prevalent, parents reported lower health, and the pain was more likely triggered by being in school. Among children with clinically significant ADHD symptoms, there were no gender differences and pain was more likely triggered by the family situation and new situations. No differences regarding pain intensity, duration, or frequency were found between children with and without clinically significant ASD traits or ADHD symptoms.

Conclusion

Children with debilitating chronic pain, particularly girls, may present with an elevated risk of having a comorbid, possibly high-functioning, neurodevelopmental disorder. Results suggest that clinical assessment of pediatric chronic pain should include screening for neurodevelopmental disorders.

Executive Dysfunction and Functional Impairment Associated With Sluggish Cognitive Tempo in Emerging Adulthood

OBJECTIVE

Research has identified a relationship between sluggish cognitive tempo (SCT) symptoms and symptoms of ADHD, anxiety, and depression; however, no study has controlled for symptoms of ADHD, anxiety, and depression when examining impairment related to SCT symptoms. This study aimed to examine (a) the extent to which functional impairment and executive function (EF) problems were accounted for by SCT symptoms when controlling for ADHD, anxiety, and depression symptoms, and (b) which type of symptoms were associated with the greatest amount of impairment.

METHOD

College students ( N = 458) completed self-report scales of ADHD, SCT, anxiety, and depression symptoms, as well as functional impairment and EF problems.

RESULTS

Thirteen percent of the sample was found to have high levels of SCT symptoms. SCT symptoms showed a moderate to strong correlation with the other symptom sets; however, high levels of SCT symptoms often occurred separate from high levels of ADHD, anxiety, or depression symptoms. SCT symptoms accounted for the most unique variance for both EF problems and functional impairment. Students with high levels of SCT symptoms, with or without high levels of ADHD symptoms, exhibited more impairment and EF problems than the controls.

CONCLUSION

SCT is a clinical construct worthy of additional study, particularly among college students.

Memantine in the Treatment of Executive Function Deficits in Adults With ADHD

OBJECTIVE

To evaluate the efficacy and safety of memantine hydrochloride as an adjunct to stimulant pharmacotherapy for treating executive function deficits (EFDs) in adults with ADHD.

METHOD

This was a 12-week, double-blind, placebo-controlled, randomized clinical trial of memantine added to open-label treatment with stimulant medication. Because of the small sample size, we considered a standardized mean difference (equivalent to effect size) of ≥0.5 and odds ratios ≥2 as indicators of trend improvements.

RESULTS

Twelve participants received memantine and 14 received a placebo. Trend improvements favoring memantine were observed on Behavior Rating Inventory of Executive Functions-Adult Inhibition and Self-Monitor subscales when compared with Placebo. No significant changes were noted on the Cambridge Neuropsychological Test Automated Battery.

CONCLUSION

Among adults with ADHD and EFDs, adjunct treatment with memantine to osmotic release oral system-methylphenidate (OROS-MPH) was associated with improvements in selective areas of executive functioning, supporting the need for further research.

Repetitive Transcranial Magnetic Stimulation for the Treatment of Executive Function Deficits in Autism Spectrum Disorder: Clinical Trial Approach

OBJECTIVE

Executive function (EF) deficits in patients with autism spectrum disorder (ASD) are ubiquitous and understudied. Further, there are no effective, neuroscience-based treatments to address this impairing feature of ASD. Repetitive transcranial magnetic stimulation (rTMS) has demonstrated promise in addressing EF deficits in adult neuropsychiatric disorders. This article will outline the design of a novel randomized-controlled trial of bilateral, 20 Hz, rTMS applied to the dorsolateral prefrontal cortex (DLPFC) for treatment of EF deficits in ASD that is currently ongoing. We describe prior therapeutic rTMS research for ASD and prior rTMS trials targeting EFs in adult neuropsychiatric disorders. A neurophysiological rationale for rTMS treatment of EF deficits in ASD is presented.

METHODS

An ongoing protocol will enroll participants aged 16-35 with ASD and no intellectual disability. Psychotropic medications will be continued during the 4-week trial of active 20 Hz versus sham rTMS applied to the DLPFC. Twenty, active treatment sessions consisting of 25 stimulation trains at a 90% motor threshold will be administered. The primary outcome measure is the Cambridge Neuropsychological Test Automated Battery (CANTAB) spatial working memory task. At present, recruitment, enrollment, and treatment within the described clinical trial are ongoing.

CONCLUSIONS

EF deficits are common and impairing symptoms of ASD. There are no evidence-based treatments for EF deficits in ASD. The protocol described here will provide important preliminary data on the feasibility and efficacy of 20 Hz rTMS to DLPFC for EF deficits in ASD.

Utility of an abbreviated questionnaire to identify individuals with ADHD at risk for functional impairments

OBJECTIVE

To discern whether a subset of items from the 99-item Current Behavior Scale (CBS) of behaviorally defined Executive Function Deficits (EFDs) in adults with Attention-Deficit/Hyperactivity Disorder (ADHD) can identify a group at risk for poor outcome.

METHODS

Subjects were 200 adults with ADHD participating in a family study of ADHD in adults. Factor analysis was used to reduce the number of items in the 99-item CBS.

RESULTS

The one factor solution provided eight items with factor loadings above 0.70. This abbreviated set of items was highly correlated with the 99-item CBS (0.91) and was similarly related to functional outcomes compared to the 99-item CBS (average correlation of 0.30 versus 0.32).

CONCLUSION

For adults with ADHD, a set of eight empirically-derived from the CBS similarly correlated with negative outcomes compared to the 99-item CBS, raising the possibility of utilization as a mechanism for identification of EFDs in adults with ADHD.

Executive function deficits and medial temporal lobe atrophy in late-life depression and Alzheimer's disease: a comparative study

OBJECTIVES

Alzheimer's disease (AD) and late-life depression (LLD) frequently exhibit executive function deficits (EFD) and medial temporal lobe atrophy (MTA) as shared characteristics. The objective of this research was to examine the utility of the Trail Making Test (TMT) and the MTA scale in distinguishing between LLD and AD.

METHODS

A study of 100 patients, 50 with AD and 50 with LLD, was conducted using a cross-sectional design. The individuals were subjected to clinical evaluations to assess their level of depression and overall cognitive abilities, which included the Geriatric Depression Scale (GDS), Mini-Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA). We evaluated executive function deficits (EFD) through the use of the TMT, which includes both TMT-A and TMT-B. MTA was measured using magnetic resonance imaging. To evaluate the ability of TMT and MTA scale to distinguish between the two groups, a receiver operating characteristic (ROC) curve was utilized. To investigate the connections between MTA and neuropsychological measures, a correlation analysis was performed.

RESULTS

AD patients exhibited notably reduced MMSE, MoCA, and GDS scores, as well as an increased MTA total scores, time spent on TMT-A, and TMT-B compared to LLD patients (p < 0.05). TMT-A and TMT-B both exhibited excellent discriminatory power between AD and LLD, achieving area under curve (AUC) values of 92.2 and 94.2%, respectively. In AD patients, there was a negative correlation between MMSE and MoCA scores and MTA scores, while in LLD patients, there was a positive correlation between time spent on TMT-A and GDS scores and MTA scores.

CONCLUSION

AD patients experience more severe EFD and MTA than LLD patients. The differential diagnosis of AD and LLD can be aided by the useful tool known as TMT. It is important to acknowledge that TMT is capable of capturing only a fraction of the executive function, thus necessitating a cautious interpretation of research findings.

Executive Functioning Rating Scale as a Screening Tool for ADHD: Independent Validation of the BDEFS-CA

Objective: This study provides independent examination of the validity of the Barkley Deficits of Executive Functioning Scale-Children and Adolescents (BDEFS-CA) in a sample of children diagnosed with ADHD (n = 50) and typically developing controls (n = 50). Method: Parents of participants completed the BDEFS-CA and the Conners 3 rating scales. Validity of BDEFS-CA was examined using a confirmatory factor analysis, correlational analyses with Conners 3 ratings, and receiver operating characteristic (ROC) curve analysis of diagnostic accuracy. Results: Findings support the construct, concurrent, and discriminant validity of the BDEFS-CA in a mixed sample. Conclusion: Findings provide independent examination of the validity of the BDEFS-CA as a measure of executive dysfunction and a screening tool for ADHD.

The Executive Checklist (EC-10) - a new rating instrument for clinicians assessing dysexecutive behavior

Assessment of executive functions (EF) is often criticized for its lack of ecological validity. As a consequence, several self- and partner rating scales for EF have been developed, while rating scales designed for clinicians are lacking. We therefore developed the Executive Checklist (EC-10), a new rating scale for clinicians assessing dysexecutive behavior during neuropsychological assessment and examined its psychometric properties. Consecutive referrals from a memory clinic with subjective cognitive impairment (SCI; n = 27), mild cognitive impairment (MCI; n = 29), dementia (DEM; n = 16), as well as 11 healthy controls were assessed with the EC-10 while performing common neuropsychological tests. Results showed that the EC-10 had excellent inter-rater reliability, good internal consistency and modest relations to cognitive laboratory measures. The EC-10 increased the classification rate above and beyond the influence of neuropsychological tests when comparing patients with SCI and MCI or between cognitively impaired and non-impaired patients. Conclusively, the present study demonstrates that clinical observations can be quantified using the EC-10 and that this rating provides valuable information. As executive deficits are common in many neurological and neuropsychiatric disorders, validating the EC-10 in broader patient groups should be an important avenue for future research.

Bilingualism May Be Protective Against Executive Function and Visual Processing Deficits Among Children With Attention Problems

Objective: The current study examined how the opposing effects of bilingualism and attention problems operate on executive functioning, visual processing, and verbal fluency in children with clinically significant levels of attention problems. Method: We tested whether bilingualism moderated associations between attention problems and visual processing, executive functioning, and verbal fluency. Results: Bilingual children (n = 331) showed visual processing advantages relative to their monolingual peers (n = 165), but only at higher, and not lower, levels of attention problems. Bilingualism did not moderate the association between attention problems and interference control; however, across all children, those with higher levels of attention problems had more difficulty with interference control. Monolingual children demonstrated advantages in verbal fluency relative to bilingual children, but this did not vary with attention problems. Conclusion: Visual processing advantages in bilinguals are detected among children with heightened attention problems, but advantages in interference control are not; findings may have implications for classroom interventions.

Executive function deficits mediate the relationship between employees' ADHD and job burnout

Adults with Attention-Deficit/Hyperactivity Disorder (ADHD) often face significant deficits in executive function and adverse work-related outcomes. This study aimed to explore the role of executive function deficits in job burnout of employees with ADHD. We hypothesized that employees with ADHD, relative to employees without ADHD, will experience higher levels of job burnout and deficits in executive function. We also hypothesized that the ADHD-job burnout relationship would be mediated through executive function deficits, specifically by self-management to time and self-organization/problem-solving. A field study with 171 employees provided support for the research hypotheses and mediation model in which the employees' ADHD-job burnout relationship was mediated through executive function deficits. Additional mediation analyses indicated that the specific executive function of self-management to time and self-organization/problem-solving mediated the effect of ADHD on job burnout and its facets. Specifically, for physical fatigue, the mediation was realized through self-management to time, and for emotional exhaustion and cognitive weariness, the mediation was significant through self-organization/problem-solving. The present findings shed light on the relevance of referring ADHD among employees, their vulnerability to job burnout, and the role of executive function deficits in job burnout of employees with ADHD.

Verbal Memory Interference in Attention-Deficit Hyperactivity Disorder: A Meta-Analytic Review

OBJECTIVE

Interference control is used to overcome conflict among competing memory representations and may contribute to memory difficulties in ADHD. This meta-analytic review examined memory interference to evaluate susceptibility to proactive, retroactive, and memory control interference among those with ADHD.

METHOD

Twenty studies (1987-2019) examining verbal memory interference in ADHD met inclusion criteria (age: 8-36 years). Proactive and retroactive interference indices were extracted from list-learning tasks, and memory control indices were extracted from experimental paradigms (e.g., directed-forgetting).

RESULTS

Children with ADHD were less affected by proactive interference (g=-0.53, 95% CI [-0.75, -0.31]), whereas no significant differences were found in adults (g=0.13, 95% CI [-0.02, 0.28]). Adults and children with ADHD exhibited more retroactive interference (g=0.17, 95% CI [0.05, 0.29]) and performed worse on memory control tasks (g=0.35, 95% CI [0.08, 0.62]) relative to controls.

CONCLUSION

Differences in verbal memory interference control in ADHD were observed but effects were different depending upon interference type and participant age.

Inside the Functional Individualized Therapy for Teenagers with Executive Deficits (FITTED): Insights from the Adolescents and Their Parents

This study explores Functional Individualized Therapy for Teenagers with Executive Deficits (FITTED) factors facilitating adolescents' improvement. At each of eight therapy sessions, 41 adolescents with executive function deficits and their parents wrote the primary concept they "took away." Experts categorized their answers by the FITTED model's main factors-goals, strengths, and strategies-adding child's difficulties for the parents' answers. Results describe answer frequencies by factor in each session. Across time, strengths and strategies dominated among adolescents, and strategies and difficulties among parents. Cognitive strategies are integral to the FITTED process for improving the daily functioning of adolescents with executive function deficits.

Treating Executive Function in Youth With Attention Deficit Hyperactivity Disorder: A Review of Pharmacological and Non-Pharmacological Interventions

INTRODUCTION

Executive function (EF) deficits are common in youth with ADHD and pose significant functional impairments. The extent and effect of interventions addressing EF in youth with ADHD remain unclear.

METHODS

We conducted a systematic literature review using PRISMA guidelines. Included studies were randomized controlled trials of interventions to treat EF in youth with ADHD.

RESULTS

Our search returned 136 studies representing 11,443 study participants. We identified six intervention categories: nonstimulant pharmacological (N = 3,576 participants), neurological (N = 1,935), psychological (N = 2,387), digital (N = 2,416), physiological (N = 680), and combination (N = 366). The bulk of the evidence supported pharmacological interventions as most effective in mitigating EF, followed by psychological and digital interventions.

CONCLUSION

A breadth of treatments exists for EF in youth with ADHD. Pharmacological, psychotherapeutic, and digital interventions had the most favorable, replicable outcomes. A lack of outcome standardization across studies limited treatment comparison. More data on the persistence of intervention effects are necessary.

Disorganized Functional Connectivity of Anterior Insular Subnetworks in Adults with Executive Dysfunction after Trauma Exposure

There is increasing evidence that major trauma can adversely affect the brain and cognition. In some cases, trauma may lead to deficits in executive function (EF). The anterior insula may be a causal outflow hub acting to coordinate EF-related brain networks. To clarify the neural underpinnings of EF deficits (EFD) after trauma, we performed a resting-state functional magnetic resonance imaging (rs-fMRI) study of anterior insular subnetworks in adults who have lost their only child. A total of 167 participants completed various psychological and cognitive assessments to assess EF-related deficits. Correlations were computed between abnormal connectivity and cognitive/post-traumatic stress symptoms. The results showed abnormal anterior insular subregion connectivity in the default mode network (DMN), prefrontal lobe, and cerebellum lobe in participants with EFD. No correlation was found between abnormal connectivity and cognitive/post-traumatic stress symptoms in participants with EFD. These results suggest that excessive connections between the insula and DMN could contribute to EFD after trauma. Overall, this study provides novel references into the neural mechanisms of EF status after trauma exposure.

Specific Language Impairment and Executive Functions in School-Age Children: A Systematic Review

This systematic review examines the relationship between specific language impairment (SLI) and executive functions (EFs) in school-age children. The study investigates the impact of SLI on EF in comparison to children who develop normally. A total of 2,658 articles from three databases (PubMed, Scopus, and Virtual Health Library) were assessed for inclusion. Ultimately, 22 articles were selected for analysis, which contained information on both SLI and EF. The findings indicate that children diagnosed with SLI exhibit deficits, low performance, and, in some cases, significant deterioration in the development of EF when compared to typically developing children in 62%-91% of cases as early as three to four years of age; the most commonly found alterations were in working memory (including phonological, auditory, and visual/verbal memory), followed by deficits in attention, processing speed, inhibition, planning, cognitive flexibility, and internalized speech. We also discuss the close relationship and importance between language and EF in SLI children.