Inhibition explains the relationship between the efficiency of brain networks and adaptive outcomes in pediatric brain tumor survivors.

OBJECTIVE: Research has found altered brain network connectivity in pediatric brain tumor survivors. Efficient brain networks are critical for performing complex behaviors involved in adaptive functioning (AF). The present study explored relationships between structural brain network characteristics and AF in survivors. We examined whether this relationship is mediated by inhibition and cognitive flexibility, important cognitive abilities for AF. METHOD: Thirty-seven young adult survivors and 37 matched healthy controls (HC; overall Mage = 23.1, SD = 4.9) underwent neuropsychological assessment. Informants completed the Scales of Independent Behavior-Revised (SIB-R) interview. Color-Word Interference Inhibition and Inhibition-Switching from the Delis-Kaplan Executive Functioning System measured inhibition and cognitive flexibility performance. Deterministic tractography was performed on diffusion-weighted imaging, the Automated Anatomical Labeling (AAL) atlas defined nodes, and edges were the average fractional anisotropy between nodes. Global efficiency (GE), average clustering coefficient (CC), and density were computed. Partial correlations and analysis of indirect effects were conducted. RESULTS: There were significant relationships between GE and all SIB-R scales, but findings with CC were limited to two subscales. Inhibition was moderately related to GE, but this was no longer significant after Holm's correction. Cognitive flexibility was not found to be related to graph metrics. Finally, significant indirect effects were found such that inhibition explained the relationship between GE and SIB-R Motor and Social/Communication. CONCLUSIONS: Based on these findings, higher levels of brain network integration, as measured by GE, is related to inhibition in survivors, which facilitates proficient adaptive motor and social/communication skills. Future work should investigate tumor location and treatment factors as potential moderators of the relationships found in this study to better understand specific risk factors in this group. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Graph Theoretical Analysis of Brain Network Characteristics in Brain Tumor Patients: A Systematic Review.

Graph theory is a branch of mathematics that allows for the characterization of complex networks, and has rapidly grown in popularity in network neuroscience in recent years. Researchers have begun to use graph theory to describe the brain networks of individuals with brain tumors to shed light on disrupted networks. This systematic review summarizes the current literature on graph theoretical analysis of magnetic resonance imaging data in the brain tumor population with particular attention paid to treatment effects and other clinical factors. Included papers were published through June 24th, 2020. Searches were conducted on Pubmed, PsycInfo, and Web of Science using the search terms (graph theory OR graph analysis) AND (brain tumor OR brain tumour OR brain neoplasm) AND (MRI OR EEG OR MEG). Studies were eligible for inclusion if they: evaluated participants with a primary brain tumor, used graph theoretical analyses on structural or functional MRI data, MEG, or EEG, were in English, and were an empirical research study. Seventeen papers met criteria for inclusion. Results suggest alterations in network properties are often found in people with brain tumors, although the directions of differences are inconsistent and few studies reported effect sizes. The most consistent finding suggests increased network segregation. Changes are most prominent with more intense treatment, in hub regions, and with factors such as faster tumor growth. The use of graph theory to study brain tumor patients is in its infancy, though some conclusions can be drawn. Future studies should focus on treatment factors, changes over time, and correlations with functional outcomes to better identify those in need of early intervention.

Cerebellar-Subcortical-Cortical Systems as Modulators of Cognitive Functions.

Over the past few decades, research has established that the cerebellum is involved in executive functions; however, its specific role remains unclear. There are numerous theories of cerebellar function and numerous cognitive processes falling under the umbrella of executive function, making investigations of the cerebellum's role in executive functioning challenging. In this review, we explored the role of the cerebellum in executive functioning through clinical and cognitive neuroscience frameworks. We reviewed the neuroanatomical systems and theoretical models of cerebellar functions and the multifaceted nature of executive functions. Using attention deficit hyperactivity disorder and cerebellar tumor as clinical developmental models of cerebellar dysfunction, and the functional magnetic resonance imaging literature, we reviewed evidence for cerebellar involvement in specific components of executive function in childhood, adolescence, and adulthood. There is evidence for posterior cerebellar contributions to working memory, planning, inhibition, and flexibility, but the heterogeneous literature that largely was not designed to study the cerebellum makes it difficult to determine specific functions of the cerebellum or cerebellar regions. In addition, while it is clear that cerebellar insult in childhood affects executive function performance later in life, more work is needed to elucidate the mechanisms by which executive dysfunction occurs and its developmental course. The limitations of the current literature are discussed and potential directions for future research are provided.

Oral processing speed as a key mechanism in the relationship between neurological risk and adaptive functioning in survivors of pediatric brain tumors.

PURPOSE: Brain tumor (BT) survivors are at risk for difficulties with adaptive functioning (AF). Recent work has associated neurological risk with poorer AF outcomes using the Neurological Predictor Scale (NPS), a quantification of neurological risk factors. Survivors also have poorer attention, processing speed, and working memory, which are all important for AF. The current study examined whether these cognitive constructs explain the relationship between the NPS and AF in survivors. METHODS: Ninety-five adult BT survivors and 135 healthy controls were recruited from the Atlanta area. The Oral Symbol Digits Modalities test was used to measure processing speed, Digit Span Backward assessed working memory, and Digit Span Forward measured attention. Informants completed the Scales of Independent Behavior (SIB-R) to measure AF. Group differences and correlations were assessed, and the PROCESS macro for SPSS tested indirect effects. RESULTS: Survivors were significantly lower on AF and cognitive measures compared with controls. Attention span and processing speed had significant indirect effects in relationship between NPS and AF individually, but processing speed was the only variable with a significant indirect effect when all cognitive variables were included in the model. The NPS and processing speed together account for approximately 39% of variance in AF outcomes. CONCLUSIONS: BT survivors in our sample have lower AF than controls, and processing speed appears to be particularly important in explaining the relationship between neurological risk and AF. In the future, the development of interventions aimed at increasing young adult independence should target both cognitive processing speed and AF skills.

Implementing standard screening for autism spectrum disorder in CHD.

INTRODUCTION: While the overall prevalence of autism is 1.7% in the United States of America, research has demonstrated a two- to five-fold increase in CHD. The Cardiac Neurodevelopmental Outcome Collaborative recommends screening for autism from infancy through adolescence. This study investigated the frequency of autism concerns at a single Cardiac Neurodevelopmental Program and examined current clinical practice as a way to improve quality of care. MATERIALS AND METHODS: Patients (n = 134; mean age = 9.0 years) included children with high-risk CHD who completed a neurodevelopmental evaluation following a formalised referral to the Cardiac Neurodevelopmental Program between 2018 and 2019. Retrospective chart review included parent report on the Behaviour Assessment System for Children-3 and Adaptive Behaviour Assessment System-3. Descriptive and correlation analyses were completed. RESULTS: In this sample, 11.2% presented with autism-related concerns at referral, 2 were diagnosed with autism, 9 were referred to an autism specialist (6 confirmed diagnosis; 3 not completed). Thus, at least 5.9% of the sample were diagnosed with autism following thorough clinical evaluation. Analyses showed atypicality, along with deficient adaptability, leisure, social, and communication skills. Frequency of early intervention, school supports, and relation with comorbidities are reported. DISCUSSION: Prior to assessment recommendations by the Cardiac Neurodevelopmental Outcome Collaborative, autism screening may not be completed systematically in clinical care for CHD. The current sample demonstrates a high frequency of autism in the typically referred clinical sample. Commonly used parent-report measures may reveal concerns but will not help diagnosis. Systematic use of an autism screener is essential.