Cognitive reserve and brain volumes in pediatric acute lymphoblastic leukemia

Progression of brain injuries associated with methotrexate chemotherapy in childhood acute lymphoblastic leukemia

BACKGROUND

Brain bases and progression of methotrexate-associated neurotoxicity and cognitive disturbances remain unknown. We tested whether brain abnormalities worsen in proportion to intrathecal methotrexate(IT-MTX) doses.

METHODS

In this prospective, longitudinal study, we recruited 19 patients with newly diagnosed acute lymphoblastic leukemia 4-to-20 years of age and 20 matched controls. We collected MRI and neuropsychological assessments at a pre-methotrexate baseline and at week 9, week 22, and year 1 during treatment.

RESULTS

Patients had baseline abnormalities in cortical and subcortical gray matter(GM), white matter(WM) volumes and microstructure, regional cerebral blood flow, and neuronal density. Abnormalities of GM, blood flow, and metabolites worsened in direct proportions to IT-MTX doses. WM abnormalities persisted until week 22 but normalized by year 1. Brain injuries were localized to dorsal and ventral attentional and frontoparietal cognitive networks. Patients had cognitive deficits at baseline that persisted at 1-year follow-up.

CONCLUSIONS

Baseline abnormalities are likely a consequence of neuroinflammation and oxidative stress. Baseline abnormalities in WM microstructure and volumes, and blood flow persisted until week 22 but normalized by year 1, likely due to treatment and its effects on reducing inflammation. The cytotoxic effects of IT-MTX, however, likely contributed to continued, progressive cortical thinning and reductions in neuronal density, thereby contributing to enduring cognitive deficits.

IMPACT

Brain abnormalities at a pre-methotrexate baseline likely are due to acute illness. The cytotoxic effects of intrathecal MTX contribute to progressive cortical thinning, reductions in neuronal density, and enduring cognitive deficits. Baseline white matter abnormalities may have normalized via methotrexate treatment and decreasing neuroinflammation. Corticosteroid and leucovorin conferred neuroprotective effects. Our findings suggest that the administration of neuroprotective and anti-inflammatory agents should be considered even earlier than they are currently administered. The neuroprotective effects of leucovorin suggest that strategies may be developed that extend the duration of this intervention or adapt it for use in standard risk patients.

Current investigation of neurocognitive functioning in preschool children with cancer: A cross-sectional study from western China

BACKGROUND AND AIMS

Cancer and its treatments may cause neurocognitive impairments in preschool children, but there is limited research on the neurocognitive outcomes of this population. This study, which assessed the neurocognitive function of preschool children with cancer and analyzed various influencing factors of neurocognitive functioning, is of significant importance. We aimed to investigate neurocognitive function and related risk factors in preschool children with cancer to inform preventive and intervention strategies.

METHODS

From September 2023 to May 2024, we recruited 100 preschool children with cancer. The Chinese version of the Ages & Stages Questionnaires, the Spence Preschool Anxiety Scale Chinese Version, and the Sleep Disturbance Scale for Children were used to collected data. Binary logistic stepwise regression analysis was used to explore the influencing factors of neurocognitive function in preschool children with cancer.

RESULTS

49% of the preschool children with cancer had abnormalities in at least one neurocognitive dimension. The majority of children had abnormalities in gross motor dimension, accounting for 30%, which was related to age and frequency of participation in neurocognitive activities. Communication dimension was related to father's education level, dietary habit, and frequency of participation in activities. Fine motor dimension was associated with age, sex, and father's education level. Problem-solving dimension was associated with age and dietary habit. Personal-social dimension was related to age and radiotherapy.

CONCLUSIONS

Nearly half of preschool children with cancer experienced neurocognitive impairment. The Chinese version of the Ages & Stages Questionnaires is a simple and effective tool for screening children with possible neurocognitive impairment. It was found that children's neurocognitive function was significantly influenced by family environment, dietary habit, cognitive activities, and cancer treatment. Therefore, it is recommended to strengthen family and social support, and to formulate personalized intervention such as cognitive therapy and dietary adjustment based on children's age and family background, which are important for promoting neurocognitive recovery.

Impact of Propofol Exposure on Neurocognitive Outcomes in Children With High-Risk B ALL: A Children's Oncology Group Study

PURPOSE

Many children treated for ALL develop long-term neurocognitive impairments. Increased risk of these impairments is associated with treatment and demographic factors. Exposure to anesthesia is an additional possible risk factor. This study evaluated the impact of cumulative exposure to anesthesia on neurocognitive outcomes among a multicenter cohort of children with ALL.

METHODS

This study was embedded in AALL1131, a Children's Oncology Group phase III trial for patients with high-risk B-ALL. In consenting patients age 6-12 years, prospective uniform assessments of neurocognitive function were performed during and at 1 year after completion of therapy. Exposure to all episodes of anesthetic agents was abstracted. Multivariable linear regression models determined associations of cumulative anesthetic agents with the primary neurocognitive outcome reaction time/processing speed (age-normed) at 1 year off therapy, adjusting for baseline neurocognitive score, age, sex, race/ethnicity, insurance status (as a proxy for socioeconomic status), and leukemia risk group.

RESULTS

One hundred and forty-four children, 76 (52.8%) males, mean age of 9.1 (min-max, 6.0-12.0) years at diagnosis, underwent a median of 27 anesthetic episodes (min-max, 1-37). Almost all patients were exposed to propofol (140/144, 97.2%), with a mean cumulative dose of 112.3 mg/kg. One year after therapy, the proportion of children with impairment (Z-score ≤-1.5) was significantly higher compared with a normative sample. In covariate-adjusted multivariable analysis, cumulative exposure to propofol was associated with a 0.05 Z-score decrease in reaction time/processing speed per each 10 mg/kg propofol exposure (P = .03).

CONCLUSION

In a multicenter and uniformly treated cohort of children with B-ALL, cumulative exposure to propofol was an independent risk factor for impairment in reaction time/processing speed 1 year after therapy. Anesthesia exposure is a modifiable risk, and opportunities to minimize propofol use should be considered.

Cognitive Reserve Potential: Capturing Cognitive Resilience Capability in Adolescence

Cognitive reserve (CR) represents the adaptive response of the cognitive system responsible for preserving normal functioning in the face of brain damage. Experiential factors such as education, occupation, and leisure activities influence the development of CR. Theoretically, such factors build up from childhood and across adulthood. Thus, appropriate tools to define and measure CR as early as adolescence are essential to understand its developmental processes. To this aim, we introduce the construct of "Cognitive Reserve Potential" (CRP) and its corresponding index of experiential factors tailored to youth. We investigated prototypical youth exposures potentially associated with the lifelong development of CR (e.g., sport practice, musical experiences, cultural activities, and relationships with peers and family). Principal component analysis and confirmatory factor analysis identified and replicated the CRP factor structure on two independent samples of Italian students: N = 585 (295 F) and N = 351 (201 F), ages 11 to 20. CRP was associated mainly with family socio-cultural status (i.e., socioeconomic status [SES], Home Possessions, and Books at Home). Results confirmed the strength of the factorial model and warranted the proposal of the CRP-questionnaire as an innovative tool for understanding CR evolutionary dynamics.

Modeling the development of cognitive reserve in children: A residual index approach

OBJECTIVE

To model cognitive reserve (CR) longitudinally in a neurodiverse pediatric sample using a residual index approach, and to test the criterion and construct validity of this index.

METHOD

Participants were N = 115 children aged 9.5-13 years at baseline (MAge = 10.48 years, SDAge = 0.61), and n = 43 (37.4%) met criteria for ADHD. The CR index represented variance in Matrix Reasoning scores from the WASI that was unexplained by MRI-based brain variables (bilateral hippocampal volumes, total gray matter volumes, and total white matter hypointensity volumes) or demographics (age and sex).

RESULTS

At baseline, the CR index predicted math computation ability (estimate = 0.50, SE = 0.07, p < .001), and word reading ability (estimate = 0.26, SE = 0.10, p = .012). Longitudinally, change in CR over time was not associated with change in math computation ability (estimate = -0.02, SE = 0.03, p < .513), but did predict change in word reading ability (estimate = 0.10, SE = 0.03, p < .001). Change in CR was also found to moderate the relationship between change in word reading ability and white matter hypointensity volume (estimate = 0.10, SE = 0.05, p = .045).

CONCLUSIONS

Evidence for the criterion validity of this CR index is encouraging, but somewhat mixed, while construct validity was evidenced through interaction between CR, brain, and word reading ability. Future research would benefit from optimization of the CR index through careful selection of brain variables for a pediatric sample.

Changed cortical thickness and sulcal depth in pediatric acute lymphoblastic leukemia survivors treated with chemotherapy only

The purpose of this study is to observe the changes of cortical morphological characteristics and their potential contribution to cognitive function in ALL survivors by using surface-based morphometry (SBM). Using SBM analysis, we calculated and compared group differences in cortical thickness, sulcal depth, gyrification, and fractal dimension of the cerebral cortex between 18 pediatric ALL survivors treated on chemotherapy-only protocols and off treatment within 2 years, and 18 healthy controls (HCs) with two-sample t-tests [P < 0.05, family-wise error (FWE) corrected]. Relationships between abnormal cortical characteristic values and cognitive function parameters were investigated with partial correlation analysis, taking age as a covariate. We found decreased cortical thickness mainly located in the prefrontal and temporal region, and increased sulcal depth in left rostral middle frontal cortex and left pars orbitalis in the ALL survivors compared to HCs. There were no statistically significant differences in the gyrification and fractal dimension between the two groups. In ALL survivors, cortical thickness and sulcal depth of above areas values revealed no significant correlation with the cognitive function parameters. In conclusion, pediatric ALL survivors show decreased cortical thickness in prefrontal and temporal regions, and increased sulcal depth in prefrontal region. These results suggest that SBM-based approach can be used to assess changes of cortical morphological characteristics in pediatric ALL survivors.

Performance and Symptom Validity in Outpatient Pediatric Neuropsychological Evaluations

This study aimed to clarify the value of using different types of validity measures in pediatric neuropsychological evaluations. We examined the relationship between performance (PVT) and symptom (SVT) validity tests as well as demographic variables and results from a screening test of learning and memory (i.e. Child and Adolescent Memory Profile [ChAMP]) in a mixed pediatric sample (n = 103). There was minimal overlap between PVT and SVT failures. Regression analyses demonstrated that PVT results, parental education, and history of special education were statistically significant predictors of ChAMP results, whereas SVT results were not.

Predicting overall survival in diffuse glioma from the presurgical connectome

Diffuse gliomas are incurable brain tumors, yet there is significant heterogeneity in patient survival. Advanced computational techniques such as radiomics show potential for presurgical prediction of survival and other outcomes from neuroimaging. However, these techniques ignore non-lesioned brain features that could be essential for improving prediction accuracy. Gray matter covariance network (connectome) features were retrospectively identified from the T1-weighted MRIs of 305 adult patients diagnosed with diffuse glioma. These features were entered into a Cox proportional hazards model to predict overall survival with 10-folds cross-validation. The mean time-dependent area under the curve (AUC) of the connectome model was compared with the mean AUCs of clinical and radiomic models using a pairwise t-test with Bonferroni correction. One clinical model included only features that are known presurgery (clinical) and another included an advantaged set of features that are not typically known presurgery (clinical +). The median survival time for all patients was 134.2 months. The connectome model (AUC 0.88 ± 0.01) demonstrated superior performance (P < 0.001, corrected) compared to the clinical (AUC 0.61 ± 0.02), clinical + (AUC 0.79 ± 0.01) and radiomic models (AUC 0.75 ± 0.02). These findings indicate that the connectome is a feasible and reliable early biomarker for predicting survival in patients with diffuse glioma. Connectome and other whole-brain models could be valuable tools for precision medicine by informing patient risk stratification and treatment decision-making.

Is Brain Network Efficiency Reduced in Young Survivors of Acute Lymphoblastic Leukemia?-Evidence from Individual-Based Morphological Brain Network Analysis

Altered cerebral structure and function have been observed in young survivors of acute lymphoblastic leukemia (ALL). However, the topological organization of the morphological brain networks (MBNs) has not yet been investigated at the individual level. Twenty-three young survivors of ALL and twenty healthy controls (HCs) were recruited and underwent T1-weighted magnetic resonance imaging (MRI) scanning. After preprocessing and segmentation, individual-based MBNs were constructed based on the morphological similarity of gray matter using the combined Euclidean distance. Young survivors showed a significantly lower global clustering coefficient (p = 0.008) and local efficiency (p = 0.035) compared with HCs. In addition, ALL survivors exhibited bidirectional alterations (decreases and increases) in nodal centrality and efficiency around the Rolandic operculum and posterior occipital lobe (p < 0.05, false discovery rate (FDR) corrected). Altered nodal topological efficiencies were associated with off-therapy duration and verbal memory capacity in the digit span test (p < 0.05, FDR corrected). Network-based statistical analysis revealed decreased morphological connections mainly in the pallidum subnetwork, which was negatively correlated with off-therapy durations (p < 0.05). Overall, the topological organization of the individual-based MBNs was disrupted in the young survivors of ALL, which may play a crucial role in executive efficiency deficits.

Long-term Cognitive Outcomes and Socioprofessional Attainment in People With Multiple Sclerosis With Childhood Onset

Background and Objectives

Patients with pediatric-onset multiple sclerosis (MS) can be especially vulnerable to cognitive impairment (CI) due to the onset of MS during a critical period for CNS development and maturation. The objective of this longitudinal study was to assess long-term cognitive functioning and socioprofessional attainment in the Italian pediatric MS cohort, previously assessed at baseline and 2 and 5 years.

Methods

The 48 patients evaluated at the 5-year assessment were screened for inclusion. All participants were assessed with a cognitive test battery exploring 4 different cognitive abilities. Depression, fatigue, and socioprofessional attainment were also assessed. Mean cognitive z scores were calculated for the whole cohort, and their evolution over time was analyzed with an analysis of variance for repeated measurements test. Predictors of cognitive worsening or improvement were assessed with a linear mixed-model analysis.

Results

Thirty-three participants were included (mean follow-up 12.8 ± 0.8 years). The global cognitive performance worsened at year 2 and improved at year 5, although the z score remained significantly lower than at baseline (−0.9 ± 1.2 vs −0.3 ± 0.9, p = 0.002). There was no significant variation between years 5 and 12 (−0.7 ± 1.1, p = 0.452). Higher IQ (>90) at baseline (effect 0.3, 95% CI 0.1–0.5, p = 0.017) and lower number of relapses in the 2 years before baseline (effect −0.1, 95% CI −0.1 to 0.1, p = 0.025) predicted better cognitive performances. Eighteen (54.5%) patients failed at least 2 tests compared with healthy controls and were defined as cognitively impaired. The presence of CI predicted worse socioprofessional attainment (β = 4.8, 95% CI 1.4–8.2, p = 0.008).

Discussion

The longitudinal cognitive trajectory in pediatric-onset MS has a heterogeneous course over time, with a decline in the first years followed by a partial recovery over the long term. However, at the last follow-up evaluation, the proportion of impaired patients was more than double compared with baseline, with a negative impact on the individual’s socioprofessional attainment in adulthood. This study underscores how cognitive reserve may partially mitigate the negative effects of brain damage, highlighting the critical importance of intellectual enrichment early during the disease course.

Structural and Functional Brain Imaging in Long-Term Survivors of Childhood Acute Lymphoblastic Leukemia Treated With Chemotherapy: A Systematic Review

Background

The effect of chemotherapy on brain development in long-term survivors of pediatric acute lymphoblastic leukemia (ALL) was systematically reviewed.

Methods

A systematic search of Pubmed, Scopus, and PsycINFO databases was conducted to identify articles published between January 2000 and February 2020 that implemented magnetic resonance imaging to assess brain structure and function in pediatric ALL survivors (diagnosed younger than 21 years of age). The review included articles that were published on children diagnosed with ALL between 0 and 21 years of age and treated with chemotherapy-only protocols. Articles meeting the inclusion criteria described survivors on average of 5 years or more from diagnosis and were peer-reviewed articles and original studies.

Results

The search yielded 1975 articles with 23 articles meeting inclusion criteria. The review revealed that survivors had statistically significant alterations in brain anatomy, most commonly a smaller hippocampus and impaired microstructural white matter integrity in frontal brain regions. Survivors also had impaired brain function including lower brain network efficiency and altered resting state connectivity. Survivors also displayed widespread reductions in brain activation (ie, frontal, temporal, parietal brain regions) during cognitive tasks.

Conclusion

Although the neurotoxic effects of cancer treatment are reduced in the absence of cranial radiation, survivors treated on chemotherapy-only protocols still display long-term alterations in brain structure and function, which contribute to lifelong neurocognitive late effects.

The Working Memory Network and Its Association with Working Memory Performance in Survivors of non-CNS Childhood Cancer

Childhood cancer and its treatment puts survivors at risk of low working memory capacity. Working memory represents a core cognitive function, which is crucial in daily life and academic tasks. The aim of this functional MRI (fMRI) study was to examine the working memory network of survivors of childhood cancer without central nervous system (CNS) involvement and its relation to cognitive performance. Thirty survivors (aged 7-16 years, ≥ 1 year after cancer treatment) and 30 healthy controls performed a visuospatial working memory task during MRI, including a low- and a high-demand condition. Working memory performance was assessed using standardized tests outside the scanner. When cognitive demands increased, survivors performed worse than controls and showed evidence for slightly atypical working memory-related activation. The survivor group exhibited hyperactivation in the right-hemispheric superior parietal lobe (SPL) in the high- compared to the low-demand working memory condition, while maintaining their performance levels. Hyperactivation in the right SPL coincided with poorer working memory performance outside the scanner in survivors. Even in survivors of childhood cancer without CNS involvement, we find neural markers pointing toward late effects in the cerebral working memory network.AbbreviationsfMRI: Functional magnetic resonance imaging; CNS: Central nervous system; MNI: Montreal Neurological Institute; SES: Socioeconomic status; SPL: Superior parietal lobe.

Cortical Morphometry and Its Relationship with Cognitive Functions in Children after non-CNS Cancer

Background: Childhood cancer survivors (Ccs) are at risk for cognitive late-effects, which might result from cortical alterations, even if cancer does not affect the brain. The study aimed to examine gray and white matter volume and its relationship to cognition. Methods: Forty-three Ccs of non-central nervous system cancers and 43 healthy controls, aged 7-16 years, were examined. Cognitive functions and fine motor coordination were assessed and T1-weighted images were collected for voxel-based morphometry. Results: Executive functions (p = .024, d = .31) were poorer in Ccs than controls, however still within the normal range. The volume of the amygdala (p = .011, ŋ² = .117) and the striatum (p = .03, ŋ² = .102) was reduced in Ccs. No significant structure-function correlations were found, neither in patients nor controls. Conclusion: Non-CNS childhood cancer and its treatment impacts on brain structures relevant to emotion processing.

Influence of socioeconomic status on cognitive outcome after childhood arterial ischemic stroke

AIM

To determine whether socioeconomic status (SES) is a stronger predictor for cognitive outcome after childhood arterial ischemic stroke compared to clinical factors.

METHOD

We investigated perceptual reasoning, executive functions, language, memory, and attention in 18 children and adolescents (12 males, six females, median age at testing 13y 4mo, range 7y-17y 5mo) after arterial ischemic stroke; collected sociodemographic information (education of parents, household income); and used clinical information (initial lesion volume, residual lesion volume, age at stroke, time since stroke). Linear regression models were used to investigate the potential influence of SES and clinical parameters on cognitive abilities.

RESULTS

SES had a moderate effect on all cognitive outcome parameters except attention by explaining 41.9%, 37.9%, 38.0%, and 22.5% of variability in perceptual reasoning, executive functions, language, and memory respectively. Initial lesion volume was the only clinical parameter that showed moderate importance on cognitive outcome (33.1% and 25.6% of the variability in perceptual reasoning and memory respectively). Overall, SES was a stronger predictor of cognitive outcome than clinical factors.

INTERPRETATION

Future paediatric studies aiming at clinical predictors of cognitive outcome should control their analyses for SES in their study participants. The findings of the present study further point to the need for more attention to the treatment of children with low SES.

WHAT THIS PAPER ADDS

Socioeconomic status (SES) explains up to 42% of variance in cognitive outcome after childhood arterial ischemic stroke. SES is a stronger predictor of outcome than clinical factors.

Brain biomarkers and neuropsychological outcomes of pediatric posterior fossa brain tumor survivors treated with surgical resection with or without adjuvant chemotherapy

PURPOSE

Children with brain tumors experience cognitive late effects, often related to cranial radiation. We sought to determine differential effects of surgery and chemotherapy on brain structure and neuropsychological outcomes in children who did not receive cranial radiation therapy (CRT).

METHODS

Twenty-eight children with a history of posterior fossa tumor (17 treated with surgery, 11 treated with surgery and chemotherapy) underwent neuroimaging and neuropsychological assessment a mean of 4.5 years (surgery group) to 9 years (surgery + chemotherapy group) posttreatment, along with 18 healthy sibling controls. Psychometric measures assessed IQ, language, executive functions, processing speed, memory, and social-emotional functioning. Group differences and correlations between diffusion tensor imaging findings and psychometric scores were examined.

RESULTS

The z-score mapping demonstrated fractional anisotropy (FA) values were ≥2 standard deviations lower in white matter tracts, prefrontal cortex gray matter, hippocampus, thalamus, basal ganglia, and pons between patient groups, indicating microstructural damage associated with chemotherapy. Patients scored lower than controls on visuoconstructional reasoning and memory (P ≤ .02). Lower FA in the uncinate fasciculus (R = -0.82 to -0.91) and higher FA in the thalamus (R = 0.73-0.91) associated with higher IQ scores, and higher FA in the thalamus associated with higher scores on spatial working memory (R = 0.82).

CONCLUSIONS

Posterior fossa brain tumor treatment with surgery and chemotherapy affects brain microstructure and neuropsychological functioning years into survivorship, with spatial processes the most vulnerable. Biomarkers indicating cellular changes in the thalamus, hippocampus, pons, prefrontal cortex, and white matter tracts associate with lower psychometric scores.

Impact of non-CNS childhood cancer on resting-state connectivity and its association with cognition

INTRODUCTION

Non-central nervous system cancer in childhood (non-CNS CC) and its treatments pose a major threat to brain development, with implications for functional networks. Structural and functional alterations might underlie the cognitive late-effects identified in survivors of non-CNS CC. The present study evaluated resting-state functional networks and their associations with cognition in a mixed sample of non-CNS CC survivors (i.e., leukemia, lymphoma, and other non-CNS solid tumors).

METHODS

Forty-three patients (off-therapy for at least 1 year and aged 7-16 years) were compared with 43 healthy controls matched for age and sex. High-resolution T1-weighted structural magnetic resonance and resting-state functional magnetic resonance imaging were acquired. Executive functions, attention, processing speed, and memory were assessed outside the scanner.

RESULTS

Cognitive performance was within the normal range for both groups; however, patients after CNS-directed therapy showed lower executive functions than controls. Seed-based connectivity analyses revealed that patients exhibited stronger functional connectivity between fronto- and temporo-parietal pathways and weaker connectivity between parietal-cerebellar and temporal-occipital pathways in the right hemisphere than controls. Functional hyperconnectivity was related to weaker memory performance in the patients' group.

CONCLUSION

These data suggest that even in the absence of brain tumors, non-CNS CC and its treatment can lead to persistent cerebral alterations in resting-state network connectivity.

Assessment of Executive Functions after Treatment of Childhood Acute Lymphoid Leukemia: a Systematic Review

Individuals treated for childhood acute lymphoblastic leukemia (ALL) have a high survival rate. This fact, however, may lead to neurocognitive impairments in survivors, as shown in some studies. The prefrontal cortex and executive functions seem to be particularly vulnerable due to the late maturation in the development process. Executive impairments have been associated with poorer quality of life in childhood cancer survivors. A systematic review was carried out with studies that assessed executive functions in childhood ALL survivors.\ Studies were collected from five electronic databases: MEDLINE (PubMed); PsycInfo; WebOfScience; LILACS and IBECS. Eighty-four studies were retrieved from the database search, of which 50 were read in full and 26 met the inclusion criteria. The studies were heterogeneous as to the instruments used to assess executive function, the skills assessed and the comparison methods. Despite some discrepancies, ALL survivors seem to exhibit poorer executive functioning than typical controls, but this result did not hold true when subjects were compared to normative mean. Changes in brain structure and dynamics resulting from the disease itself, the toxicity of the treatment and difficulties in coping with the stress during treatment may be related to executive impairments in ALL survivors. Discussion proposed standardized methods and measures for assessing executive functioning in children during and after ALL treatment.

Anatomical brain MRI study of pediatric cancer survivors treated with chemotherapy: Correlation with behavioral measures

The negative impacts of chemotherapy on pediatric patients treated with chemotherapy during the formative years of brain development are understudied compared to adult chemotherapy cancer patients. This work investigated the morphometry, cortical thickness, and subcortical volumes using MRI and their correlations with behavioral measures in pediatric oncology survivors treated with chemotherapy. Chemotherapy-treated childhood cancer survivors (N = 15, 15.12 ± 5.98 years old) diagnosed with a non-central nervous system malignancy and healthy age-matched controls (N = 15, 15.13 ± 4.21 years old) were studied. MRI was acquired at 3 Tesla. Behavioral Rating Inventory of Executive Functioning (BRIEF) Parental Rating, Purdue Pegboard manual dexterity and n-back working memory measures were administered. Structural MRI scans at 3 Tesla were acquired. Voxel-based morphometry, cortical thickness and subcortical volumes were analyzed and correlated with behavioral scores. Parametric statistics with a p < .05 and adjusted for multiple comparison corrections were performed. Patients exhibited significantly smaller gray-matter volumes in the left globus pallidum, bilateral thalami, left caudate and left nucleus accumbens (p < .05) and thinner cortex in the right parahippocampal gyrus (p < .05) compared to controls. BRIEF scores were similar to normative values. Purdue Pegboard revealed manual dexterity deficits compared to normative values, and the n-back task showed working-memory deficits in patients compared to controls. Left thalamus volume positively correlated with dexterity performance (p = .029). The number of correct answers positively correlated and the number of incorrect answers negatively correlated with total-brain and white-matter volume (p < .05), but not gray-matter volume (p > .05). Our results support the hypothesis that the neurotoxicity of systemic chemotherapy has widespread negative effects on brain development in pediatric oncology patients with relatively mild cognitive deficits. MRI identified neuroanatomical changes have the potential to provide neural correlates of the sequelae associated with pediatric chemotherapy.

Gray Matter Structural Network Disruptions in Survivors of Acute Lymphoblastic Leukemia with Chemotherapy Treatment

OBJECTIVES

Neuroimaging studies of acute lymphoblastic leukemia (ALL) during chemotherapy treatment have shown alterations in structure, function, and connectivity in several brain regions, suggesting neurobiological impairment that might influence the large-scale brain network. This study aimed to detect the alterations in the topological organization of structural covariance networks of ALL patients.

METHODS

This study included 28 ALL patients undergoing chemotherapy and 20 matched healthy controls. We calculated the gray matter volume of 90 brain regions based on an automated anatomical labeling template and applied graph theoretical analysis to compare the topological parameters of the gray matter structural networks between the two groups.

RESULTS

The results demonstrated that both the ALL and healthy control groups exhibited a small-world topology across the range of densities. Compared to healthy controls, ALL patients had less highly interactive nodes and a reduced degree/betweenness in temporal regions, which may contribute to impaired memory and executive functions in these patients.

CONCLUSION

These results reveal that ALL patients undergoing chemotherapy treatment may have decreased regional connectivity and reduced efficiency of their structural covariance network. This is the first report of anomalous large-scale gray matter structural networks in ALL patients undergoing chemotherapy treatment and provides new insights regarding the neurobiological mechanisms underlying the chemo-brain network.

Changes in neurocognitive function and central nervous system structure in childhood acute lymphoblastic leukaemia survivors after treatment: a meta-analysis

Acute lymphoblastic leukaemia (ALL) is the most common malignancy in children. Although the survival rate has increased dramatically over the last decades, patients struggle with the adverse side effects of treatment. Treatment for ALL includes chemotherapy and irradiation - both of which are linked to cognitive impairments and alterations in central nervous system (CNS) structure and function detected by neuroimaging and in neurocognitive studies. The present article is a meta-analysis of the existing evidence for the mechanisms underlying changes in the CNS and neurocognitive function in ALL survivors after treatment. We found that compared with controls, ALL survivors develop: (i) cognitive sequelae in intelligence, academics, attention, memory, processing speed and executive function domains; (ii) decreased grey and white matter volume in cortical and several subcortical brain regions, with functional changes particularly in frontal regions and the hippocampus; (iii) neurocognitive impairments related to CNS changes; and (iv) reduction, but not resolution, of late neurocognitive sequelae in patients in whom prophylactic irradiation was replaced by systemic/intrathecal chemotherapy. Continued work with advanced functional magnetic resonance imaging techniques will hopefully allow the detection of early CNS changes as biomarkers to help guide early diagnosis and intervention for neurocognitive defects in patients with childhood ALL.

Sluggish cognitive tempo in children with traumatic brain injuries

This exploratory study is the first to investigate whether the construct of sluggish-cognitive tempo (SCT) is related to slowed processing speed in children with traumatic brain injury (TBI), while also considering pre-morbid and injury variables. The study evaluated SCT, as measured by the Child Behavior Checklist (CBCL), and processing speed, as assessed with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV Processing Speed Index), in children who sustained TBI with a wide range of injury severity. Injury variables examined included the length of coma, presence of neuroimaging findings, and time between injury and assessment. Children's cognitive reserve, as estimated by parental level of education, was a non-injury variable. The participants included 50 children, ages 6-16 years, without co-morbid neurological or psychiatric conditions who underwent a neuropsychological evaluation within 1-12 months after injury. Results indicated no significant correlations between SCT and any of the WISC-IV index scores. Children with a moderate-severe TBI did not differ from those with uncomplicated mild TBI on SCT but they had statistically significant lower WISC-IV Processing Speed. Although parents of children with uncomplicated mild TBI had higher levels of education as compared to parents of children with moderate-severe TBI, there was no statistically significant relationship between the level of parental education and either SCT or Processing Speed. This study suggests that SCT, as measured by the CBCL, is not a sensitive measure of sequelae of pediatric TBI.

Predictors of neuropsychological late effects and white matter correlates in children treated for a brain tumor without radiation therapy

BACKGROUND

Little is known about cognition and predictors of neuropsychological outcomes in pediatric low-grade glioma (PLGG) survivors treated without radiation therapy. This research expands upon our previous work by further identifying the cognitive profile of PLGG patients treated without radiation therapy, investigating the specific medical and demographic variables that predict functioning, and examining white matter structure and its relationship to neuropsychological performance.

PROCEDURE

Nineteen PLGG patients (11-19 years) were administered the Wechsler Intelligence Scale for Children/Wechsler Adult Intelligence Scale, and subtests from the Woodcock-Johnson Tests of Cognition (visual matching, rapid picture naming, and pair cancellation) and Cambridge Neuropsychological Test Automated Battery (pattern recognition memory, delayed matching to sample, intra-extra dimensional set shift, motor screening task, rapid visual information processing, and spatial span).

RESULTS

The sample had normative weaknesses in verbal working memory, brief attention/vigilance, psychomotor speeded output, visual perception and matching, overall cognition, working memory, and processing speed. Increased surgeries or subtotal resections, hydrocephalus, shunting procedures, chemotherapy, NF1, and supratentorial location were predictive of cognitive deficits. Broad white matter involvement of the frontal, temporal, parietal, and occipital lobes as well as the cerebellum, as inferred from diffusion tensor imaging indices of decreased fiber orientation and increased water diffusion, was related to many cognitive difficulties.

CONCLUSIONS

This study comprehensively examines cognitive functioning in PLGG patients treated without radiation therapy, predictors of cognition, and its relation to white matter structure. Our findings indicate that medical and demographic variables other than radiation therapy can lead to cognitive late effects with diffuse white matter involvement.

Adaptive functioning in pediatric brain tumor survivors: An examination of ethnicity and socioeconomic status

BACKGROUND

Survivors of pediatric brain tumor are at risk for adaptive difficulties. The present study examined adaptive functioning in a multiethnic sample of survivors accounting for socioeconomic status, and whether demographic, diagnostic, and/or treatment-related variables predict adaptive outcomes.

METHOD

Participants included a multiethnic sample of survivors (58 Caucasian, 34 Hispanic, and 22 other non-Caucasian; M age = 14.05 years, SD = 4.33) who were approximately seven years post-treatment. Parents rated adaptive functioning and provided demographic information. Diagnostic and treatment-related information was abstracted from the electronic medical record.

RESULTS

Parent ratings of adaptive functioning were similar across Caucasian, Hispanic, and other non-Caucasian survivors covarying for family income and primary caregiver education, both of which served as proxies for socioeconomic status. All ethnic groups were rated lower than the normative mean in overall adaptive functioning as well as the specific domains of conceptual, social, and practical skills. Demographic, diagnostic, and treatment-related variables were differentially associated with adaptive functioning in survivors of pediatric brain tumor, though socioeconomic status emerged as a strong significant predictor of adaptive functioning domains.

CONCLUSIONS

Adaptive outcomes do not differ as a function of ethnicity after accounting for primary caregiver education and family income. Racial and ethnic minorities may be at increased risk for poorer outcomes given their overrepresentation at lower income levels. Assessing demographic and treatment-related variables early on may be helpful in identifying children likely to develop adaptive difficulties.

Interactions between visual working memory and visual attention among survivors of pediatric acute lymphoblastic leukemia (ALL) and their healthy peers

Introduction: There is increasing concern for adverse cognitive late effects among survivors of pediatric acute lymphoblastic leukemia (ALL) given the widespread impact they have on academic achievement, particularly working memory and attention. We assessed performance among survivors and their healthy peers on a dual task paradigm measuring visual working memory (VWM) and visual attention independently and the dynamic relationship between the two. Assessing specific subsets within cognitive domains allows for understanding the distinct nature of cognitive impairments. Method: Participants were 34 survivors of ALL who have been off-treatment and disease free for 7.5 years; and 20 healthy controls, all between the ages of 10 and 18 years. We utilized behavioral single- and dual-task paradigms. In the dual tasks, participants maintained several items in VWM while performing a visual attention task (Eriksen Flanker Task) that required processing of a target stimulus while inhibiting the processing of distractor stimuli. The single tasks involved performing only the VWM task or only the visual attention task. Results: Results revealed survivors of ALL performed significantly worse than their healthy peers on the single visual attention task but not the single VWM task. Of particular interest, group differences were obtained on the dual VWM and visual attention tasks, such that the VWM and attention tasks reciprocally interfered with each other only among survivors and not their healthy peers. Conclusions: Our results highlight a core deficit in visual attention that is exacerbated by VWM demands among survivors of ALL. The implementation of tasks from cognitive neuroscience paradigms may be sensitive to cognitive impairments experienced by cancer survivors. Assessment and intervention practices among survivors of pediatric ALL are discussed.

Brain morphology and information processing at the completion of chemotherapy-only treatment for pediatric acute lymphoblastic leukemia

Background: Approximately 50% of survivors of childhood acute lymphoblastic leukemia (ALL) demonstrate cognitive impairments. However, the trajectory of change and contributing neuropathology is unclear, limiting our ability to tailor intervention content and timing. This study aimed to explore information processing abilities and brain morphology early post-treatment for pediatric ALL. Procedure: Twenty-one children at the end of ALL treatment and 18 controls underwent neuropsychological assessment. A subset also completed structural magnetic resonance imaging. Results: A principal component analysis generated two cognitive factors: information processing capacity and information processing speed. Compared to control group, the ALL group displayed deficits in capacity, but not speed. No group differences were identified in morphology. No relationship was identified between capacity or speed and morphology. Conclusion: Early cognitive intervention should target information processing abilities using a system-wide approach. Future studies should employ alternative imaging techniques sensitive to white-matter microstructure when exploring pathology underlying information processing deficits.

Effect of Cognitive Reserve on Children With Traumatic Brain Injury

OBJECTIVES

Traumatic brain injury can result in cognitive impairments in children. The objective of this retrospective study was to determine to what extent such outcomes are moderated by cognitive reserve, as indexed by parental education.

METHODS

Sixty 6- to 16-year-old children completed the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V) within 30-360 days after having sustained a traumatic brain injury (TBI). Their Full-Scale IQ and factor index scores were compared to those of demographically matched controls. In addition, regression analysis was used to investigate in the TBI group the influence of injury severity in addition to parental education on WISC-V factor index scores.

RESULTS

Cognitive reserve moderated the effect of TBI on WISC-V Full Scale IQ, Verbal Comprehension, and Visual Spatial. In the TBI group, it also had a protective effect with regard to performance on the Verbal Comprehension, Visual Spatial, and Fluid Reasoning indices. At the same time, greater injury severity was predictive of lower Visual Spatial and Processing Speed index scores in the TBI group.

CONCLUSIONS

Cognitive reserve as reflected in parental education has a moderating effect with regard to children's performance on the WISC-V after TBI, such that higher cognitive reserve is associated with greater preservation of acquired word knowledge and understanding of visual relationships. Measures that emphasize speed of processing remain affected by severity of TBI, even after accounting for the protective effect associated with cognitive reserve. (JINS, 2019, 25, 355-361).

Neurocognitive and Neuroanatomical Changes in Children with Acute Lymphoblastic Leukemia Treated with the Modified BFM-95 Protocol

Background: The use of cranial radiotherapy for central nervous system (CNS) prophylaxis in children with acute lymphoblastic leukemia (ALL) is debated owing to its effect on neurocognitive functioning, as only <30% of the patients present with low risk in India and majority of the patients with high risk have to be treated with cranial radiation therapy (CRT) to prevent relapse. Given the increasing number of ALL survivors in India, the effect of CRT on neurocognitive functioning in children with ALL needs to be studied. Methods: Children (n = 44) with ALL who received CRT, intrathecal methotrexate (IT-MTX), and high-dose methotrexate (HD-MTX) for CNS prophylaxis as part of the modified Berlin-Frankfurt-Munster 95 protocol were included. Neurocognitive assessments and magnetic resonance image were performed to assess neurocognitive functioning and neuroanatomical structures, respectively. Five assessments were performed during the induction, end of re-induction I and II, commencement of maintenance, and end of maintenance phases of the modified BFM-95 protocol. Neurocognitive data of children with ALL were compared with those of healthy children (n = 60) at the baseline and after the final assessment. Results: A significant deterioration was observed in the performance intelligence, visuospatial ability, processing speed, and verbal retention domains after the completion of CNS prophylaxis. Three children had white matter changes on magnetic resonance imaging and showed reduced functioning in performance intelligence quotient, working memory, visual immediate and delayed memory, processing speed, verbal retention, visuospatial ability, processing speed, attention, planning and fine motor skills, and verbal comprehension. Children with ALL had poorer neuropsychological functioning when compared with healthy children. Conclusion: CNS prophylactic therapy as part of the BFM-95 protocol had an adverse effect on the neuropsychological functioning of children with ALL, and the effect was more pronounced when CRT was added to the treatment.

Pupillary response: cognitive effort for breast cancer survivors

PURPOSE

The purpose of this cross-sectional comparative pilot study was to evaluate cognitive effort, indexed by pupillary response (PR), for breast cancer survivors (BCS) with complaints of cognitive dysfunction following chemotherapy.

STUDY AIMS

Compare the cognitive effort employed by BCS to healthy controls (HC) during neuropsychological tests (NPT) for memory, sustained attention, verbal fluency, visuospatial ability, processing speed and executive function; and Investigate the relationship between PR-indexed cognitive effort and participants' self-report of cognitive function.

METHODS

Self-report of cognitive function was collected from 23 BCS and 23 HC. PR was measured during NPT. Independent two-sample t tests or Wilcoxon rank sum tests were used to compare group scores. Between-group effect size (Cohen's d) was calculated for each outcome. Correlation between mean self-report scores and PR values, as well as 95% confidence intervals, was calculated.

RESULTS

No group differences were demonstrated for NPT performance. BCS reported more issues with cognitive function than HC (p < .0001). A group effect for BCS was seen with PR-indexed cognitive effort for components of most NPT (p < .05). PR was correlated with most self-report measures of cognitive function (r = 0.33-0.45).

CONCLUSIONS

PR sensitivity to cognitive effort across a variety of NPT and correlation with self-report of cognitive function was demonstrated. The portability, affordability, and "real-time" aspects of PR are attractive for potential use in the clinic setting to assess cognitive function. A larger study is needed to confirm these results. Prospective investigation of PR in BCS is needed to demonstrate sensitivity to cognitive function changes over time.

Neurocognitive Outcomes and Interventions in Long-Term Survivors of Childhood Cancer

Recent research has demonstrated that survivors of childhood cancer are at risk for a myriad of late effects that affect physical and mental quality of life. We discuss the patterns and prevalence of neurocognitive problems commonly experienced by survivors of CNS tumors and acute lymphoblastic leukemia, the two most commonly researched cancer diagnoses. Research documenting the direct effects of tumor location and treatment type and intensity is presented, and patient characteristics that moderate outcomes (eg, age at diagnosis and sex) are discussed. Potential biologic mechanisms of neurotoxic treatment exposures, such as cranial irradiation and intrathecal and high-dose antimetabolite chemotherapy, are reviewed. Genetic, brain imaging, and neurochemical biomarkers of neurocognitive impairment are discussed. Long-term survivors of childhood cancer are also at risk for physical morbidity (eg, cardiac, pulmonary, endocrine) and problems with health behaviors (eg, sleep); research is reviewed that demonstrates these health problems contribute to neurocognitive impairment in survivors with or without exposure to neurotoxic therapies. We conclude this review with a discussion of literature supporting specific interventions that may be beneficial in the treatment of survivors who already experience neurocognitive impairment, as well as in the prevention of impairment manifestation.

Neurodevelopmental consequences of pediatric cancer and its treatment: applying an early adversity framework to understanding cognitive, behavioral, and emotional outcomes

Today, children are surviving pediatric cancer at unprecedented rates, making it one of modern medicine's true success stories. However, we are increasingly becoming aware of several deleterious effects of cancer and the subsequent "cure" that extend beyond physical sequelae. Indeed, survivors of childhood cancer commonly report cognitive, emotional, and psychological difficulties, including attentional difficulties, anxiety, and posttraumatic stress symptoms (PTSS). Cognitive late- and long-term effects have been largely attributed to neurotoxic effects of cancer treatments (e.g., chemotherapy, cranial irradiation, surgery) on brain development. The role of childhood adversity in pediatric cancer - namely, the presence of a life-threatening disease and endurance of invasive medical procedures - has been largely ignored in the existing neuroscientific literature, despite compelling research by our group and others showing that exposure to more commonly studied adverse childhood experiences (i.e., domestic and community violence, physical, sexual, and emotional abuse) strongly imprints on neural development. While these adverse childhood experiences are different in many ways from the experience of childhood cancer (e.g., context, nature, source), they do share a common element of exposure to threat (i.e., threat to life or physical integrity). Therefore, we argue that the double hit of early threat and cancer treatments likely alters neural development, and ultimately, cognitive, behavioral, and emotional outcomes. In this paper, we (1) review the existing neuroimaging research on child, adolescent, and adult survivors of childhood cancer, (2) summarize gaps in our current understanding, (3) propose a novel neurobiological framework that characterizes childhood cancer as a type of childhood adversity, particularly a form of early threat, focusing on development of the hippocampus and the salience and emotion network (SEN), and (4) outline future directions for research.

Anti-leukemic treatment-induced neurotoxicity in long-term survivors of childhood acute lymphoblastic leukemia: impact of reduced central nervous system radiotherapy and intermediate- to high-dose methotrexate

The aim of the study was to evaluate the long-term neurodevelopmental consequences of currently applied acute lymphoblastic leukemia (ALL) therapy containing chemotherapy alone or combined with 12 Gy radiotherapy. Seventy-nine children aged 6.3-21.7 years diagnosed with ALL and treated according to ALL IC-BFM 2002 have been studied. The control group consisted of 23 children newly diagnosed with ALL. We assessed subcortical gray matter volume using automatic MRI segmentation and cognitive performance to identify differences between three therapeutic schemes and patients prior to treatment. Irradiated patients had smaller selected subcortical volumes than those treated with chemotherapy alone and than the controls, while the chemotherapy group had similar volumes as the control one. In neurocognitive assessment, irradiated children performed worse in major domains than the control group. There were no significant results for patients after high dose chemotherapy without radiotherapy. There was a significant relationship between full scale IQ together with verbal learning and volumes of hippocampus, amygdala, and pallidum. In all children treated for ALL, both decreased volume of selected subcortical structures and cognitive impairment were observed, especially in children who were irradiated.

Changes in cognition and dendritic complexity following intrathecal methotrexate and cytarabine treatment in a juvenile murine model

Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer and accounts for 26.8% of cancer diagnoses among children, worldwide-approximately 3000 children each year. While advancements in treating ALL have led to a remission rate of more than 90%, many survivors experience adverse neurocognitive and/or neurobehavioral effects as a result of intrathecal chemotherapy. Methotrexate (MTX) is commonly administered with cytosine arabinoside (AraC, cytarabine) during intrathecal chemotherapy for ALL. To date, few studies exist that test the cognitive effects of intrathecal injections of MTX/AraC on juvenile populations. The purpose of our study was to investigate the combined effects of MTX/AraC on cognition and dendritic structure in the hippocampus in juvenile male mice. Twenty, 21-day-old male C57BL/6 mice were used in this study; 10 mice received intrathecal MTX/AraC treatment, and 10 were given intrathecal saline injections. Five weeks after injections, we tested the animals' hippocampus-dependent cognitive performance in the Morris water maze. After the first day of hidden-platform training, we observed that the mice that received MTX/AraC treatment showed signs of significant impairment in spatial memory retention. MTX/AraC treatment significantly compromised the dendritic architecture and reduced mushroom spine density in the dorsal ganglion (DG), CA1, and CA3 areas of the hippocampus. The present data provided evidence that MTX/AraC compromised the dendritic architecture and impaired hippocampal dependent cognition. This could provide insight into chemotherapy-induced cognitive decline in juvenile patients treated for ALL.

Abnormal topological organization in white matter structural networks in survivors of acute lymphoblastic leukaemia with chemotherapy treatment

Previous diffusion tensor imaging (DTI) studies have detected white matter (WM) integrity abnormalities in some specific fibre bundles in acute lymphoblastic leukaemia (ALL) patients with chemotherapy. However, little is known about the changes in the topological organization of the WM structural network in ALL patients with chemotherapy. In the present study, we acquired DTI datasets from 28 ALL patients (mean age: 40.71 ± 8.58 years, years since diagnosis: 7–38) with chemotherapy and 20 matched healthy controls (mean age: 42.95 ± 6.39 years) and performed WM network analysis using a deterministic fibre-tracking approach. Graph theoretical analysis was used to compare the topological parameters of the WM networks between the two groups. Both ALL patients with chemotherapy and healthy controls had small-worldness in their WM networks. ALL patients showed significantly reduced global network efficiency, as indicated by the abnormally decreased clustering coefficient Cp and the normalized clustering coefficient γ and increased shortest path length Lp compared with healthy controls. Moreover, hubs were located more in parietal regions of healthy controls and in temporal regions in the ALL patients. We revealed the abnormal topological organization of the WM networks of ALL patients with chemotherapy, which may improve our understanding of the neural mechanism of chemotherapy in ALL from a WM topological organization level.

The relationship between cognitive and neuroimaging outcomes in children treated for acute lymphoblastic leukemia with chemotherapy only: A systematic review

Cognitive late-effects have been identified in patients treated with chemotherapy-only protocols for childhood acute lymphoblastic leukemia (ALL), yet the underlying neuropathology is not well understood. This review synthesized recent findings from eight articles investigating the relationship between neurocognitive and neuroimaging outcomes for patients treated for ALL with chemotherapy-only protocols. Reported cognitive domains, imaging methods, and neuroanatomy examined were variable. Despite this, 62.5% (n = 5) of the reviewed studies found a significant relationship between cognitive and imaging outcomes. Greater understanding of the effects of treatment on neuroanatomy and cognitive outcomes is critical for proactively managing ALL cognitive late-effects. Research directions are suggested.

Long-term brain structural magnetic resonance imaging and cognitive functioning in children treated for acute lymphoblastic leukemia with high-dose methotrexate chemotherapy alone or combined with CNS radiotherapy at reduced total dose to 12 Gy

INTRODUCTION

The aim of this study was to assess the long-term side effects of central nervous system prophylaxis (high-dose chemotherapy alone vs chemotherapy and CNS radiotherapy) according to the ALL IC-BFM 2002.

METHODS

Thirty-tree children aged 6.7-19.9 years have been studied. The control group consisted of 12 children newly diagnosed with acute lymphoblastic leukemia. We assessed subcortical gray matter volume using automatic MRI segmentation and cognitive performance to identify differences between two therapeutic schemes and patients prior to treatment.

RESULTS

Patients treated with chemotherapy and CNS radiotherapy had smaller hippocampi than two other subgroups and lower IQ score than patients treated with chemotherapy alone. Both treated groups, whether with chemotherapy only or in combination with CNS radiotherapy, had significantly lower volumes of caudate nucleus and performed significantly worse on measures of verbal fluency in comparison with patients prior to treatment. There were no differences in the mean volumes of total white matter, total gray matter, thalamus, putamen, and amygdala between the studied groups.

CONCLUSION

In all children treated according to the ALL IC-BFM 2002 with high-dose chemotherapy, both decreased volume of selected subcortical structures and cognitive impairment was observed, especially in children who received chemotherapy in combination with reduced dose CNS radiotherapy. In all children treated according to the ALL IC-BFM 2002 with high-dose chemotherapy, both decreased volume of selected subcortical structures and cognitive impairment were observed, especially in children who received chemotherapy in combination with CNS radiotherapy.

The cognitive reserve theory in the setting of pediatric-onset multiple sclerosis

Background:

The study of cognitive reserve (CR) in relationship with cognitive impairment (CI) in pediatric-onset multiple sclerosis (POMS) may provide cues to identifying subjects at higher risk of impairment and scope for therapeutic strategies.

Objectives:

To assess the potential impact of CR on cognition in a cohort of POMS patients.

Methods:

In all, 48 POMS patients were followed up for 4.7 ± 0.4 years. CI was defined as the failure of ⩾3 tests on an extensive neuropsychological battery. Change of neuropsychological performance was assessed through the Reliable Change Index (RCI) method. At baseline, CR was estimated by measuring the intelligence quotient (IQ). The relationships were assessed through multivariable regression analyses.

Results:

At baseline, CI was detected in 14/48 (29.2%) patients. Two out of 57 healthy control (HC; 3.5%) met the same criteria of CI ( p < 0.001). A deteriorating cognitive performance using the RCI method was observed in 18/48 patients (37.6%). Among the 34 cases who were cognitively preserved at baseline, a higher reserve predicted stable/improving performance (odds ratio (OR) = 1.11; 95% confidence interval (CI): 1.03–1.20; p = 0.006).

Conclusion:

Our results suggest that higher CR in POMS patients may protect from CI, particularly in subjects with initial cognitive preservation, providing relevant implications for counseling and rehabilitation strategies.

Chemotherapy-induced neurotoxicity in pediatric solid non-CNS tumor patients: An update on current state of research and recommended future directions

Neurocognitive sequelae are known to be induced by cranial radiotherapy and central-nervous-system-directed chemotherapy in childhood Acute Lymphoblastic Leukemia (ALL) and brain tumor patients. However, less evidence exists for solid non-CNS-tumor patients. To get a better understanding of the potential neurotoxic mechanisms of non-CNS-directed chemotherapy during childhood, we performed a comprehensive literature review of this topic. Here, we provide an overview of preclinical and clinical studies investigating neurotoxicity associated with chemotherapy in the treatment of pediatric solid non-CNS tumors. Research to date suggests that chemotherapy has deleterious biological and psychological effects, with animal studies demonstrating histological evidence for neurotoxic effects of specific agents and human studies demonstrating acute neurotoxicity. Although the existing literature suggests potential neurotoxicity throughout neurodevelopment, research into the long-term neurocognitive sequelae in survivors of non-CNS cancers remains limited. Therefore, we stress the critical need for neurodevelopmental focused research in children who are treated for solid non-CNS tumors, since they are at risk for potential neurocognitive impairment.

Atypical Structural Connectome Organization and Cognitive Impairment in Young Survivors of Acute Lymphoblastic Leukemia

Survivors of pediatric acute lymphoblastic leukemia (ALL) are at increased risk for cognitive impairments that disrupt everyday functioning and decrease quality of life. The specific biological mechanisms underlying cognitive impairment following ALL remain largely unclear, but previous studies consistently demonstrate significant white matter pathology. We aimed to extend this literature by examining the organization of the white matter connectome in young patients with a history of ALL treated with chemotherapy only. We applied graph theoretical analysis to diffusion tensor imaging obtained from 31 survivors of ALL age 5-19 years and 39 matched healthy controls. Results indicated significantly lower small-worldness (p = 0.007) and network clustering coefficient (p = 0.019), as well as greater cognitive impairment (p = 0.027) in the ALL group. Regional analysis indicated that clustered connectivity in parietal, frontal, hippocampal, amygdalar, thalamic, and occipital regions was altered in the ALL group. Random forest analysis revealed a model of connectome and demographic variables that could automatically classify survivors of ALL as having cognitive impairment or not (accuracy = 0.89, p < 0.0001). These findings provide further evidence of brain injury in young survivors of ALL, even those without a history of central nervous system (CNS) disease or cranial radiation. Efficiency of local information processing, reorganization of hub connectivity, and cognitive reserve may contribute to cognitive outcome in these children. Certain connectome properties showed U-shaped relationships with cognitive impairment suggesting an optimal range of regional connectivity.

Monitoring and Assessment of Neuropsychological Outcomes as a Standard of Care in Pediatric Oncology

Central nervous system cancers or exposure to CNS-directed therapies increase risk for neuropsychological deficits. There are no accepted guidelines for assessment of neuropsychological functioning in this population. A multifaceted literature search was conducted and relevant literature reviewed to inform the guidelines. Studies of neuropsychological outcomes are widely documented in the pediatric oncology literature. There is strong evidence of need for neuropsychological assessment, but insufficient evidence to guide the timing of assessment, nor to recommend specific interventions. Children with brain tumors and others at high risk for neuropsychological deficits should be monitored and assessed for neuropsychological deficits.

Cortical surface area and thickness in adult survivors of pediatric acute lymphoblastic leukemia

BACKGROUND

Advances in the treatment of acute lymphoblastic leukemia (ALL) have led to great improvements in survival rates and outcomes, but there is concern about cognitive late effects. We aimed to determine whether ALL survivors have smaller cortical surface area and/or thickness, and test whether this is related to disease and treatment variables and self-reported executive functioning in everyday life.

PROCEDURE

Magnetic resonance imaging (MRI) scans from 130 adult long-term survivors of childhood ALL (age: 18-46 years; age at diagnosis: 0-16 years; years since diagnosis: 7-40) and 130 healthy controls were assessed to estimate and compare regional cortical surface area and thickness. Information on disease and treatment factors were obtained from patients' records, and executive functioning in survivors was measured using a validated questionnaire (BRIEF-A).

RESULTS

Smaller cortical surface area was observed in several regions in both cerebral hemispheres in ALL survivors. In these regions, mean surface area was 4.1-5.5% smaller in ALL survivors compared to healthy controls. In contrast, only one region showed lower cortical thickness in ALL survivors. There were no significant associations between cortical surface area/thickness in these regions and disease or treatment variables. In ALL survivors, smaller surface area in prefrontal regions, encompassing parts of the superior frontal gyri and the left anterior cingulate cortex, was associated with problems in executive functioning, specifically with emotional control and self-monitoring.

CONCLUSIONS

ALL survivors had smaller surface area in several cortical regions and smaller surface area in prefrontal regions was associated with reported problems in executive functioning.

Brain network alterations and vulnerability to simulated neurodegeneration in breast cancer

Breast cancer and its treatments are associated with mild cognitive impairment and brain changes that could indicate an altered or accelerated brain aging process. We applied diffusion tensor imaging and graph theory to measure white matter organization and connectivity in 34 breast cancer survivors compared with 36 matched healthy female controls. We also investigated how brain networks (connectomes) in each group responded to simulated neurodegeneration based on network attack analysis. Compared with controls, the breast cancer group demonstrated significantly lower fractional anisotropy, altered small-world connectome properties, lower brain network tolerance to systematic region (node), and connection (edge) attacks and significant cognitive impairment. Lower tolerance to network attack was associated with cognitive impairment in the breast cancer group. These findings provide further evidence of diffuse white matter pathology after breast cancer and extend the literature in this area with unique data demonstrating increased vulnerability of the post-breast cancer brain network to future neurodegenerative processes.