Genome-wide analyses of individual differences in quantitatively assessed reading- and language-related skills in up to 34,000 people.

The use of spoken and written language is a fundamental human capacity. Individual differences in reading- and language-related skills are influenced by genetic variation, with twin-based heritability estimates of 30 to 80% depending on the trait. The genetic architecture is complex, heterogeneous, and multifactorial, but investigations of contributions of single-nucleotide polymorphisms (SNPs) were thus far underpowered. We present a multicohort genome-wide association study (GWAS) of five traits assessed individually using psychometric measures (word reading, nonword reading, spelling, phoneme awareness, and nonword repetition) in samples of 13,633 to 33,959 participants aged 5 to 26 y. We identified genome-wide significant association with word reading (rs11208009, P = 1.098 × 10-8) at a locus that has not been associated with intelligence or educational attainment. All five reading-/language-related traits showed robust SNP heritability, accounting for 13 to 26% of trait variability. Genomic structural equation modeling revealed a shared genetic factor explaining most of the variation in word/nonword reading, spelling, and phoneme awareness, which only partially overlapped with genetic variation contributing to nonword repetition, intelligence, and educational attainment. A multivariate GWAS of word/nonword reading, spelling, and phoneme awareness maximized power for follow-up investigation. Genetic correlation analysis with neuroimaging traits identified an association with the surface area of the banks of the left superior temporal sulcus, a brain region linked to the processing of spoken and written language. Heritability was enriched for genomic elements regulating gene expression in the fetal brain and in chromosomal regions that are depleted of Neanderthal variants. Together, these results provide avenues for deciphering the biological underpinnings of uniquely human traits.

Identification of brain cell types underlying genetic association with word reading and correlated traits.

Neuroimaging studies implicate multiple cortical regions in reading ability/disability. However, the neural cell types integral to the reading process are unknown. To contribute to this gap in knowledge, we integrated genetic results from genome-wide association studies for word reading (n = 5054) with gene expression datasets from adult/fetal human brain. Linkage disequilibrium score regression (LDSC) suggested that variants associated with word reading were enriched in genes expressed in adult excitatory neurons, specifically layer 5 and 6 FEZF2 expressing neurons and intratelencephalic (IT) neurons, which express the marker genes LINC00507, THEMIS, or RORB. Inhibitory neurons (VIP, SST, and PVALB) were also found. This finding was interesting as neurometabolite studies previously implicated excitatory-inhibitory imbalances in the etiology of reading disabilities (RD). We also tested traits that shared genetic etiology with word reading (previously determined by polygenic risk scores): attention-deficit/hyperactivity disorder (ADHD), educational attainment, and cognitive ability. For ADHD, we identified enrichment in L4 IT adult excitatory neurons. For educational attainment and cognitive ability, we confirmed previous studies identifying multiple subclasses of adult cortical excitatory and inhibitory neurons, as well as astrocytes and oligodendrocytes. For educational attainment and cognitive ability, we also identified enrichment in multiple fetal cortical excitatory and inhibitory neurons, intermediate progenitor cells, and radial glial cells. In summary, this study supports a role of excitatory and inhibitory neurons in reading and excitatory neurons in ADHD and contributes new information on fetal cell types enriched in educational attainment and cognitive ability, thereby improving our understanding of the neurobiological basis of reading/correlated traits.

Language and reading impairments are associated with increased prevalence of non-right-handedness.

Handedness has been studied for association with language-related disorders because of its link with language hemispheric dominance. No clear pattern has emerged, possibly because of small samples, publication bias, and heterogeneous criteria across studies. Non-right-handedness (NRH) frequency was assessed in N = 2503 cases with reading and/or language impairment and N = 4316 sex-matched controls identified from 10 distinct cohorts (age range 6-19 years old; European ethnicity) using a priori set criteria. A meta-analysis (Ncases  = 1994) showed elevated NRH % in individuals with language/reading impairment compared with controls (OR = 1.21, CI = 1.06-1.39, p = .01). The association between reading/language impairments and NRH could result from shared pathways underlying brain lateralization, handedness, and cognitive functions.

Cognitive and behavioral risk factors for low quality of life in survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: With high survival rates for pediatric acute lymphoblastic leukemia (ALL), long-term quality of life is a prominent consideration in treatment. We concurrently evaluated cognition, behavior, and quality of life in child and adolescent ALL survivors and determined associations between them. METHODS: The sample included 83 controls (mean age: 12.5 years) and 71 ALL survivors (mean age: 11.9 years, mean age at diagnosis: 3.8 years). Participants completed measures of general intellectual abilities, math achievement, and fine motor skills. Parents and teachers completed a survey assessing child participants' cognitive, behavioral, and emotional function. Parents additionally completed a survey about their child's quality of life. RESULTS: Survivors had lower scores on measures of working memory, processing speed, timed math, and fine motor skills (effect size 0.5-1, p < 0.001). Parents identified more problems with executive function and learning in survivors than controls (effect size > 0.7, p < 0.001), and indicated a lower quality of life in all categories evaluated (effect size > 0.7, p < 10-4). Reduced quality of life was associated with lower math achievement scores and with inattention and executive function problems. CONCLUSIONS: ALL survivors experience diffuse cognitive, behavioral, and motor impairments, which are associated with reduced quality of life. These findings underscore the need to address these challenges in ALL survivors. IMPACT: Compared with cancer-free peers, parents of childhood acute lymphoblastic leukemia survivors treated with chemotherapy only reported reduced quality of life. Math difficulties and behavioral problems increased the risk for reduced quality of life. Reduced quality of life is associated with mild cognitive and behavioral difficulties, suggesting that even relatively mild impairments have broad implications for ALL survivors. Screening and early intervention targeting cognitive and behavioral function may enhance quality of life for ALL survivors.

Survival and functional outcomes of molecularly defined childhood posterior fossa ependymoma: Cure at a cost.

BACKGROUND: Posterior fossa ependymoma (PFE) comprises 2 groups, PF group A (PFA) and PF group B (PFB), with stark differences in outcome. However, to the authors' knowledge, the long-term outcomes of PFA ependymoma have not been described fully. The objective of the current study was to identify predictors of survival and neurocognitive outcome in a large consecutive cohort of subgrouped patients with PFE over 30 years. METHODS: Demographic, survival, and neurocognitive data were collected from consecutive patients diagnosed with PFE from 1985 through 2014 at the Hospital for Sick Children in Toronto, Ontario, Canada. Subgroup was assigned using genome-wide methylation array and/or immunoreactivity to histone H3 K27 trimethylation (H3K27me3). RESULTS: A total of 72 PFE cases were identified, 89% of which were PFA. There were no disease recurrences noted among patients with PFB. The 10-year progression-free survival rate for all patients with PFA was poor at 37.1% (95% confidence interval, 25.9%-53.1%). Analysis of consecutive 10-year epochs revealed significant improvements in progression-free survival and/or overall survival over time. This pertains to the increase in the rate of gross (macroscopic) total resection from 35% to 77% and the use of upfront radiotherapy increasing from 65% to 96% over the observed period and confirmed in a multivariable model. Using a mixed linear model, analysis of longitudinal neuropsychological outcomes restricted to patients with PFA who were treated with focal irradiation demonstrated significant continuous declines in the full-scale intelligence quotient over time with upfront conformal radiotherapy, even when correcting for hydrocephalus, number of surgeries, and age at diagnosis (-1.33 ± 0.42 points/year; P = .0042). CONCLUSIONS: Data from a molecularly informed large cohort of patients with PFE clearly indicate improved survival over time, related to more aggressive surgery and upfront radiotherapy. However, to the best of the authors' knowledge, the current study is the first, in a subgrouped cohort, to demonstrate that this approach results in reduced neurocognitive outcomes over time.

Neurocognitive evaluation of long term survivors of atypical teratoid rhabdoid tumors (ATRT): The Canadian registry experience.

BACKGROUND: Because atypical teratoid rhabdoid tumor(ATRT) is a rare disease of infancy carrying a grim prognosis, focus on long-term outcome, especially neurocognitive remained very limited. With new era of multimodality therapy, an increasing proportion of patients are now long-term survivors. PROCEDURE: Retrospective review of neuropsychological (NP) status of survivors from the Canadian ATRT registry. RESULTS: Among 77 patients diagnosed between 1995-2012, 16(22%) were survivors. Formal NP assessments were available in eight patients. Partial information on academic achievement was available on three additional patients. There were four girls and seven boys diagnosed at a median age of 27.5 months. Seven patients underwent complete resection and three had metastatic disease. All but one received sequential high dose chemotherapy. Five patients received intrathecal chemotherapy. Three patients underwent radiation. Median age at time of formal NP assessment was 7.6 years (3.9-9.8). Full Scale Intellectual Quotient (FSIQ) ranged from less than 50-119 (mean 78). Simple expressive and receptive language appeared relatively preserved. Three recently diagnosed patients (median time assessment from diagnosis 2.6 years (1.6-4.7)) had average to high average FSIQ, academic and visual spatial skills, visual, and verbal memory. Five other patients diagnosed earlier and tested at a median time of 4.9 years (3.3-8.3) post-diagnosis had a FSIQ ranging from <50 to 71. Approximately 50% of their scores were in the impaired range. CONCLUSION: Overall this cohort appears significantly impaired at school age despite the absence of systematic radiotherapy. Larger series focusing on neurocognitive outcome are needed in the current context where treatment strategies include adjuvant radiation.

School attendance in childhood cancer survivors and their siblings.

OBJECTIVE: To investigate school absenteeism among childhood cancer survivors and their siblings and examine factors related to absenteeism in survivors. STUDY DESIGN: A cross-sectional study was conducted among consecutive cancer survivors attending a large pediatric cancer survivor clinic. Absenteeism rates were obtained for survivors and their closest in age sibling from school report cards. Absenteeism was compared with a population control group of 167752 students using 1-sample t tests. The Child Vulnerability Scale, Pediatric Quality of Life Inventory, and Behavior Assessment System for Children were administered to survivors. Univariate and multiple regression analyses assessed variables associated with days absent. RESULTS: One hundred thirty-one survivors (median age at assessment: 13.4 years, range 8.0-19.2; median age at diagnosis: 9.4 years, range 4.3-17.3) and 77 siblings (median age at assessment: 13 years, age range 7-18) participated. Survivors and siblings missed significantly more school days than the population control group (mean ± SD: 9.6 ± 9.2 and 9.9 ± 9.8 vs 5.0 ± 5.6 days, respectively, P < .0001). Among matched survivor-sibling pairs (N = 77), there was no difference in absenteeism (9.6 ± 9.2 vs 9.9 ± 9.8 days, P = .85). Absenteeism in survivors was significantly associated with a low Pediatric Quality of Life Inventory Physical Health Summary Score (P = .01). Parents' perception of their child's vulnerability and emotional and social functioning were not associated with absenteeism. CONCLUSIONS: Childhood cancer survivors and siblings miss more school than the general population. The only predictor of absenteeism in survivors is poor physical quality of health. More research should be devoted to school attendance and other outcomes in siblings of childhood cancer survivors.

Measuring what gets done: Using goal attainment scaling in a vocational counseling program for survivors of childhood cancer.

BACKGROUND: Childhood cancer survivors face education and employment challenges due to physical, cognitive, and psychosocial effects of the disease and treatments, with few established programs to assist them. The objectives of this study were to describe the implementation of Goal Attainment Scaling (GAS) to evaluate an educational and vocational counseling program established for survivors of childhood cancer, and analyze patterns of program engagement and client outcomes, stratified by demographic and diagnostic characteristics. METHODS: A population-based retrospective cohort study of childhood cancer survivors who were engaged with the Pediatric Oncology Group of Ontario's School and Work Transitions Program (SWTP) between January 2015 and December 2018 was utilized. Survivors were followed from SWTP engagement until May 30, 2019 to capture goal attainment. Individual goals were summarized across various demographic, disease, and treatment strata. RESULTS: In total, 470 childhood cancer survivors (median age = 17.9, 58% male) set 4,208 goals in the SWTP during the study period. The mean length of observation was 130.8 weeks (SD = 56.9). Overall, 68% of the goals were achieved. Eighty-three percent of the goals related to further education. Clients diagnosed with a solid tumor set the most goals on average, followed by those with central nervous system tumors and leukemia/lymphoma. CONCLUSIONS: The SWTP assists childhood cancer survivors in realizing their academic and vocational goals. Application of GAS in this setting is a feasible way to evaluate program outcomes. From the volume and breadth of the GAS goals set and achieved, the overall success of the SWTP appears strong.

High-frequency ultrasound-guided intrathecal injections in a young mouse model: Targeting the central nervous system in drug delivery.

BACKGROUND: Intrathecal injections provide important access to the central nervous system for delivery of anesthetic, analgesic or chemotherapeutic drugs that do not otherwise cross the blood-brain barrier. The administration of drugs via this route in animal models is challenging due to an inability to visualize the small target space during injection. Successful drug delivery therefore requires expertise in indirectly assessing vertebral and spinal cord anatomy and gaining advanced procedural skills. These factors are especially compounded in small animals such as mice (the most common mammalian model) and in investigations modeling pediatric drug delivery, where the animal is even smaller. NEW METHOD: To address these issues, we have developed a method in which high-frequency ultrasound imaging is used to visualize and target the lumbar intrathecal space for injections. The technique is demonstrated in mice as young as postnatal day 16. To evaluate the method, a gadolinium-based magnetic resonance imaging (MRI) contrast agent was injected intrathecally, and subsequent brain delivery was verified post-injection by MRI. RESULTS: Successful intrathecal injections of the MRI contrast agent showed distribution to the brain. In this study, we achieved a targeting success rate of 80% in 20 animals. COMPARISON WITH EXISTING METHODS AND CONCLUSION: We expect that the new method will be convenient for drug delivery to the central nervous system in rodent research and provide higher reliability than unguided approaches, an essential contribution that will enable intrathecal delivery in pediatric mouse models.

Hypothesis-driven genome-wide association studies provide novel insights into genetics of reading disabilities.

Reading Disability (RD) is often characterized by difficulties in the phonology of the language. While the molecular mechanisms underlying it are largely undetermined, loci are being revealed by genome-wide association studies (GWAS). In a previous GWAS for word reading (Price, 2020), we observed that top single-nucleotide polymorphisms (SNPs) were located near to or in genes involved in neuronal migration/axon guidance (NM/AG) or loci implicated in autism spectrum disorder (ASD). A prominent theory of RD etiology posits that it involves disturbed neuronal migration, while potential links between RD-ASD have not been extensively investigated. To improve power to identify associated loci, we up-weighted variants involved in NM/AG or ASD, separately, and performed a new Hypothesis-Driven (HD)-GWAS. The approach was applied to a Toronto RD sample and a meta-analysis of the GenLang Consortium. For the Toronto sample (n = 624), no SNPs reached significance; however, by gene-set analysis, the joint contribution of ASD-related genes passed the threshold (p~1.45 × 10-2, threshold = 2.5 × 10-2). For the GenLang Cohort (n = 26,558), SNPs in DOCK7 and CDH4 showed significant association for the NM/AG hypothesis (sFDR q = 1.02 × 10-2). To make the GenLang dataset more similar to Toronto, we repeated the analysis restricting to samples selected for reading/language deficits (n = 4152). In this GenLang selected subset, we found significant association for a locus intergenic between BTG3-C21orf91 for both hypotheses (sFDR q < 9.00 × 10-4). This study contributes candidate loci to the genetics of word reading. Data also suggest that, although different variants may be involved, alleles implicated in ASD risk may be found in the same genes as those implicated in word reading. This finding is limited to the Toronto sample suggesting that ascertainment influences genetic associations.

Impact of home-based cognitive or academic intervention on working memory and mathematics outcomes in pediatric brain tumor survivors: the Keys to Succeed pilot randomized controlled clinical trial.

Pediatric brain tumour survivors experience deficits in mathematics and working memory. An open question is whether it is most optimal to target direct cognitive skills (i.e. working memory) or focus on specific academic outcomes (i.e. mathematics) for in remediation. We conducted a pilot randomized controlled trial to determine the feasibility of comparing a working memory versus mathematics intervention. Pediatric brain tumor survivors (7-17 years) were randomly assigned to Cogmed or JumpMath interventions, or an Active Control/Reading group. All participants received Educational Liaison support and completed ~12-weeks of home-based intervention with weekly, telephone-based consultation in one of the three conditions. Standardized assessments of auditory and visual working memory, mathematics calculation and reasoning were completed pre- and post- intervention. Twenty-nine participants completed the interventions; 94% of parents reported a high degree of satisfaction with the interventions and ease of implementation. Participants in JumpMath demonstrated improved mathematics calculation from pre- to post- intervention (p=0.02). Further, participants in both Cogmed and JumpMath showed evidence of pre- to post- intervention improvements in auditory working memory relative to controls (p=0.01). The Cogmed group also showed improvements in visual working memory (p=0.03). Findings suggest that targeted intervention is feasible in survivors of pediatric brain tumors, though with a relatively low recruitment rate. With preliminary findings of improved calculation and working memory following JumpMath and working memory following Cogmed, this pilot trial lays the groundwork for future programs that investigate different inteCognitiveRehabilitationrventions that may be applied to target the unique needs of each survivor.

Language Difficulties in School-Age Children With Developmental Dyslexia.

Developmental dyslexia (DD) is a common reading disability, affecting 5% to 11% of children in North America. Children classified as having DD often have a history of early language delay (ELD) or language impairments. Nevertheless, studies have reported conflicting results as to the association between DD-ELD and the extent of current language difficulties in children with DD. To examine these relationships, we queried the parents of school-age children with reading difficulties on their child's early and current language ability. Siblings were also examined. Children were directly assessed using quantitative tests of language and reading skills. To compare this study with the literature, we divided the sample (N = 674) into three groups: DD, intermediate readers (IR), and skilled readers (SR). We found a significant association between DD and ELD, with parents of children in the DD/IR groups reporting their children put words together later than the SR group. We also found a significant association between DD and language difficulties, with children with low reading skills having low expressive/receptive language abilities. Finally, we identified early language predicted current language, which predicted reading skills. These data contribute to research indicating that children with DD experience language difficulties, suggesting early recognition may help identify reading problems.

Longitudinal evaluation of neurocognitive function after treatment for central nervous system germ cell tumors in childhood.

BACKGROUND: Central nervous system germ cell tumors (CNS GCT) are typically localized to midline structures of the brain, including the pineal and suprasellar/pituitary regions. Management of these tumors depends on underlying histology (germinoma or nongerminomatous germ cell tumor). Knowledge about neurocognitive outcome in these patients is limited. Longitudinal neurocognitive outcome in CNS GCT patients seen for neuropsychological evaluation at a single institution was explored. METHODS: Thirty-five patients were seen for neurocognitive evaluation after diagnosis and treatment for a CNS GCT. Mean age at diagnosis was 11.66 years. Tumor location was suprasellar in 12 patients, pineal in 9, bifocal in 10, multifocal in 3, and thalamic in 1. Standardized cognitive tests of intelligence, receptive language, visual-motor ability, memory, and academic achievement were administered. Longitudinal and cross-sectional analyses were conducted. RESULTS: Intelligence, academic functioning, and receptive vocabulary were not significantly compromised in most patients treated for CNS GCT. Working memory, information processing speed, and visual memory declined significantly over time in all patients. Patients with pineal tumors showed early and stable deficits, whereas patients with suprasellar and bifocal tumors showed more protracted declines from initial average functioning. Patients treated with ventricular versus craniospinal radiation displayed better outcome. CONCLUSIONS: Although general cognitive abilities appeared stable and intact after treatment for most children with CNS GCT, a significant decline over time in working memory, processing speed, and visual memory was evident. Tumor location appeared to be important in understanding the trajectory of stability and decline in CNS GCT patients, as did radiation field.

A theory-driven training programme in the use of emerging commercial technology: Application to an adolescent with severe memory impairment.

We describe a theory-driven memory intervention programme for training individuals with moderate to severe memory impairment in the use of emerging commercial technology. Here we demonstrate the application of the programme to training MK, an 18-year-old woman with severe memory impairment following treatment for a suprasellar germinoma, to autonomously use a smartphone to support her day-to-day memory. A within-subject A(1)B(1)A(2)B(2) single-case experimental design was used to evaluate the impact of smartphone use on MK's real-life functioning. Following intervention MK showed increased confidence in dealing with memory-demanding situations and generalised smartphone use across all aspects of her life as quantified by several and varied ecologically valid measures including a phone call schedule, behaviour memory observations and questionnaires. Moreover the intervention also benefited her family as indicated by a sustained reduction in caregiver strain and an increase in reported quality of life. These findings suggest that individuals with severe memory impairment, particularly young adults with potentially life-long dependence on their families, are able to capitalise on emerging commercial technology to function more autonomously. The findings also suggest that the gap between individuals with severe memory impairment and potent emerging technology can be closed by provision of a theory-driven structured training programme.

Genome-wide association study of word reading: Overlap with risk genes for neurodevelopmental disorders.

Reading disabilities (RD) are the most common neurocognitive disorder, affecting 5% to 17% of children in North America. These children often have comorbid neurodevelopmental/psychiatric disorders, such as attention deficit/hyperactivity disorder (ADHD). The genetics of RD and their overlap with other disorders is incompletely understood. To contribute to this, we performed a genome-wide association study (GWAS) for word reading. Then, using summary statistics from neurodevelopmental/psychiatric disorders, we computed polygenic risk scores (PRS) and used them to predict reading ability in our samples. This enabled us to test the shared aetiology between RD and other disorders. The GWAS consisted of 5.3 million single nucleotide polymorphisms (SNPs) and two samples; a family-based sample recruited for reading difficulties in Toronto (n = 624) and a population-based sample recruited in Philadelphia [Philadelphia Neurodevelopmental Cohort (PNC)] (n = 4430). The Toronto sample SNP-based analysis identified suggestive SNPs (P ~ 5 × 10-7 ) in the ARHGAP23 gene, which is implicated in neuronal migration/axon pathfinding. The PNC gene-based analysis identified significant associations (P < 2.72 × 10-6 ) for LINC00935 and CCNT1, located in the region of the KANSL2/CCNT1/LINC00935/SNORA2B/SNORA34/MIR4701/ADCY6 genes on chromosome 12q, with near significant SNP-based analysis. PRS identified significant overlap between word reading and intelligence (R2 = 0.18, P = 7.25 × 10-181 ), word reading and educational attainment (R2 = 0.07, P = 4.91 × 10-48 ) and word reading and ADHD (R2 = 0.02, P = 8.70 × 10-6 ; threshold for significance = 7.14 × 10-3 ). Overlap was also found between RD and autism spectrum disorder (ASD) as top-ranked genes were previously implicated in autism by rare and copy number variant analyses. These findings support shared risk between word reading, cognitive measures, educational outcomes and neurodevelopmental disorders, including ASD.

Quantitative MRI outcomes in child and adolescent leukemia survivors: Evidence for global alterations in gray and white matter.

INTRODUCTION: Cure rates for pediatric acute lymphoblastic leukemia (ALL) have reached an all-time high (>90%); however, neurocognitive difficulties continue to affect quality of life in at least a subset of survivors. There are relatively few quantitative neuroimaging studies in child and adolescent ALL survivors treated with chemotherapy only. Use of different outcome measures or limited sample sizes restrict our ability to make inferences about patterns of brain development following chemotherapy treatment. In this study, we used magnetic resonance imaging (MRI) to evaluate brain outcomes in ALL survivors, comparing against a group of typically developing, cancer free peers. MATERIALS AND METHODS: Participants included 71 ALL survivors, on average 8 years after diagnosis and 8-18 years of age, and 83 typically developing controls. Anatomical MRI was performed to evaluate brain structure; diffusion and magnetization transfer MRI were used to examine brain tissue microstructure. RESULTS: Successful MRI scans were acquired in 67 survivors (94%) and 82 controls (99%). Structurally, ALL survivors exhibited widespread reductions in brain volume, with 6% less white matter and 5% less gray matter than controls (p = 0.003 and 0.0006 respectively). Much of the brain appeared affected - 71 of 90 evaluated structures showed smaller volume - with the most notable exception being the occipital lobe, where no significant differences were observed. Average full-scale IQ in the survivor and control groups were 95 (CI 92-99) and 110 (CI 107-113), respectively. Using data from the NIH Pediatric MRI Data Repository, we evaluated the extent to which elevated IQ in the control group might affect the structural differences observed. We estimated that two thirds of the observed brain differences were attributable to ALL and its treatment. In addition to the structural changes, survivors showed, on average, globally lower white matter fractional anisotropy (-3%) and higher radial diffusivity (+5%) (p < 10-6), but no differences in magnetization transfer ratio. CONCLUSIONS: Neuroanatomical alterations in late childhood and adolescent ALL survivors treated with chemotherapy-only protocols are widespread, with white matter being somewhat more affected than gray matter. These MRI results indicate brain development is altered in ALL survivors and highlight the need to examine how these alterations emerge.

Brain Development and Heart Function after Systemic Single-Agent Chemotherapy in a Mouse Model of Childhood Leukemia Treatment.

PURPOSE: Chemotherapy for childhood acute lymphoblastic leukemia (ALL) can cause late-appearing side effects in survivors that affect multiple organs, including the heart and brain. However, the complex ALL treatment regimen makes it difficult to isolate the causes of these side effects and impossible to separate the contributions of individual chemotherapy agents by clinical observation. Using a mouse model, we therefore assessed each of eight representative, systemically-administered ALL chemotherapy agents for their impact on postnatal brain development and heart function. EXPERIMENTAL DESIGN: Mice were treated systemically with a single chemotherapy agent at an infant equivalent age, then allowed to age to early adulthood (9 weeks). Cardiac structure and function were assessed using in vivo high-frequency ultrasound, and brain anatomy was assessed using high-resolution volumetric ex vivo MRI. In addition, longitudinal in vivo MRI was used to determine the time course of developmental change after vincristine treatment. RESULTS: Vincristine, doxorubicin, and methotrexate were observed to produce the greatest deficiencies in brain development as determined by volumes measured on MRI, whereas doxorubicin, methotrexate, and l-asparaginase altered heart structure or function. Longitudinal studies of vincristine revealed widespread volume loss immediately following treatment and impaired growth over time in several brain regions. CONCLUSIONS: Multiple ALL chemotherapy agents can affect postnatal brain development or heart function. This study provides a ranking of agents based on potential toxicity, and thus highlights a subset likely to cause side effects in early adulthood for further study.

Characterizing neurocognitive late effects in childhood leukemia survivors using a combination of neuropsychological and cognitive neuroscience measures.

Knowledge about cognitive late effects in survivors of childhood acute lymphoblastic leukemia (ALL) is largely based on standardized neuropsychological measures and parent reports. To examine whether cognitive neuroscience paradigms provided additional insights into neurocognitive and behavioral late effects in ALL survivors, we assessed cognition and behavior using a selection of cognitive neuroscience tasks and standardized measures probing domains previously demonstrated to be affected by chemotherapy. 130 ALL survivors and 158 control subjects, between 8 and 18 years old at time of testing, completed the n-back (working memory) and stop-signal (response inhibition) tasks. ALL survivors also completed standardized measures of intelligence (Wechsler Intelligence Scales [WISC-IV]), motor skills (Grooved Pegboard), math abilities (WIAT-III), and executive functions (Delis-Kaplan Executive Function System). Parents completed behavioral measures of executive functions (Behavior Rating Inventory of Executive Function [BRIEF]) and attention (Conners-3). ALL survivors exhibited deficiencies in working memory and response inhibition compared with controls. ALL survivors also exhibited deficits on WISC-IV working memory and processing speed, Grooved Pegboard, WIAT-III addition and subtraction fluency, and numerical operations, as well as DKEFS number-letter switching. Parent reports suggested more attention deficits (Conners-3) and behavioral difficulties (BRIEF) in ALL survivors compared with referenced norms. Low correspondence between standardized and experimental measures of working memory and response inhibition was noted. The use of cognitive neuroscience paradigms complements our understanding of the cognitive deficits evident after treatment of ALL. These measures could further delineate cognitive processes involved in neurocognitive late effects, providing opportunities to explore their underlying mechanisms.

Neuroradiological findings of bleomycin leakage in cystic craniopharyngioma. Report of three cases.

Intracystic bleomycin therapy has been proposed as a treatment for predominantly cystic craniopharyngioma. The risks of using this therapy, however, have not been clearly identified. The authors report on three children treated with intracystic bleomycin who developed initially mild symptoms during their course of therapy. They describe the neuroimaging findings from computed tomography (CT) scans and magnetic resonance (MR) images and the medical management of these three cases. Two patients in whom craniopharyngioma was recently diagnosed and one patient with recurrent craniopharyngioma were treated with a course of 3 mg of intracystic bleomycin three times a week for 5 weeks, followed by once every week for 10 weeks. All patients had a negative reservoir permeability test prior to beginning intracystic bleomycin therapy. Patients were asymptomatic or had mild symptoms at the time of neuroimaging. Magnetic resonance images revealed extensive vasogenic edema surrounding the cyst in all three patients, consistent with signs of bleomycin leakage. The edema occurred near the time of the 12th injection in two patients, and at the end of treatment in the remaining patient. Subsequently, two patients developed further symptoms suggestive of hypothalamic injury. These two patients received corticosteroids, leading to a rapid and sustained clinical improvement. Follow-up serial MR images showed a progressive regression of the surrounding edema. Neuroimaging documentation of bleomycin toxicity has been described mainly in adults experiencing severe toxicity. There was no correlation between clinical symptoms and the extent of edema in these three patients. An MR image provides a higher resolution than CT scans for evaluating the adjacent cerebral structures and is very sensitive in detecting early abnormalities, even in asymptomatic patients. Bleomycin therapy requires close clinical monitoring. Imaging evaluation should be performed using MR imaging during treatment to ensure the safety of the therapy. In the authors' experience, the toxicity to bleomycin was transient. Management of the toxicity using high-dose steroid administration appears to contribute to controlling the bleomycin-induced inflammatory process.

Brain structure, working memory and response inhibition in childhood leukemia survivors.

INTRODUCTION: Survival rates for children with acute lymphoblastic leukemia (ALL) approach 95%. At the same time, there is growing concern that chemotherapy causes alterations in brain development and cognitive abilities. We performed MRI measurements of white and gray matter volume to explore how variation in brain structure may be related to cognitive abilities in ALL survivors and healthy controls. METHODS: The sample included 24 male ALL survivors who had completed contemporary treatment 3-11 years prior, and 21 age- and sex-matched controls. Participants were between 8 and 18 years old. Working memory and motor response inhibition were measured with the N-Back and Stop Signal Tasks (SST), respectively. Participants underwent 3T structural MRI to assess white and gray matter volumes overall, lobe-wise, and in cortical and atlas-identified subcortical structures. Mental health was assessed with the Child Behavioral Checklist. RESULTS: ALL survivors performed more poorly on measures of working memory and response inhibition than controls. Frontal and parietal white matter, temporal and occipital gray matter volume, and volumes of subcortical white and gray matter structures were significantly reduced in ALL survivors compared with controls. Significant structure-function correlations were observed between working memory performance and volume of the amygdala, thalamus, striatum, and corpus callosum. Response inhibition was correlated with frontal white matter volume. No differences were found in psychopathology. CONCLUSIONS: Compared with controls, a reduction in volume across brain regions and tissue types, was detectable in ALL survivors years after completion of therapy. These structural alterations were correlated with neurocognitive performance, particularly in working memory. Confirming these observations in a larger, more representative sample of the population is necessary. Additionally, establishing the time course of these changes-and the treatment, genetic, and environmental factors that influence them-may provide opportunities to identify at-risk patients, inform the design of treatment modifications, and minimize adverse cognitive outcomes.