White matter compromise predicts poor intellectual outcome in survivors of pediatric low-grade glioma

BACKGROUND

While the impact of cranial radiation on white matter following treatment for pediatric brain tumor has been the focus of many recent studies, the effect of treatment in the absence of radiation has received little attention. The relations between white matter and cognitive outcome have not been explored in patients who have undergone radiation-free treatment. As most patients treated without cranial radiation survive long after their diagnosis, it is critical to identify factors that may impact structural and neurocognitive outcomes.

METHODS

Using diffusion tensor imaging, we examined white matter structure in 32 patients with pediatric low-grade glioma (PLGG) (19 with subtentorial location and 13 with supratentorial location) and 32 healthy participants. Indices of intellectual functioning were also evaluated. Radiation was not used to treat this cohort, aged 8-19 years.

RESULTS

We detected evidence of deficits in IQ and compromised supra- and subtentorial white matter in patients relative to healthy children (P < .05). Compromise of supratentorial white matter mediated the impact of treatment for PLGG on IQ. Greater white matter compromise was observed in patients who presented without multiple symptoms, were treated with biopsy/no surgery, had positive neurofibromatosis 1 status, were younger age at diagnosis, and whose parents had lower levels of education (P < .05).

CONCLUSIONS

Our findings provide evidence of increased risk of intellectual and white matter compromise in patients treated for PLGG without radiation. We identify a neural origin of cognitive deficit useful for predicting outcome and mitigating long-term adverse effects in pediatric brain tumor patients treated without cranial radiation.

Working memory abilities among children treated for medulloblastoma: parent report and child performance

OBJECTIVE

We investigated the 5-year postsurgical developmental trajectory of working memory (WM) in children with medulloblastoma using parent and performance-based measures.

METHOD

This study included 167 patients treated for medulloblastoma. Serial assessments of WM occurred at predetermined time points for 5 years.

RESULTS

There was a subtle, statistically significant increase in parental concern about WM, coupled with a statistically significant decrease in age-standardized scores on performance-based measures. However, whole-group mean scores on both parent and performance-based measures remained in the age-expected range. Posterior fossa syndrome was consistently associated with poorer WM. Younger age at treatment and higher treatment intensity were associated with greater negative change in WM performance only.

CONCLUSIONS

Most children treated for medulloblastoma display WM within the age-appropriate range according to parent report and performance. However, the subtle negative changes over time and identified subgroups at increased risk highlight the need for ongoing monitoring of this population.

Examination of risk factors for intellectual and academic outcomes following treatment for pediatric medulloblastoma

BACKGROUND

The aim of this study was to prospectively examine the effects of hearing loss and posterior fossa syndrome (PFS), in addition to age at diagnosis and disease risk status, on change in intellectual and academic outcomes following diagnosis and treatment in a large sample of medulloblastoma patients.

METHODS

Data from at least 2 cognitive and academic assessments were available from 165 patients (ages 3-21 years) treated with surgery, risk-adapted craniospinal irradiation, and 4 courses of chemotherapy with stem cell support. Patients underwent serial evaluation of cognitive and academic functioning from baseline up to 5 years post diagnosis.

RESULTS

Serious hearing loss, PFS, younger age at diagnosis, and high-risk status were all significant risk factors for decline in intellectual and academic skills. Serious hearing loss and PFS independently predicted below-average estimated mean intellectual ability at 5 years post diagnosis. Patients with high-risk medulloblastoma and young age at diagnosis (<7 years) exhibited the largest drop in mean scores for intellectual and academic outcomes.

CONCLUSIONS

Despite a significant decline over time, intellectual and academic outcomes remained within the average range at 5 years post diagnosis for the majority of patients. Future studies should determine if scores remain within the average range at time points further out from treatment. Patients at heightened risk should be closely monitored and provided with recommendations for appropriate interventions.

Physical functioning in pediatric survivors of childhood posterior fossa brain tumors

BACKGROUND

Survival rates for children diagnosed with posterior fossa brain tumors (PFBTs) have improved significantly over the past several decades, and long-term functioning assessments have become priorities. These evaluations have occurred frequently in adults but only rarely in children. This study describes a cross-sectional assessment of physical functioning in pediatric survivors of PFBTs using the Bruininks-Osteretsky Test of Motor Performance, Second Edition (BOT-2).

METHODS

Primary analyses compared BOT-2 scores to normative data using 1-sample t tests for each gross motor subscale (Bilateral Coordination, Balance, Running Speed/Agility, Strength) and motor-area composite (Body Coordination and Strength and Agility). Second, the cohort was stratified by diagnostic or treatment variables. Group differences and groups vs norms were evaluated using independent 2-sample and 1-sample t tests, respectively. Primary analyses compared BOT-2 scores with normative data using 1-sample t tests for each gross motor subscale (Bilateral Coordinationcoordination, Balance, Running Speed/Agility, Strength) and motor-area composite (Body Coordination and Strength and Agility). Second, the cohort was stratified by diagnostic or treatment variables. Group differences and groups vs norms were evaluated using independent 2-sample and 1-sample t tests, respectively.

RESULTS

Mean age of 30 participants was 11.4 years (range, 4.9y-18.2y), and mean time from diagnosis was 6.1 years (range, 1.1y-16.7y). Cerebellar astrocytoma (43.3%) and medulloblastoma (40%) were the most common diagnoses. As a group, significantly decreased functioning, compared with norms, was observed in Balance (P < .001) and Running Speed/Agility (P = .005). Specifically in Balance, 21 (70%) participants performed below or well-below average. Participants with a non-astrocytoma performed significantly lower than norms in all areas, independent of age at diagnosis. Survivors with tumors infiltrating the vermis demonstrated significantly lower Body Coordination than norms (P < .001).

CONCLUSIONS

Pediatric survivors of PFBTs demonstrated decreased physical functioning, most notably in Balance. These data underscore the need for further research and implementation of physical activity programs aimed specifically at approaches to minimize physical limitations.

Neural correlates of delayed visual-motor performance in children treated for brain tumours

Both structural and functional neural integrity is critical for healthy cognitive function and performance. Across studies, it is evident that children who are affected by neurological insult commonly demonstrate impaired cognitive abilities. Children treated with cranial radiation for brain tumours suffer substantial structural damage and exhibit a particularly high correlation between the degree of neural injury and cognitive deficits. However the pathophysiology underlying impaired cognitive performance in this population, and many other paediatric populations affected by neurological injury or disease, is unknown. We wished to investigate the characteristics of neuronal function during visual-motor task performance in a group of children who were treated with cranial radiation for brain tumours. We used Magnetoencephalography to investigate neural function during visual-motor reaction time (RT) task performance in 15 children treated with cranial radiation for Posterior Fossa malignant brain tumours and 17 healthy controls. We found that, relative to controls, the patient group showed: 1) delayed latencies for neural activation in both visual and motor cortices; 2) muted motor responses in the alpha (8-12Hz) and beta (13-29Hz) bandwidths, and 3) potentiated visual and motor responses in the gamma (30-100Hz) bandwidth. Collectively these observations indicate impaired neural processing during visual-motor RT performance in this population and that delays in the speed of visual and motor neuronal processing both contribute to the delays in the behavioural response. As increases in gamma activity are often observed with increases in attention and effort, increased gamma activities in the patient group may reflect compensatory neural activity during task performance. This is the first study to investigate neural function in real-time during cognitive performance in paediatric brain tumour patients.

Clinical and neuroanatomical predictors of cerebellar mutism syndrome

Cerebellar mutism syndrome (CMS) is an important medical challenge in the management of pediatric posterior fossa brain tumors, because it occurs in a subset of children following tumor resection. A definitive clinical profile and neuroanatomical substrate associated with CMS remains unclear. We investigated the relationship between presurgical and clinical variables and the incidence of CMS, along with diffusion tensor imaging, to characterize the integrity of cerebello-thalamo-cerebral white matter pathways. Seventeen children with posterior fossa tumors and CMS, 34 children with posterior fossa tumors without CMS, and 28 healthy children were enrolled in this study. Bilateral cerebello-thalamo-cerebral pathways were delineated and segmented into anatomical regions. Mean integrity measures for each region were compared among children with CMS, children without CMS, and healthy children. Left-handedness, medulloblastoma histology, and larger tumor size distinguished between patients with CMS and patients without CMS (P < .04). Right cerebellar white matter within the cerebello-thalamo-cerebral pathway was compromised in children with CMS relative to children without CMS and healthy children (P < .02). We provide a potential schema for CMS risk among children treated for posterior fossa tumors. Left-handed children treated for medulloblastoma may be the most at risk for CMS, and unilateral, localized damage within the cerebello-thalamo-cerebral pathway at the level of the right cerebellum is implicated in the presentation of CMS. This disruption in communication between the right cerebellum and left frontal cortex may contribute to speech-language problems observed in children with CMS. Our findings may be relevant for surgical planning and speech-language therapy to mitigate symptoms of CMS.

Impact of radiation avoidance on survival and neurocognitive outcome in infant medulloblastoma

Purpose

Concerns about radiotherapy-related neurocognitive sequelae in young children have led to deferral or avoidance of radiation in contemporary treatment for this fragile group of patients. We compared survival and neurocognitive outcome in two groups of infants with medulloblastoma who received adjuvant conventional craniospinal irradiation (csi) or reduced or no radiotherapy during an era of change in the philosophy of infant medulloblastoma treatment.

Patients and Methods

From 1985 to 2007, 29 patients 3 years of age or younger were diagnosed and treated with curative intent in our institution. Children treated before 1994 received adjuvant radiation with chemotherapy; subsequently, radiation was prescribed essentially for disease progression or relapse.

Results

Median age at diagnosis was 24 months (range: 1–36 months); 15 patients (52%) presented with metastatic disease at diagnosis. As part of initial treatment, 8 children received adjuvant radiotherapy with chemotherapy, and 21 children received postoperative chemotherapy only. Five children treated with chemotherapy alone are in prolonged remission. The 5-year event-free and overall survivals were 35.9% ± 9.8% and 50.2% ± 9.6% respectively. Extent of resection, metastatic status, and desmoplastic histology were not found to be significant prognostic factors.

On serial neurocognitive evaluations, patients treated with chemotherapy with or without reduced radiotherapy demonstrated improvement of intellectual function over time. Patients treated with conventional csi exhibited significantly lower intelligence quotient scores and academic performance, with the exception of receptive vocabulary.

Conclusions

Avoidance of conventional csi in treatment of very young children with medulloblastoma appears to be associated with a preserved neurocognitive profile. Neurocognitive evaluation should be integrated into the primary objectives of future infant protocols.

Early aging in adult survivors of childhood medulloblastoma: long-term neurocognitive, functional, and physical outcomes

Treatment for medulloblastoma during childhood impairs neurocognitive function in survivors. While those diagnosed at younger ages are most vulnerable, little is known about the long-term neurocognitive, functional, and physical outcomes in survivors as they approach middle age. In this retrospective cohort study, we assessed 20 adults who were treated with surgery and radiotherapy for medulloblastoma during childhood (median age at assessment, 21.9 years [range, 18-47 years]; median time since diagnosis, 15.5 years [range, 6.5-42.2 years]). Nine patients also underwent chemotherapy. Cross-sectional analyses of current neurocognitive, functional, and physical status were conducted. Data from prior neuropsychological assessments were available for 18 subjects; longitudinal analyses were used to model individual change over time for those subjects. The group was well below average across multiple neurocognitive domains, and 90% had required accommodations at school for learning disorders. Longer time since diagnosis, but not age at diagnosis, was associated with continued decline in working memory, a common sign of aging. Younger age at diagnosis was associated with lower intelligence quotient and academic achievement scores, even many years after treatment had been completed. The most common health complications in survivors were hearing impairment, second cancers, diabetes, hypertension, and endocrine deficiencies. Adult survivors of childhood medulloblastoma exhibit signs of early aging regardless of how young they were at diagnosis. As survival rates for brain tumors continue to improve, these neurocognitive and physical sequelae may become evident in survivors diagnosed at different ages across the lifespan. It will become increasingly important to identify factors that contribute to risk and resilience in this growing population.

White matter maturation in visual and motor areas predicts the latency of visual activation in children

In humans, white matter maturation is important for the improvement of cognitive function and performance with age. Across studies the variables of white matter maturity and age are highly correlated; however, the unique contributions of white matter to information processing speed remain relatively unknown. We investigated the relations between the speed of the visually-evoked P100m response and the biophysical properties of white matter in 11 healthy children performing a simple, visually-cued finger movement. We found that: (1) the latency of the early, visually-evoked response was related to the integrity of white matter in both visual and motor association areas and (2) white matter maturation in these areas accounted for the variations in visual processing speed, independent of age. Our study is a novel investigation of spatial-temporal dynamics in the developing brain and provides evidence that white matter maturation accounts for age-related decreases in the speed of visual response. Developmental models of cortical specialization should incorporate the unique role of white matter maturation in mediating changes in performance during tasks involving visual processing.

Neurocognitive outcome 12 months following cerebellar mutism syndrome in pediatric patients with medulloblastoma

The aim is to prospectively assess early neurocognitive outcome of children who developed cerebellar mutism syndrome (CMS) following surgical resection of a posterior fossa embryonal tumor, compared with carefully matched control patients. Children who were enrolled on an ongoing IRB-approved protocol for treatment of embryonal tumors, were diagnosed with postoperative CMS, and had completed prospectively planned neuropsychological evaluation at 12 months postdiagnosis were considered eligible. The cognitive outcomes of these patients were examined in comparison to patients without CMS from the same treatment protocol and matched with regard to primary diagnosis, age at diagnosis, and risk/corresponding treatment (n = 22 pairs). Seventeen were also matched according to gender, and 14 were also matched according to race. High-risk patients received 36-39.6 Gy CSI and 3D conformal boost to the primary site to 55.8-59.4 Gy. Average-risk patients received 23.4 Gy CSI and 3D conformal boost to the primary site to 55.8 Gy. Significant group differences were found on multiple cognitive outcomes. While the matched control patients exhibited performance in the average range, patients who developed CMS postsurgery were found to have significantly lower performance in processing speed, attention, working memory, executive processes, cognitive efficiency, reading, spelling, and math. Patients treated for medulloblastoma who experience postoperative CMS show an increased risk for neurocognitive impairment, evident as early as 12 months following diagnosis. This study highlights the need for careful follow-up with neuropsychological evaluation and for obtaining critical support for patients and their families.

Use of ifosfamide, carboplatin, and etoposide chemotherapy in choroid plexus carcinoma

OBJECT

Choroid plexus carcinomas (CPCs) are rare pediatric tumors with a generally poor prognosis. Although the role of surgery is well recognized, the role of adjuvant chemotherapy and radiation therapy remains unclear. In this paper, the authors' goal was to assess the role of second-look surgery and neoadjuvant ifosfamide, carboplatin, etoposide (ICE) chemotherapy in the management of CPC and to study neurocognitive outcome.

METHODS

The authors performed an institutional retrospective review of patients in whom CPC was diagnosed between 1985 and 2006 at the Hospital for Sick Children in Toronto. Fourteen patients (7 boys and 7 girls) were included. The median age at diagnosis was 18.6 months (range 1.1-65.3 months). Four patients had evidence of metastatic disease at diagnosis. Two of the 14 patients underwent gross-total resection during initial surgery; 12 of the patients received neoadjuvant chemotherapy, 10 of whom underwent second surgery. In total, of 12 patients who received chemotherapy with a curative intent, 11 underwent a greater than 95% resection. Neoadjuvant ICE chemotherapy was given prior to second surgery (median 4 cycles, range 2-5 cycles) and was continued after second resection for a median total of 7 cycles (range 4-16 cycles).

RESULTS

No tumor progression was observed during chemotherapy prior to second surgery. Five patients subsequently experienced tumor progression/relapse. At a median follow-up of 6.9 years (range 1.9-18.5 years), 8 patients are alive. None of the survivors received radiation therapy. However, 6 of 8 display significant neurocognitive and/or sensorial deficit.

CONCLUSIONS

In this experience, second surgery following neoadjuvant ICE chemotherapy led to a high rate of complete or near-complete resection. Chemotherapy appears to facilitate second-look surgery, in particular through a reduction of intraoperative blood loss. Despite radiation avoidance, the majority of survivors experienced significant neurocognitive impairment.

Bilateral diffusion tensor abnormalities of temporal lobe and cingulate gyrus white matter in children with temporal lobe epilepsy

PURPOSE

Bilateral diffusion tensor imaging (DTI) abnormalities have been reported in the white matter associated to the hippocampus in adults with mesial temporal lobe epilepsy (TLE). In children with a shorter duration of epilepsy, such changes may not have yet emerged. The aim of this study was to investigate interictal changes in the temporal lobe white matter (TLWM) and cingulate gyrus white matter (CGWM) of children with TLE using DTI.

METHODS

DTI was performed in eight children with TLE and 10 healthy, age-matched controls. Fractional anisotropy (FA), trace, parallel (lambda(||)) and perpendicular (lambda( perpendicular)) diffusivity were calculated for a volume of interest in the TLWM and CGWM on the seizure focus side and the contralateral side. Data were compared for differences between sides for patients and between patients and controls.

RESULTS

There was no significant difference in FA, trace, lambda(||) and lambda( perpendicular) between TLWM and CGWM on the seizure focus side versus the contralateral side in TLE patients. Increased diffusivity, lambda(||) and lambda( perpendicular) within the TLWM and CGWM were found in TLE patients compared to controls, but no significant difference in FA was seen.

CONCLUSIONS

Bilaterally increased diffusivity, lambda(||) and lambda( perpendicular) in the white matter in children with TLE may be related to seizure induced functional or structural changes. The preserved FA in our pediatric cohort is in contrast to the reduced FA in the white matter of adults with TLE and may relate to differences in the duration of epilepsy or in the vulnerability of white matter to seizures.

Computational skills, working memory, and conceptual knowledge in older children with mathematics learning disabilities

Knowledge and skill in multiplication were investigated for late elementary-grade students with mathematics learning disabilities (MLD), typically achieving age-matched peers, low-achieving age-matched peers, and ability-matched peers by examining multiple measures of computational skill, working memory, and conceptual knowledge. Poor multiplication fact mastery and calculation fluency and general working memory discriminated children with MLD from typically achieving age-matched peers. Furthermore, children with MLD were slower in executing backup procedures than typically achieving age-matched peers. The performance of children with MLD on multiple measures of multiplication skill and knowledge was most similar to that of ability-matched younger children. MLD may be due to difficulties in computational skills and working memory. Implications for the diagnosis and remediation of MLD are discussed.

Neurocognitive function in same-sex twins following focal radiation for medulloblastoma

Increased neurotoxicity and poor long-term neurocognitive outcome of preschool children treated for brain tumors have led to innovative therapeutic strategies in order to delay or avoid the use of craniospinal radiation and to improve survival. Because these protocols are relatively new, few data exist regarding cognitive outcome. We conducted a twin case-control study to investigate neurocognitive and behavioral outcome in a preschool patient who was 16 months old at diagnosis of medulloblastoma and was treated with surgery, chemotherapy, stem cell transplant, and focal radiation to the tumor bed. Stability and change over two assessments were compared for the patient and her nonaffected twin for standardized measures of cognitive function and experimental measures of parent-child interaction, social competence, and goal-directed play. A striking finding was improvement in intelligence, receptive language, and visual-motor functioning in the affected twin from 12 months to 24 months after treatment. Improvement in ratings of parent-child interaction and social competence for the affected twin was also evident. These findings are notable compared with the potentially devastating impact of craniospinal tumor, and this study is among the first to document the relative benefit of focal radiation in sparing cognitive function, albeit in a single case study.

White matter growth as a mechanism of cognitive development in children

We examined the functional role of white matter growth in cognitive development. Specifically, we used hierarchical regression analyses to test the unique contributions of age versus white matter integrity in accounting for the development of information processing speed. Diffusion tensor imaging was acquired for 17 children and adolescents (age range 6-17 years), with apparent diffusion coefficient (ADC) and fractional anisotropy (FA) calculated for 10 anatomically defined fiber pathways and 12 regions of hemispheric white matter. Measures of speeded visual-spatial searching, rapid picture naming, reaction time in a sustained attention task, and intelligence were administered. Age-related increases were evident across tasks, as well as for white matter integrity in hemispheric white matter. ADC was related to few measures. FA within multiple hemispheric compartments predicted rapid picture naming and standard error of reaction time in sustained attention, though it did not contribute significantly to the models after controlling for age. Independent of intelligence, visual-spatial searching was related to FA in a number of hemispheric regions. A novel finding was that only right frontal-parietal regions contributed uniquely beyond the effect of age in accounting for performance: age did not contribute to visual-spatial searching when FA within these regions was first included in the models. Considering we found that both FA in right frontal-parietal regions and speed of visual-spatial searching increased with age, our findings are consistent with the growth of regional white matter organization as playing an important role in increased speed of visual searching with age.

Diffusion tensor imaging of white matter after cranial radiation in children for medulloblastoma: correlation with IQ

Treatment of children with cranial-spinal radiation (CSR) for brain tumors is associated with adverse intellectual outcome and white matter damage. However, the correlation between IQ and measures of white matter integrity has received little attention. We examined apparent diffusion coefficient (ADC), fractional anisotropy (FA), and intelligence in pediatric patients treated with CSR for medulloblastoma relative to control subjects. ADC and FA measures were obtained for eight patients and eight control children and evaluated in multiple regions of interest in the cerebral hemispheres. Mean ADC and mean FA for each region were calculated, group differences were evaluated, and the relationship between these measures and intelligence were examined. In our study group, decreased IQ was associated with increased ADC and decreased FA (P < 0.01). Mean IQ for the CSR group was lower than that for the control group, but the difference was not significant when controlling for overall mean FA or ADC (P > 0.10). Overall mean FA was lower and ADC was higher in the CSR group relative to controls (P < 0.01). Specifically, FA was lower in the genu of the corpus callosum, the anterior and posterior limbs of the internal capsule, inferior frontal white matter, and high frontal white matter, and ADC was higher in all regions in patients relative to controls (P < 0.01). Compromised white matter integrity was observed for multiple regions within the cerebral hemispheres following CSR. A novel finding was that microscopic damage in normal-appearing white matter, as indexed by higher ADC and lower FA, was related to poor intellectual outcome relative to age-matched controls.

Pathological laughter and behavioural change in childhood pontine glioma

Children with pontine glioma usually present classically with ataxia, motor deficits and cranial nerve palsies. The pons has generally not been regarded as a structure that mediates complex affective behaviour. However, we report nine children who either at the time of presentation or progression demonstrated marked behavioural changes manifesting as either "pathological laughter" or separation anxiety in the form of school refusal. A mechanism of how pontine lesions can cause such complex affective and cognitive behaviour has been suggested to consist of the disruption of a network of cerebro-ponto-cerebellar pathways and the evidence for this mechanism is discussed.

Serial Evaluation of Academic and Behavioral Outcome After Treatment With Cranial Radiation in Childhood

Purpose

To evaluate academic and behavioral outcome in radiated survivors of posterior fossa (PF) tumors.

Patients and Methods

Fifty-three patients (36 males) treated for malignant PF tumors were seen for evaluation of academics and/or behavioral functioning. Forty-six patients were treated for medulloblastoma, and seven patients were treated for ependymoma. Fourteen patients were treated with reduced-dose cranial radiation, and 34 patients were treated with standard-dose cranial radiation (dose was not available for four patients). All patients received an additional boost to the PF. One patient was treated with PF radiation only. Standardized achievement tests and behavioral questionnaires were administered at different times after diagnosis for each child. First, the influence of demographic and medical variables on outcome was examined. Second, the rate of change in scores was determined using mixed model regression for patients seen for serial assessment.

Results

The presence of hydrocephalus was related to poorer academics, but outcome was not related to radiation dose, extent of surgery, or treatment with chemotherapy. Younger age predicted poor reading ability and lower parent rating of academic achievement. Children's performance declined for spelling, mathematics, and reading. Significant declines were also evident in parent and teacher's ratings of academic ability. Behavioral functioning was generally not related to medical and demographic variables, and few clinically significant problems in externalizing behavior were evident. Increases in social and attention problems emerged over time.

Conclusion

Cranial radiation is associated with declines in academic ability, social skills, and attention. However, neither psychological distress nor behavior problems were a significant concern for this sample.

Change in Neurocognitive Functioning After Treatment With Cranial Radiation in Childhood

Purpose

To evaluate the pattern of stability and change over time across multiple domains of neurocognitive function in radiated survivors of posterior fossa (PF) tumors.

Patients and Methods

Thirty-four children (25 males) treated for malignant PF tumors were observed with serial clinical neuropsychologic assessments. Thirty patients were treated for medulloblastoma and four patients were treated for ependymoma. Twelve patients were treated with reduced-dose and 21 patients were treated with standard-dose cranial radiation. All patients received an additional boost to the PF. One patient was treated with PF radiation only. Standardized neuropsychologic tests were administered at different times after diagnosis for each child. The rate of change in scores was determined using a mixed model regression.

Results

Results showed a 2- to 4-point decline per year in intelligence scores. For our relatively young sample, intellectual function declined quickly in the first few years after treatment, and then more gradually. Significant declines in visual-motor integration, visual memory, verbal fluency, and executive functioning were also documented. No decline was evident for verbal memory and receptive vocabulary.

Conclusion

Cranial radiation is associated with a decline in multiple neurocognitive domains, with a few notable exceptions. Our results must be interpreted in the context of common limitations of clinical research, including patient variability, changes in test versions, small sample size, and clinical referral bias.

Developmental change and individual differences in children's multiplication

Age-related change and patterns of individual differences in children's knowledge and skill in multiplication were investigated for students in Grades 4 and 6 (approximately ages 9 and 11, respectively) by examining multiple measures of computational skill, conceptual knowledge, and working memory. Regression analyses revealed that indexes reflecting probability of retrieval and special problem characteristics overshadow other, more general indexes (problem size and frequency of presentation) in predicting solution latencies. Some improvement in the use of conceptual knowledge was evident between Grades 4 and 6, but this change was neither strong nor uniform across tasks. Finally, patterns of individual differences across tasks differed as a function of grade level. The findings have implications for understanding developmental change and individual differences in mathematical cognition.

Memory in children with temporal or extra-temporal excisions

Memory was assessed before and after surgery in 44 children and adolescents with focal epilepsy who underwent either right temporal, left temporal or extra-temporal excisions. Measures included tests of verbal (story recall, and verbal list learning) and visually mediated (recall of a complex design, face recognition) memory. Changes in children's memory from pre- to post-operative assessment were examined and individual differences in outcome were evaluated. Although substantial variability existed in performance, no group differences or post-operative changes were found for measures of verbal memory or design recall. For face recognition, all groups improved after surgery, although children with right temporal resections performed more poorly than the other groups. Finally, with the exception of face recognition, no material-specific effects were observed before or after surgery.