Non-adherence in pediatric transplantation: a review of the existing literature.

The degree of medical adherence in pediatric solid-organ transplant recipients frequently correlates with the degree of psychological distress, family functioning, and the physiological side-effects of immunosuppressant medications. This article examines the current literature regarding each of these factors and proposes recommendations for increasing the medical compliance among childhood transplant recipients.

Neurocognitive deficits in medulloblastoma survivors and white matter loss.

Although previous studies have documented a significant risk of intellectual loss after treatment for childhood medulloblastoma (MED), the pathophysiology underlying this process is poorly understood. The purpose of this study was to test the hypotheses that (1) patients treated for MED in childhood have reduced volumes of normal white matter (NWM) related to their treatment with craniospinal irradiation with or without chemotherapy, and (2) deficits in NWM among patients surviving MED can at least partially explain deficits in their intellectual performance. Eighteen pediatric patients previously treated for MED were matched on the basis of age at the time of evaluation to 18 patients previously treated for low-grade posterior fossa tumors with surgery alone (mean difference, 3.7 months). Evaluations were conducted with age-appropriate neurocognitive testing and quantitative magnetic resonance imaging by using a novel automated segmentation and classification algorithm constructed from a hybrid neural network. Patients treated for MED had significantly less NWM (p < 0.01) and significantly lower Full-Scale IQ values than those treated for low-grade tumors (mean, 82.1 vs 92.9). In addition, NWM had a positive and statistically significant association with Full-Scale IQ among the patients treated for MED. We conclude that irradiation- or chemotherapy-induced destruction of NWM can at least partially explain intellectual and academic achievement deficits among MED survivors.

A hybrid neural network analysis of subtle brain volume differences in children surviving brain tumors.

In the treatment of children with brain tumors, balancing the efficacy of treatment against commonly observed side effects is difficult because of a lack of quantitative measures of brain damage that can be correlated with the intensity of treatment. We quantitatively assessed volumes of brain parenchyma on magnetic resonance (MR) images using a hybrid combination of the Kohonen self-organizing map for segmentation and a multilayer backpropagation neural network for tissue classification. Initially, we analyzed the relationship between volumetric differences and radiologists' grading of atrophy in 80 subjects. This investigation revealed that brain parenchyma and white matter volumes significantly decreased as atrophy increased, whereas gray matter volumes had no relationship with atrophy. Next, we compared 37 medulloblastoma patients treated with surgery, irradiation, and chemotherapy to 19 patients treated with surgery and irradiation alone. This study demonstrated that, in these patients, chemotherapy had no significant effect on brain parenchyma, white matter, or gray matter volumes. We then investigated volumetric differences due to cranial irradiation in 15 medulloblastoma patients treated with surgery and radiation therapy, and compared these with a group of 15 age-matched patients with low-grade astrocytoma treated with surgery alone. With a minimum follow-up of one year after irradiation, all radiation-treated patients demonstrated significantly reduced white matter volumes, whereas gray matter volumes were relatively unchanged compared with those of age-matched patients treated with surgery alone. These results indicate that reductions in cerebral white matter: 1) are correlated significantly with atrophy; 2) are not related to chemotherapy; and 3) are correlated significantly with irradiation. This hybrid neural network analysis of subtle brain volume differences with magnetic resonance may constitute a direct measure of treatment-induced brain damage.

The effect of Achievement orientation on response to success and failure in pediatric cancer patients.

OBJECTIVE: To assess the effects of different cognitive orientations focused on social comparison or self-comparison, followed by success or failure feedback, on mood, task persistence, and task difficulty choice in children with cancer. METHOD: Children with cancer (N = 79) and a group of age-matched controls (N = 72 were randomly assigned in a 2 (Achievement Orientation) x 2 (Feedback) between-subjects design. RESULTS: Between-group differences revealed that children with cancer chose more difficult tasks for the future than those in the comparison group, while the comparison subjects chose to persist longer with the problems than did children with cancer, with no significant differences on measures of mood. CONCLUSIONS: The beneficial effects of achievement orientation as a clinical manipulation may not be as robust as expected with a medically ill population, due to the apparent stability of achievement orientations.

Psychological functioning of adolescent and young adult survivors of pediatric malignancy.

OBJECTIVE: To assess the psychological functioning of adolescent and young adult survivors of pediatric malignancy, and identify risk factors for maladjustment. DESIGN: Patients age > or = 14.5 years (N = 161) receiving surveillance follow-up at a major pediatric cancer center completed the SCL-90-R, a self-report measure of psychological symptomatology. Comparisons were made with the normative standardization sample, and the relationship of selected demographic and medical variables with psychological distress was explored using logistic regression analyses. RESULTS: Survivors mean scores on all SCL-90-R subscales were lower than those of the standardization sample, and the distribution of scores on the Anxiety, Psychoticism, Global severity Index, and Positive Symptom Total scales were significantly below normative values. No SCL-90-R subscale displayed an excessive frequency of clinically elevated scores. For patients who displayed clinical elevations on the SCL-90-R, three factors were identified which were associated with increased risk of maladjustment; older patient age at follow-up, more frequent disease relapse, and more severe functional impairment. CONCLUSIONS: This cohort of childhood cancer survivors is characterized by very low levels of psychological distress and significantly better psychological health than would be expected according to normative data. These findings contrast with those of another study from the same institution in which a fourfold increase in social and behavioral problems was found amongst younger survivors, in the age range 7-15. The use of self-report vs. parent-report, and the potential influence of repressive adaptation on the self-reports of pediatric cancer survivors, are raised as possible explanations for these findings.

Automated segmentation and classification of multispectral magnetic resonance images of brain using artificial neural networks.

We present a fully automated process for segmentation and classification of multispectral magnetic resonance (MR) images. This hybrid neural network method uses a Kohonen self-organizing neural network for segmentation and a multilayer backpropagation neural network for classification. To separate different tissue types, this process uses the standard T1-, T2-, and PD-weighted MR images acquired in clinical examinations. Volumetric measurements of brain structures, relative to intracranial volume, were calculated for an index transverse section in 14 normal subjects (median age 25 years; seven male, seven female). This index slice was at the level of the basal ganglia, included both genu and splenium of the corpus callosum, and generally, showed the putamen and lateral ventricle. An intraclass correlation of this automated segmentation and classification of tissues with the accepted standard of radiologist identification for the index slice in the 14 volunteers demonstrated coefficients (ri) of 0.91, 0.95, and 0.98 for white matter, gray matter, and ventricular cerebrospinal fluid (CSF), respectively. An analysis of variance for estimates of brain parenchyma volumes in five volunteers imaged five times each demonstrated high intrasubject reproducibility with a significance of at least p < 0.05 for white matter, gray matter, and white/gray partial volumes. The population variation, across 14 volunteers, demonstrated little deviation from the averages for gray and white matter, while partial volume classes exhibited a slightly higher degree of variability. This fully automated technique produces reliable and reproducible MR image segmentation and classification while eliminating intra- and interobserver variability.