Absence of synergistic effects of CNS treatments on neuropsychologic test performance among children.

Three hypotheses are proposed to account for neurobehavioral impairments following treatment with cranial radiation therapy (CRT) and intrathecal (IT) chemotherapy: CNS treatments exert a synergistic effect (A x B), an additive effect (A + B), or a single-agent effect (A or B). Eighty-five long-term survivors of non-CNS cancers aged 6 to 16 years were classified into groups on the basis of CNS treatments: CRT-IT (n = 25), CRT-No IT (n = 11), No CRT-IT (n = 24), and No CRT-No IT (n = 25). Study I findings did not provide support for synergistic mechanisms; nonorthogonal analysis of variance showed interaction effects (CRT x IT) restricted to tactile-perceptual speed. However, main effects were significant for a single agent (CRT) across a wide range of measures. General intelligence, academic achievement, verbal knowledge and reasoning, and perceptual-motor abilities were found to be significantly lower among CRT-treated groups. Study II findings provided additional support for the role of CRT; Pearson correlations within the CRT-No IT group indicated significant negative associations between CRT dose estimates for cortical regions and perceptual-motor abilities.

Neuropsychological effects of childhood cancer treatment.

The potential neuropsychological effects of treatment were investigated in 124 childhood cancer patients. Children were classified into groups on the basis of treatment modality and treatment status. All patients received systemic chemotherapy. Other treatment modalities included intrathecal chemotherapy and intrathecal chemotherapy plus central nervous system radiation therapy. Treatment status was determined by whether children were newly diagnosed patients in active treatment or long-term survivors of cancer. This classification resulted in five groups; group 1 (n = 29)--children with newly diagnosed disease who were receiving intrathecal chemotherapy; group 2 (n = 21)--children with newly diagnosed disease who were receiving systemic chemotherapy without central nervous system treatment; group 3 (n = 24)--long-term survivors who had received intrathecal chemotherapy; group 4 (n = 25)--long-term survivors who had received intrathecal chemotherapy plus cranial radiotherapy; and group 5 (n = 25)--long-term survivors who had received systemic chemotherapy only (no specific central nervous system treatment). Groups were compared by using multivariate analysis of variance on sets of neuropsychological test variables that represent major cognitive domains. Results of comparisons indicated significant group differences for most dependent-variable sets. Follow-up pairwise comparisons showed that the group of long-term survivors who had received intrathecal chemotherapy plus cranial radiotherapy consistently obtained lower test scores than the other four groups. These findings are consistent with results of previous studies, thus indicating that intrathecal chemotherapy plus cranial radiotherapy is associated with significant effects on neuropsychological performance. Comparisons among newly diagnosed and long-term groups of patients who did not receive cranial radiotherapy yielded null results on measures of higher-order cognitive functions. However, significant group differences were observed on measures of fine-motor and visual-motor skills; newly diagnosed groups obtained lower scores than the nonirradiated long-term survivor groups. Findings were attributed to chemotherapy-induced peripheral neuropathy that differentially affected the newly diagnosed groups.

A prospective study of neuropsychological sequelae in children with brain tumors.

Surgery and radiotherapy are the primary modalities of treatment for pediatric brain tumors. Despite the widespread use of these treatments, little is known of their acute effects (within one year posttreatment) on neuropsychological functions. An understanding of acute treatment effects may provide valuable feedback to neurosurgeons and a baseline against which delayed sequelae may be evaluated. This study compares pre- and posttherapy neuropsychological test performance of pediatric brain tumor patients categorized into two groups on the basis of treatment modalities: surgery (n = 7) and radiotherapy (n = 7). Treatment groups were composed of children aged 56 to 196 months at the time of evaluation with heterogeneous tumor diagnoses and locations. Comparisons of pretherapy findings with normative values using confidence intervals indicated that both groups performed within the average range on most measures. Outstanding deficits at baseline were observed on tests of fine-motor, psychomotor, and timed language skills, and are likely to be attributable to tumor-related effects. Comparisons of pre- versus posttherapy neuropsychological test findings indicated no significant interval changes for either group. Results suggest that surgery and radiotherapy are not associated with acute effects on neuropsychological functions.

Normal pressure hydrocephalus. Influences on cerebral hemodynamic and cerebrospinal fluid pressure--chemical autoregulation.

Blood flow in the cerebral gray matter was measured in normal pressure hydrocephalus and Alzheimer disease by 133Xe inhalation. Flow values in the frontal and temporal gray matter increased after lowering cerebrospinal fluid (CSF) pressure by lumbar puncture in normal pressure hydrocephalus (p less than 0.05) and also after shunting. One case with cerebral complications did not improve clinically. In Alzheimer disease the reverse (decreases in flow in the gray matter) occurred after removal of CSF. Normal pressure hydrocephalus was associated with impaired cerebral vasomotor responsiveness during 100% oxygen and 5% carbon dioxide inhalation. This complication was restored toward normal after CSF removal and/or shunting. Cerebral blood flow measurements appear to be useful for confirming the diagnosis of normal pressure hydrocephalus and predicting the clinical benefit from shunting.

Cerebral pathology and neuropsychological effects. Differential effects of cranial radiation as a function of age.

Cranial radiation therapy (CRT) has been associated with an increased incidence of neuropsychological impairments and pathologic changes in the CNS among children. However, findings regarding a causal relationship between CRT and neurobehavioral impairments and the differential impact of CRT as a function of treatment age have been equivocal. Inconsistent findings may be attributed to the current research focus on description of impairments to the neglect of a larger theoretical framework and the failure of investigators to integrate findings from the various disciplines involved in assessing CRT effects. Two theories regarding the etiology of CRT effects on neuropsychological functions have been proposed. The myelination hypothesis suggests that CRT effects are attributable to direct effects on myelin synthesis. Findings indicating that the child is in a state of particular vulnerability to teratogens due to the rapid growth phase of myelin during the first 48 months of life provide the basis for this hypothesis. The myelination hypothesis predicts a differential effect for CRT as a function of age/maturation. The vascular hypothesis proposes that CRT effects are due to pathological changes in vascular tissues. Results indicating prominent white matter changes among some CRT recipients provide the basis for this hypothesis. The vascular hypothesis predicts no age effect or an inverse age effect; it places more emphasis on the relationship between indices of cerebral blood flow and neuropsychological test performance. Two basic mechanisms underlying the effects of CRT are outlined to provide a theoretical framework on which future research may be based.(ABSTRACT TRUNCATED AT 250 WORDS)

Survival and neurologic outcome of infants with medulloblastoma treated with surgery and MOPP chemotherapy. A preliminary report.

The results of treatment of infants with medulloblastoma using surgery and chemotherapy, without the use of radiation therapy, are reported. Both survival and outcome, in terms of growth, neurologic deficit, and intelligence are compared with the same parameters in children treated conventionally. Although preliminary, our results suggest that chemotherapy combined with surgery is a valid option for the treatment of infants with this type of neoplasm.

Cerebral blood flow and brain atrophy correlated by xenon contrast CT scanning.

Correlations between cerebral blood flow (CBF) measured during stable xenon contrast CT scanning and standard CT indices of brain atrophy were investigated in the patients with senile dementia of Alzheimer type, multi-infarct dementia and idiopathic Parkinson's disease. Compared to age-matched normal volunteers, significant correlations were found in patients with idiopathic Parkinson's disease between cortical and subcortical gray matter blood flow and brain atrophy estimated by the ventricular body ratio, and mild to moderate brain atrophy were correlated with stepwise CBF reductions. However, in patients with senile dementia of Alzheimer type and multi-infarct dementia, brain atrophy was not associated with stepwise CBF reductions. Overall correlations between brain atrophy and reduced CBF were weak. Mild degrees of brain atrophy are not always associated with reduced CBF.