Human intelligence: the brain, an electromagnetic system synchronised by the Schumann Resonance signal

The human brain is a biological organ. On one hand it is soft, flexible and adaptive, but on the other hand is relatively stable and coherent with well developed intelligence. In order to retain intelligent thinking in a soft and adaptive organ there needs to be a constant, globally available, synchronization system that continuously stabilizes the brain. Rapid intelligence and reactions requires and electromagnetic signalling system, supported by a biochemical system. The Schumann Resonance signal provides a brain frequency range matching electromagnetic signal, providing the synchronization needed for intelligence.

Predicting Intellectual Outcome Among Children Treated With 35-40 Gy Craniospinal Irradiation for Medulloblastoma

Fifty children diagnosed with medulloblastoma completed 188 psychological evaluations using the Wechsler Intelligence Scales for Children (D. Wechsler, 1974, 1991) over a 7-year study period following 35-40 Gy postoperative craniospinal irradiation. Random coefficient models were used to predict the trend in the children's intellectual performance as a function of time since diagnosis, with both patient and treatment variables as parameters of this function. A quadratic model demonstrated a delay prior to decline in performance for older patients, whereas the younger patients showed an immediate loss of performance with a plateau at approximately 6 years postdiagnosis. A steeper decline was found for those with higher baseline performance. Clinicians may use the proposed predictive model to identify those patients who are at risk of significant intellectual decline.

Craniopharyngioma: the St. Jude Children's Research Hospital experience 1984-2001

PURPOSE

To review our institution's experience in the treatment of craniopharyngioma and assess the merits of initial therapy with limited surgery and irradiation.

METHODS AND MATERIALS

The data of 30 patients (median age 8.6 years) with a diagnosis of craniopharyngioma between April 1984 and September 1997 were reviewed. Their course of treatment, neurologic, endocrine, and cognitive function, and quality of life at last follow-up were compared.

RESULTS

Fifteen patients were initially treated with surgery (8 required irradiation after relapse) and 15 with limited surgery and irradiation (2 required additional treatment for tumor progression). Only 1 patient died of tumor progression. The surgery group lost a mean of 9.8 points in full-scale IQ, and the combined-modality group lost only 1.25 points (p <0.063). Patients in the surgery group who had relapses (n = 9) lost a mean of 13.1 points (p <0.067). A loss of 10 points was considered clinically significant. The surgery group also had more frequent neurologic, ophthalmic, and endocrine complications. The mean Health Utility Index (a functional quality-of-life index) was higher for the combined-modality group (0.85) than for the surgery group (0.71; p <0.063, one-sided t test).

CONCLUSIONS

The acute neurologic, cognitive, and endocrine effects of surgery often affect long-term function and quality of life. Our experience suggests that limited surgery and radiotherapy cause lesser or comparable sequelae. Diabetes insipidus was the only endocrine deficiency that differed substantially in frequency between the two groups. Newer radiation planning and delivery techniques may make a combined-modality approach a good initial option for most patients.

[Assessment of cognitive function after preventive and therapeutic whole brain irradiation using neuropsychological testing]

PURPOSE

Aim of this study was the assessment of neuropsychological changes after whole brain irradiation.

PATIENTS AND METHOD

64 patients were tested before, and 29 after whole brain irradiation, including 28 patients with small cell lung cancer (SCLC) before prophylactic cranial irradiation (PCI) and 36 patients with cerebral metastases before therapeutic cranial irradiation (TCI), as well as 14 patients after PCI and 15 after TCI (Table 1). Intelligence, attention and memory were assessed applying a 90-minute test battery of standardized, neuropsychological tests (Table 3).

RESULTS

Patients with SCLC showed test results significantly below average before PCI (n = 28, mean IQ = 83, SD = 17). Neither after PCI, nor after TCI the tested neuropsychological functions decreased significantly (Tables 4, 5). A comparison between SCLC-patients with and without cerebral metastases before whole brain irradiation showed better test-results in patients with cerebral metastases and fewer cycles of preceding chemotherapy (Table 7).

CONCLUSION

Neuropsychological capacity in patients with SCLC was impaired even before PCI. Possible reason is the preceding chemotherapy. Whole brain irradiation did not induce a significant decline of cognitive functions in patients with PCI or TCI. A decline in a longer follow-up nevertheless seems possible.

[Pregnancy and medical irradiation; summary and conclusions from the International Commission on Radiological Protection, Publication 84]

Prenatal exposure to ionising radiation as used during most diagnostic procedures generally presents no increased risk of prenatal death, malformation or impairment of mental development (i.e. deterministic effects) compared to the background incidence of these entities. Higher doses of radiation used in therapeutic procedures can result in significant foetal harm. In general, malformations only occur above a threshold dose of 100-200 mGy. These doses are not normally reached with most properly executed diagnostic procedures. During the period from 8 to 25 weeks after conception, the central nervous system is particularly sensitive to radiation. Foetal doses in excess of about 100 mGy may result in a decrease in IQ. Between 8-15 weeks after conception, a foetal dose of 1000 mGy (1 Gy) reduces IQ by about 30 points. This reduction is less marked during the period from 16-25 weeks. At foetal doses of 1000 mGy in the period from 8 to 15 weeks after conception the risk of severe mental retardation is about 40%. During the period from 16 to 25 weeks, this risk is practically zero at a dose of 1000 mGy. Radiation exposure of the embryo/foetus is associated with an increased risk of tumour induction (stochastic effect). Recent absolute risk estimates for fatal cancer risk for ages 0-15 year after in utero irradiation have been estimated to be 6% per Gy (0.06% per 10 mGy). For the whole life span this risk is about 15% per Gy (0.15% per 10 mGy). Pre-conception irradiation of either parent's gonads has not been shown to result in increased cancer or malformations in the children.

[Neuropsychological sequelae in children with AML treated with or without prophylactic CNS-irradiation]

BACKGROUND

In study AML-BFM 87 the relapse rate was lower in patients receiving cranial irradiation (CRT). However, CRT has always been associated with adverse cognitive side effects. Therefore, the impact of CRT on neuropsychological function in children with AML was retrospectively evaluated.

PATIENTS

We tested 53 children (30 boys, 23 girls) treated according to the AML-BFM-87 protocol (median age at diagnosis: 8.5 years, range 0.3 - 17.5; median time since diagnosis: 5.7 yrs, 3.8 - 10.7 yrs). To avoid any bias from additional therapy elements, patients with relapse or initial CNS involvement and transplanted patients were excluded (n=32). Our cohort was representative of the total group of 104 long term survivors of study AML-BFM 87. CNS prophylaxis consisted of ARA-C i.th., high dose ARA-C i. v. and either no CRT (n=15) or CRT (n=38) at a dose of 12 - 18 Gy depending on age.

METHODS

Neuropsychological function was evaluated by psychological tests of attention and concentration (test d2 by Brickenkamp) and an intelligence test (Progressive Matrices by Raven). In addition, patients and their parents were interviewed about the occurrence of learning problems, subjective deficits in concentration and physical impairment.

RESULTS

In the total group, no significant differences were seen between irradiated and non-irradiated patients regarding the psychological tests. However, the irradiated patients scored below the non-irradiated control group in test "d2" (concentration: 41st vs. 59th percentile). In the interview, irradiated patients tended to report more learning problems (lp) (10/36 vs. 1/14; p=0.15) and subjective deficits in concentration (con). In irradiated girls (con: 6/15 vs. 0/8; p=0.06; lp: 5/15 vs. 0/8; p=0.12) and younger patients (0 - 5 years at diagnosis; con: 7/12 vs. 2/9; p=0.18; lp 3/10 vs. 1/9; p=0.18) this trend was even more pronounced.

CONCLUSION

Children with AML and CRT had no significant intellectual impairment in standardized tests when compared to non-irradiated patients. However, more irradiated patients reported learning problems and subjective concentration deficits.

Intellectual outcome after reduced-dose radiation therapy plus adjuvant chemotherapy for medulloblastoma: a Children's Cancer Group study

PURPOSE

To investigate the intellectual outcomes of children with medulloblastomas/primitive neuroectodermal tumors (MB/PNET) treated with reduced-dose craniospinal radiotherapy (RT) plus adjuvant chemotherapy.

PATIENTS AND METHODS

Forty-three children with average-risk posterior fossa MB/PNETs underwent longitudinal intelligence testing. All had been treated with a reduced-dose craniospinal RT regimen (23.4 Gy to the neuraxis, 32.4-Gy boost to the posterior fossa) and adjuvant chemotherapy.

RESULTS

The estimated rate of change from baseline was significant for Full Scale Intelligence Quotient (FSIQ), Verbal IQ (VIQ), and Nonverbal IQ (NVIQ) (P <.001 for all three outcomes). The rate of change was estimated to be -4.3 FSIQ points per year, -4.2 VIQ points per year, and -4.0 NVIQ points per year. Females were more subject to VIQ decline than were males (P =.008), and young children (< 7 years of age) were more negatively affected than were older children, with a significant decline in NVIQ (P =.016). Finally, patients with higher baseline evaluations suffered greater declines in IQ than did those with lower baseline scores.

CONCLUSION

This study represents the largest series of patients with average-risk MB/PNETs treated with a combination of reduced-dose RT and adjuvant chemotherapy whose intellectual development has been followed prospectively. Intellectual loss was substantial but suggestive of some degree of intellectual preservation compared with effects associated with conventional RT doses. However, this conclusion remains provisional, pending further research.

Learning difficulties in children treated for acute lymphoblastic leukaemia (ALL)

Concern about the adverse affects of brain irradiation used in treatment for childhood leukaemia on children's learning have been put forward since the 1960s. Early work based on assessment of IQ suggested considerable problems associated with CNS irradiation of 2400cGy, and that children who were younger on diagnosis (below 5 years) were particularly at risk. Consequently, new protocols were introduced in which the amount of irradiation was reduced, or children were treated by chemotherapy alone. There is some evidence that reduction from 2400 to 1800cGy irradiation is beneficial, especially for younger children, as is treatment by chemotherapy alone. Methodological problems in conducting this work and limitations in relying on IQ tests are discussed. Where there are no indications of differences in survival, there would seem to be implications for reducing as far as possible the use of CNS directed therapy among young children treated for leukaemia.

Prospective evaluation of delayed central nervous system (CNS) toxicity of hyperfractionated total body irradiation (TBI)

PURPOSE

Prospective evaluation of chronic radiation effects on the healthy adult brain using neuropsychological testing of intelligence, attention, and memory.

METHODS AND MATERIALS

58 patients (43 +/- 10 yr) undergoing hyperfractionated total body irradiation (TBI) (TBI, 14.4 Gy, 12 x 1.2 Gy in 4 days) before bone marrow or peripheral blood stem cell transplantation were prospectively included. Twenty-one recurrence-free long-term survivors were re-examined 6-36 months (median 27 months) after completion of TBI. Neuropsychological testing included assessment of general intelligence, attention, and memory using normative, standardized psychometric tests. Mood status was controlled, as well. Test results are given as IQ scores (population mean 100) or percentiles for attention and memory (population mean 50).

RESULTS

The 21 patients showed normal baseline test results of IQ (101 +/- 13) and attention (53 +/- 28), with memory test scores below average (35 +/- 21). Test results of IQ (98 +/- 17), attention (58 +/- 27), and memory (43 +/- 28) showed no signs of clinically measurable radiation damage to higher CNS (central nervous system) functions during the follow-up. The mood status was improved.

CONCLUSION

The investigation of CNS toxicity after hyperfractionated TBI showed no deterioration of test results in adult recurrence-free patients with tumor-free CNS. The median follow-up of 27 months will be extended.

Processing speed, working memory, and IQ: a developmental model of cognitive deficits following cranial radiation therapy

IQ decrements following cranial radiation therapy (CRT) for acute lymphoblastic leukemia (ALL) are most apparent years after treatment. The authors examined a developmental model for delayed deficits by evaluating the relationship between processing speed, working memory, and IQ in long-term survivors of childhood ALL (n = 27) compared with demographically matched controls (n = 27). The ALL group treated with CRT showed deficits in IQ, working memory, and processing speed relative to controls. Differences in IQ between the CRT group and controls were mediated by differences in working memory. Processing speed did not fully account for the working memory deficit in the CRT group. Participants with ALL treated only with chemotherapy showed similar working memory and processing speed as matched controls. Data suggest that deficits in processing speed and working memory following CRT may underlie declines in IQ.

EEG, cognitive and psychopathological abnormalities in children irradiated in utero

Computerised EEG, a clinical neuropsychiatric examination, and IQ tests were examined in 50 randomly selected prenatally irradiated 9-10-year-old children and compared with 50 randomly selected non-exposed control children of the same age. In the prenatally irradiated children a disorganised EEG-pattern with slow and paroxysmal activity (acute and high-voltage delta-waves, sometimes: spike-waves) in the left fronto-temporal region was disclosed. There was also a significant predominance of delta- and beta (dominant frequency: 20 Hz)-power in the frontal lobe, particularly, in the left fronto-temporal region, together with depressed spectral theta-power. The more disorganised EEG-patterns were observed in those children exposed at 8-15 weeks of prenatal development, while left-hemisphere abnormalities were more typical for those exposed later at 16-25 weeks of gestation. There was also a significant increase of borderline and low range (70-90) IQ scores and a significant decrease of high verbal (> 110) IQ scores. Disorders of psychological development, particularly specific developmental disorders of speech, language, and scholastic skills were more common and correlated with left-sided slow- and fast-wave activity. Behavioural and emotional disorders (social estrangement, exhaustion, emotional lability, tearfulness, apathy) were also more common and associated with a L > R imbalance in arousal. We hypothesise that the cerebral basis of mental disorders in the prenatally irradiated children is the malfunction of the left hemisphere limbic-reticular structures, particularly in those exposed at the most critical period of cerebrogenesis (16-25 weeks of gestation). We propose that the left hemisphere is more vulnerable to prenatal irradiation than the right.

Long-term intellectual outcome in children with posterior fossa tumors according to radiation doses and volumes

PURPOSE

To analyze the relationship between craniospinal irradiation (CSI) and intellectual outcome in children with posterior fossa (PF) tumors.

METHODS AND MATERIALS

A neuropsychological evaluation was performed retrospectively in 31 children, aged 5-15 years, who had received radiotherapy for PF tumors, and who had been off therapy for at least 1 year. Factors evaluated for impact on intellectual outcome were: socioeconomic status, disease presentation, histology, complications, chemotherapy, age at radiotherapy, interval between radiotherapy and testing, and radiation doses and volumes. Patients were divided into 3 subgroups according to the CSI doses (0 Gy [i.e., PF irradiation only], 25 Gy, and 35 Gy), with 11, 11, and 9 patients, respectively.

RESULTS

Long-term cognitive impairment occurred in most of the patients, even after PF irradiation only. Moreover, there was a significant correlation between the full-scale IQ score (FSIQ) and the CSI dose, with mean FSIQ scores at 84.5 (SD = 14.0), 76.9 (SD = 16.6), and 63.7 (SD = 15.4) for 0 Gy, 25 Gy, and 35 Gy of CS1, respectively. A marked drop in verbal comprehension scores was noted in children who had received the higher dose.

CONCLUSION

This preliminary study further supports the rationale for de-escalation of CSI doses and volumes in standard-risk PF tumors.

Cognitive function and prenatal exposure to ionizing radiation

It is clear from the many studies of the prenatally exposed survivors of the atomic bombing of Hiroshima and Nagasaki that exposure to ionizing radiation during gestation has harmful effects on the developing human brain, particularly if that exposure occurs at critical stages in the development of the neocortex. Data on a variety of measures of cognitive function, including the occurrence of severe mental retardation as well as variation in the intelligence quotient (IQ) and school performance, show significant effects on those survivors exposed 8-15 weeks and 16-25 weeks after ovulation. Studies of seizures, primarily those without known precipitating cause, also exhibit a radiation effect on those individuals exposed in the first 16 weeks after ovulation. The cellular and molecular events that subtend these abnormalities are still largely unknown although some progress toward an understanding has occurred. For example, magnetic resonance imaging of the brain of some of the mentally retarded survivors has revealed a large region of abnormally situated gray matter, suggesting an abnormality in neuronal migration, but cell killing could also contribute importantly to the effects on cognitive function that have been seen. The retardation of growth in stature observed in individuals exposed in the first and second trimesters of pregnancy suggests that the development of an atypically small head size, without conspicuously impaired cognitive function, may reflect a generalized retardation of growth.

Preirradiation evaluation and technical assessment of involved-field radiotherapy using computed tomographic (CT) simulation and neoadjuvant chemotherapy for intracranial germinoma

PURPOSE

To investigate the importance of preirradiation mental and endocrinological evaluation, and the effectiveness of involved-field radiotherapy following neoadjuvant chemotherapy.

METHODS AND MATERIALS

Following etoposide and cisplatin with or without ifosfamide, 13 patients with nondisseminated disease received involved-field irradiation of 24 Gy in 12 fractions within 3 weeks and 2 patients with disseminated germinoma received 24 Gy craniospinal irradiation (CSI). CT simulation was used to cover the tumor bed.

RESULTS

Full-scale intelligence quotient (IQ) tests given at the time of the initial radiotherapy showed less than 90 in 7 of 11 patients who had tumors involving the neurohypophyseal region, but the 4 patients who had solitary pineal tumors showed higher scores. Panhypopituitarism was observed in 9 patients with tumors involving the neurohypophyseal region. All patients are alive without disease, with a median follow-up period of 40 months. No in-field relapse was noted after the involved-field radiotherapy. One patient experienced a recurrence outside of the planning target volume.

CONCLUSION

Decline of neurocognitive and endocrine functions were often seen in patients with tumors involving the hypophyseal region, but not in patients with solitary pineal germinoma before radiotherapy. Involved-field radiotherapy using 24 Gy is effective with the help of CT simulation and neoadjuvant chemotherapy.

The psychological development of children from Belarus exposed in the prenatal period to radiation from the Chernobyl atomic power plant

This study examined psychological development in 138 children at the age of 6-7 and 10-11 years, who had suffered prenatal radiation exposure at the time of the Chernobyl accident in 1986. These children were compared to a control group of 122 children of the same age from noncontaminated areas of Belarus. The examination included neurological and psychiatric examination, intellectual assessment, and clinical psychological investigation of parents as well as the estimation of thyroid exposure in utero. The exposed group manifested a relative increase in psychological impairment compared with the control group, with increased prevalence in cases of specific developmental speech-language disorders (18.1% vs. 8.2% at 6-7 years; 10.1% vs. 3.3% at 10-11 years) and emotional disorders (20.3% vs. 7.4% at 6-7 years; 18.1 vs. 7.4% at 10-11 years). The mean IQ of the exposed group was lower than that of the control group, and there were more cases of borderline IQ (IQ = 70-79) (15.9% vs. 5.7% at 6-7 years; and 10.1% vs. 3.3% at 10-11 years). The mean value of thyroid doses from 131I 0.4 Gy was estimated for children exposed in utero. No correlation was found between individual thyroid doses and IQ at age 6-7 years or 10-11 years. We notice a positive moderate correlation between IQ of children and the educational level of their parents. There was a moderate correlation between high personal anxiety in parents and emotional disorders in children. We conclude that a significant role in the genesis of borderline intellectual functioning, specific developmental disorders of speech, language and scholastic skills, as well as emotional disorders in the exposed group of children was played by unfavourable social-psychological and social-cultural factors such as a low educational level of parents, the break of microsocial contacts, and adaptational difficulties, which appear following the evacuation and relocation from the contaminated areas.

Assessment of neuropsychological changes in patients with arteriovenous malformation (AVM) after radiosurgery

PURPOSE

The purpose of this study was to investigate neuropsychological effects of radiosurgery in patients with cerebral arteriovenous malformation (AVM), with special focus on attention and memory. This report describes the study setup and presents the first results during a follow-up of up to 1 year.

MATERIALS AND METHODS

Seventy-nine patients were studied before, acutely after radiosurgery, and during the regular follow-up (subacute phase: Weeks 6-12, chronic phase: Months 6-12). Radiosurgery was performed using a modified linear accelerator (minimum doses to the target volume: 15-22 Gy, median 20 Gy). Estimated whole brain dose was 0.5 to 2 Gy. Neuropsychological testing included assessment of general intelligence (Wechsler Adult Intelligence Scale), attention (modified Trail-Making Test A, Digit Symbol Test, D2 Test, Wiener Determination Machine) and memory (Rey Auditory Verbal Learning Test, Benton Visual Retention Test). During follow-up, alternate test versions were used. Neuropsychological deficits were defined as a test score of at least one standard deviation (SD) below the mean of the normal distribution.

RESULTS

The pretherapeutic evaluation revealed marked deviations from the normal population; 24% had deficits in intelligence (range 23-31% in different subtests), attention (35%, 23-59%) and memory (48%, 31-61%). The overall percentage of aberrant results was reduced by 12% (memory) to 14% (attention) in the chronic phase up to 12 months after therapy. The improvement in test scores was significant (p < 0.05) in 3 of 4 subtests of attention functions.

CONCLUSIONS

The acute tolerance of radiosurgery seems to be very good in these patients, showing no relevant increase in number of patients with neuropsychological deficits. Although the long-term follow-up needs to be further increased, our data indicate a tendency to slight improvement in the overall neuropsychological performance of AVM patients in the chronic phase after radiosurgery.

Psychophysiologic aftereffects of prenatal irradiation

Prenatally irradiated children (n = 544), who were born between 26 April 1986 and 26 February 1987, in regions of the Ukraine which were radioactively contaminated as a result of the Chernobyl disaster, their mothers and teachers have been examined with psychometric tests. The control group of relevant children (n = 759), their mothers and teachers, were living at the radioecological 'clear' regions (Kharkov and Kharkov Region). Further, we randomly selected 50 prenatally irradiated children whose mothers were evacuated from the Chernobyl exclusion zone and 50 age-and-gender-matched non-exposed children. At this phase clinical examinations, psychometric tests, computerized EEG, thyroid function assessment and dosimetric reconstruction were used. We found a significant increase in mental retardation (IQ < 70) and of borderline and low range IQ, as well as emotional and behavioral disorders and a decrease in high IQ (IQ > 110) in children irradiated in utero as a result of the Chernobyl disaster, in comparison with the controls. One important biological mechanism in the genesis of mental disorders in prenatally irradiated children is the radiation-induced malfunction of the thyroid-pituitary system with the effect threshold of 0.30 Sv of thyroid exposure dose. We hypothesize that the cerebral basis of mental disorders in the prenatally irradiated children is the malfunction of the left hemisphere limbic-reticular structures, particularly in those exposed at the most critical period of cerebrogenesis (8-25 weeks of gestation). The data obtained reveal mental disorders in prenatally irradiated children and obviously reflect developmental abnormalities of brain structure and function as a result of the interaction of prenatal and post-natal factors where it is possible to assume radiation effects on the developing brain. A follow-up study of the children irradiated in utero, who may be at risk for schizophrenia, is proposed because of its particular importance to clinical medicine and neuroscience.

[Neuropsychological effects of preventive CNS irradiation in adult tumor patients]

Prophylactic cranial irradiation (PCI) has led to marked prolongation of survival, but also to intellectual and neuropsychological retardation in children with ALL. PCI has also been conducted in adult patients with small-cell bronchial carcinoma in the stage of minimal disease or with breast cancer. There are no studies assessing cognitive or other neuropsychological consequences of PCI in adult cancer patients. We report on a longitudinal prospective study of the effects of PCI on five major neuropsychological domains (intelligence, concentration, attention, memory and psychomotor performance). We report on our ongoing study, in which up to now 11 patients with small-cell lung cancer undergoing PCI have been investigated. Patients are assessed immediately before therapy started as well as 4 weeks and 3 months after onset of PCI. The used instruments are Standard Progressive Matrices (SPM), d2 Concentration Test, Minimental State, Verbal Learning Test and Psychomotor Tests (Steadiness, Aiming, Tapping, Tracking, Pursuit Rotor Test). Although our sample is small, results indicate that there is no evidence for a decrease in neuropsychological abilities in adults after three months. This is in contrast to the observed results after PCI in children. As compared to baseline measures, differences in memory, intelligence, concentration and attention were marginal over time. Moreover the progress of motor performance skills showed no clear tendency.

[Late sequelae of CNS recurrence of acute lymphoblastic leukemia in childhood]

Study objective was to evaluate retrospectively central nervous system (CNS) morbidity of children with acute lymphoblastic leukemia treated with intensive chemotherapy and cranial radiotherapy for a first isolated or combined CNS relapse. Neurological (Touwen), neuropsychological (CFT 20, Wechsler scales, d2 attention test) and neuromorphological (CT, MRI) assessments were performed in 17 children (9 girls, 8 boys) aged between 7 and 14 years. Patients were off therapy for median 4 years; cranial radiotherapy for CNS relapse (12-24 Gy) was given to all patients 2 to 9 years ago (median 5.5 years). Ten patients had received preventive cranial radiotherapy during front-line treatment, previously. In this group, the cumulative radiation dose ranged between 30 and 39 Gy. Patients received 12 to 30 intrathecal methotrexate doses (median 22). Compared with normative levels for age (100 points) performance IQ (89.9) and full scale IQ (92.0), Culture Fair IQ (88.3) and attention and concentration (90.9) were significantly impaired. Verbal IQ (95.5) was not significantly different from normal expectations. Neurological investigations of 16 patients showed mild signs in 7 (44%) of them, mostly of fine-motor skills and coordination, but no major motor disability. In MRI and CT, white matter changes or ventricular enlargement were noted in 10 of 16 patients (63%). Parent-completed questionnaires indicated problem behaviors in 5 children. Cumulative doses of methotrexate correlated significantly with neuropsychological test results. Children irradiated twice as well as girls had poorer cognitive functions, not being statistically significant. Despite pathological test results, all children attended a normal school and did not exhibit obvious impairment in daily life. In conclusion, CNS relapse and attendant therapy, mostly consisting of a second course of cranial radiotherapy, caused measurable intellectual deficits and CNS morbidity, which did not result in severely impaired performance. Periodic psychological und clinical examinations are recommended for recognition of delayed morbiditiy and early intervention.

Neuropsychologic functioning of survivors of childhood medulloblastoma randomized to receive conventional or reduced-dose craniospinal irradiation: a Pediatric Oncology Group study

PURPOSE

The purpose of this study was to test the hypothesis that survivors of medulloblastoma who were younger at diagnosis and those who received standard-dose cranial irradiation (SRT) of 36 Gy would have a lower performance on standardized tests of cognitive function and achievement than children who were older and those treated with reduced-dose cranial irradiation (RRT) of 23.4 Gy.

PATIENTS AND METHODS

Eligible patients had been treated on Pediatric Oncology Group (POG) study 8631 for low-risk medulloblastoma that randomized patients to receive RRT or SRT after surgical resection. Those who were alive and free of progressive disease 6.1 to 9.9 years from completion of treatment were eligible for this study. Of the 35 eligible patients, 22 patients (13 SRT, nine RRT) participated in a battery of tests that included intellectual and academic development as well as ratings of health-related quality of life.

RESULTS

Patients were stratified by treatment group (SRT v RRT) and into younger (Y) and older (O) groups by the median age at diagnosis (8.85 years), which resulted in four groups that we hypothesized would show neuropsychologic test scores in the following order: Y/SRT less than Y/RRT less than O/SRT less than O/RRT. Evidence to support the hypothesized ordering of groups in terms of neuropsychologic toxicity was obtained with regard to Performance Intelligence Quotient (IQ), Full Scale IQ, Attention, Reading, and Arithmetic.

CONCLUSION

Children treated for medulloblastoma experienced less severe neuropsychologic toxicity when treated with 23.4 Gy instead of 36 Gy cranial irradiation. Older children experienced less toxicity than children who were younger at the time of irradiation.

[Neurological and psychological sequelae in children with acute lymphoblastic leukemia who had received radiotherapy and intrathecal methotrexate]

Our objective was to compare the neurologic and psychological sequelae of children with acute lymphoblastic leukemia (ALL) after three or more years without antineoplasic treatment who underwent cranial irradiation plus intrathecal methotrexate (Group 1) or just intrathecal methotrexate (Group 2). In both groups, a neurologic evaluation, electroencephalogram (EEG) and cranial computed tomography (CCT) were performed. Intellectual quotient and the Bender test were done for the psychological evaluation. Investigators did not know the kind of treatment of each patient.

STATISTICS

Fisher's exact test and Mann-Whitney U. There were fourteen patients in group 1 and eight patients in group 2. Intellectual quotient was statistically lower in the first group (median 83.5) than in the second (90.5). Neurologic impairments were found in one patient of each group, alterations of the EEG were found in 6 and 4 in group 1 and 2, respectively, and in the CCT of two patients in group 2 without statistical difference. Children with ALL after cranial irradiation have a greater alteration of intellectual performance than children with intrathecal methotrexate. Neurologic alterations were seen in both groups.

[Some aspects of reproductive function and social adaptation after comprehensive therapy of childhood Hodgkin's disease]

An analysis of the data available on the reproductive status and social adjustment of 443 children who received three modalities of complex treatment for Hodgkin's disease in 1976-1994 established no impairment of reproductive function or its formation, although full therapeutic effect had been achieved. Nor were their intelligence or professional and social function affected in any way.

Neurobehavioural sequelae following cranial irradiation and chemotherapy in children: an analysis of risk factors

Neurobehavioural deficits are commonly reported following treatment for childhood cancers. This study examined the impact of cranial irradiation (CRT) and chemotherapy in children, aiming to identify factors detrimental to long-term outcome. The study compared survivors of acute lymphoblastic leukemia (ALL), treated with CRT and chemotherapy (CRT group: n = 100), survivors of cancers treated with chemotherapy only (n = 50) and healthy controls (n = 100) for intelligence, academic achievement, information processing, learning, and executive function. CRT and chemotherapy in combination were associated with reduced intelligence, educational skill, immediate memory, processing speed, and executive function. Children treated with chemotherapy alone exhibited subtle information processing deficits. Within the CRT group, younger age at treatment was predictive of deficits in non-verbal ability, educational skills and executive functions. High dose CRT was associated with poorer information processing and lower arithmetic ability.

Neuropsychological sequelae after treatment for medulloblastoma in childhood--the Taiwan experience

The purpose of this study was to investigate the functional independence, intellectual performance and academic achievement of children treated for medulloblastoma at the Veterans General Hospital-Taipei. Adverse factors that it was thought would result in significant intellectual impairment were also studied. Nineteen patients with medulloblastoma located over the posterior fossa were enrolled in this study. Their mean age at tumor removal was 6.16 +/- 3.30 (range 2-14) years. Mean full intelligent quotient (FIQ) was 86.00 +/- 22.66, performance intelligent quotient (PIQ) was 85.29 +/- 21.23, and verbal intelligent quotient (VIQ) was 90.50 +/- 23.50. In 11 cases academic achievement at school was poor. Sixteen patients received radiation therapy after tumor removal. Significant negative correlations were noted between IQ and whole-brain irradiation dose (r = -0.72) and between IQ and years after radiation therapy (r = -0.63). The results indicate a need for ongoing attention and intervention to prevent, remedy or minimize deficits produced by the tumor itself and by the cancer treatment.

Progressive deterioration of intellect and motor function occurring several decades after cranial irradiation. A new facet in the clinical spectrum of radiation encephalopathy

OBJECTIVE

To report the cases of 2 patients who developed the features of radiation encephalopathy 33 and 28 years after cranial irradiation.

DESIGN

Case reports; clinical data were available for 2 years in each instance.

CONCLUSION

Latent intervals approaching 2 decades have been reported in cases of radiation necrosis following cranial irradiation, but a similar or greater delay before the onset of radiation encephalopathy has not been described previously. This report indicates that a diagnosis of radiation encephalopathy must be considered when any individual who has received cranial irradiation presents with deterioration in intellectual or motor function, whatever the interval.