The brains of high functioning autistic individuals do not synchronize with those of others.

Multifaceted and idiosyncratic aberrancies in social cognition characterize autism spectrum disorders (ASDs). To advance understanding of underlying neural mechanisms, we measured brain hemodynamic activity with functional magnetic resonance imaging (fMRI) in individuals with ASD and matched-pair neurotypical (NT) controls while they were viewing a feature film portraying social interactions. Pearson's correlation coefficient was used as a measure of voxelwise similarity of brain activity (InterSubject Correlations-ISCs). Individuals with ASD showed lower ISC than NT controls in brain regions implicated in processing social information including the insula, posterior and anterior cingulate cortex, caudate nucleus, precuneus, lateral occipital cortex, and supramarginal gyrus. Curiously, also within NT group, autism-quotient scores predicted ISC in overlapping areas, including, e.g., supramarginal gyrus and precuneus. In ASD participants, functional connectivity was decreased between the frontal pole and the superior frontal gyrus, angular gyrus, superior parietal lobule, precentral gyrus, precuneus, and anterior/posterior cingulate gyrus. Taken together these results suggest that ISC and functional connectivity measure distinct features of atypical brain function in high-functioning autistic individuals during free viewing of acted social interactions. Our ISC results suggest that the minds of ASD individuals do not 'tick together' with others while perceiving identical dynamic social interactions.

Incidence of death in patients with intractable epilepsy during nitrazepam treatment.

PURPOSE: Increased risk of death has been reported in patients with intractable epilepsy (IE) taking nitrazepam (NZP). METHODS: Between January 1983 and March 1994, 302 patients with IE were entered into a NZP compassionate-plea protocol. NZP was discontinued if there was < 50% seizure reduction or significant side effects. In some patients with > 50% reduction, it also was discontinued for lack of sufficient effect. At the end of follow-up for this study, 62 patients remained taking NZP. Patients took NZP from 3 days to 10 years. RESULTS: Twenty-one of 302 patients died after institution of NZP. Fourteen of 21 of these were taking NZP at death, and in five of 21, the NZP had been discontinued. Two patients were excluded from analysis, because it is unclear whether NZP had been discontinued before death. Six other patients were lost from follow-up. Of the 14 deaths with NZP, seven were sudden, six were of pneumonia, and one was of cystinosis. Nine had at least one contributing factor, such as dysphagia, gastroesophageal reflux, or recurrent aspirations. The 294 patients took NZP for a total of 704 patient years (ptyrs), and were discontinued for a total of 856 ptyrs. There were 1.98 deaths/ 100 ptyrs on NZP compared with 0.58 deaths/100 ptyrs without NZP, most of the former being associated with side effects of NZP. Mortality in patients younger than 3.4 years was 3.98 with NZP compared with 0.26 deaths/100 ptyrs without NZP (p = 0.0002). Corresponding figures in patients 3.4 years or older were 0.50 and 0.86 deaths/100 ptyrs, respectively. CONCLUSIONS: NZP therapy for epilepsy apparently increases the risk of death, especially in young patients with IE. This should be considered in antiepileptic drug (AED) management decisions.

Clinical role of positron emission tomography in children with tuberous sclerosis complex.

We evaluated the clinical role of positron emission tomography (PET) in 23 children with tuberous sclerosis complex. Mean age of the children when first scanned was 3.3 years. Mean age when seizures began was 8.7 months. All, except three, were at least mildly developmentally delayed. PET images were visually analyzed and compared to computed tomography (CT), magnetic resonance imaging (MRI), and the electroencephalogram (EEG). In two infants, interictal PET study was normal. One of the studies was performed with a low resolution early generation scanner at age 7 months; the other infant was 2 days old. Twenty-one of the 23 children had focal or multifocal cortical hypometabolism. Some hypometabolic cortical regions on PET did not show corresponding abnormalities on CT and MRI, and may be due to epileptogenic mechanisms or small tubers. PET provides additional localizing information to CT and MRI in patients with tuberous sclerosis complex. However, because of the normally low cerebral glucose metabolism in infancy, PET may give false negative findings if performed prior to about 1 year of age. The usefulness of glucose metabolism PET in most patients with tuberous sclerosis complex is limited. However, if the EEG, CT, and MRI abnormalities are unifocal or unilateral, and surgery is being contemplated, more detailed evaluation with PET may help to determine if contralateral tubers are present and evaluate the functional integrity of the brain as a whole.

Microscopic cortical dysplasia in infantile spasms: evolution of white matter abnormalities.

PURPOSE: To determine whether microscopic cortical lamination defects in patients with infantile spasms, not initially identifiable on MR, may be inferred from evolving changes in the adjacent white matter. METHODS: Three infants between 3 and 6 months of age presented with infantile spasms. Based on negative metabolic assessment and normal MR findings, they were classified as cryptogenic. Despite therapy the children deteriorated with seizure recurrence and the advent of lateralizing clinical and neurophysiologic findings. MR studies were repeated and positron emission tomography was done. RESULTS: The second MR studies demonstrated abnormalities of myelination, corresponding to localized clinical and neurophysiologic findings. Positron emission tomography findings did not show a strong correlation; one was normal, one showed no abnormality in the major area of MR abnormality, and one showed significantly less abnormality than on MR. Two patients have undergone surgery, both with good response. DISCUSSION: Subtle lamination defects may be identifiable on positron emission tomography but are usually not detectable on MR. White matter abnormality on MR images is usually attributable to primary disease. We suggest that in certain cases progressive white matter changes may be induced as a secondary phenomenon by overlying microscopic cortical lamination defects. Serial MR imaging may be beneficial in children with infantile spasms in whom signs of laterality evolve.

Landau-Kleffner syndrome with continuous spikes and waves during slow-wave sleep.

The Landau-Kleffner syndrome is sometimes associated with continuous spike-waves during slow-wave sleep. The clinical significance of this association is unclear. In order to investigate differences in glucose metabolic patterns between awake and sleep states in two children with Landau-Kleffner syndrome and continuous spike-waves during slow-wave sleep, fluorodeoxyglucose positron-emission tomographic (PET) studies were performed in each state. In the first patient, the awake interictal PET study revealed moderate hypometabolism in the thalamus and frontal and temporal cortex and mild hypometabolism in the parietal and anterior cingulate cortex bilaterally. Occipital cortex was severely hypometabolic bilaterally. In a repeat PET study performed during sleep in which continuous spike-waves during slow-wave sleep were present, the only difference noted compared to the awake study was a marked bilateral increase in temporal cortex metabolism. The awake interictal PET in the second child was normal, except for mildly increased relative glucose metabolism in the left inferior temporal cortex. The sleep PET study with continuous spike-waves during slow-wave sleep in this child showed hypermetabolism in both temporal lobes; however, this was more pronounced, with a wider distribution in the left temporal cortex. In normal subjects, PET studies performed during awake and sleep states have not revealed such differences. Whether the temporal lobes are involved in the generation of continuous spike-waves during slow-wave sleep remains to be confirmed in a larger group of patients. The first child was treated surgically with multiple subpial transection, following which continuous spike-waves during slow-wave sleep disappeared and language function improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Ictal patterns of cerebral glucose utilization in children with epilepsy.

To determine seizure propagation patterns, we analyzed ictal positron emission tomography (PET) studies of regional cerebral glucose utilization in 18 children (11 male and 7 female aged 2 weeks to 16 years) with epilepsy (excluding infantile spasms IS). Three major metabolic patterns were determined based on degree and type of subcortical involvement: Nine children had type I; asymmetric glucose metabolism of striatum and thalamus. Of these, the 7 oldest children showed unilateral cortical hypermetabolism (always including frontal cortex) and crossed cerebellar hypermetabolism. Two infants (aged < 1 year) had a similar ictal PET pattern but no cerebellar asymmetry, presumably owing to immaturity of corticopontocerebellar projections. Five children had type II, symmetric metabolic abnormalities of striatum and thalamus; this pattern was accompanied by hippocampal or insular cortex hypermetabolism, diffuse neocortical hypometabolism, and absence of any cerebellar abnormality. Four children had type III, hypermetabolism restricted to cerebral cortex. This classification can accommodate ictal PET and single photon emission computed tomography (SPECT) patterns described by other investigators. Future studies should be directed at the clinical relevance of this classification, particularly with regard to epilepsy surgery.

Hemimegalencephaly: evaluation with positron emission tomography.

We performed positron emission tomographic (PET) studies with 2-deoxy-2[18F]fluoro-D-glucose in 8 children with hemimegalencephaly (HME). HME is a developmental brain malformation associated with epilepsy, hemianopsia, and varying degrees of developmental delay. We hypothesized that the relatively poor overall developmental outcome of surgically hemispherectomized HME patients as a group, compared to children undergoing hemispherectomy for Sturge-Weber syndrome or chronic focal encephalitis, is related to dysfunction of the structurally "normal" non-HME side and that PET would be helpful in the pre-surgical evaluation of HME patients with intractable epilepsy. Visual analysis of the non-HME side on PET clearly revealed evidence of cortical hypometabolism in 4 patients compared to controls. Seven children underwent epilepsy surgery. One child had a glucose metabolic pattern suggesting a cortical lamination defect in the non-HME hemisphere, bilateral independent seizure onset, and was not considered to be a surgical candidate. We found a general correlation between the pattern of glucose utilization in the less affected hemisphere and prognosis. Although the follow-up periods are short, it is recommended that HME children with intractable epilepsy undergo hemispherectomy in the first year of life in order to allow maximal brain plasticity to occur; however, preoperative evaluation should also include an assessment of the integrity of the non-HME hemisphere.

Anaphylactic death: the effect of aminoguanidine and heparin on histamine and stress hormones in guinea pigs.

The modifying effect of aminoguanidine (a histaminase inhibitor) and heparin (a histaminase liberator) on anaphylactic shock in guinea pigs was studied using ovalbumin as an antigen and trigger. The animals died of the shock, the time to death remaining unaltered by the drugs. Serum histamine and cortisol values were high after shock, but were reduced by heparin. Both noradrenaline and adrenaline in plasma were also elevated after shock, the final concentration of the latter being lowered by heparin. The lungs were dilated, indicating bronchoconstriction. The results confirm the role of histamine in anaphylactic shock and its potential value for the diagnosis in this kind of rapid death, in which morphological signs are scarce or lacking. Its diagnostic value still requires confirmation, however, which only autopsy studies can supply. It also appears that pretreatment of the animals with heparin affected the blood cortisol and catecholamines, which are involved in the shock mechanism as countermeasures, although aminoguanidine did not have any effect.

The epidemiology of sudden infant death syndrome in Finland in 1969-1980.

SIDS cases were defined by examining all death certificates, in which sudden deaths were expected to be found from the years 1969-80 from the Central Statistical Office of Finland. The age limits were 28-364 days. If the death certificate did not give enough information as to whether the cause of death was explained or unexplained, autopsy records and microscopic specimens were examined. If the death was sudden, but no autopsy was done, no microscopic specimens were taken, or there were some slight findings which could have partly explained the death were classified as borderline cases. The mean annual incidence of SIDS in Finland was 0.41/1000 livebirths in 1969-80. In 1969-74 and 1975-80 the incidences were 0.31 and 0.51, respectively. The increasing tendency of SIDS was partly due to more borderline cases in the first period and partly due to more twins, and infants with small birth weight, dying of SIDS in the second period. Deaths at weekends and sleeping with parents in the second period were more common than in the first study period. In the SIDs group the young maternal age, low social class, family type unmarried couple or single mother, maternal anemia during pregnancy were more common than in the control group. Mothers of SIDS infants had more previous children and fewer visits and later first visit to prenatal clinics than control mothers. The duration of gestation was shorter and the mean birth weight and length were smaller in the SIDS case than in the control group. Twins were more common among SIDS infants than in the common population. The most important risk factor of SIDS was maternal smoking during pregnancy. The epidemiological results conform with the hypoxia hypotheses.