Heikki Rantala

Associated Medical Disorders and Disabilities in Children with Autistic Disorder: A Population-based Study

A population-based survey was conducted among 152,732 Finnish children and adolescents aged under 16 years and living in northern Finland. Diagnoses and associated medical conditions were derived from the hospital and institutional records of this area. One hundred and eighty-seven children with DSM-IV autistic disorder were identified. Associated medical disorders or associated disorders of known or suspected genetic origin were found in 12.3 percent, including tuberous sclerosis, Down syndrome, fragile X syndrome, Klinefelter syndrome, XYY syndrome, chromosome 17 deletion, chromosome 46, XX, dup(8)(p) and mitochondriopathy. Other associated medical disorders identified were epilepsy, hydrocephalus, foetal alcohol syndrome and cerebral palsy. Hearing impairments were found in 8.6 percent and severe impairment of vision in 3.7 percent of the individuals with autistic disorder. Medical disorders seem to have a special impact on the genesis of autistic disorder and need to be thoroughly examined in each child with autistic disorder.

Slow vasomotor fluctuation in fMRI of anesthetized child brain.

Signal intensity changes in fMRI during rest caused by vasomotor fluctuations were investigated in this work. Resting‐state baseline fluctuations were evaluated in 12 children anesthetized with thiopental. Five subjects had fluctuations related to subvoxel motion. In seven subjects without significant motion, slow signal fluctuation at 0.025–0.041 Hz near one or more primary sensory cortices was observed. In each subject the amplitude and frequency of the fluctuations were stable. It is hypothesized that thiopental, which reduces blood pressure and flow in the cortex, alters the feedback in neurovascular coupling leading to an increase in the magnitude and a reduction in the frequency of these fluctuations. The use of anesthesia in fMRI may provide new insight into neural connectivity and the coupling of blood flow and neural metabolism. Magn Reson Med 44:373–378, 2000.

Effect of acetaminophen and of low intermittent doses of diazepam on prevention of recurrences of febrile seizures.

Acetaminophen and low doses of diazepam were evaluated for the prevention of recurrences of febrile seizures in a placebo-controlled, double-blind trial. Children after their first febrile seizure were assigned to receive either one dose of rectally administered diazepam, and then, after 6 hours, oral doses of 0.2 mg/kg three times a day for the first 2 days if the fever stayed greater than 38.5 degrees C, or a placebo similarly during forthcoming febrile episodes. In addition, each febrile episode was randomly assigned to be treated with acetaminophen or the placebo. Thus four groups were examined for 2 years: patients receiving two kinds of placebo, patients receiving diazepam and a placebo, patients receiving acetaminophen and a placebo, and patients receiving both diazepam and acetaminophen. Of a total of 180 patients (102 boys), 161 were followed for the 2-year period and 157 were seen at the last outpatient examination: 80 in the diazepam group and 77 in the placebo group. The final analysis of the efficacy of the drugs was made on the basis of the data from 153 patients who had had at least one febrile episode during follow-up. There were 641 fever events during this period, and 38 children (21.1%) had 55 recurrences of febrile seizures. Acetaminophen had no effect on the recurrence rate. Seizures recurred at least once in 21 patients (28.4%) receiving diazepam and 17 (21.5%) receiving a placebo (p = 0.4138, log-rank test). The combination of antipyretic agents with anticonvulsant medication did not reduce the recurrence of febrile seizures. Our results show that low doses of acetaminophen or diazepam or both are ineffective for preventing febrile seizures.

Epidemiology of encephalitis in children. A prospective multicentre study

Abstract We found 175 cases with acute encephalitis in a population of 791,712 children aged 1 month – 15 years during a 2-year surveillance period in 1993–1994. The overall incidence was 10.5/100,000 child-years with the highest figure in children < 1 year of age, 18.4/100 000 child-years. The microbial diagnosis was considered proven or suggested in 110 cases (63%); varicella zoster, respiratory and enteroviruses comprised 61% of these, and adeno, Epstein Barr-, herpes simplex and rota viruses comprised 5% each. A clearcut change seems to have occurred in the aetiology of encephalitis. Mumps, measles, and rubella virus associated encephalitides have been almost eliminated. Varicella zoster, respiratory, and enteroviruses have increased in frequency and occur in younger age groups. New causes were identified, especially Chlamydia pneumoniae and HHV-6. Our data should assist in making a specific diagnosis and defining appropriate antimicrobial therapy. ConclusionThe spectrum of encephalitis in children has changed due to vaccination programs. The incidence, however, appears to be about the same due to increasing frequency of other associated old and new microbes.

Febrile seizures and mesial temporal sclerosis No association in a long-term follow-up study

Objective: To determine whether febrile seizures cause mesial temporal sclerosis (MTS), the occurrence of MTS was evaluated in an unselected series of patients with febrile seizures. Methods: Twenty-four patients with a prolonged first febrile seizure, 8 with an unprovoked seizure after the first febrile seizure, and 32 age-, sex-, and handedness-matched control subjects with a single simple febrile seizure without later unprovoked seizures were selected from 329 febrile seizure patients followed up prospectively. The occurrence of MTS was evaluated after a mean follow-up time of 12.3 years by MR volumetry of amygdala and hippocampal formation and qualitative analysis of mesial temporal structures. Results: None of the patients had MTS. The mean total volumes of the right and left hippocampal formations and amygdala did not differ significantly between any of the three groups. The qualitative analysis revealed no sclerotic changes in the mesial temporal area. The patients with a prolonged initial febrile seizure had a lower mean right–left volume difference in hippocampal formations than the control subjects, but this had no effect on the outcome. Conclusion: The occurrence of MTS following even prolonged febrile seizures is an uncommon event, confirming the good clinical outcome of febrile seizures.

Occurrence, outcome, and prognostic factors of infantile spasms and Lennox-Gastaut syndrome.

Summary: Purpose: To analyze the occurrence, outcome, and prognostic factors of infantile spasms (IS) and the Lennox‐Gastaut syndrome (LGS) in a defined population.

Visual Field Constriction in 91 Finnish Children Treated with Vigabatrin

Summary:  Purpose: To study the prevalence and features of visual field constrictions (VFCs) associated with vigabatrin (VGB) in children.

Prevalence, segregation, and phenotype of the mitochondrial DNA 3243A>G mutation in children

We studied the prevalence, segregation, and phenotype of the mitochondrial DNA 3243A>G mutation in children in a defined population in Northern Ostrobothnia, Finland.

Alterations in regional homogeneity of baseline brain activity in pediatric temporal lobe epilepsy

Recent findings on intracortical EEG measurements show that the synchrony of localized neuronal networks is altered in epileptogenesis, leading to generalized seizure activity via connector hubs in the neuronal networks. Regional homogeneity (ReHo) analysis of blood oxygen level-dependent (BOLD) signals has demonstrated localized signal synchrony and disease-related alterations in a number of instances. We wanted to find out whether the ReHo of resting-state activity can be used to detect regional signal synchrony alterations in children with non-lesional temporal lobe epilepsy (TLE). Twenty-one TLE patients were compared with age and gender-matched healthy controls. Significantly increased ReHo was discovered in the posterior cingulate gyrus and the right medial temporal lobe of the patients, and they also had significantly decreased ReHo in the cerebellum compared with the healthy controls. However, the alterations in ReHo differed between the patients with normal and abnormal interictal EEGs, the latter showing significantly increased ReHo in the right fusiform gyrus and significantly decreased ReHo in the right medial frontal gyrus relative to the controls, while those with normal EEGs had significantly increased ReHo in the right inferior temporal gyrus and the left posterior cingulate gyrus. We conclude that altered BOLD signal synchrony can be detected in the cerebral and cerebellar cortices of children with TLE even in the absence of interictal EEG abnormalities.

A meta-analytic review of the preventive treatment of recurrences of febrile seizures

OBJECTIVE To assess the efficacy of various medications in the prevention of recurrent febrile seizures. STUDY DESIGN A meta-analysis of all published randomized, placebo-controlled trials of the preventive treatment of febrile seizures published in English; 45 articles were found, but only 9 trials were randomized and placebo-controlled--4 using phenobarbital; 3, diazepam; 1, pyridoxine; and 1, phenytoin. In one of the phenobarbital trials, valproate was also compared with placebo. RESULTS The risk of recurrences was significantly lower in children receiving continuous phenobarbital therapy than placebo (odds ratio 0.54, 95% confidence intervals 0.33 to 0.90, p = 0.017). The odds ratio for recurrences in the valproate group was 0.09, 95% CI 0.01 to 0.78, p = 0.011. No difference in the risk was found for recurrences between children receiving intermittent diazepam and placebo (odds ratio 0.81, 95% CI 0.54 to 1.22, p = 0.31). The risk for recurrences in children receiving pyridoxine or phenytoin did not differ from the risk among children receiving placebo. Four children would have to be treated with valproate (95% CI 2 to 11) or eight children would have to be treated with phenobarbital (95% CI 5 to 27), continuously, to prevent one febrile seizure. CONCLUSIONS Because both agents found to be effective in prevention of recurrent febrile seizures have known adverse effects, prophylaxis of febrile seizures cannot be recommended.