Clinical Study
Positron emission tomography findings in children with infantile spasms and autism

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Abstract

The purpose of this study was to evaluate positron emission tomography (PET) findings in patients diagnosed with infantile spasms and autism. This study includes 90 patients who were diagnosed with infantile spasms at the Department of Pediatric Neurology in the Istanbul University Medical Faculty between 1995 and 2007. Of the 90 patients, 15 patients who were diagnosed with autism using the Autism Behaviour Checklist and Childhood Autism Rating Scale and a control group of nine patients without autism but with infantile spasms underwent PET examination. Mean patient age (± standard error, SE) varied between 3 years and 16 years (7.8 ± 4 years), while the mean follow-up time (±SE) varied between 2 years and 16 years (average: 7.1 ± 4 years). Autism was present in 11 patients with symptomatic spasms and in four patients with cryptogenic spasms (p = 0.009). On the PET scans of the 15 patients with autism, 13 (86.7%) had significantly decreased metabolic activity in the temporal lobe (p < 0.001), nine (60%) had significantly decreased activity in the frontal lobe (p = 0.004), and seven (46.7%) had significantly decreased activity in the parietal lobe (p = 0.022). In our opinion, hypometabolism in the frontal and parietal lobes, in addition to that previously reported in the temporal lobe, plays a role in the development of autism in patients with infantile spasms.

Introduction

Infantile spasms are one of the epileptic syndromes etiologically related to autism. Existing studies report a 9% to 17.6% rate of autism in patients with infantile spasms.[1], [2], [3] Studies in which such patients underwent positron emission tomography (PET) examination have reported focal or diffuse hypometabolism that regresses when seizures cease.[4], [5], [6] Studies on autistic children have reported bilateral temporal lobe hypometabolism, especially in the associative auditory cortex (superior temporal gyrus) and in the multimodal cortex (superior temporal sulcus).[7], [8]

A study by Chugani et al.9 that prospectively followed children with infantile spasms has linked bilateral temporal hypometabolism with the development of autism. Apart from this study, there have been no other studies where patients with autism and infantile spasms underwent PET examination. For this reason, we set out to evaluate PET findings in children with infantile spasms and autistic features in this cross-sectional study.

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Materials and methods

The present study enrolled 90 patients with infantile spasms who were above 3 years of age (52 male and 38 female) and had been followed at the Department of Pediatric Neurology of the Istanbul University Medical Faculty. The Autism Behaviour Checklist (ABC) and the Childhood Autism Rating Scale (CARS) were administered by a trained clinician to the parents/guardians and these children, respectively. For ascertainment of autism status, we used DSM IV diagnostic criteria for autism spectrum

Results

The age of the 24 patients enrolled in the study varied between 3 years and 16 years, the average age being 7.8 ± 4 years. Fifteen patients were male (62.5%) and nine were female (37.5%). Nine male patients and six female patients were diagnosed with autism (Table 1). No significant relation was found between the sex of the patients and autism (Fisher’s exact test, p = 1.000). Follow-up time varied between 2 years and 16 years, the average being 7.1 ± 4 years. (Table 1).

The seizures were symptomatic in 12

Discussion

We evaluated 90 patients with infantile spasms, older than 3 years of age, and included 17 (18.9%) with autism in the study group. Riikonen et al.3 diagnosed autism in 12.5% of 192 patients with infantile spasms; Sidenvall et al.1 diagnosed autism in 9% of 57 patients. In contrast to these two studies, the rate of autism in a small 17-patient group was 35% in a study by Saemundsen et al.,2 and 17.6% when only patients with a mental age above 24 months were taken into account. In our opinion, the

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