Brain perfusion SPECT and EEG findings in children with autism spectrum disorders and medically intractable epilepsy

Abstract

Objective: We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both autism spectrum disorders (ASD) and medically intractable epilepsy. Methods: Fifteen children aged 4–16 years underwent multimodal examinations (MRI, interictal and/or ictal ECD-SPECT, EEG and MEG) to investigate their indications for surgical treatment. All children were diagnosed with ASD according to DSM-IV criteria and intractable epilepsy. Despite medical treatment for more than a year, all experienced at least one seizure per month. All had no underlying basic disorders. Each SPECT result was statistically analyzed by comparing with standard SPECT images obtained from our institute (easy Z-score imaging system; eZIS). The relationship between the eZIS pattern and EEG abnormalities or clinical symptoms was investigated. Results: All children showed focal abnormal patterns on eZIS and focal spikes on EEG. In all children, eZIS revealed a mixed hypoperfusion pattern, especially in the prefrontal cortex, medial frontal cortex, anterior cingulate cortex, medial parietal cortex, and/or anterior temporal cortex. In seven of 12 children who underwent interictal SPECT studies, areas of hypoperfusion were related to the focus observed on EEG; in six children, the focal EEG spikes represented areas of hyperperfusion. The children were divided into two groups according to the main type of hypoperfusion patterns seen on eZIS; medial-cingulate type and temporal type. No significant relationship was observed between the areas of hypoperfusion and clinical symptoms. eZIS showed the epileptic focus clearly on ictal SPECT. Conclusions: SPECT was useful to detect the abnormal brain region not only in searching for the epileptic focus but also in assessing the low or high functioning region of the brain.

Introduction

A high rate of seizures and electroencephalogram (EEG) abnormalities in children with autism was first noted in the 1960s [1], [2]. Subsequently, a large number of studies concerning these combinations have been performed and published [3], [4], [5]. It is now widely known that children with autism have a high risk of epilepsy. However, the precise pathophysiological relationship between autism and seizures/EEG abnormalities has not yet been well elucidated. The types of epilepsy in children with autism vary from generalized to partial epilepsy [3]. In children with both autism spectrum disorders (ASD) and epilepsy, the focus of paroxysmal discharges is frequently found in the frontal lobes and/or temporal lobes [6], [7], [8], [9], [10]. As for epilepsy, localization-related epilepsy is more frequent than generalized epilepsy among children with ASD [6], [7], [8], [9]. Although seizures in some children with ASD responded relatively well to ordinary antiepileptic drug (AED) therapy, most children with ASD were resistant to AED therapy [7], [11]. By studying children with both ASD and epilepsy, we may be able to gain new insights that will advance our understanding of the pathophysiology of autism [1], [3].

We performed brain perfusion single-photon emission computed tomography (SPECT) to detect the abnormal brain region in children with both ASD and intractable epilepsy.