Ictal EEG and single photon emission computed tomography in a patient with cortical dysplasia presenting with atonic seizures.
OBJECTIVE
Ictal studies of atonic seizures in children with epilepsy are rare. To clarify the neurophysiologic mechanism of such seizures, we describe a cluster of atonic seizures in a 6-year-old girl with cortical dysplasia.


METHODS
Ictal activity was recorded as slow-wave bursts beginning over the right frontocentral regions, where the cortical dysplasia was detected by magnetic resonance imaging (MRI), and propagating to the left hemisphere.


RESULTS
The polygraphic recording demonstrated that the atonia indicated by the sudden interruption of electromyogram (EMG) discharges corresponded to the bilaterally synchronous spike-and-wave complexes. An ictal single photon emission computed tomography (SPECT) study with 99mTc hexamethyl propylene amine oxime ([99mTc]HMPAO) simultaneously performed during EEG recording showed marked bilateral mesial frontal and right frontoparietal hyperperfusion.


CONCLUSIONS
Our findings suggest that the neurophysiological mechanism of the atonic seizures may be produced by a strong inhibition in the bilateral motor cortexes. Ictal SPECT is valuable in demonstrating the pathophysiology of both atonic seizures and secondary bilaterally synchronous spike-and-wave complexes in the EEG.
Aihara
M
M
Department of Pediatrics, Yamanashi Medical University, Japan.
Hatakeyama
K
K
Koizumi
K
K
Nakazawa
S
S
D002540:Cerebral Cortex / Q000002:abnormalities* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002648:Child; D018450:Disease Progression; D004569:Electroencephalography; D004829:Epilepsy, Generalized / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime