Elsevier

Pediatric Neurology

Volume 20, Issue 1, January 1999, Pages 73-77
Pediatric Neurology

Original Articles
Cognitive deterioration associated with focal cortical dysplasia

https://doi.org/10.1016/S0887-8994(98)00102-7Get rights and content

Abstract

Surgery for an area of focal cortical dysplasia in a critical region is reported in a right-handed female manifesting intractable focal epilepsy and verbal cognitive deterioration. She developed the first seizure at 2 years of age and was treated with phenytoin and zonisamide, with good control until 10 years of age. Although seizures did not occur at 9 years of age, she manifested dyscalculia, right-left disorientation, and finger agnosia, and N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (SPECT) revealed focal hypoperfusion in the left parietal lobe. At 11 years of age, she developed regular nocturnal seizures and gradually lost the ability to understand the meaning of sentences. Verbal IQ declined from 94 to 63, and the area of hypoperfusion detected by interictal N-isopropyl-p-iodoamphetamine SPECT spread over the left parietotemporal lobes. Magnetic resonance imaging revealed focal cortical dysplasia mainly in the left parietal lobe, and ictal technetium-99m-ethyl cysteinate dimer SPECT images demonstrated an area of hyperperfusion around the focal cortical dysplasia, including the left precentral gyrus. Because of the overlap between the epileptogenic and functional cortex, the authors concluded that cortical resection, including focal cortical dysplasia, was inappropriate in this patient.

Introduction

Because focal cortical dysplasia (FCD) is highly and intrinsically epileptogenic [1], [2], neurosurgery has been used when medical treatment has failed [3], [4], [5], [6]. However, unsatisfactory outcomes occur after incomplete removal of the lesions or in patients with lesions in the extratemporal lobes [6], [7], [8]. Therefore, it is important to identify how the epileptogenic lesions relate to the structural abnormality in the functional cortex before surgery [3], [9].

The authors describe the case of an 11-year-old female with FCD in the left parieto-occipital lobes. Because she manifested daily focal seizures and cognitive impairment, the authors discuss the relationship between an epileptic focus and the functional cortex. The epileptic focus was identified by ictal electroencephalographic (EEG) video monitoring, ictal technetium-99m-ethyl cysteinate dimer single-photon emission computed tomography (SPECT) superimposed on magnetic resonance imaging [10], and magnetoencephalogram [11]. Her intellectual abilities, obtained from Wechsler Intelligence Scale of Children-Revised (WISC-R) during the interictal state, were compared with findings of serial N-isopropyl-p-iodoamphetamine (123I-IMP). SPECT scans were performed using a Hitachi SPECT 2000 H-40 (Hitachi Medico, Tokyo, Japan) equipped with high-resolution collimators. Acquisition data were collected using 64 total steps of 15 seconds each into a 64 × 64 matrix, yielding a pixel size of 4 mm, and axial, sagittal, and coronal images with an 8-mm thickness were reconstructed. Computer-automated square regions of interest (16.8 × 16.8 mm) were created over the frontal, parietal, temporal, and occipital cortices and cerebellar hemicortices. The average pixel values in each region of interest were normalized to the cerebellar value. Also, somatosensory/auditory cortices were investigated by evoked magnetic dipoles [9], [12].

Section snippets

Case report

A right-handed female was admitted to the authors’ hospital at 11 years, 8 months of age because of daily epileptic seizures and verbal cognitive impairment. Physical examination revealed mild gum hypertrophy and hirsutism but no paralysis, hemianopsia, or cutaneous lesions of tuberous sclerosis. She was born at term after an uncomplicated pregnancy, weighing 2,940 gm. She had one older healthy sibling. There was no family history of epilepsy or mental disorder. Her early development was

Discussion

The long-term effects of seizures on the developing brain are a difficult problem to study because cognitive impairment may be related to the etiologic agent responsible for the seizures, age at the time of onset of seizures, or the antiepileptic drugs used to treat the seizures [14]. The authors’ patient demonstrated an increased subcortical signal on T2-weighted images, compatible with FCD, mainly in the left parietal lobe. She manifested three symptoms of Gerstmann syndrome even during a

Acknowledgements

The authors thank Professor Akimasa Okuno for review of the manuscript, Mr. Yukio Ishikawa and Mr. Junichi Satou for technical assistance in performing SPECT examinations, and Dr. Yutaka Watanabe for examining the patient with magnetoencephalogram.

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