Original articleMigration of epileptic spike foci in encephalograms may correlate with a better outcome in pediatric epilepsy
Introduction
The onset of childhood epilepsy is age-dependent [1] and related to the maturation of the brain. The evolution of an epileptic focus is variable in childhood epilepsy, in which different electroencephalogram (EEG) epileptic discharges occur at different ages. The focus may change or remain stationary over time [2], [3]. For example, both rolandic discharges in benign childhood epilepsy with centrotemporal spikes (BECTs) and early-onset benign childhood seizures with occipital spikes (Panayiotopoulos syndrome (PS)) develop in early school age and disappear before late adolescence; some children with both syndromes show a migration of epileptic focus in their EEGs [4], [5], [6].
Migration of EEG spike foci in childhood epilepsy is common [7] and thought to be age-dependent [8], [9]; EEG spike foci may migrate more in childhood epilepsy than in adult epilepsy. Whether a migrated epileptic focus in an EEG correlates with a better outcome than does a fixed focus, however, has not been reported. It is worth determining whether children with migrated foci (MF) have different clinical outcomes than children with fixed foci (FF) do. Our hypothesis is that fixed epileptic spike foci in a series of EEG may represent a focal brain lesion or a focal micropathological lesion that results in a worse outcome. Our objectives were to study the migration of the EEG focus, and to determine whether children with these two types of foci have different clinical outcomes.
Section snippets
Patients and methods
We collected, from the department of Pediatric Neurology, 1046 EEG tracings from pediatric patients with epilepsy. After eliminating tracings from patients more than 17 years old, there were 969 tracings from 423 patients from newborn to 17 years old. EEGs were collected for a minimum of 3 years to a maximum of 11 years on each patient. The EEGs were acquired every 6 months, while the patients were asleep and awake, and we looked for possible unobservable seizures – e.g., brief general and
Statistical analysis
Statistical significance was set at P < 0.05. The differences in the ratios and distributions of the outcomes between groups were assessed using a χ2 test. Fisher’s exact probability test is appropriate when there are fewer than 6 cases. P-values are all continuity-corrected. The statistical differences between different groups were analyzed using an independent t-test (SPSS 14.0; SPSS Institute, Chicago, IL). Multivariate statistical analysis was used to determine factors that affected outcomes.
Results
Seventy-nine cases met the inclusion criteria: 24 (30%) in the FF group and 55 (70%) in the MF group (Table 1). In the latter group, in 16 patients (29%), migration was from posterior to anterior; in 29 (53%), migration was from anterior to posterior; in 3 (5%), migration was lateral; and in 7 (13%), migration was unclassified. In the 16 anterior migration cases, 6 (38%) showed movement from the occipital to the central region, 5 (31%) from the occipital to the frontal region, and 5 (31%) from
Discussion
We used a new method to survey epileptic children’s long-term (more than 3 years) EEGs to determine whether their epileptic spike foci were fixed or migrated. Children with FF had worse outcomes – they took more antiepileptic drugs, and had worse seizure control, more abnormal lesions in image studies, and more mental retardation – than did children with MF. This implied that fixed epileptic spike foci on consecutive EEGs meant that the patient had one or more micropathological lesions that
Conflict of interest statement
All authors declare that they have no financial or personal relationships with other people or organizations that could inappropriately influence their work.
References (22)
- et al.
EEG development of healthy boys and girls: results of a longitudinal study
Electroencephalogr Clin Neurophysiol
(1984) - et al.
The benign partial nonrolandic epilepsies
J Clin Neurophysiol
(1991) - et al.
Migration of epileptic foci in children
Adv Neurol
(1999) - et al.
EEG and clinical study of epilepsy during maturation in man
Epilepsia
(1962) Benign childhood epilepsy with occipital paroxysms: a 15-year prospective study
Ann Neurol
(1989)- et al.
Childhood occipital epilepsy: seizure manifestations and electroencephalographic features
Brain Dev
(1997) - et al.
Panayiotopoulos syndrome: a consensus view
Dev Med Child Neurol
(2006) - et al.
Disappearance and migration of epileptic foci in childhood
Am J Dis Child
(1954) EEG epileptiform abnormalities at different ages
Epilepsia
(1967)Long-term clinical and EEG changes in patients with epilepsy
Arch Neurol
(1985)
Clinical and electroencephalographical classification of epileptic seizures
Epilepsia
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