Frontal Lobe Epilepsy with Secondarily Generalized 3 Hz Spike-Waves: A Case Report

Abstract

We report a case of frontal lobe epilepsy with bursts of 3 Hz spike-wave, often dominant in the left frontal lobe, that sometimes developed into a secondary bilateral generalization. This patient was a 69-year-old male with a history of epileptic seizures that began 3 months following a head injury at the age of 17. His seizures occurred two or three times a day, but after medication the frequency was halved. The seizures began with a feeling of heaviness of the head, accompanied by myoclonus at both angles of the mouth. Consciousness was clear for most of the seizures, which ranged from several seconds to many minutes. When seizures lasted for longer than 10 minutes, a temporary generalization accompanied by a loss of consciousness was sometimes observed. Neurological tests and cranial MRI yielded no abnormal local findings. The secondary generalized seizure seen in this case is the so called "secondary bilateral synchrony (SBS)." We succeeded in making an EEG recording of the bilateral generalization of a seizure discharge originating in the left frontal lobe, which until now has not been done. This case is direct proof that a primary frontal focus can give rise to SBS.

Magnetoencephalographic Analysis of Secondary Bilateral Synchrony

“…Such EEG bursts tended to rapidly become widespread from the onset. 4,5 In our patients, the bursts of spike-and-slow-wave complexes seen on EEG were also bilaterally synchronous from the onset, and the identification of SBS was difficult by using visual inspection of the scalp EEG alone. Moreover, the seizures in these patients were similar to absence seizures in sharing the same electroclinical features, including the clinical pattern of loss of consciousness and generalized spike-and-slow-wave complexes on EEG.…”

Generalized Spike-Wave Discharges with Focal Onset in a Patient with Head Trauma and Diffuse Cerebral Lesions: A Case Report with EEG and Cranial MRI Findings

“…Itwas thought that secondary bilateral synchrony (SBS) was triggered due to these foci.a.13 Ictal EEGs with generalized 3 Hz spike-wave burst complexes preceded byfocal spike-wave discharges were also reported in one patient with absence seizures. 8 Although there was a focal finding in the ictal EEGs, the responsible lesions could not be demonstrated by neuroimaging techniques. The triggering of SBS from a lesion located outside the frontal lobe has not been demonstrated byEEG.…”

Focal onset in absence seizures: evidence from MEG spatio-temporal dynamics

“…Spike and wave events are first detected by left frontal MEG channels with no clear correspondence on the simultaneous EEG absence seizures may be of frontal origin was already suggested by Kubota et al (1997) [1] in a study of frontal lobe epilepsy with secondarily generalized 3 Hz spike-waves. The involvement of the neocortex in the initiation and synchronization of the generalized spike and wave discharges is supported by the finding that, after thalamectomy, the initiation of spike-wave complexes persists, although the thalamus seems to be required for rhythm maintenance [8].…”

“…In this context, absence seizures are commonly described as primarily generalized seizures, featuring a sudden bilateral synchronous spike and wave burst on the electroencephalography (EEG). Some studies have reported a focal origin for absence seizures giving evidence that although spikewave discharges develop rapidly they may not be diffuse [1][2][3][4][5][6]. In these instances generalization may be due to rapid spread and secondary bilateral synchrony.…”