Three phase-ictal scalp EEG patterns in patients with seizures arising from the cortex facing the interhemispheric fissure

Seizure focus in the frontal interhemispheric fissure leads to ipsilateral isolated eye deviation

OBJECTIVE

Few studies have examined the localization of seizures presenting with ictal eye deviation (ED) in the absence of other motor symptoms. We aimed to investigate differences in the localization of the ictal onset zone (IOZ) between patients with isolated ED and those with ED plus head turning (HT) during focal seizures.

METHODS

We reviewed intracranial video-EEG data for 931 seizures in 80 patients with focal onset epilepsy in whom the IOZ could be confirmed. The 233 seizures in 49 patients with ED were classified into two semiological groups based on initial ED and the presence/absence of HT: (1) isolated ED (i.e., ED without HT), and (2) ED + HT (i.e., ED with HT). We analyzed the localization and lateralization of IOZs in each semiological group. We performed multivariate logistic regression analysis using a mixed-effects to determine the associations between IOZs and isolated ED/ED + HT.

RESULTS

A total of 183 IOZs in 24 patients were included in the isolated ED group, while a total of 143 IOZs in 31 patients were included in the ED + HT group. Sixty-eight IOZs of eight patients in the isolated ED group were located in the ipsilateral frontal interhemispheric fissure (F-IHF). Only ipsilateral F-IHF was significantly associated with isolated ED (odds ratio [OR], 2.43; 95% confidence interval [CI], 0.37-4.49; P = 0.021). The contralateral lateral frontal cortex (latF) (P = 0.007) and ipsilateral mesial temporal region (mT) (P = 0.029) were significantly associated with ED + HT.

CONCLUSION

The present study is the first to demonstrate that seizures with an F-IHF focus tend to present with initial ipsilateral isolated ED. This finding may aid in identifying the seizure focus in patients with isolated ED prior to resection.

Cellular-Scale Microelectrode Arrays to Monitor Movement-Related Neuron Activities in the Epileptic Hippocampus of Awake Mice

OBJECTIVE

Epilepsy affects 50 million people worldwide and its pathogenesis is still unknown. In particular, the movement-related neural activities involving glutamate (Glu) and electrophysiological signals at cellular level remains unclear.

METHODS

A cellular-scale implantable microelectrode array (MEA) was fabricated to detect the movement-related neural activities involving Glu concentration and electrophysiological signals. Platinum and reduced graphene oxide nanocomposites were deposited to enhance the surface area. Glu oxidase (Gluox) were coated to effectively recognize Glu molecule.

RESULTS

Neural activities in the hippocampus of normal and epileptic mice is different, and the changes are closely connected with movement. Glu concentration and spike firing rate in the epileptic mice were much higher than those in the normal ones. And the neural activities with significant synchronization were detected in the epileptic mice even without seizure occurrence. Meanwhile, the spikes fire more intensively and Glu level became much higher during the movement of the mice compared to the stationary state.

CONCLUSION

The existing abnormality of neural activities in the epileptic mice are potential factors to induce a seizure. Movement may impact the neural activities and the duration of seizure.

SIGNIFICANCE

The MEA can monitor changes of movement, Glu and neuron discharges synchronously and provides us an effective technology to understand the neuronal disease.