Advances in the diagnosis and treatment of epilepsy

Differential contribution of excitatory and inhibitory neurons in shaping neurovascular coupling in different epileptic neural states

Understanding the neurovascular coupling (NVC) underlying hemodynamic changes in epilepsy is crucial to properly interpreting functional brain imaging signals associated with epileptic events. However, how excitatory and inhibitory neurons affect vascular responses in different epileptic states remains unknown. We conducted real-time in vivo measurements of cerebral blood flow (CBF), vessel diameter, and excitatory and inhibitory neuronal calcium signals during recurrent focal seizures. During preictal states, decreases in CBF and arteriole diameter were closely related to decreased γ-band local field potential (LFP) power, which was linked to relatively elevated excitatory and reduced inhibitory neuronal activity levels. Notably, this preictal condition was followed by a strengthened ictal event. In particular, the preictal inhibitory activity level was positively correlated with coherent oscillating activity specific to inhibitory neurons. In contrast, ictal states were characterized by elevated synchrony in excitatory neurons. Given these findings, we suggest that excitatory and inhibitory neurons differentially contribute to shaping the ictal and preictal neural states, respectively. Moreover, the preictal vascular activity, alongside with the γ-band, may reflect the relative levels of excitatory and inhibitory neuronal activity, and upcoming ictal activity. Our findings provide useful insights into how perfusion signals of different epileptic states are related in terms of NVC.

Association between epilepsy and oral maxillofacial trauma: A systematic review and meta-analysis

A systematic literature search was conducted (through April 2017), using Web of Science, PubMed and Virtual Health Library, manual reference list, and grey literature searches. The quality of the studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale. The meta-analysis was performed using R software. A total of 30 studies was included in this review. From a total of 25 studies included in the meta-analysis, the prevalence of oral and maxillofacial injuries among epileptic subjects was 19%. Among the epileptic patients who suffered some type of injury due to epileptic seizures, 52% had facial soft tissue injuries (95%CI: 28-75%), 18% suffered dental trauma (95%CI: 11-29%), and 12% (95%CI: 4-28%) suffered maxillofacial fractures. Epileptic patients were more likely to have oral and maxillofacial injuries than healthy individuals (OR: 5.22, 95%CI: 2.84-9.36) and subjects with psychogenic nonepileptic seizures (OR: 2.77, 95%CI: 1.28-5.99), but not than patients with special needs (OR: 2.45,95%CI: 0.95-6.31).

Triple pathology in patients with temporal lobe epilepsy: A case report and review of the literature

The coexistence of three intracranial lesions related to epileptic pathogenesis is known as ‘triple pathology’ and has rarely been reported. In this study we report a case of temporal lobe epilepsy (TLE) with the coexistence of hippocampal sclerosis (HS), focal cortical dysplasia (FCD) and ganglioglioma in the temporal lobe. A 29-year-old male who had experienced recurrent seizures for four years was admitted to hospital. Cerebral magnetic resonance imaging (MRI) was conducted and T2-weighted and fluid-attenuated inversion recovery sequence (FLAIR) images revealed a reduced hippocampal volume with an increased FLAIR signal on the right side and a slightly enlarged temporal horn, which are typical imaging findings for HS and FCD. The patient underwent resectioning of the right anterior temporal lobe, hippocampus and amygdala, in addition to the lesion located in the medial temporal lobe. Immunohistochemical analysis of the medial temporal lobe lesion confirmed a ganglioglioma (WHO grade I) in the medial temporal lobe. During the first eight months following surgery, the patient's seizures were controlled with zonisamide and phenytoin. Electroencephalogram (EEG) assessment post-surgery confirmed the absence of epileptic discharges. Based on a literature review and a detailed review of this case, we postulate two possible explanations for the pathogenesis of ‘triple pathology’: i) ‘triple pathology’ is a combination of pathological progression and occasionality; and ii) ‘triple pathology’ lesions have similar pathological origins.