Electroclinical features of lateral and medial orbitofrontal epilepsy: a case series

Abstract

To better understand the electroclinical features and epileptic network of lateral and medial orbitofrontal epilepsy (OFE). We evaluated four patients who had undergone epilepsy surgery. Epileptic foci in two patients originated from the lateral orbitofrontal cortex, and those in the other two originated from the medial orbitofrontal cortex, which was confirmed by stereoelectroencephalography (SEEG). Time-frequency spectrograms were also provided for assistance, and the change in high-frequency energy was superimposed on the 3D reconstructed brain with a colour code in order to more intuitively show the transfer of high-frequency energy as the seizure evolves. All patients underwent SEEG-guided radiofrequency thermocoagulation (RF-TC) or focal resection and achieved satisfactory results. Lateral OFE and medial OFE were relatively independent with regards to clinical symptoms and epileptic network, however, lateral OFE was likely to propagate to the dorsolateral frontal lobe, whereas medial OFE (gyrus rectus) was more likely to propagate to the medial temporal lobe or insular lobe with long duration. There were significant differences in duration (21.17 ± 11.5 vs. 127.22 ± 235.05) and early propagation time (7.92 ± 4.44 vs. 29.0 ± 33.47) between the two origins. A better understanding of the electroclinical features of lateral and medial OFE is helpful to understand their epileptic networks and perform accurate resections in order to protect the cognitive and behavioural functions of patients.