Background and Objective
Frontal lobe epilepsy is the second most common localization-related or focal epilepsy. Frontal lobe seizures are challenging to diagnose as the clinical manifestations are diverse due to the complexity and variability of the patterns of epileptic discharges, and the scalp electroencephalograph (EEG) can often be normal or misleading. This review focuses on the clinical and EEG features of seizures arising from the frontal lobe.
The clinical manifestations in patients with frontal lobe epilepsy are varied. Frontal lobe seizures can be divided into perirolandic, supplementary sensorimotor area, dorsolateral, orbitofrontal, anterior frontopolar, opercular, and cingulate types. Seizures originating from the perirolandic and supplementary sensorimotor areas are clinically distinct, characterized by motor activity or asymmetric tonic posturing with preserved awareness. Seizures arising from dorsolateral, orbitofrontal, frontopolar, and cingulate areas are not as well characterized and have more variable clinical manifestations. Scalp EEG recording is sometimes helpful in localization but is usually normal or misleading in frontal lobe epilepsy. The treatment is similar to other localization-related or focal epilepsies. Medications are the first line of therapy, and surgery is considered for patients who fail to respond to medications. The surgical outcome in frontal lobe resections is less favorable than in anterior temporal lobectomies due to the challenge in locating the epileptogenic zone and the presence of functional areas (eloquent cortex) that can limit the resection.
Frontal lobe seizures are characterized by diverse behavioral manifestations. Only a few well-described frontal lobe syndromes exist. The variety of clinical manifestations reflects both the varying sites of seizure origin and propagation routes that seizures may take. Although this review provides a framework for the understanding of these seizures, one should remain cautious in diagnosing seizure localization based on clinical or EEG description. Only a few patients have well-described syndromes and can be diagnosed with confidence. For most patients, new diagnostic methods and genetic testing may help improve our ability to diagnose and treat the conditions discussed in this study.