Abstracts

Rationale: Occipital lobe seizures are relatively uncommon and under-recognized as compared with other focal seizures. Where medical therapy is ineffective, responsive stimulation (RNS System)  is another therapeutic option. However, the outcome and complications with RNS System treatment of occipital lobe seizures have not been well-studied. Our goal was to evaluate the characteristics of the patients who received an RNS System for occipital onset seizures and their outcomes.

Methods: The authors reviewed seizure detection and clinical data obtained in patients that had RNS System leads placed in or over the occipital lobe at the University of California in Los Angeles.

Results: Between August 4, 2014, and April 19, 2022, 111 RNS cases at our center were reviewed, of which 4 (3.6%) were occipital RNS patients. Two cases were pediatric, a 6-year-old female and a 17-year-old male, with leads: at thalamus (CM nucleus and pulvinar nucleus)/right occipital (case 1), and L-Occ (case 2). Two adults (27M, 37F) with electrodes at R-Occ, L-Occ (case 3) and R-Occ, R Temporal (case 4). There was a 60%-70% seizure frequency reduction and 80%-90% seizure intensity reduction after RNS placement compared with pre-RNS seizures (Figure 1). The RNS settings are summarized in Table 1. One of the 4 cases had a complaint of reporting visual changes with fleeting visual manifestations of flashes related to stimulation directly over the visual cortex. This happened right after the RNS was turned on and in the clinic. Adjusting the settings decreased the severity of the complaint and was resolved after the patient went home.

Conclusions: The RNS System can be effective in treating medically refractory epilepsy in the occipital lobe, with a 60%-70% seizure frequency reduction and 80%-90% seizure intensity reduction. However, placing the leads in the occipital area can have the risk of visual complaints at higher currents, which can be resolved with reprogramming.

Funding: None