Managing Seizures: From Medication to Advanced Procedures

Treatment for Periventricular Nodular Heterotopia (PVNH) is highly personal. Because the brain of every person with PVNH is “wired” differently, there is no single “best” medication or surgical path ^[1]. The goal of treatment is to control seizures and support your quality of life while minimizing side effects.

Starting with Medication

The first line of defense against seizures is antiseizure medication (ASM).

• Individualized Choice: Doctors typically treat PVNH as a form of “focal epilepsy,” meaning the seizures start in one part of the brain ^[2]. While medications like carbamazepine or levetiracetam are frequently used, your doctor will choose a drug based on your specific seizure type, age, and other health factors ^[3].
• Seizure Control: A significant portion of people with PVNH who have seizures will find they are “pharmacoresponsive” (well-controlled with medication). For example, in a cohort of 100 people seeking epilepsy care, 35 were pharmacoresponsive and 10 had a self-limited course ^[1]. If a person fails two different, appropriately chosen and adequately dosed medications, they are considered to have drug-resistant epilepsy and should be evaluated for other options ^[1].

Mapping the Seizure Network

If seizures continue despite medication, a comprehensive epilepsy-center workup is recommended. This typically includes a review of seizure recordings, video-EEG, high-quality MRI, neuropsychological assessment, and sometimes PET/SPECT/MEG scans.

It is a common myth that seizures always start exactly where the nodules are seen on an MRI. In reality, the seizure “network” often involves the nodules and the normal-looking brain tissue nearby (the cortex) ^[4][5].

To find the exact “seizure-onset zone” if noninvasive testing is inconclusive, specialized centers use Stereoelectroencephalography (SEEG). This involves placing thin, temporary electrodes directly into the brain to record activity from both the nodules and the surrounding cortex ^[6][7]. SEEG is considered only after comprehensive noninvasive evaluation, as it is critical because:

1. Seizures might start in just one or two nodules, while the others are “innocent bystanders” ^[8].
2. Treating only the nodules seen on an MRI might not stop the seizures if the nearby cortex is also involved ^[4].

Surgical and Minimally Invasive Options

Once the map is complete, several options may be considered. These interventions are supported largely by small, selected, retrospective series, and should be discussed at an epilepsy center.

1. Laser and Heat Therapies (Ablation)

• MR-guided Laser Interstitial Thermal Therapy (LITT): This uses a tiny laser to heat and destroy only the specific nodules or tissue causing seizures. In a highly selected retrospective series of 39 patients, 80% with unilateral PVNH and no other brain abnormalities became seizure-free. However, for those with bilateral PVNH, the seizure freedom rate was 50% ^[8].
• Radiofrequency Thermocoagulation (RFTC): This uses the SEEG electrodes themselves to deliver heat to the seizure-onset zone ^[9]. In selected cohorts, it can reduce seizures in about 71% of patients, with roughly 46% to 62% achieving total seizure freedom ^[9][10].

2. Neuromodulation

If seizures start in multiple areas or in eloquent parts of the brain (areas responsible for speech or movement), neuromodulation (implanted devices) may be considered to reduce seizure frequency and severity, though it generally aims to reduce seizures rather than guarantee seizure freedom.

• Responsive Neurostimulation (RNS): This device monitors brain waves 24/7. When it detects the start of a seizure, it sends a tiny electrical pulse to stop it before it spreads ^[11]. In a small eight-patient series of PVNH patients followed for a mean of 10.1 years, disabling seizures decreased by a mean of 85.7% ^[11]. RNS is primarily an adult treatment in many jurisdictions, requiring specific qualification for pediatric use.

Understanding the Risks

All brain procedures carry meaningful risks. The most common specific risk for PVNH surgery is a visual-field deficit. Because some nodules are located near the “wiring” for your vision, a procedure can sometimes cause a permanent “blind spot” in your peripheral vision ^[12][13]. Systematic reviews report permanent morbidity in around 10.4% of cases ^[12]. Your surgical team will use advanced imaging to help avoid these pathways whenever possible.

Ultimately, the decision to move from medication to surgery is a collaborative one, based on finding the right balance for your unique brain and safety goals.