Prevention of SUDEP

Wednesday, August 8, 2012

Research findings during the past several decades have identified a number of risk factors for SUDEP that can be modified and suggest strategies to help prevent SUDEP. Seizure control is a primary focus of prevention. Complete seizure control – especially for generalized tonic-clonic seizures (GTCS) - is the goal but this must be balanced against side effects of antiepileptic drugs (AEDs) and quality-of-life. Often, seizures cannot be fully controlled despite the best medical care. Other modifiable risk factors include AED drug polytherapy and alcohol abuse. Although lamotrigine is a risk factor for SUDEP in some studies, meta-analyses that control for GTCS frequency found no increased risk with lamotrigine. A meta-analysis of randomized AED clinical trials found that an adjunctive AED at an efficacious dose was associated with a 10-fold reduction in SUDEP compared to placebo. Although these clinical trials were short-term and cannot be generalized to routine clinical care, they provide compelling evidence that improved seizure control reduces the rate of SUDEP, at least in the short-term.

Evidence from epidemiological studies, cases of SUDEP witnessed in the community and recorded on video EEG all suggest that seizures, most often GTCS, precede the majority of SUDEPs. In many patients, GTCS cannot be fully controlled with AEDs and patient education on AED adherence, sleep deprivation, etc. In these cases, what can be done to prevent SUDEP after a GTCS or another seizure type? Nothing is proven to prevent SUDEP. However, several studies found that epilepsy patients are more likely to fall victim to SUDEP when they are unsupervised, especially at night, as compared to those who are supervised during sleep with a monitoring device (e.g., sound monitor) or observer who can reposition them. Recent unpublished observations suggest that intervention by nurses in an epilepsy monitoring unit (Bateman, unpublished) may shorten seizure duration and the severity and duration of postictal hypoxemia. We need more studies to address the role of repositioning, specific forms of stimulation, and the use of oxygen. We also need to understand why some seizures that occur in medical settings are followed by SUDEP despite prompt resuscitative measures.

Accumulating evidence that many SUDEPs follow GTCS, especially in sleep and that patients are found prone. Together with data that unsupervised patients are at higher risk of SUDEP, this suggests that devices to detect seizures and alarm caregivers could potentially prevent SUDEP. A variety of seizure detection devices have been or are being developed. Studies on these devices remains limited and none are approved in the United States for seizure detection and their role in preventing SUDEP remains unproven. Although EEG based devices can offer high sensitivity and specificity, they are limited by difficulty with application and patient compliance. Most available devices are motion detectors, and include accelerometers (e.g., SmartWatch*, EpiLert (watch), EpDetect phone app*), mattress sensory (e.g., Medpage MP5*, Emfit Movement Detector*), or video motion detectors. They are inexpensive and noninvasive but detect only convulsive seizures and may have limited specificity. Several multimodal devices are in development that detect combinations of motion, electrodermal skin response, heart rate, and respiratory rate (e.g., MIT-Boston Children’s Hospital and RTI). In addition, lattice pillows that allow airflow even if a patient’s face is flush against the surface, are a Class I medical device in the United Kingdom but have never been tested and remain unproven. Finally, seizure detection devices are limited by the availability of a nearby caregiver who can respond. We need to address systems that can detect seizures and prevent progression to SUDEP for those who live alone.

Education may be the most effective current tool to combat SUDEP. Many SUDEPs occur in young adults, a population at high risk for non-adherence to AED therapy, sleep deprivation, and intermittent consumption of excess alcohol. In addition, many epilepsy patients are unaware of the dangers of seizures, which extend beyond SUDEP. We need to better identify educational strategies that reduce seizure activity in different populations.

* Commercially available

Authored by: Orrin Devinsky, MD on 8/2012

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