Functional Seizures Associated With Stroke, Psychiatric Disorders

January 8, 2021
In a large-scale study of electronic health records (EHRs), researchers have determined the prevalence of functional seizures and characterised comorbidities associated with them. The research team, headed by Lea Davis, PhD, Vanderbilt Genetics Institute, Nashville, Tennessee, confirmed associations between functional seizures and psychiatric disorders including posttraumatic stress disorder, anxiety, and depression as well as sexual assault trauma. They also discovered a novel association between functional seizures and cerebrovascular disease, including stroke. The findings were reported in JAMA Network Open. About 80% of patients experiencing functional seizures are initially misdiagnosed with epilepsy and treated with anti-epileptic drugs, said Slavina Goleva, Vanderbilt University. An accurate diagnosis requires assessment with video electroencephalogram (EEG). “We initially recognised that finding these patients within the EHR would be a challenge because the ICD [International Classification of Diseases] codes are not as specific as they are for a lot of diseases,” she said. In addition to ICD codes, the researchers included Current Procedural Terminology (CPT) codes and used natural language processing to search within the records for a list of keywords. The researchers manually reviewed charts to confirm that the algorithm correctly identified patients with functional seizures. The study included more than 2.3 million patients aged 18 years and older in the VUMC-EHR system from 1989 to 2018. The researchers identified 3,341 patients with functional seizures, 74% of whom were women. They calculated a prevalence of 0.14% (140 cases per 100,000 people); previous estimates ranged from 2 to 33 cases per 100,000 people. “Our report is the first direct calculation of the prevalence of functional seizures,” Goleva said, noting that the epilepsy monitoring unit at VUMC may result in a higher prevalence of functional seizures in patients in the VUMC-EHR compared with the general population. Among the patients with functional seizures, the researchers validated comorbidities including psychiatric disorders and sexual assault trauma and discovered a novel association with cerebrovascular disease. They also found that sexual assault trauma explained about a quarter of the increased rate of functional seizures among women. “Functional seizures are not occurring in isolation,” said Dr. Davis. “Patients who are experiencing these seizures are also experiencing a higher burden of additional healthcare issues.” The researchers recommended that patients experiencing seizures who have psychiatric comorbidities or a history of sexual assault trauma be referred for video-EEG assessment. Patients who develop seizures after a stroke and do not initially respond to treatment with medications should also be considered for early video-EEG assessment. Up to 30% of patients referred for video-EEG are eventually diagnosed with functional seizures, they noted. “It’s frustrating that there is no ICD code for functional seizures, given how common the diagnosis is and the fact that codes exist for strange things like alligator bite, second occurrence,” said Dr. Davis. “It really emphasises how little attention this population of patients has gotten.” Reference: SOURCE: Vanderbilt University Medical Center