Patients with focal epilepsy with difficult-to-detect, subtle seizures experienced long delays in diagnosis and treatment, and these delays were associated with a high incidence of motor vehicle accidents, a cross-sectional study showed.

Among 246 patients with focal epilepsy with subtle, non-motor seizures, the median time to diagnosis from the first reported seizure was 616 days, reported Dr. Jacob Pellinen of the University of Colorado Medical School at Aurora and co-authors. In contrast, the median diagnosis for 201 patients with disruptive motor seizures occurred within 60 days (P <0.001).

The proportion of patients who had an injury prior to diagnosis and the severity of those injuries were similar between the two groups. However, 19 out of 23 (82.6%) motor vehicle accidents occurred in people with undiagnosed subtle seizures, they wrote in Epilepsia.

“The results underscore the fact that non-motor seizures are poorly recognized by patients, family members and health professionals,” Pellinen said. “Improving detection could help fill this treatment gap.”

Undiagnosed subtle seizures can include brief hallucinations or episodes of déjà vu and are not benign, Pellinen pointed out. “The vast majority of pre-diagnostic motor vehicle accidents in our study occurred in people with undiagnosed non-motor seizures,” he told MedPage Today. “This has not been previously reported and has a significant impact on the health of people with emerging epilepsy and the communities in which they live.”

“Driving safety is very important to the quality of life of people with epilepsy,” said Dr. Hal Blumenfeld of Yale University in New Haven, Connecticut, who was not involved in the research. “These new findings shed light on a previously unknown cause of car accidents in people who are unaware that they have epilepsy.”

The study analyzed data from participants who participated in the Human Epilepsy Project from June 2012 to November 2017. The project included 34 participating epilepsy centers and ambulances in the USA, Canada, Europe and Australia.

Participants were referred for newly diagnosed focal epilepsy within 4 months of treatment. A total of 447 patients completed the registration data for this analysis.

“To determine if starting treatment was effective, we obtained a very thorough history of these patients’ seizures prior to registration,” said co-author Jacqueline French, MD, of the NYU Comprehensive Epilepsy Center in New York City. “It quickly became clear that many patients had a long delay in diagnosis and treatment.”

The researchers grouped patients into two categories based on initial seizure semiology: subtle seizures (mainly motor stasis or focal consciousness without a motor) or disturbing seizures (mainly motor activity or verbal performance, including generalized tonic-clonic seizures). Demographics were similar between the two groups. Most of the patients were women and the mean age at the onset of the seizure was 30 years.

More patients with emerging focal epilepsy had initially subtle seizures than disruptive seizures (55% versus 45%, P = 0.001). Two-thirds of patients with initial subtle seizures (67.5%) were not diagnosed until they developed seizures with disruptive characteristics, including bilateral tonic-clonic seizures.

Approximately 72% of the patients with initial subtle seizures had retained consciousness, while 90% of the patients with initial disruptive seizures had a loss of consciousness. Patients with subtle seizures and retained consciousness were diagnosed for a median of 801 days.

Prior to diagnosis, 40.7% of people with subtle seizures had injuries, as did 49.3% of those with disruptive seizures. The difference between the groups was insignificant. However, most potentially avoidable motor vehicle accidents (MVAs) occurred in patients with initial subtle seizures (P <0.001).

“While our study did not demonstrate that prior treatment would prevent injuries including MVAs or the progression from non-motor seizures to motor seizures, it does highlight this as an important area for further investigation,” noted Pellinen and colleagues.

“As a conservative estimate, among the US population between the ages of 12 and 60 years (as in our study) and considering the annual incidence of epilepsy of approximately 67.77 per 100,000 people, there are approximately 142,500 new-onset epilepsy cases each year “, write.

“About half of the cases start in people of driving age, and about 60% of these epilepsies are focal. We have found that there are about 1,816 MVAs each year in the US alone due to undiagnosed non-motor partial seizures,” they continued. “In particular, our study would not have included people who died or had serious injuries during an MVA, and we relied on participants to disclose MVAs, so the number may actually be the tip of the iceberg.”

Although detailed information on seizure semiology was collected in the Human Epilepsy Project database, one caveat is that it relied on patient-reported retrospective data from months or years prior to diagnosis, the researchers said. This may have underestimated the frequency of subtle events that patients did not seek evaluation for and the number of previous injuries, especially minor ones, in undiagnosed patients.

Last updated on October 20, 2020

  • Judy George covers neurology and neuroscience news for MedPage Today, writing on Brain Aging, Alzheimer’s, Dementia, MS, Rare Diseases, Epilepsy, Autism, Headache, Stroke, Parkinson’s, ALS, Concussion, CTE, Sleep, Pain, and more. consequences


This study had no specific funding.

The researchers reported relationships with UCB, Acorda, Neurelis, Lumetra Healthcare Solutions, and the Epilepsy Foundation.