Study shows over 50 per cent of seizures go unreported in patients with epilepsy

Above: Dr Amy Halliday

A study led by St Vincent’s Hospital Melbourne has found that patients with epilepsy often don’t recognise they are having a seizure, resulting in 51 per cent of seizure events going unreported.

A large proportion of these undetected seizures happened while patients were asleep, but, alarmingly, 55 per cent occurred when they were awake. The findings form part of a research project that investigated prolonged ambulatory (in-home) video electroencephalogram (EEG) monitoring as an alternative to hospital inpatient EEG monitoring to help improve seizure diagnosis and in turn, improve the management and treatment of epilepsy.

The study, which was published in the Epilepsy & Behaviour medical journal, involved a retrospective data analysis of more than 3,000 EEG reports from 598 patients who had been referred to a diagnostic service for in-home video EEG monitoring. 

The study also showed that 58 per cent of patient-reported seizures were not seizures at all, reinforcing that self-reporting is not a perfect marker of true seizure frequency.

“Clinical management of epilepsy relies heavily on accurate seizure reporting from patients. Most patients use a physical or digital seizure diary to help record their events. But understandably, many people are not good at identifying when they are having a seizure,” said Dr Amy Halliday, a Neurologist at St Vincent’s Hospital Melbourne and the Project Lead.

“Seizure diaries can be inaccurate for a number of reasons. Patients may be unaware of their seizures or forget to log events in the diary, or report events as seizures that are not in fact epileptic seizures. This leads to both under-reporting and over-reporting of the true seizure frequency in a way that varies from person to person.

“It is often not possible to know how accurate an individual patient is at self-reporting their seizures when the neurologist is talking to the patient.”

Easing the burden

Above: Professor Mark Cook

The ability to do video EEG monitoring at home provides a viable option that can potentially ease pressure on the hospital system, where waiting lists can be up to 18 months to 2 years for a week-long EEG study, Dr Halliday explained.

“As this study shows, you can get a wealth of data from an EEG. It is a relatively non-invasive way of looking at what the brain is doing. Even though it is technology that has been around for a while we are at early stages of being able to understand exactly what we can do with it – things such as seizure forecasting, for instance, and also using it to help determine what medication or treatment might best suit a patient,” she added.

Around 250,000 Australians are currently living with epilepsy and around 1 in 25 Australians are diagnosed in their lifetime.

Professor Mark Cook, Director of Neurology at St Vincent’s Hospital Melbourne, said access to in-hospital video EEG monitoring is limited, and is generally prioritised for patients who need surgical evaluation for their epilepsy.

Distinguishing an epilepsy event is challenging and a lot of the work done by a neurologist in managing epilepsy relates to information the patient and their family provides and how that information is interpreted.

“We often don’t have a lot of hard evidence to go off. The most accurate identification is through recording a seizure event while it is happening using an EEG and video at the same time,” said Prof Cook.

“This type of testing has the ability to dramatically change the management of patients with epilepsy. It can make the diagnosis, and it can change the diagnosis. It can also recognise other serious health issues otherwise thought to be epilepsy.

“About 1 in 200 patients who present with epilepsy have a life-threatening heart problem that is causing the seizures and can be fixed. Some seizures reported turn out to be as a result of a person’s heart stopping, which can resemble the same effects as a seizure. These are the things we can pick up with video EEG monitoring.”