Epileptic seizures (ES) are caused by disturbances in electrical activity in the brain. However, in 20-40% of individuals whose seizures are not controlled by antiseizure medications, seizure activity does not correlate with changes in an electroencephalogram (EEG).[1] These seizures are classified as psychogenic non-epileptic seizures (PNES), also known as functional or dissociative seizures (FDS).[2] Many people with FDS have experienced abuse, trauma, or neglect. FDS can co-occur with depressive disorders, personality disorders, and post-traumatic stress disorders. FDS are often debilitating and are associated with a decreased quality of life, substantial emotional burden, and financial and psychosocial loss.[3,4] There is value to the epilepsy field in understanding and studying FDS for several reasons: first, ES and FDS can co-exist,[5] and second, both ES and FDS can impact the cardiac system, leading to changes in heart rate, arrhythmias, and other abnormalities seen on an electrocardiogram (ECG).[6,7] Disturbances in the autonomic nervous system have been seen in individuals with ES and FDS, and this is especially true in drug-resistant epilepsy and cases of Sudden Unexpected Death in Epilepsy (SUDEP).[8,9]
It is important to be able to differentiate between ES and FDS because the characteristics and treatment options for each differ. Similar to ES, there is a high risk of sudden death in individuals with FDS. Alarmingly, those with FDS have 2.5 times the rate of sudden death compared to the general population.[10] People with suspected FDS may undergo testing in an epilepsy monitoring unit using video EEG, but tests done there can lead to inconclusive results. Not being able to properly diagnose FDS can have many detrimental impacts such as delays in getting proper treatment, and inappropriate or even inadvertently dangerous medical treatment.[11,12] Hence, there is an urgent need to develop ways to diagnose FDS and differentiate ES from FDS.
