Sleep-related hypermotor epilepsy (SHE), previously known as nocturnal frontal lobe epilepsy, is a form of focal epilepsy characterized by seizures which arise during sleep. The seizures are most typically characterized by complex motor behaviors. It is a relatively uncommon form of epilepsy that constitutes approximately 9-13% of cases. This disorder is associated with cognitive impairment in at least half of patients as well as excessive daytime sleepiness due to poor sleep quality. This disorder is sometimes misdiagnosed as a non-epileptic sleep disorder. There are many potential causes of SHE including genetic, acquired injuries and structural abnormalities. History
In 1981, Lugaresi and Cirignotta described a group of 5 patients with paroxysmal attacks of violent movements of the extremities and dystonic-tonic posturing. It was initially uncertain whether these events constituted seizures or something else. However, the patients had a good clinical response to the anti-seizure medication carbamazepine. Ultimately, the epileptic nature of this condition was confirmed with EEG and suggested that they were coming from the frontal lobe. The term “nocturnal frontal lobe epilepsy” was suggested as a name for this condition. Later in 2014, a consensus conference recommended that the name be changed to sleep-related hypermotor epilepsy. There were three main justifications for this change: (1) not all seizures arise from the frontal lobe; (2) seizures do not necessarily occur during the night but rather from sleep; (3) hypermotor describes the most common visible clinical manifestation of the seizures. Symptoms
Seizures in SHE are brief and usually have an abrupt onset and offset.
People who have nocturnal seizures may notice unusual conditions upon awakening in the morning, such as a headache, having wet the bed, having bitten the tongue, a bone or joint injury, muscle strains or weakness, fatigue, or lightheadedness. Others may notice unusual mental behaviors consistent with the aftermath of a seizure. Objects near the bed may have been knocked to the floor, or the subject may be surprised to find themselves on the floor. Diagnosis is based on clinical history but often EEG and/or polysomnography is required. In many patients the EEG can also be unhelpful as seizures may originate from deep in the brain. Polysomnography can be helpful distinguishing SHE from parasomnias as they often arise from different stages of sleep. Treatment
Like other forms of epilepsy, SHE can be treated with anti-seizure medications. Adequate control of seizures occur in approximately two-thirds of patients with anti-seizure medications while approximately one-third of patients do not appropriately respond. The relative efficacy of different medications has not been systematically investigated. Historically, low-dose carbamazepine has been the preferred medication for SHE and is often considered to be first-line. Other anti-seizure medications which have been studied for the treatment of SHE and found to have efficacy include: oxcarbazepine, topiramate, lacosamide and perampanel. Epilepsy surgery can be efficacious in refractory patients. In addition, there have been reports of successfully treating SHE due to mutations in CHRNA4 with nicotine patches. References
Sources
Manford, Mark (2003), Practical Guide to Epilepsy, Butterworth-Heinemann, ISBN 978-0-7506-4621-5