Seizures frequently occur during sleep. A seizure is a transient disturbance of brain function resulting from abnormal, excessive, or synchronous electrical activity in the brain. These episodes, known as nocturnal seizures, are a common manifestation of epilepsy. Epilepsy is a neurological condition where a person experiences two or more unprovoked seizures, and a significant portion of these events happen during sleep.
Why Sleep Affects Seizure Activity
The brain’s electrical state changes dramatically during the sleep-wake cycle, directly influencing seizure likelihood. Seizure activity is often promoted by the synchronized electrical patterns characteristic of non-rapid eye movement (NREM) sleep. This type of sleep, which includes deeper stages, features highly synchronized neuronal firing that lowers the seizure threshold in susceptible individuals. The diffuse cortical synchronization during NREM sleep facilitates the spread and activation of interictal epileptiform discharges, which are abnormal electrical spikes seen between seizures.
In contrast, rapid eye movement (REM) sleep, characterized by a desynchronized, wake-like electroencephalogram (EEG) pattern, is generally protective against seizures. REM sleep suppresses the synchronized activity that can lead to a seizure event. Seizures are much more likely to occur during transitions between sleep stages, such as falling asleep, moving from light to deep sleep, or just before waking up. This fluctuation in brain state creates an unstable period where the balance between excitatory and inhibitory neuronal activity can tip toward seizure generation.
Recognizing the Signs of Nocturnal Seizures
Nocturnal seizures are often unwitnessed, making recognition challenging. If a partner is present, they may observe sudden, forceful jerking or stiffening of the limbs, sometimes leading to falling out of bed. Loud cries, vocalizations, or a sudden change in breathing pattern may also signal the onset. These signs, particularly generalized shaking or muscle rigidity, suggest a tonic-clonic seizure occurred.
For the person who experienced the event, indicators are often noticed upon waking. A severe, unexplained morning headache is a common post-seizure symptom, as is significant muscle soreness or fatigue. A tell-tale sign is waking up with an injured tongue or cheek, often bitten during the involuntary muscle contractions. Waking up in a state of confusion, known as the post-ictal state, can last from minutes to hours, and unexplained bedwetting (urinary incontinence) can also be a sign.
Specific Syndromes Associated with Sleep
Certain epilepsy syndromes are specifically linked to the sleep-wake cycle, with seizures predominantly or exclusively occurring during rest. Benign Epilepsy of Childhood with Centrotemporal Spikes (BECTS), also known as Rolandic Epilepsy, is the most common focal epilepsy syndrome in children. Seizures in BECTS typically present as twitching or tingling on one side of the face or tongue, often progressing to a generalized seizure. This syndrome is considered self-limiting, with most children spontaneously outgrowing the seizures by mid-adolescence.
Another condition is Autosomal Dominant Nocturnal Frontal Lobe Epilepsy (ADNFLE), now often referred to as Sleep-Related Hypermotor Epilepsy (SHE). This type is characterized by brief, repetitive, and often bizarre movements, such as bicycling movements of the legs or sudden thrashing of the arms. These seizures occur almost exclusively during NREM sleep and frequently happen in clusters throughout the night. They can sometimes be mistaken for parasomnias, such as night terrors or sleepwalking, due to the complex motor behaviors involved.
Diagnosis and Treatment Pathways
If nocturnal seizures are suspected, the first step is consulting a neurologist for a proper diagnosis. Diagnosis often begins with a standard electroencephalogram (EEG), which records the brain’s electrical activity, but this may not capture a sleep-related event. Therefore, specialized tests are required to capture nocturnal activity, such as a sleep-deprived EEG, where the patient is intentionally kept awake to increase the likelihood of recording abnormal electrical activity.
The most definitive diagnostic tool is Video-EEG Monitoring, which involves continuous, simultaneous recording of the EEG and video, typically over several nights in a dedicated unit. This allows physicians to correlate observed physical movements with corresponding electrical spikes, confirming whether they are epileptic seizures or a non-epileptic sleep disorder. The primary management for confirmed nocturnal epilepsy involves Anti-Epileptic Drugs (AEDs) tailored to the specific seizure type and syndrome. Maintaining excellent sleep hygiene is also a fundamental part of the treatment plan, as sleep deprivation is a known trigger that increases seizure susceptibility.