Seizures

By | February 12, 2012

There is both increased association of seizures with sleep deprivation as well as increased incidence of seizures during non-rapid eye movement (non-rapid eye movement) sleep. In fact, 7.5% to 45% of patients with seizures have events confined to the sleep period. Sleep disturbances in patients with epilepsy are a key predictor of quality of life in these patients. A brief description of seizures and clues from their sleep that may contribute to their diagnosis is given. Those reviewed by age of peak onset include continuous spike and slow wave discharges during sleep, Lennox-Gastaut syndrome, absence epilepsy, juvenile myoclonic epilepsy, epilepsy with generalized tonic-clonic seizures on awakening, benign childhood epilepsy with centrotemporal spikes, frontal lobe epilepsy, and temporal lobe epilepsy. Nocturnal paroxysmal dystonia is considered a form of frontal lobe epilepsy and will be described as well.

Continuous spike and slow wave discharges during sleep (CSWS) is characterized by continuous slow spike-and-wave complexes on the electroencephalographic throughout at least 85% non-rapid eye movement sleep. It is formerly known as electrical status epilepticus of sleep. Movement does not occur. During wake and rapid eye movement sleep, epileptiform activity is more focal and noncontinuous. It may be associated with progressive intellectual decline.

Lennox-Gastaut syndrome is a severe epilepsy syndrome with onset in childhood (peak onset 3-5 years). Cognitive and neurologic deficits are present. Seizure types range from axial tonic seizures that occur during sleep (in particular non-rapid eye movement) to tonic-clonic seizures, atypical absence, and myoclonic and atonic seizures. Interictal electroencephalographic reveals 2 to 2.5 Hz spike-and-wave complexes.

Juvenile myoclonic epilepsy (peak onset 14 years) is characterized by myoclonic jerks, tonic-clonic seizures, and absence seizures. Events commonly occur within a few hours of awakening. electroencephalographic reveals 3.5 to 6 Hz spike-and-wave discharges worsened with photic stimuli.

Absence seizures are generalized seizures with peak onset at age six to seven years. The duration is brief (5-10 seconds), with disruption of ongoing activity and a blank stare, then return to activity. Eye blinking and lip smacking may be present. electroencephalographic shows a characteristic three-second spike-and-wave discharge. Such patterns and behavior should lead to systematic sleep investigations despite absence of clinical manifestations during sleep. Sleep activates seizures, which are most prominent during non-rapid eye movement sleep and the first sleep cycle.

Epilepsy with generalized tonic-clonic seizures on awakening is another generalized epilepsy, with peak age of onset at age 11 to 15 years. A genetic basis is probable. Seizures occur almost predominately upon awakening or during evening drowsiness.

Benign childhood epilepsy with centrotemporal spikes peaks at age 9 to 10 years and is characterized by perioral numbness, guttural sounds, excess salivation, and focal facial twitching. Clonic jerks of the arm and leg may also occur. Events most often occur during sleep and drowsiness. They resolve by adulthood. electroencephalographic shows centrotemporal sharp waves in the region of origination.

Nocturnal frontal lobe epilepsy can present with both motor and cognitive changes and may be difficult to detect on the electroencephalographic, depending on depth of focus. It may present with partial arousal from sleep with behaviors that mimic parasomnia, as nocturnal paroxysmal dystonia, and as unexplained arousals or stereotyped behavior. electroencephalographic may show a focal epileptiform abnormality that is, by definition, localized to the frontal lobe.

Nocturnal mesiotemporal seizures may also underlie abnormal stereotyped behavior out of non-rapid eye movement sleep, mimicking sleepwalking in a manner similar to mesiofrontal seizures.

Evaluation of Seizures

In general, when seizure is expected, evaluation should begin with a careful history and neurologic workup directed to any daytime symptoms. Sleep-deprived electroencephalographic evaluation for characteristic electroencephalographic features is diagnostic in many cases, though up to three EEGs may be required to increase sensitivity. When symptoms are confined mostly to the sleep period, nocturnal video-polysomnography is indicated. This is the case when nocturnal frontal lobe epilepsy is suspected. If seizure disorder is already known, diagnostic workup is directed to the primary sleep symptom. For example, excessive daytime sleepiness may be secondary to obstructive sleep apnea, central sleep apnea, hypoventilation, restless legs syndrome, and periodic limb movement disorder. Since sleep disturbances can impact quality of life, a high index of suspicion for their evaluation and treatment is important. Improvement of seizure frequency is reported following continuous positive airway pressure in patients with sleep apnea and epilepsy

Treatment of Seizures

Nonpharmacologic treatment should be directed as described elsewhere to treat the identified sleep disorder. Given the increased incidence of seizure with sleep deprivation, educating the patient regarding keeping a regular sleep-wake cycle is important.

Pharmacologic treatment should be directed as described elsewhere to treat the identified sleep disorder.

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