Patients with epilepsy are at risk for sleep disorders. One of the reasons is that seizures or the epileptic state itself may alter sleep organization. Seizures have immediate effects on sleep, resulting in a stage shift to a lighter stage of NREM sleep or to the awake state. They also have more delayed effects on REM sleep and other sleep parameters.

A study of 77 patients with primary or secondarily generalized tonic-clonic seizures compared sleep parameters on nights when generalized seizures occurred, as compared to seizure-free nights.1 On nights with seizures, the subjects had:

  • reduced total sleep time
  • reduced proportion of REM sleep
  • increased wake time after sleep onset
  • increased proportion of stage-2 NREM sleep time

In a separate study of 80 subjects with partial seizures, total sleep time and the relative proportion of NREM sleep were not different on nights when partial seizures occurred than during seizure-free nights. If recurrent partial seizures occurred during sleep, the relative proportion of REM sleep time (but not total sleep time) was reduced, suggesting that the REM-suppressing effects of seizures are independent of reductions in total amounts of sleep.

A separate group of investigators independently reported this REM-suppressing effect of seizures, as well as other effects on sleep organization, in 11 subjects with temporal lobe epilepsy.2 On nights when seizures occurred, sleep architecture was disturbed:

  • increased wake time after sleep onset
  • decreased sleep efficiency
  • decreased proportion of stage 3 NREM sleep
  • decreased proportion of REM sleep
  • prolonged REM sleep latency

These subjects were sleepier on the day after nocturnal seizures, as assessed by the Maintenance of Wakefulness Test3 and the Stanford Sleepiness Scale.4 In a separate study of these 11 subjects, daytime seizures also affected sleep organization. They showed a significant decrease in the amount of REM sleep and a prolongation of REM sleep latency on nights after daytime seizures.5

Even on seizure-free nights, people with epilepsy may have more sleep disruptions than those without epilepsy. A decrease in sleep efficiency, an increase in the number of sleep stage shifts and entries to wakefulness, and an increase in the number and duration of awakenings was noted in 80 patients with primary generalized epilepsy or complex partial seizures, as compared to 17 healthy controls.6 Those with temporal lobe epilepsy were the most affected. The duration and percentages of the different stages of NREM and REM sleep, the number of sleep cycles, and the REM sleep latency were not statistically different from those of controls. Sleep fragmentation by awakenings was greater in untreated, newly diagnosed patients. After treatment with carbamazepine for 1 month, the newly diagnosed epilepsy patients showed improvement in these parameters.

Survey studies have reported results similar to results of polysomnographic studies. Miller, interviewing 60 patients with epilepsy, found that 68% complained of feeling sleepy during the day, 39% had difficulty falling asleep or staying asleep, and 42% complained that their sleep difficulties interfered with their work performance.7 In a survey of 30 independently living adults with partial or generalized seizures and 23 healthy controls, night awakenings were reported more frequently by those with epilepsy.8 Those who had at least one seizure a month were the most affected. The majority of the people with epilepsy described feeling mildly tired or very tired on awakening.

Adapted from: Malow, BA, and Vaughn BV. Sleep disorders and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;255–267.
With permission from Elsevier (www.elsevier.com). 

Reviewed by: Steven C. Schachter, MD on 4/2004
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