Department of Neurology

Sleep and seizures

Q: My EEGs, and there have been several, have always shown that I have many seizures daily. The Doctors have always said that since there were only two seizures witnessed during waking hours that I must be having them during sleep. For the first time in 20 years of marriage my wife witnessed two tonic-clonic seizures while I was sleeping a few nights ago. The question is: Are these sleep seizures any more of a threat to my life than seizures only occuring during waking time would be? I am already taking 500mg of dilantin a day, without side effects that I am aware of, and since Saturday am very concerned.

A: A few points need clarification. A routine EEG study, that is, one that is performed for about 20 min, cannot indicate how many seizures per day you are having. Only a prolonged study that is recorded continously would provide this information. Otherwise the most accurate indicator of seizure frequency is a count performed by an observer such as a family member.

Sleep and sleep deprivation are major activators of seizures for many persons, and some have their seizures only in sleep. The reason for this has been speculated, but may relate to regulation of brain activity during different levels of consciousness. Some of the sleep associated epilepsy syndromes respond better to different medications.

I am not aware of data that indicates seizures are more harmful during sleep than during wakefulness.

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