Whatever the ’cause’, most people with epilepsy analyse their day to day lives in an attempt to detect factors which precipitate seizures.
Virtually every conceivable life event may be blamed by some people with epilepsy, who may become overly obsessional about avoiding factors they consider important. For example, a man had each of his two seizures on railway trains. He firmly believes that in some way trains make him have seizures. It is likely that this occurrence is just coincidental, but we cannot be entirely sure that he is wrong!
There are, however, a number of factors which do seem to precipitate seizures in at least some people with epilepsy.
Sleep and lack of sleep-The electroencephalogram (EEG). At this stage, it is only necessary to know that it records the changes in voltage resulting from activity of cerebral nerve cells. The EEGs of people without epilepsy change during the passage from normal wakefulness, through drowsiness, to sleep. Sleep is not constant, as judged by body movements and EEG patterns, throughout the night. At various intervals one pattern of brain waves occur in association with rapid movements of the eyes. Through waking patients at this time we know that it is during this stage of sleep that dreams occur.
The changing electrical activity of the brain during drowsiness and sleep may allow seizure discharges to ‘escape’. Indeed, those analysing EEGs hope that their patients drop off to sleep during the procedure as the possibility of recording an abnormality is considerably enhanced.
Some subjects have all or virtually all the seizures whilst asleep—but they can never be entirely sure that a daytime attack will not occur. A follow-up study of one group of people with ‘nocturnal’ epilepsy showed that about a third had a daytime seizure in the next five years. The effects of depriving people of sleep have also been studied by keeping volunteers continuously awake, or by waking them up every time the EEG showed the pattern of rapid eye movement sleep. In each case EEGs on subsequent undisturbed nights showed that the subjects were catching up on the rapid eye movement sleep they had missed. Deprivation of sleep, therefore, has been shown to alter cerebral electrical activity, and it is not surprising that this is another factor in precipitating seizures. In practical terms, repeatedly staying up late may precipitate seizures in young adults.
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