Abnormal theta response to nociceptive stimuli during sleep EEG in children with febrile convulsions and control children.

Nociceptive stimuli were tested in 373 sleep EEG from 349 children with febrile convulsions and 50 control children (mean age: 2.54 and 2.05 years, respectively). Stimuli consisted of light pecks on each limb with a beveled cut plastic straw or a toothpick. Responses were deemed abnormal if frontal theta episodes would repeat three times without awakening. These abnormal responses appeared in 232 (62%) out of the 373 children of the febrile convulsive group, and in only 4 (8%) out of the 50 children in the normal control group: confidence interval significant at 95%. During sleep recording without stimulation, this sign is directly related to spontaneous theta bursts and inversely related to focal activity, but bears no relationship with sleep induction agents, generalized spike and waves, or delta discharges. In 24 repeat recordings, it begins to disappear at 3.7 years of age. Such responses to nociceptive stimuli should be considered characteristic of febrile convulsions.