Paroxysmal spike and wave activity in drowsiness in young children: its relationship to febrile convulsions.

Paroxysmal rhythmic theta waves appearing during early stages of sleep have long been recognized in the EEGs of normal children. A similar pattern with intermixed spikes appears to have a different correlation. We called this pattern 'hypnagogic paroxysmal spike wave activity' or 'hypnagogic PSW.' This investigation was designed to test whether there exists a relationship between hypnagogic PSW, febrile convulsions (FC) and age. We selected 3 cohorts of children: G-1 or normal control consisted of 94 children selected with the following criteria: complete normal neurodevelopmental examination and no personal or family history of FC, epilepsy, or other neurological disorder. They all had one EEG obtained without drug induction showing a clear sequence of awake-drowsy-sleep-arousal-awake states. G-2 or pathological control group consisted of 126 children selected at random, referred to the Division of Neurophysiology at the Children's Hospital Medical Center for any problem excluding FC. At least one EEG met the criteria mentioned above. G-3 or FC group consisted of 375 children in whom the very first seizure was associated with fever without evidence of other causes for the convulsion. All met the same EEG criteria of G-1 and G-2. The medical record of 169 children of this group (40 with hypnagogic PSW and 129 without hypnagogic PSW) were reviewed.(ABSTRACT TRUNCATED AT 250 WORDS)