Abstracts

Attainment of sleep during an EEG is important as interictal epileptiform discharges are often enhanced during drowsiness, stage I and stage II sleep and transition from drowsiness to arousal. Sleep deprivation is often used as a technique to obtain sleep during a routine EEG recording while some EEG laboratories routinely sedate young children to obtain a sleep recording. Both techniques have their drawbacks. Hyperventilation during an EEG is often followed by drowsiness; we therefore hypothesized that hyperventilation early in the course of an EEG would encourage sleep production. Conversely, photic stimulation early in an EEG delays sleep due to its arousing effect. This was a prospective study of children over the age of 2 years who were scheduled for a non sleep deprived EEG between 9-11 am in the Neurophysiology Laboratory of a tertiary children[apos]s hospital over a 3 month period. The first 32 children received photic stimulation in the beginning of the EEG and hyperventilation at the end; the next 32 children were hyperventilated early in the course of the EEG and photic stimulation was performed at the end of the EEG. Both groups were assessed for presence or absence of sleep during their EEG recording. One of the 32 (3.1%) children in the first group who received photic stimulation in the beginning of the recording transitioned to sleep. Twelve of 32 children (37.5%) who hyperventilated at the beginning of the recording attained stage II sleep. This was statistically significant (p =0.001). Hyperventilation performed early during an EEG increases the likelihood of attaining sleep, while photic stimulation early in the recording decreases the chances of inducing sleep. Therefore, in order to optimize attainment of sleep, pediatric neurophysiology labs should routinely begin the EEG with hyperventilation and end with photic stimulation