Approaches to staging sleep in polysomnographic studies with epileptic activity

The Standardized Sleep Manual of Rechtschaffen and Kales is well established and reliable in scoring the majority of polysomnograms (PSGs) encountered in clinical practice. In patients with epilepsy, however, abnormal brain activity may confound the interpretation of sleep waveforms. Our goal is to identify features that are problematic in analyzing sleep stages in patients with epilepsy and to offer approaches to score these PSGs.

Ninety eight PSGs from 43 patients with epilepsy were scored using Rechtschaffen and Kales guidelines. Features interfering with sleep staging were noted.

In scoring polysomnograms (PSGs) of patients with epilepsy we noted epileptic seizures, interictal epileptiform discharges (IEDs) and abnormal EEG background to be features of epilepsy that compromised sleep scoring. Overall, 48% of the studies in our sample contained one or more of these epileptic features to the extent that sleep scoring by standard criteria was compromised. Approaches for staging sleep in the setting of these abnormalities are outlined.

The Rechtschaffen and Kales method of sleep scoring is useful in staging the majority of PSGs of patients with epilepsy. However, we advocate some modifications because the abnormal electrical activity of epilepsy may interfere with accurate scoring of sleep waveforms. These approaches to scoring PSGs of patients with epilepsy will require empirical testing.