Sleep and EEG power spectrum in post encephalitis hypersomnia: a case report

The nocturnal recordings of breathing, and sleep and daytime multiple sleep latency tests over the 5 year follow-up of a patient with post encephalitis hypersomnia are presented. EEG power spectrum analysis was performed on the last polysomnographic recording, and the results were compared with those obtained for a matched control subject. The patient presented initially a hypoventilation syndrome controlled by nasal bilevel positive pressure at night. The syndrome progressively improved, but daytime sleepiness stayed unchanged with limited help from stimulants. Fast Fourier transformation analysis of the last nocturnal recording demonstrates a decrease in absolute power for all frequency bands in all sleep stages, but a cyclical presence of the NREM/REM.