Spectral analysis of the eeg in paediatric anti-NMDAR encephalitis

It has been recently reported that the electroencephalographic (EEG) background activity in Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis evolve in phases, paralleling the clinical course of the disease. Quantification of EEG changes may help to monitoring therapeutic interventions and to predict outcome but, the EEG spectral analysis has not yet been studied in this disorder. To contribute to characterize EEG activity in paediatric anti-NMDAR encephalitis is important using a quantitative approach. The EEG was recorded during sleep and wakefulness in 3 children in different clinical phases of the disease. The relative spectral power in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8 −13 Hz), and beta (13–30 Hz) frequency bands was calculated using the Fast Fourier Transformation and correlated with disease stages. The spectral EEG time was characterized in all patients by decrease in alpha power at occipital sites and widespread increase in theta and delta power prevalent at frontal locations. The reappearance of alpha power at occipital sites preceded clinical recovery. Spectral analysis of the EEG had an added value over traditional EEG on quantification of electrical changes and in short term outcome.