Differences in electroencephalographic findings among categories of narcolepsy-spectrum disorders.

OBJECTIVE

To clarify the differences in quantitative electroencephalographic (EEG) measures and their relation to clinical symptoms among narcolepsy-spectrum disorders.

METHODS

The enrolled patients were: 28 with narcolepsy with cataplexy (NA-CA); 16 with NA without cataplexy (NA w/o CA) and HLA-DRB1*1501/DQB1*0602 positive (NA w/o CA HLA+); 22 with NA w/o CA and HLA negative (NA w/o CA HLA-); and 22 with idiopathic hypersomnia without long sleep time (IHS w/o LST). Nocturnal polysomnography (n-PSG) and quantitative EEG evaluation, as well as the Multiple Sleep Latency test (MSLT), were conducted for all patients.

RESULTS

Patients with NA-CA or NA w/o CA HLA+ showed lower alpha power, higher delta and theta power during wakefulness, and higher alpha and beta power during rapid eye movement (REM) sleep, compared to those with NA w/o CA HLA- or IHS w/o LST. The former two groups also showed lower sleep efficiency and a higher rate of positivity of REM-related symptoms than the other two groups.

CONCLUSIONS

In narcolepsy, the presence of cataplexy and HLA positivity are associated with EEG slowing during wakefulness and increased fast EEG activity during REM sleep, REM-related symptoms and disrupted nocturnal sleep in narcolepsy.