Electroencephalographic Abnormalities in Patients with Idiopathic Insomnia

Objective: The main goal of the present research is to describe the electroencephalographic activity during sleep and the cyclic alternating pattern (CAP) on idiopathic insomniac patients. Methods: 22 idiopathic insomnia patients were included. Sleep recording included: fully conventional EEG recording (32 electrodes, with 16 channels getting ipsilateral bipolar recordings), EOG, EMG, EKG, thoracic and abdominal respiratory movements, nasal flow and oximetry. Results: Out of the 22 registered patients, 10 (45%) showed no electroencephalographic alteration, while 12 (55%) exhibited an electroencephalographic alteration (irritative activity). Concerning PSG variables, significant differences between groups (no EEG alteration and EEG alterations) were detected in: sleep latency, total sleep time, total wake time, sleep efficiency, light sleep percentage, slow waves sleep percentage and on the sub type A1 index of the cyclic alternant pattern CAP. Conclusions: The present data strongly suggest that within the population diagnosed with idiopathic insomnia, there is a subgroup in which the electroencephalographic alterations may play a critical role as the source of the sleep abnormality.