To evaluate a new measure of EEG synchrony or stability using fundamental frequency analysis provided by Morpheus in subjects with severe obstructive sleep apnea (OSA) adequately treated with CPAP using a split night protocol.
A total of 27 adults were selected with a primary diagnosis of obstructive sleep apnea and who were treated with CPAP during their initial study. Each individual had a baseline and treatment period. Only those individuals with a respiratory disturbance index (RDI) < 10 episodes per hour and oxygen saturation greater than 85% during the ideal CPAP titration period were selected. When there was more than one CPAP level that this occurred, the multiple levels were included. Fundamental frequency values below 4 Hz are believed to represent increased EEG synchrony. The percentage of fundamental frequency below 4 Hz was calculated during the baseline period and ideal CPAP titration period (total sleep time).
Means with standard deviations are reported. There were 24 males (ages 25-77) and 3 females (ages 46-52). Body mass index was 35(7); Epworth Sleepiness Scale 12(5), and SleepMed Insomnia Index 16(8). Low oxygen saturation at baseline was 81%(6); oxygen saturation at ideal CPAP level 91%(2); RDI at baseline 71(26); and RDI at ideal CPAP level 3(3). Fundamental frequency under 4Hz during the baseline period was 12%(13) and at the ideal CPAP pressure 31%(13). Independent t-tests comparing % of fundamental frequency below 4Hz at the baseline period with the ideal CPAP period were significant p<0.001.
Early intervention with CPAP in OSA improves sleep quality. Automated analysis that calculates modal frequency of adaptive segmentation and fuzzy logic segments in sleep EEG demonstrates EEG synchrony that is believed to reflect improvement in sleep quality.
Enhanced resolution by automated analysis offers improved efficiencies, reproducibility, and insights into sleep states and processes.
Richard Bogan, Shareholder SleepMed Inc.