Macrostructural and microstructural sleep variables for distinguishing normal sleep from pathologic sleep

Abstract

The aim of the present study is to examine the function of indices of macrostructural sleep and microstructural sleep for the objective evaluation of sleep quality, to test and find out the indices which could distinguish normal sleep from four types of pathologic sleep, including insomnia, nocturnal frontal lobe epilepsy (NFLE), periodic leg movements and rapid eye movement (REM) behavior disorder. The role of sleep indices for the evaluation of sleep quality was analyzed, including 29 macrostructure indices and 23 microstructure indices. Totally five sleep groups were selected from the cyclic alternating pattern (CAP) sleep database, including controls (no pathology, N=16), insomniacs (N=9), nocturnal epileptics (N=40), periodic leg movements (N=10) and REM behavior disorder (N=22). The macrostructure indices were calculated according to the sleep stages annotation in the database, and the microstructure sleep indices were obtained by analyzing the CAP annotation. The discrimination ability of these macrostructure and microstructure indices was tested by analysis of variance for distinguishing the normal sleep from four types of pathologic sleep. For macrostructure sleep indices, four REM-related indices of controls were distinguished from that of pathologic groups significantly (P<0.05, controls vs. each pathologic group), including the time of REM sleep, the percent of REM sleep to all sleep period time, the ratio of REM sleep to non-rapid eye movement (NREM) sleep, and the maximal sustained REM sleep time. For microstructure sleep indices, three phase A3-related indices of controls were significantly distinguished from that of pathologic groups (P<0.05, controls vs. each pathologic group), including the number of phase A3 per hour during NREM sleep, the total number of phase A3, and the total duration of phase A3. In conclusion, REM sleep indices can distinguish normal sleep from four types of pathologic sleep, including insomnia, nocturnal epilepsy, periodic leg movements and REM behavior disorder. Besides, indices of phase A3 are better than CAP ratio to distinguish normal sleep from above pathologic sleep.