Investigating Sleep Fragmentation By Autonomic Arousals in Depressed Patients With Obstructive Sleep Apnea

The aim of this study is to look at if there is any difference of arousal patterns in polysomnography (PSG) and Pulse Transit Time (PTT) recordings in Obstructive Sleep Apnea (OSA) patients with Major Depressive Disorder (MDD) and without MDD subjects. Nine overnight PSG recordings ($7\sim 8$ hours) were acquired from OSA subjects (AHI: $15\sim 60; \ \ 36.68\pm 13.55$ events/hour) with MDD diagnoses [OSAMDD](5 cases) and OSA subjects (AHI: $15\sim 60;\ \ 38.37\pm 19.61$) without MDD [OSA](4 cases) from a local psychiatric clinic. Selection criteria include the age [39.5± 5 vs 41.4± 3.5 yrs; p > 0.05] and weight [120.2± 10 vs 118.6± 12 Kgs; p > 0.05] matched subjects. Diagnoses of MDD were made by the Mini-International Neuropsychiatric Interview with ICD-10 questionnaire. A PTT arousal (ArPTT) was defined as a decrease in PTT by at least 15 milliseconds of the baseline lasting at least 5 seconds. Expert scored EEG based cortical arousals (ArEEG) include respiratory, movement, periodic leg movement and spontaneous arousals. Mann-Whitney $U$ test showed that ArPTT index (events per hour) of OSA+MDD was significantly (p < 0.05) higher than that of OSA groups [36.56± 5.6 vs 28.78± 4.6]. In contrast, ArEEG indices in both groups were not found significantly different [24.18± 6.7 vs 25.74± 8.3].