Nadir oxygen desaturation is correlated with cognitive impairment in obstructive sleep apneoa

Aims: The present research used a novel computer-based task, the Subtle Cognitive Impairment Test (SCIT), to investigate whether mild cognitive impairment is associated with blood oxygen saturation (SpO2) levels during sleep in individuals with OSA. Methods: Eleven individuals with OSA (RDI > 7) and 12 individuals without OSA (RDI < 5) were tested on the SCIT before and after a night of sleep. Blood oxygen saturation was measured throughout sleep. The Karolinska Sleepiness Scale (KSS) and the Auditory Psychomotor Vigilance Task (PVT) were administered to measure subjective sleepiness and alertness, respectively. Results: No significant differences in SCIT performance between OSA and non-OSA participants were observed [F(8,14) = 0.29, p = .96). However, within the OSA group, performance on the response time component of the SCIT (SCIT-RTT), both before and after sleep, was significantly correlated with nadir O2 levels and mean minimum O2 levels (p < .05; Pearson correlation, 2-tailed). Pre-sleep PVT lapses and mean reaction times were significantly correlated with SCIT-RTT, nadir O2 and mean minimum O2 (p < .05; Pearson correlation, 2-tailed), whereas post-sleep PVT performance was not.