Polysomnographic risk factors for vigilance-related cognitive decline and obstructive sleep apnea

Purpose Cognitive decline (CD) and obstructive sleep apnea (OSA) are often comorbid. Some modifiable risk factors (RF) for CD are also associated with OSA. Diagnostic polysomnography (PSG) measures these RF and may identify at risk patients prior to the onset of CD. We aim to determine whether there are severe RF associated with established CD and an increasing severity of OSA that could identify patients at risk for CD for medical intervention. Methods We gathered information from subjects having type 1 PSG for suspected OSA. The psychomotor vigilance task (PVT) measured established CD (group 0 and group1). We compared levels of severe RF in group 0 and group 1 with a larger group (group 2) without the PVT. We used severe standardized values of excessive daytime sleepiness (Epworth Sleepiness Score [ESS]), overnight change of systolic blood pressure (Delta SBP), change of oxygen desaturation (Delta SpO2), and sleep arousal (ArI) as RF. We compared the severe levels of ESS, Delta SBP, Delta SpO2, and ArI by group and OSA severity. Results A total of 136 patients underwent diagnostic PSG. PVT parameters were available for 43 subjects. The severity of the RF was consistent with risk for CD (Delta SBP 22.0 +/- 5.6, ESS 18.2 +/- 2.2, ArI 58.8 +/- 18.7, Delta SpO2 61.7 +/- 21.9). The levels of RF increased with increasing severity of OSA. There were significant between-group differences for severe Delta SpO2 (p = 0.004) and Delta SpO2 + ArI (p = 0.019). Conclusion The levels of RF increase with increasing OSA severity. Subjects with severe RF Delta SpO2 and Delta SpO2 + ArI are likely to have PVT-determined CD. Risk factor analysis may screen for CD.

Automated summary

The study aimed to identify severe risk factors associated with established cognitive decline (CD) and increasing severity of obstructive sleep apnea (OSA) that could indicate patients at risk for CD and in need of medical intervention. The research found that the levels of risk factors increased with the severity of OSA, and subjects with severe risk factors Delta SpO2 and Delta SpO2 + ArI were likely to have CD determined by the psychomotor vigilance task (PVT). Risk factor analysis may be helpful in screening for CD.