Pathological respiratory chemoreflex activation predicts improvement of neurocognitive function in response to comtinuous positive airway pressure therapy

Introduction There is a need for biomarkers predicting neurocognitive improvement following treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP). The role of sleep apnea endotypes as predictors are promising. Objective To assess the relationship between a high loop gain biomarker, elevated low frequency narrow band (e-LFC NB ), and improvements in neurocognitive function in the Apnea Positive Pressure Long-term Efficacy Study (APPLES). Methods The e-LFC NB % metric was estimated on baseline polysomnography. Logistic regression analysis was performed to identify the potential association between e-LFC NB % of total sleep time and the observed improvement in neurocognitive function following the specified treatment. Results A total of 362 subjects received CPAP and had e-LFC NB % measurements. For Sustained Working Memory Test-Overall Mid-Day (SWMT-OMD), e-LFC NB % > 2.35% correlates positively with the proportion of participants who showed an increase in test scores > 0.65 after 2 months CPAP treatment (OR: 2.617, 95% CI: 1.095–6.252, p : 0.030); e-LFC NB % > 9.45% correlates positively with improvement in test scores > 0.8 after 6 months CPAP treatment (OR: 2.553, 95% CI: 1.017–6.409, p : 0.046). For Buschke Selective Reminding Test sum recall (BSRT-SR), e-LFC NB % > 3.65% correlates positively with an increase in test scores > 12 after 2 months CPAP treatment (OR: 2.696, 95% CI: 1.041–6.982, p : 0.041). Results of the Pathfinder Number Test-Total Time (PFN-TOTL) were not significant. Conclusion e-LFC NB % (probable high loop gain) may be a clinically useful predictor of cognitive improvement following CPAP.