Comparison of longitudinal cognitive changes in CPAP-compliant and non-compliant older adults assessed with the Addenbrooke's Cognitive Examination - Revised.

INTRODUCTION

Cognitive screening instruments may provide an efficient means to monitor the long-term effects of continuous positive airway pressure (CPAP) on cognitive function in patients with obstructive sleep apnoea (OSA). This study examined changes in Addenbrooke's Cognitive Examination - Revised (ACE-R) scores in relation to CPAP compliance, with the Epworth Sleepiness Scale (ESS) included as secondary measure of daytime sleepiness.

METHODS

In this prospective comparative cohort study, 30 older adults (70.3yrs ± 6.6) with OSA who had completed ACE-R and ESS testing between 2016-20, were reassessed in 2021. Participants were categorized as CPAP compliant or non-compliant at follow-up, and changes in ACE-R and ESS were compared.

RESULTS

No significant baseline differences were observed between CPAP compliant (n = 20) and non-compliant (n = 10) participants. The CPAP-compliant group demonstrated significant improvements in memory scores whilst the non-compliant group demonstrated deterioration in the memory domain (Δ 1.3 ± 2.3 vs. Δ -1.3 ± 2.1, p < .01). An unexpected result was an improvement in verbal fluency in the non-compliant group compared to the CPAP-compliant group (Δ .0 ± 1.5 vs. Δ 1.0 ± 1.4, p < .05). CPAP use was also associated with a greater reduction in ESS scores (Δ -4.4 ± 4.5 vs. Δ -2.6 ± 3.5, p < .05).

CONCLUSIONS

These preliminary findings indicate that some ACE-R items may be able to detect a response to CPAP treatment; however, the small sample size and potential selection bias limit the strength of these conclusions. Larger cohorts are needed to validate the longitudinal utility of the ACE-R and its successor, the ACE-III, as clinical outcome metrics for assessing CPAP treatment response.