Mentation Tracks Severity but not Oxygenation in Obstructive Sleep Apnea

Area of Science:

• Neuroscience
• Sleep Medicine
• Cognitive Psychology

Background:

• Obstructive sleep apnea (OSA) is broadly linked to cognitive deficits, particularly in executive functioning (EF), attention/working memory (A/WM), episodic memory (EM), and speed of information processing (SIP).
• Consensus is lacking on the influence of OSA severity, specific sleep variables, and comorbidities on these cognitive impairments.

Purpose of the Study:

• To investigate the relationship between OSA severity (apnea-hypopnea index - AHI) and cognitive function.
• To determine if AHI impacts cognitive domains independently of oxygen saturation nadir (NOS) and common comorbidities like hypertension and diabetes.

Main Methods:

• 40 participants with OSA underwent polysomnography and neuropsychological testing using the Halstead-Reitan Test Battery.
• Cognitive domain scores (EF, A/WM, EM, SIP) were regressed against AHI, NOS, hypertension, and diabetes mellitus.

Main Results:

• The AHI significantly predicted executive functioning (p = .015; sr2 = .13) and attention/working memory (p = .023; sr2 = .11).
• In secondary analyses, AHI also predicted episodic memory (p = .027; sr2 = .10).
• These associations remained significant after accounting for NOS and the presence of hypertension and diabetes.

Conclusions:

• The apnea-hypopnea index (AHI) appears to be a significant predictor of cognitive impairments in executive functioning, attention/working memory, and episodic memory in individuals with OSA.
• These cognitive effects of AHI may be independent of oxygen desaturation and common OSA comorbidities.
• Further research is warranted to explore the mechanisms underlying these relationships and their clinical implications.