Increased Flow Limitation During Sleep Is Associated With Increased Psychomotor Vigilance Task Lapses in...Suspected OSA, 2024, Staykov et al.

[nataliezzz]

Increased Flow Limitation During Sleep Is Associated With Increased Psychomotor Vigilance Task Lapses in Individuals With Suspected OSA
Eric Staykov, Dwayne L Mann, Brett Duce, Samu Kainulainen, Timo Leppänen, Juha Töyräs, Ali Azarbarzin, Thomas Georgeson, Scott A Sands, Philip I Terrill
https://www.sciencedirect.com/science/article/abs/pii/S0012369223058233 (no full text link available)

Background
Impaired daytime vigilance is an important consequence of OSA, but several studies have reported no association between objective measurements of vigilance and the apnea-hypopnea index (AHI). Notably, the AHI does not quantify the degree of flow limitation, that is, the extent to which ventilation fails to meet intended ventilation (ventilatory drive).

Research Question
Is flow limitation during sleep associated with daytime vigilance in OSA?

Study Design and Methods
Nine hundred ninety-eight participants with suspected OSA completed a 10-min psychomotor vigilance task (PVT) before same-night in-laboratory polysomnography. Flow limitation frequency (percent of flow-limited breaths) during sleep was quantified using airflow shapes (eg, fluttering and scooping) from nasal pressure airflow. Multivariable regression assessed the association between flow limitation frequency and the number of lapses (response times > 500 ms, primary outcome), adjusting for age, sex, BMI, total sleep time, depression, and smoking status.

Results
Increased flow limitation frequency was associated with decreased vigilance: a 1-SD (35.3%) increase was associated with 2.1 additional PVT lapses (95% CI, 0.7-3.7; P = .003). This magnitude was similar to that for age, where a 1-SD increase (13.5 years) was associated with 1.9 additional lapses. Results were similar after adjusting for AHI, hypoxemia severity, and arousal severity. The AHI was not associated with PVT lapses (P = .20). In secondary exploratory analysis, flow limitation frequency was associated with mean response speed (P = .012), median response time (P = .029), fastest 10% response time (P = .041), slowest 10% response time (P = .018), and slowest 10% response speed (P = .005).

Interpretation
Increased flow limitation during sleep was associated with decreased daytime vigilance in individuals with suspected OSA, independent of the AHI. Flow limitation may complement standard clinical metrics in identifying individuals whose vigilance impairment most likely is explained by OSA.

 

[nataliezzz]

There is no full-text link available and it's not on Sci-Hub.

Regarding flow limitation driving symptoms like decreased psychomotor vigilance and self-reported sleepiness (as shown in the study below - S4ME link), there needs to be some additional factor accounting for how flow limitation is driving these symptoms beyond flow limitation itself, since many asymptomatic people have significant flow limitation (for ex, see: A comparison of inspiratory airflow dynamics during sleep between upper airway resistance syndrome patients and healthy controls, Gold et al. 2013 - multiple controls [who were rigorously screened to be free of any medical conditions, fatigue/pain/etc.] had >90% of their breaths flow limited during stage 2 non-REM sleep).

Flow Limitation Is Associated with Excessive Daytime Sleepiness in Individuals without Moderate or Severe Obstructive Sleep Apnea, 2024, Mann et al.

This is where Dr. Gold's theory of UARS/OSAS being driven by a stress response in the brain to inspiratory flow limitation comes in (S4ME link - AI Summary)