In-Laboratory Polysomnography Worsens Obstructive Sleep Apnea by Changing Body Position Compared to Home Testing

Area of Science:

• Sleep Medicine
• Respiratory Physiology

Background:

• Home sleep apnea testing (polysomnography type 3, PSG3) often underestimates respiratory events compared to in-laboratory polysomnography (PSG1).
• The absence of head electrodes in home settings may lead to more natural body positioning, potentially reducing obstructive sleep apnea (OSA) severity.
• This underestimation may be independent of hypopneas missed due to lack of arousal scoring.

Purpose of the Study:

• To investigate the impact of sleep scoring and body positioning on OSA severity assessment between home and in-lab sleep tests.
• To identify patient subgroups where OSA severity differs significantly between PSG1 and PSG3.
• To determine if the testing location influences body position and OSA evaluation.

Main Methods:

• Patients with suspected OSA underwent randomized PSG1 and PSG3.
• A reduced polysomnography analysis excluded sleep and arousal scoring from PSG1 to mimic home testing conditions.
• Patients were categorized based on a clinically relevant difference (apnea-hypopnea index change ≥ 15) between PSG1 and PSG3.

Main Results:

• Excluding sleep scoring reduced OSA severity in lab tests, similar to home test results.
• Patients with clinically relevant differences had more severe OSA in-lab (AHI 42.5 vs. 20.2, p=0.002), a difference that vanished in home tests.
• Greater variations in supine apnea-hypopnea index and time in supine position were observed in the clinically relevant difference group, indicating site-specific effects on body position.

Conclusions:

• In-laboratory polysomnography might artificially inflate OSA severity in some patients due to altered body positioning.
• The testing location appears to influence OSA evaluation, particularly for patients with more severe disease.
• Body position variations between home and lab settings significantly impact OSA severity assessment.