Studies show that up to 70 percent of sleep apnea cases may go undiagnosed when home sleep tests rely solely on indirect signals like oxygen desaturation or peripheral arterial tone, rather than directly measuring airflow.

While home sleep apnea testing (HSAT) has dramatically improved access to diagnosis, many devices on the market rely on indirect signals—like oxygen desaturation or arterial tone—to infer breathing disturbances. But sleep apnea is a condition defined by disrupted airflow. Without capturing this core signal, critical events like hypopneas can be missed, misclassified, or misunderstood. As clinical research and expert consensus increasingly affirm, airflow isn't optional—it's essential.

The American Academy of Sleep Medicine (AASM) recommends airflow monitoring as the primary signal for scoring apneas and hypopneas, stating that 'airflow is the most important respiratory signal' for event detection in sleep studies.

Without airflow, hypopneas are frequently missed, leading to underestimation of sleep apnea severity. Recognizing that the human respiratory system is interconnected with only two degrees of freedom, the AASM determines that using an airflow channel based on two respiratory effort signals is adequate for scoring apnea and hypopnea events.

Wesper Lab, a Type III HSAT, has developed the first and only FDA-cleared airflow channel that is substantially equivalent to a nasal cannula, without any facial appliance.

By using two wearable biosensor patches—one on the chest and one on the abdomen—Wesper detects thoracoabdominal movement to compute airflow without requiring a nasal cannula. This approach aligns with gold-standard PSG methods and has been validated by the FDA as substantially equivalent to nasal cannula airflow (510k clearance).