TABLE 2.

PHENOTYPIC TRAITS IN INDIVIDUALS WITH UPPER AIRWAY COLLAPSIBILITY BETWEEN −5 AND −2 cm H₂O

AHI (Number of Events per Hour of Sleep)	Pcrit (cm H2O)	GG Response (% Maximum EMG/−cm H2O Pepi)	Arousal Threshold (cm H2O)	Loop Gain (Dimensionless)
Control subjects
2.8	−3.8	−1.597	−7.4	−4.5
3.5	−3.5	−0.194	−5.2	—
3.9	−3.4	−1.650	−13.3	—
5.6	−3.9	−0.187	−21.9	−3.1
9.3	−2.7	−0.052	−8.4	−5.1
9.7	−3.0	−0.321	−20.7	−1.7
Patients with OSA
11.1	−2.1	−2.166	−22.5	−10.9
11.9	−4.8	−1.726	−15.7	−5.9
12	−4.1	−0.008	−14.8	−4.5
17.9	−3.9	−0.711	−22.7	−6.0
19.3	−2.0	−1.513	−13.8	−8.8
19.4	−2.6	−0.019	−7.9	−2.5
19.6	−2.6	−0.061	−7.8	−6.3
31.9	−3.1	−0.272	−23.5	−11.7
39	−4.7	−0.026	−18.5	−3.1
39.3	−3.0	−0.042	−26.5	−5.7
59.1	−2.9	−0.085	−10.4	—

Definition of abbreviations: AHI = apnea-hypopnea index; GG = genioglossus; OSA = obstructive sleep apnea; Pcrit = pharyngeal critical closing pressure; Pepi = epiglottic pressure.

Values in bold indicate poor muscle responsiveness, a low respiratory arousal threshold, or a high loop gain.