Supine predominant OSA (spOSA)	$\frac{{\text{AHI}}_{\text{supine}}}{{\text{AHI}}_{\text{nonsupine}}}\ge 2$, and ${\text{AHI}}_{\text{nonsupine}}>5$.
Supine isolated OSA (siOSA)	$\frac{{\text{AHI}}_{\text{supine}}}{{\text{AHI}}_{\text{nonsupine}}}\ge 2$, and ${\text{AHI}}_{\text{nonsupine}}\le 5$.
Lateral predominant OSA (lpOSA)	$\frac{{\text{AHI}}_{\text{nonsupine}}}{{\text{AHI}}_{\text{supine}}}\ge 2$, and ${\text{AHI}}_{\text{supine}}>5$.
Lateral isolated OSA (liOSA)	$\frac{{\text{AHI}}_{\text{nonsupine}}}{{\text{AHI}}_{\text{supine}}}\ge 2$, and ${\text{AHI}}_{\text{supine}}\le 5$.