Fig. 1.

Survival from baseline sleep studies (time point T1) in patients with ALS. a–c refer to patients who did not undergo non-invasive ventilation, d–f depict Kaplan-Meyer plots for patients who started enduring NIV following T1. Survival analyses were performed using critical cut-off values for respiratory sleep outcomes at T1. AHI apnea hypopnea index, EMBE early morning base excess, ptcCO₂ maximum nocturnal transcutaneous CO₂ tension, X axis months, Y axis cumulative survival. p values < 0.05 were considered significant