Jackson 2001.

Methods	Single‐centre, single‐blind study, randomisation stratified according to bulbar versus limb onset
Participants	13 adults with ALS of less than 3 years duration, with an FVC ≥ 70% and nocturnal oxygen desaturation for ≥ 1 minute or at least 2 clinical symptoms of chronic hypoventilation
Interventions	Control: no respiratory support until FVC fell below 50% Experimental: nocturnal positive pressure ventilation
Outcomes	No clear primary outcome ALS functional rating scale‐respiratory version (ALSFRS‐R) Short Form 36 Modified Calgary Sleep Apnea Quality of Life Index (SAQLI) FVC% (sitting and supine, maximal inspiratory force (MIP), maximal expiratory force (MEP)) Daytime and nocturnal oximetry, and peak cough expiratory flow (PCEF) Symptoms of hypoventilation, assessed using a pulmonary symptom scale consisting of 14 questions, which were answered on a scale from 1 to 7
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated list
Allocation concealment (selection bias)	Unclear risk	No information was provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel were not blinded to the intervention
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The outcomes were assessed by a blinded clinical evaluator
Incomplete outcome data (attrition bias) All outcomes	High risk	One participant out of 7 in the experimental arm was lost to follow‐up at 3 months
Selective reporting (reporting bias)	High risk	Only preliminary data were published