Al‐Showair 2007.

Study characteristics
Methods	Design: parallel‐group randomised controlled trial; blinding not stated Duration: 6 weeks Setting: 1 outpatient clinic, UK Trial registration: not reported
Participants	Population: 108 people with asthma randomised to verbal training plus 2Tone Trainer (n = 36) or verbal training alone (n = 36) Age: mean age (SD) in the intervention group 58.3 (13.7) years, and in the control group 52.6 (16.7) years Baseline asthma severity: intervention group: FEV1 % predicted (SD) 71.4 (22.0); mini‐AQLQ (SD) 3.8 (1.1). Control group: FEV1 % predicted (SD) 76.9 (24.1); mini‐AQLQ (SD) 3.9 (1.0) Inclusion criteria: Patients with asthma who were attending an outpatient clinic were invited to take part in this study. Each patient had to be receiving an inhaled corticosteroid from an MDI without a spacer device. Patients with adequate co‐ordination but too rapid inspiratory flow were randomised to 1 of the 2 intervention groups Exclusion criteria: patients who had experienced an acute exacerbation in the past 4 weeks; patients who were deaf or unable to distinguish between 1 and 2 tones with the 2T; patients with poor inhaler co‐ordination who were ineligible for the study and were referred to the asthma nurse for inhaler technique training Percentage withdrawn: 0% of participants withdrew from the intervention group, and 3% from the control group Other allowed medication: "There were no changes to patients' prescriptions"
Interventions	Intervention summary: The 2Tone Trainer looks like an MDI but does not have a canister, so that when it is used, the patient does not receive a dose. During use, this training aid provides users with audible feedback according to the patient’s inhalation rate. It makes a 2‐tone sound when the patient is inhaling at 60 L/min, 1 tone when inhaling between 30 and 60 L/min and no sound when inhaling at 30 L/min. Patients are advised to obtain the 1‐tone noise and thus become accustomed to the degree of inspiratory effort they need to make to achieve this rate through an MDI. Participants were given a 2Tone Trainer to use at home and received the same verbal training as the verbal training alone group Control summary: Verbal training participants were trained on the most desirable inhalation technique with emphasis on breathing out slowly as far as comfortable and actuating a dose at or soon after the start of a slow inhalation. A slow inhalation was defined as an inhalation that filled the lungs with air that lasted 5 seconds
Outcomes	Outcomes measured: peak inspiratory flow (PIF), FEV1 and quality of life (AQLQ) Technique assessment method used: PIF was used as a measure of inhaler technique
Notes	Type of publication: single peer‐reviewed journal article plus 2 conference abstracts Funding: 2Tone Trainers were donated by Canday Medical Ltd. Dr Al‐Showair was financially supported by a scholarship from the Saudi Arabian Government, and the study was part of his PhD thesis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Subjects in the intervention group were randomly allocated into the verbal training (VT) group or the 2T group" ‐ no further details of sequence generation
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	High risk	No description of procedures intended to blind participants or personnel to group assignment
Blinding of outcome assessment (detection bias) All outcomes	High risk	No description of procedures intended to blind outcome assessors to group assignment; for outcomes such as AQLQ, the participant/caregiver is the outcome assessor; therefore these outcomes may be at risk of detection bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	Only 1 participant withdrew from the study
Selective reporting (reporting bias)	Unclear risk	No prospective trial registration identified. However, all outcomes listed in Methods clearly reported in paper
Other bias	Low risk	None noted