Yardley 2004.

Methods	Design: randomised controlled trial
Participants	Number: 170 Age: intervention group: mean age 62.9 (SD 15.2), comparator group: mean age 61.0 (SD 14.4) Gender: intervention group: 24 males, comparator group: 25 males Setting: conducted in 20 general practices, delivered by primary care nurse Eligibility criteria: dizziness of vestibular origin diagnosed by case history and MPD Exclusion criteria: non‐vestibular cause for dizziness, duration of dizziness less than 2 months in the past 2 years, vigorous head or body movement contraindicated, serious comorbid conditions Baseline characteristics: no differences between groups
Interventions	Intervention group: VR (primary care: demonstration, booklet and follow‐up) (n = 83) Comparator group: control, usual medical care (n = 87) VR versus control (usual medical care)
Outcomes	Primary outcome: VSS (short form) Secondary outcomes: CDP, DHI, MPD
Notes	25 participants were lost to follow‐up: 5 from each group at the end of the 3‐month intervention, then a further 7 and 8 respectively from the intervention and comparator groups at the 6‐month follow‐up
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Stratified block randomisation was performed by an independent researcher
Allocation concealment (selection bias)	Low risk	Allocation was concealed in sealed, opaque envelopes
Blinding (performance bias and detection bias) All outcomes	Low risk	Outcome assessors were blinded to group allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data were missing at several time points but this was accounted for in the intention‐to‐treat analysis
Selective reporting (reporting bias)	Low risk	Study protocol is available and all data appear to be reported
Other bias	Low risk	The study appears to be free of other sources of bias