Comparison 1. Positive pressure therapy versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Proportion of days with vertigo in 4 weeks: vertigo scores > 2	1	62	Mean Difference (IV, Fixed, 95% CI)	‐0.01 [‐0.08, 0.06]
2 Vertigo scores after 4 months	1	68	Mean Difference (IV, Fixed, 95% CI)	‐3.68 [‐14.24, 6.88]
3 Vertigo days in 4 months: vertigo scores > 2	1	68	Mean Difference (IV, Fixed, 95% CI)	‐1.55 [‐5.40, 2.30]
4 Vertigo frequency in the 8 weeks before and after 4 weeks of treatment	1	40	Mean Difference (IV, Fixed, 95% CI)	‐2.1 [‐5.25, 1.05]
5 VAS scores for vertigo after 8 weeks of treatment	1	40	Mean Difference (IV, Fixed, 95% CI)	‐21.1 [‐35.47, ‐6.73]
6 Loss or gain of hearing in 4 months (dB)	2	123	Mean Difference (IV, Random, 95% CI)	7.38 [2.51, 12.25]
7 Cumulative activity score at 4 months	1	68	Mean Difference (IV, Fixed, 95% CI)	‐7.18 [‐17.68, 3.32]
8 Change in functional profile between 8 weeks before and after 4 weeks of treatment	1	40	Mean Difference (IV, Fixed, 95% CI)	‐1.1 [‐1.81, ‐0.39]
9 Sick days in 4 months	2	125	Mean Difference (IV, Random, 95% CI)	‐1.03 [‐3.59, 1.53]