Double-blind randomized trial on short-term efficacy of the Semont maneuver for the treatment of posterior canal benign paroxysmal positional vertigo.

The need for Class I and II studies on the efficacy of Semont's liberatory maneuver (SLM) in the treatment of posterior canal benign paroxysmal positional vertigo (PC-BPPV) motivated the present double-blind randomized trial on the short-term efficacy of SLM. A total of 342 patients with unilateral PC-BPPV were recruited for a multicenter study. Patients were randomly assigned to treatment by SLM (n = 174) or sham treatment (n = 168). Subjects were followed up twice (1 and 24 h) with the Dix-Hallpike maneuver by blinded examiners. At the 1 and 24 h follow-up, 79.3 and 86.8%, respectively, of patients undergoing SLM had recovered from vertigo, compared to none of the patients undergoing the sham maneuver (p < 0.0001). Patients who manifested liberatory nystagmus at the end of SLM showed a significantly higher percentage of recovery (87.1 vs. 55.7%; p < 0.0001). To the best of our knowledge, this is the first Class I study on the efficacy of SLM. SLM proved highly effective with respect to the sham maneuver (p < 0.0001). Liberatory nystagmus was demonstrated to be a useful prognostic factor for the efficacy of treatment. The present Class I study of efficacy of SLM changes the level of recommendation of the maneuver for treating PC-BPPV from level C to level B.