難治性の良性発作性頭位めまい症はヘッドアップした姿勢で就寝することにより治り得る：6ヶ月間のランダム化比較試験

Objectives: The aim of the present study was to assess head-position management for intractable idiopathic benign paroxysmal positional vertigo (BPPV) when lying down. We hypothesized that head-up sleep (HUS) could prevent free-floating otoliths from entering the semicircular canals. Study design: A prospective two-arm multicenter randomized controlled trial. Methods: BPPV was diagnosed in 611 patients (611/1,520; 40.2%) according to the 2015 diagnostic guidelines issued by the International Classification of Vestibular Disorders. Among them, 201 patients were intractable (201/611; 32.9%), 88 of whom were idiopathic and subsequently enrolled in the study. Patients randomly received intervention with HUS at greater than 45° (n = 44) or head-down sleep (HDS; n = 44) when lying down. Before treatment, they completed several examinations, including subjective visual vertical (SVV). The specific diagnoses for the 88 patients with BPPV included horizontal type cupula (n = 40), horizontal type canal (n = 13), posterior type (n = 26), and probable and/or atypical BPPV (n = 9). Results: Patient backgrounds did not differ significantly between the HUS and HDS groups. Visual analog scale (VAS) scores of vertiginous sensation were significantly lower in the HUS group than in the HDS group at both the third month and sixth month post-treatment. Positional/positioning nystagmus observed just before treatment disappeared significantly more often in the HUS group than in the HDS group until the sixth post-treatment month. Further, especially in HUS group, VAS scores in SVV- group (n = 24) were significantly lower than those in the SVV+ group (n = 20) sixth month post-treatment. Conclusions: Controlling free-floating otoliths is not easy due to aging of the otolith organs. Repeatedly returning the endless free-floating debris from the canals to the utricle through physical means is not a good strategy. Therefore, HUS when lying down at home could be recommended as an initial treatment for patients with intractable idiopathic BPPV. Level of evidence: 1b.博士（医学）・甲第764号・令和3年3月15日© 2019 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals, Inc. on behalf of The Triological Society. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made