1. 1. Staab JP, Eckhardt-Henn A, Horii A, et al. Diagnostic criteria for persistent postural-perceptual dizziness (PPPD): consensus document of the committee for the Classification of Vestibular Disorders of the Bárány Society. J Vestib Res 27: 191-208, 2017.
2. 2. Sekine K, Sato G, Takeda N. Incidence of vertigo and dizziness disorders at a university hospital. Nihon Jibiinkoka Gakkai Kaiho (J Otolaryng Jap) 108: 842-849, 2005 (in Japanese, Abstract in English).
3. 3. Horii A. Anxiety, depression, and persistent postural perceptual dizziness: international classification of vestibular disorders by Bárány Society. Equilibrium Res 76: 316-322, 2017 (in Japanese, Abstract in English).
4. 4. Brandt T. Vertigo. In: Its Multisensory Syndromes, 2nd ed. Springer-Verlag London, 2001: 23-48.
5. 5. Popkirov S, Staab JP, Stone J. Persistent postural-perceptual dizziness (PPPD): a common, characteristic and treatable cause of chronic dizziness. Pract Neurol 18: 5-13, 2018.