Affiliations: [a] Shigeno Otolaryngology Vertigo-Hearing Impairment Clinic, Nagasaki, Japan
| [b] Department of Otolaryngology, Shiga General Hospital, Moriyama, Japan
| [c] Institute for Biomedical Research and Innovation, Kobe, Japan
Abstract: BACKGROUND:Patients with posterior- and lateral-(canal)-benign paroxysmal positional vertigo (BPPV)-canalolithiasis sleep in the affected-ear-down head position. Posterior-BPPV-canalolithiasis typically affects the right than left ear; sleeping in the right-ear-down head position may be causal. OBJECTIVE:To investigate the relationship between habitual head position during sleep and the onset of BPPV variants. METHODS:Among 1,170 cases of BPPV variants with unknown etiology, the affected ears, habitual head positions during sleep based on interviews, and relationships among them were investigated. RESULTS:Posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic affected the right ear significantly more often. Significantly more patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-apogeotropic habitually slept in the right-ear-down head position. Patients with posterior- and lateral-BPPV-canalolithiasis and light cupula were more likely to sleep habitually in the affected-ear-down position than in the healthy-ear-down head position; no relationship was observed in patients with posterior- and lateral-BPPV-cupulolithiasis. In patients with posterior-BPPV-canalolithiasis and lateral-BPPV-canalolithiasis-geotropic, the proportion of right-affected ears in those sleeping habitually in the right-ear-down head position was significantly greater than that for the left-affected ear. CONCLUSIONS:A habitual affected-ear-down head position during sleep may contribute to BPPV-canalolithiasis and light cupula onset, but not BPPV-cupulolithiasis onset. However, habitual sleeping in the right-ear-down head position cannot explain the predominance of right-affected ears.
