Correlation between the sleep-position habits and the affected posterior semicircular canal in patients with benign paroxysmal positional vertigo

Background: Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo. It is assumed that sleep is involved in the pathogenesis of BPPV, and that habitual head-lying side during sleep correlates with the affected side in the posterior semicircular canal BPPV. Objectives: To investigate the relationship between the preferred sleeping position and the affected semicircular canal in patients with BPPV. Methods: We performed a retrospective data review of patients seeking help for vertigo/dizziness who had undergone clinical evaluation including a Dix-Hallpike test. Patients diagnosed with posterior canal BPPV (p-BPPV) were asked to define their preferred lying side (right, left, supine, or variable) during the night sleep. Affected semicircular canal (right posterior or left posterior) was registered along with demographic data. Results: In all, 237 patients were diagnosed with p-BPPV. Patients with horizontal semicircular canal BPPV (n=11) were excluded. Patient mean age was 57 years (range 14-87). There were 150 patients with right p-BPPV and 87 patients with left p-BPPV. Among the patients, 122 (52%) habitually slept on the right side. Of those, 102 (84%) were diagnosed with right p-BPPV (P = 0.0006), while 82 patients (34%) habitually slept on the left side. Fifty-three (65%) were diagnosed with left p-BPPV (P < 0.0001). There were no differences in right vs. left p-BPPV in the 33 patients (14%) who expressed no preference concerning their sleeping positions. Conclusions: Our study sheds light on the etiology of BPPV and shows that changing sleep position habits might be helpful in preventing recurrent BPPV.