Objective: To assess the association between the habitual head position during bedrest and the affected ear in benign paroxysmal positional vertigo (BPPV).
Study design: Prospective trial of patients with active BPPV of the posterior semicircular canal, confirmed on physical examination.
Methods: Seventy-five patients were asked to explain the head position and lying side they were accustomed to before falling asleep in bed.
Results: Fifty patients (67 per cent) habitually adopted a lateral head position during bedrest. The ear affected by BPPV was found to be consistent with the head-lying side during bedrest in 43 cases (86 per cent) (29 cases for the right ear and 14 cases for the left ear).
Conclusion: Habitual lateral head-positioning during bedrest can be a major factor leading to the development of BPPV in the ipsilateral ear.