Five subtypes of benign paroxysmal positional vertigo

Background Benign paroxysmal positional vertigo is classified into five subtypes according to the features of positional nystagmus: lateral canalolithiasis, lateral light cupula, lateral heavy cupula, posterior canalolithiasis and posterior heavy cupula. Objectives The first aim of the study was to clarify whether the lateral canal type or posterior canal type was more common. The second aim of the study was to assess the aetiology of benign paroxysmal positional vertigo by investigating the onset time of each subtype. Methods The subjects were 512 consecutive patients with benign paroxysmal positional vertigo. The patients were prospectively aggregated, and interviews were used to evaluate onset time. Results The lateral canal type (55.5 per cent) was more common than the posterior canal type (44.5 per cent). Time of awakening was the most common onset time in every subtype. Conclusion The incidence of lateral canal type is higher than that of posterior canal type. The aetiology of benign paroxysmal positional vertigo is closely related to sleep.