Natural history of horizontal canal benign paroxysmal positional vertigo is truly short.

The objective of the study is to characterize the natural course of positional vertigo and nystagmus in patients with horizontal canal benign paroxysmal positional vertigo (h-BPPV) and to analyze the difference in the natural course between the two variants of h-BPPV. We conducted a prospective study in 106 patients with geotropic type h-BPPV [h-BPPV (Geo)] (n = 43) and apogeotropic type h-BPPV [h-BPPV (Apo)] (n = 63) who agreed and signed the written informed consent of no treatment. All patients were asked to answer a detailed interview about the onset time of positional vertigo and to visit the hospital every 1-3 days. At every visit, they were interviewed about cessation time of positional vertigo and positional nystagmus was assessed. The mean period ± SD between the onset and remission of vertigo in the h-BPPV (Geo) was 6.7 ± 6.3 days, whereas that in the h-BPPV (Apo) was 3.7 ± 4.1 days. In addition, the mean period ± SD from the initial diagnosis to the disappearance of positional nystagmus in the h-BPPV (Geo) was 4.7 ± 3.9 days, whereas that in the h-BPPV (Apo) was 4.4 ± 5.0 days. Although the duration until natural remission of positional nystagmus did not differ between the two variants of h-BPPV, the remission of vertigo occurred faster in h-BPPV (Apo) than h-BPPV (Geo) (p < 0.05). The natural course of h-BPPV is much shorter than that indicated in previous reports. The positional vertigo disappeared faster in the h-BPPV (Apo) compared to the h-BPPV (Geo) unlike the positional nystagmus.