Can the affected semicircular canal be predicted by the initial provoking position in benign paroxysmal positional vertigo?

OBJECTIVES/HYPOTHESIS: The study evaluated the relationship between the position that initially provoked vertigo and the affected semicircular canal (SCC) in patients with benign paroxysmal positional vertigo (BPPV), and aimed to predict the side affected by BPPV through history taking regarding the provoking position.

STUDY DESIGN: Prospective study at a tertiary hospital.

METHODS: A total of 521 patients with BPPV involving the posterior or horizontal SCCs performed questionnaires at initial visit asking to choose the initial provoking position among the 10 positions corresponding to one of the three planes (roll, pitch, or yaw). After excluding 45 patients showing signs of simultaneous multiple canal or anterior canal involvement, the frequency of the provoking positions and the correlation between the side of the provoking position and the ear affected by BPPV were analyzed.

RESULTS: There were 239 patients with posterior SCC BPPV (p-BPPV) and 237 patients with horizontal SCC BPPV (h-BPPV). The waking-up position was the most common provoking position in both types of BPPV. Statistically significant correlation was demonstrated between the side of the provoking position at the onset of vertigo and the affected side by BPPV (P < .01) in patients with p-BPPV as well as h-BPPV (geotropic type [Geo]), but not in patients with h-BPPV (apogeotropic type [Apo]).

CONCLUSIONS: History taking regarding the side of provoking position at the onset of vertigo may help predict the side affected by BPPV in p-BPPV and h-BPPV (Geo). When h-BPPV (Apo) is suspected, further detailed examinations using additional localization methods should be performed.