Objective: Comparison of the bithermal test in benign paroxysmal positional vertigo (BPPV) before and after particle repositioning maneuver (PRM), identify the possible mechanisms of canal paralysis in BPPV.
Method: Ninety-six BPPV cases during 2005-2008 were randomly divided into two groups: 52 cases were carried bithermal test before PRM, and the other 44 cases were carried after successful PRM. According to the canal paresis(CP) > or = 20%, subdivided each patients group the normal semicircular canal (SC) function group and the paresis SC function group. Compared the ratio of paresis SC function between the subgroups.
Result: Except the ages of the first group were younger than the second group, the gender rate, semicircular canal involved, side involved, course of the disease, recurrent attacks were all equal between the two groups. Using chi square test to compare the ratio of paresis SC between the two groups (t = 0.654, P < 0.05), the differences between the two groups were not statistical.
Conclusion: PRM has no influence to the bithermal test in BPPV. The mechanisms of the paresis SC function may be the extensive pathological changes in the vestibular system. The floating otolith has little effect on the dynamic of the endolymph.