[The changes in subjective visual vertical after otolith reduction in patients with BPPV].

Objective

To observe and analyze the changes in subjective visual vertical（SVV） after otolith reduction in patients with BPPV.

Methods

46 patients with confirmed BPPV recieving successful otolith reduction were selected as the test group. 31 cases of posterior canal stones and 15 cases of horizontal semicircular canal stones, 29 cases of right ear and 17 cases of left ear. Fifty cases of healthy young volunteers were in the control group. Using the virtual reality SVV examination system, 0° SVV in the positive head were tested in the test group patients before and after the reduction of SVV , and were tested in the control group .The deviation angle of the SVV before and after the otolith reduction in the test group were analyzed.

Results

Before otoliths reduction, the SVV was （0.08±3.83）° of right BPPV and was （-1.69±2.23）° of left BPPV. After otoliths reduction, the SVV was （-1.52±3.74）° of right BPPV and was （-1.04±2.50）° of left BPPV. In the control group, the SVV was（-1.57±2.28）° . The changes of SVV deflection angle between the control group and the right BPPV before the otolith reduction, and before and after the otolith reduction in the right BPPV were analyzed, and the differences were all statistically significant. There was no significant difference in SVV deflection angle between the left BPPV（before and after reduction） and the control group. In the test group, after the otolith reduction, 18 cases had larger bias angles, 28 cases had smaller bias angle among which 13 cases the deviation angle even turned to the contralateral side.

Conclusion

Utriculare dysfunction in patients with BPPV leads to the judgment error of SVV. Reduction of otolithoid can cause new stimulation to the eutricule and affect its functional status. SVV detection can provide help for the evaluation of utricular function in patients with BPPV.