Objective: To evaluate the significance of additional 180-degree roll test (RT) in the determination of affected side in patients with horizontal semicircular canal benign paroxysmal vertigo (HSC-BPPV).
Method: One hundred and six patients with HSC-BPPV were performed the 90 degree RT. patients whose affected side cannot be determined by 90 degree RT were performed 180 degree roll test.
Result: The affected side was deter- mined by the 180 degree RT in 10 cases in which the lesion side cannot be determined by the 90-degree RT.
Conclusion: The affected side of HSC BPPV was able to be determined by 180 degree RT when it not possible to be determined by 90 degree RT. 180 degree RT is an effective and simple additional method.