Efficacy of the Head Rotation Test With Bowing for the Lateral Canal Benign Paroxysmal Positional vertigo.

OBJECTIVES

To evaluate the efficacy of the head rotation test with bowing (B-HRT) in the sitting position in diagnosing lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV).

METHODS

The efficacy outcomes of lateralization of 25 patients with LSC-BPPV were prospectively evaluated using B-HRT. Traditional head toration in the supine position (S-HRT) and the bow and lean test were also assessed for comparative effectiveness.

RESULTS

Direction-changing nystagmus was detected in all patients with LSC-BPPV (100%) using B-HRT. The nystagmus direction (geotropic or apogeotropic) determined by B-HRT was consistent with that determined by S-HRT with a perfect level of agreement (Cohen κ = 1.0, p < 0.001**). In 76.0% of the cases, the determination of the affected ear was concordant between B-HRT and S-HRT (Cohen κ = 0.409, p = 0.037*). The concordance rate between B-HRT and bow and lean test showed a fair level of agreement (68.0%; Cohen κ = 0.286, p = 0.126) with no statistical significance. On comparing the peak slow-phase velocity (SPV), SPVs of positional nystagmus on the stronger side and weaker side did not differ statistically significantly between S-HRT and B-HRT. In 12 of the 25 cases, in which the peak SPV asymmetry was determined as less than 30% by S-HRT (average, 11.00 ± 6.87%), the asymmetry determined by B-HRT (average, 47.31 ± 34.78%) was significantly higher, facilitating lesion identification by performing B-HRT together ( p = 0.001*).

CONCLUSION

B-HRT in the sitting position identified direction-changing nystagmus in LSC-BPPV. B-HRT is helpful in facilitating the diagnosis of LSC-BPPV in the sitting position and determination of the affected ears in cases with nonprominent differences in bilateral nystagmus intensity according to S-HRT.