Abstract
Objective
To analyze the types, directions, and intensities of nystagmus occurring during each step (positions 2, 3, and 4) of the Epley maneuver in patients with posterior semicircular canal benign paroxysmal positional vertigo (BPPV), and to explore their relationship with a positive Dix-Hallpike test at 24–48 hours post-maneuver, indicating incomplete canalith clearance.
Methods
Clinical data from 60 patients with unilateral posterior semicircular canal canalithiasis were retrospectively analyzed. All patients underwent a standard Epley maneuver under video nystagmography (VNG) monitoring. The direction and slow phase velocity (SPV) of nystagmus were recorded at each repositioning step. The need for a second repositioning was determined by repeat Dix-Hallpike test 24-48 hours after the maneuver. Univariate and multivariate logistic regression analyses were performed to identify associations between nystagmus characteristics at each step and the need for a second procedure. Sensitivity, specificity, and predictive values were calculated.
Results
Among 60 patients, 19 (31.7%) required a second repositioning. Univariate analysis showed that reverse nystagmus at position 3, reverse nystagmus at position 4, reverse nystagmus at either position 3 or 4, SPV of reverse nystagmus at position 4 ≥10°/s, diagnostic vertical SPV ≥20°/s, and latency ≤2 s were significantly associated with the need for a second procedure (all P0.05). All four patients who exhibited down-beating nystagmus did not require a second procedure.
Conclusion
During the Epley maneuver, reverse nystagmus occurring at position 4 is the strongest predictor of the need for a second repositioning, with a positive predictive value exceeding 94%. Down-beating nystagmus indicates a favorable outcome and was associated with a lower probability of requiring a second repositioning. Real-time nystagmus feedback during the procedure allows early identification of high-risk patients and enables optimized, individualized follow-up strategies.