Is the modified cupulolith repositioning maneuver effective for treatment of persistent geotropic direction-changing positional nystagmus?

Objective: Clinicians sometimes see patients with relatively persistent geotropic direction-changing positional nystagmus (DCPN) as a variant of lateral semicircular canal-benign paroxysmal positional vertigo (LSCC-BPPV). Recently, the concept of a "light cupula" in the lateral semicircular canal, exhibiting persistent geotropic DCPN, has been introduced. However, the underlying pathogenesis of light cupula is not known. We investigated the efficacy of a modified cupulopathy repositioning maneuver (mCuRM), designed to reduce light debris attached to the cupula in patients with persistent geotropic DCPN.

Study Design: Retrospective cohort study.

Methods: Participants included 65 patients with a persistent geotropic DCPN: 35 underwent treatment (mCuRM group), and 30 were followed-up but received no treatment (No CuRM group). We compared the therapeutic and survival rate of persistent geotropic DCPN between two groups.

Results: On Day 1, the persistent geotropic DCPN did not resolve in either group. On the first and second follow-up days, persistent geotropic DCPN was observed in 28 (80%) and 21 (60%) of patients, respectively, in the mCuRM group, and in 28 (93.3%) and 24 (80%) patients, respectively, in the no mCuRM group. The differences between groups were not statistically significant. Furthermore, no between-group differences were found in the time from diagnosis to resolution of nystagmus, or the time from symptom onset to resolution of nystagmus. Kaplan-Meier analysis of the time course of persistent geotropic DCPN resolution from the day of diagnosis and day of symptom onset revealed no significant differences between the groups.

Conclusion: Our findings indicate that mCuRM had no therapeutic benefit for a persistent geotropic DCPN and suggest that the pathophysiology of persistent geotropic DCPN is less likely to be a light debris attached to the cupula.