Clinical Characteristics of persistent geotropic horizontal direction-changing positional nystagmus: Experience in 189 participants.

Background: The etiology and mechanism of persistent geotropic horizontal direction-changing positional nystagmus (DCPN) are still unclear. Whether this pattern of nystagmus is a subtype of benign paroxysmal positional vertigo (BPPV) remains controversial.

Objective: The goal of this study was to observe the clinical characteristics of persistent geotropic horizontal DCPN involving the lateral semicircular canal.

Methods: The analysis was performed to participants with episodic positional vertigo in our clinic from 2014 to 2021. Participants were included via positional test. We observed and summarized the distribution data, vertigo history, follow-up tests, and recurrence situations of 189 persistent geotropic horizontal DCPN participants.

Results: The mean age at the first time showing of persistent geotropic horizontal DCPN was 56±14.7 and more women than men were affected by persistent geotropic horizontal DCPN (female-to-male ratio 2.4 : 1). Overall, 58.7% (57/94) of participants who came for the first-week follow-up test were asymptomatic. Thirty-three participants experienced recurrence (female-to-male ratio: 4.5 : 1). Fifty-three (28.0%) participants experienced the conversion of the patterns of DCPN in the history, the follow-up tests and the recurrence compared to the first showing of persistent geotropic horizontal DCPN. 24(12.1%) participants still experienced persistent geotropic horizontal DCPN attack in the follow-up tests and the recurrences without benign paroxysmal positional vertigo history.

Conclusion: Persistent geotropic horizontal DCPN affected more women than men. The persistent geotropic horizontal DCPN that with conversion to transient geotropic horizontal DCPN or to persistent apogeotropic horizontal DCPN might be a subtype of BPPV or in a stage of BPPV process. However, the persistent geotropic horizontal DCPN without conversion might be an independent disease that is not related to BPPV.