[The clinical features and efficacy of patients with geotropic direction-changing positional nystagmus]

Objective: The purpose of this study was to observe the clinical characteristics of two types of geotropic direction-changing positional nystagmus, the transient(nystagmus time <1 min) and the persistent(nystagmus time > 1 min), and to evaluate the efficacy of the barbecue roll maneuver. Methods: A total of 105 cases diagnosed by supine roll test were studied, which including 35 males and 70 females and the average age was (56.9±14.6)years. There were 70 transient geotropic DCPN and 35 persistent geotropic DCPN. The clinical characteristics and the immediate and one-week efficacy of the barbecue roll maneuver were discussed. Results: The nystagmus disappeared at the null-point position and the nystagmus in supine position were opposite to the bowing (90° nose-down) position in persistent geotropic DCPN cases. While to the transient geotropic DCPN cases, there were no NP and no nystagmus in prone position. The ratio of the first onset of the two groups was 28.6% (persistent) and 72.9% (transient) respectively, and the difference was statistically significant (P<0.05). The immediate and one-week efficacy after barbecue roll maneuver were 91.4% and 80.0% in transient geotropic DCPN cases, and 0% and 42.9% in persistent geotropic DCPN cases, which were statistically significant different(P<0.05). Conclusions: The light cupula hypothesis can mainly explain the clinical features of persistent geotropic DCPN cases; the barbecue roll maneuver is invalid to persistent geotropic DCPN cases which can be self-healing.