Relationship between Nystagmus Characteristics and Maneuver Efficacy for Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo: A Prospective Study

Objective To investigate whether a specific nystagmus observed during Gufoni or Gufoni-Appiani maneuvers can predict their efficacy, eliminating the need for deferred diagnosis of a recalcitrant lateral semicircular canal (LSC) benign paroxysmal positional vertigo (BPPV). Study design Prospective cohort. Setting Tertiary center. Patients All patients diagnosed with LSC BPPV by supine-roll test (SRT) between October 2022 and September 2024. Interventions After the SRT, the Bow and Lean test was performed in all patients to confirm its results and to define its sensitivity. All patients were treated with the Gufoni (for the geotropic variant) or Gufoni-Appiani (for the apogeotropic variant) maneuvers. The presence and characteristics of the nystagmus induced in the two intermediate positions of the maneuvers and when the patient returns to the upright position were recorded. Fifteen minutes after the therapeutic maneuver, all patients were reevaluated with the SRT to determine the therapeutic success. A successful maneuver was defined as the absence of vertigo and nystagmus (geotropic variant) and as the conversion to a geotropic variant (apogeotropic variant) in the reevaluation with the SRT after the therapeutic maneuver. Main Outcome Measures Success rates of Gufoni and Gufoni-Appiani maneuvers were calculated. A statistical analysis was performed to relate the induced nystagmus in the intermediate positions with the final result and to find clinical factors associated with no response. Results Thirty-five patients were included and were 10 males (28.6%). In 21 cases, the right-side was affected (58.3%) and 27 were geotropic (75%). A total of 53 maneuvers were performed. Bow and lean test induced a horizontal nystagmus in 28 patients (77.8%). Therapeutic success rates of Gufoni and Gufoni-Appiani maneuvers were 75.6% (N = 31) and 66.7% (N = 8), respectively. Male, tall, and heavy patients had worse outcomes (p = 0.041, p = 0.025, and p = 0.077, respectively). An apogeotropic nystagmus during Gufoni maneuver was associated with an unsuccessful result (p = 0.023). The presence of an ampullopetal flow-induced nystagmus during both maneuvers had an accuracy of 77.4% in detecting a resistant BPPV and a need of a second therapeutic maneuver. Conclusion The presence of an ampullopetal flow-induced nystagmus during Gufoni or Gufoni-Appiani maneuvers suggests an unsuccessful result. Its presence may exempt subsequent reevaluation, reducing waiting time for a second diagnostic maneuver.