Effect of ocular fixation on positional nystagmus in BPPV patients

Objective The quantitative suppression rate of positional nystagmus (PN) by ocular fixation (OF) is unknown. This study aims to analyse the effect of OF on the slow phase velocity (SPV) of PN during diagnostic positional manoeuvres (DPMs) with videonystagmography in patients with benign paroxysmal positional vertigo (BPPV).Design DPMs were performed on 58 patients with BPPV, 33 (56.9%) of whom were women. OF was initiated when PN was most evident, and recording was continued. The mean SPV of three consecutive nystagmus before (F0) and after (F1) OF initiation was calculated. The rate of suppression of PN by OF was found in percent with the formula (F0 – F1) x 100/F0.Study Sample 58 patients were included in this study.Results The mean age was 56.1 ± 11.2 (range 27–76). F0 and F1 values were calculated as 5.742 ± 5.589 and 1.948 ± 3.424 degrees/second, respectively (p < 0.001). The rate of suppression of PN by OF was found to be 66.1%.Conclusions OF significantly suppresses PN during DPMs in BPPV patients. Elimination of OF during DPMs is important for accurate diagnosis.