Pseudo-spontaneous nystagmus in patients with lateral canal benign paroxysmal positional vertigo

Pseudo-spontaneous nystagmus (PSN) can be detected in patients with lateral canal benign paroxysmal positional vertigo (LC-BPPV). Its frequency, and correlation with the therapeutic outcome have been less described and conflicting results have been reported.

This study aims to investigate its clinical and prognostic significance.

One hundred and eighty-four patients with LC BPPV (98 apogeotropic, 86 geotropic type) were enrolled for the study. Clinical parameters were reviewed in patients with or without PSN. The Chi-square and one way ANOVA tests were used to compare the difference between study groups. Statistical significance was set at p < .05.

Twenty-two patients with apogeotropic (22.4%; 98/22) and 17 patients with geotropic nystagmus (19.7%; 86/17) had PSN. The incidence, age, male-female ratio, mean slow phase velocity (SPV), duration of BPPV and the rate of recurrence were not significant in patients with LC-BPPV whether they have PSN or not.

Prognostic role of PSN in patients with LC BPPV seems to be questionable.

Appearance and disappearance of PSN with regard to head position helps to differentiate BPPV from other acute vestibular disorders. Additionally, direction of nystagmus assists to determine the site of the affected canal. However, prognostic significance is obscure.