Pseudo-Spontaneous Nystagmus and Head-Shaking Nystagmus in Horizontal Canal Benign Paroxysmal Positional Vertigo / 대한평형의학회지

ABSTRACT

OBJECTIVES: The purpose of this study was to examine the clinical manifestations and significance of pseudo-spontaneous nystagmus (PSN) and head-shaking nystagmus (HSN) in horizontal canal benign paroxysmal positional vertigo (HC-BPPV). METHODS: Two hundred fifty-two patients diagnosed as HC-BPPV were reviewed retrospectively. After excluding 55 patients with ipsilateral vestibular diseases, multiple canal BPPV, or those who were lost to follow-up, we analyzed the direction of PSN and HSN in patients with HC-BPPV. We also compared the clinical characteristics and treatment outcome between PSN-positive and PSN-negative groups. RESULTS: Our study included 197 patients composed of 80 patients with geotropic HC-BPPV and 117 patients with apogeotropic HC-BPPV. PSN was observed in 13.7% patients and HSN was observed in 45.2%. The incidence of HSN was higher in apogeotropic HC-BPPV, while the proportion of PSN was not statistically significant between the two subtypes. There was no directional preponderance in geotropic HC-BPPV, while ipsilesional PSN and contralesional HSN showed higher incidence in apogeotropic HC-BPPV. The dizziness handicap inventory score in the PSN-positive group was higher than that in the PSN-negative group (p<0.001), and the duration of symptom onset in the PSN-positive group was shorter than that in the PSN-negative group (p=0.047). However, there was no significant difference in the treatment outcome between the two groups. CONCLUSIONS: The incidence of HSN was higher than that of PSN in patients with apogeotropic HC-BPPV. Patients with HC-BPPV showing PSN demonstrated more severe initial symptoms and visited the hospital in a shorter period of time after the onset of symptoms.