Analysis of persistent geotropic and apogeotropic positional nystagmus of the lateral canal benign paroxysmal positional vertigo

Objective:This study aims to analyze the clinical characteristics of persistent geotropic and apogeotropic positional nystagmus of LC-BPPV in view of light and heavy cupula discussion.Material and method:The study group includes 184 patients with LC BPPV(98 apogeotropic,86 geotropic type)who have been examined between 2009 and 2020.Ninety-nine females and 85 males,aged between 16 and 92 years were included(Ageotropic 49.32±14.12,geotropic 44.49±13.90 years).Average slow phase velocity(SPV)of positional nystagmus was documented and those with persistent directionchanging positional nystagmus lasting more than a minute were grouped separately.Age,gender difference,side of involvement,and recurrence pattern were particularly reviewed.Chi-square and One way ANOVA tests were used to compare the difference between groups.Statistical significance was set at P<0.05.Results:Thirty-seven patients with apogeotropic nystagmus(30.7%;37/98)and 18 patients with geotropic nystagmus(20.9%;18/86)had persistent nystagmus(p?0.05).Comparison of slow phase velocity(SPV)of persistent and non-persistent geotropic and apogeotropic positional nystagmus of the affected side was significant(p?0.05).Comparison of average age,male to female ratio,side of involvement,and the recurrence rate in patients with persistent and non-persistent geotropic and apogeotropic type positional nystagmus groups were not significant(p=0.177,p=0.521,p=0.891,p=0.702).Conclusion:Persistent geotropic and apogeotropic positional nystagmus is mostly correlated with the size,amount,and position of otoconial debris.It is difficult to justify the light cupula as a new geotropic variant of cupular pathology.Patients with persistent positional nystagmus present similar therapeutic outcomes and recurrence rates.

Direction-fixed positional nystagmus following head-roll testing:how is it related with a vestibular pathology?

Objective:The goal of this study is to analyze the clinical view of patients with direction-fixed positional nystagmus(DFPN)following head-roll maneuver.Methods:Sixty patients with DFPN were reviewed retrospectively.Patients were categorized into 3 groups according to the direction of nystagmus based on rotation side.Associated problems were documented,and cumulative data were compared between groups.One-way analysis of variance(ANOVA test)was used for statistical analysis(P<0.05).Results:Thirty-three patients(55%)had stronger nystagmus beating towards the direction of head-roll(Group-A).Three patients developed geotropic LC-BPPV.Fourteen patients had inner ear disease.Sixteen patients(27%)had stronger nystagmus beating against the direction of head roll(Group-B).Nine patients had inner ear disease.None of the patients tested with head-shaking had change of direction of nystagmus.Eleven patients(18%)had DFPN with equal velocity during right or left head-roll maneuver(Group-C).Of those,nine patients had inner ear disease.None of the patients had change of direction of nystagmus.Comparison of the incidence of associated problems(migraine,vestibular neuronitis,Meniere’s disease etc.)in each group was not statistically significant(P˃0.05).Conclusion:Patients with DFPN should be followed for a possibility of vestibular pathology since vestibular problem was documented for more than half of the patients in the follow-up.On the other hand,DFPN could be related with a temporary reason(thermal,physical or drug effect etc.)in some patients who do not exhibit any associated disease.Head-shaking testing is recommended to expose the lateral canal BPPV.But the incidence is low.