[Functional analysis of the vertical semicircular canal using vertical plane swing test and study of its normal values].

Objective: The purpose of this study was to set up a method to analyze the vertical semicircular canal function and study the normal values of the vertical semicircular canal function using the vertical plane swing test.
Methods: A prospective analysis of 100 normal persons (aged from 18 to 59 years), who were treated by using the vertical plane swing test with the newly developed automatic vestibular function diagnosis and therapy system (SRM-IV). These persons were rotated 180° at a sinusoidal speed (acceleration 45°/s, maximum speed 90°/s) in the vertical semicircular canal plane. Using a PC, evoked vertical nystagmus was analyzed in order to evaluate the excitability of vertical semicircular canals, including the number and the duration of nystagmus, the slow phase velocity and other parameters. Meanwhile, the all persons were divided into two groups, order and younger than 45 years respectively. In the test procedure, with the two pairs of the right anterior vertical semicircular canal and left posterior vertical semicircular canal (RALP) as well as the left anterior vertical semicircular canal and the rear right vertical semicircular canals (LARP), the average slow phase velocity of the vertical nystagmus and the canal paresis (CP) of the two pairs of vertical semicircular canals were calculated using PC and SPSS13.0 software for statistical analysis.
Results: There was no significant difference between the two groups (P > 0.05). The general CP of RALP was 10.2% ± 7.1%, and LARP was 10.4% ± 6.2%. The normal CP range of the vertical semicircular canal in the health group was identified (idea: ≤ 20%; normal high: 20% - 25%).
Conclusion: The 180° vertical plane sinusoidal swing method is effective in functional analysis of the vertical semicircular canal, it is expected to be reliably used in clinical treatment.