AUTHOR=Li Yanjun , Yang Xiaokai 

TITLE=Design and analysis of HSC-BPPV diagnostic maneuver based on virtual simulation

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1132343

DOI=10.3389/fneur.2023.1132343

ISSN=1664-2295

ABSTRACT=Background: The preferred supine roll test for diagnosing horizontal semicircular canal BPPV has disadvantages such as difficulty in localizing the affected ear, inconsistent nystagmus performance on repeated trials, and the absence of a typical latency period, resulting in a less sensitive diagnosis.  
Objectives: Study novel diagnostic techniques with more scientific design, more accessible application, and better diagnostic sensitivity and specificity.  
Materials and methods: Based on clinical microscopic CT data, we established a virtual simulation model of BPPV by Unity software. The physical simulation of the traditional supine roll test was carried out to observe and analyze the motion of otoliths whose initial position was the typical settlement stable position. Furthermore, the normal vectors of the plane and the crista ampullaris of the horizontal semicircular canal were measured by 3D Slicer software. Based on this, we analyzed the critical steps for designing diagnostic maneuvers for BPPV in the horizontal semicircular canal. 
For a more accurate diagnosis of horizontal semicircular canal BPPV, it is critical to rotate the horizontal semicircular canal to be parallel to gravity. Further, it is necessary to move the otolith by swinging the head. As a result, we developed two diagnostic maneuvers: the 60° horizontal roll test and the prone roll test. In addition, we performed simulations to observe the otolith movement and predict nystagmus performance.
Conclusions: The 60° roll and prone roll tests can supplement the supine roll test. Compared to the supine roll test, in addition to effectively distinguishing canalolithiasis from cupulolithiasis, it is also easier to determine the position of the otoliths, and the characteristics of nystagmus are more noticeable. Significant diagnostic features have substantial potential advantages for home and telemedicine.