Objectives The aim of this study was to develop a filtering algorithm for raw nystagmus images and a diagnostic assistive algorithm using a principal component analysis (PCA) to distinguish the different types of benign paroxysmal positional vertigo (BPPV).
Methods Fifteen video clips of clinical data with typical nystagmus patterns of BPPV (13 cases) and with normal nystamgmus (two cases) were preprocessed when applied the thresholding, morphology operation, residual noise filtering, and center point extraction stages. We analyzed multiple data clusters in a single frame via a PCA; in addition, we statistically analyzed the horizontal and vertical components of the main vector among the multiple data clusters in the canalolithiasis of the lateral semicircular canal (LSCC) and the posterior semicircular canal (PSCC).
Results We obtained a clear imaginary pupil and data on the fast phases and slow phases after preprocessing the images. For a normal patient, a round shape of clustered dots was observed. Patients with LSCC showed an elongated horizontal shape, whereas patients with PSCC showed an oval shape at the (x, y) coordinates. The scalar values (mm) of the horizontal component of the main vector when performing a PCA between the LSCC- and PSCC-BPPV were substantially different (102.08±20.11 vs. 32.36±12.52 mm, respectively; p=0.0012). Additionally, the salar ratio of horizontal to vertical components in LSCC and PSCC exhibited a significant difference (16.11±10.74 mm vs. 2.61±1.07 mm, respectively; p=0.0023).
Conclusions The data of a white simulated imaginary pupil without any background noise can be a separate monitoring option, which can aid clinicians in determining the types of BPPV exhibited. Therefore, this analysis algorithm will provide assistive information for diagnosis of BPPV to clinicians.
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Development of An Algorithm for Slippage-Induced Motion Artifacts Reduction in Video-Nystagmography Yerin Lee, Young Joon Seo, Sejung Yang Research in Vestibular Science.2022; 21(4): 104. CrossRef
Background and Objectives: Vestibular function tests are very useful in diagnosing dizzy patients. Among them, bithermal caloric test is most commonly used test for localizing their permanent vestibular loss. However, it causes much discomfort to the patients with non-physiologic stimuli. In addition, it doesn't represent the present functional status of vestibular system. Therefore, normal caloric result does not accurately correspond to normal vestibular function in dizzy patients. Currently, rotation chair test and dynamic posturography have been introduced adjunctly to assess vestibular function accompanied by bithermal caloric test. It has not been elucidated for their specific role in diverse settings of vestibular disorders. So we planned this study to evaluate clinical usefulness of rotation chair test, videonystagmography and computerized dynamic posturogr-phy in dizzy patients with normal caloric response. Materials and Methods: We reviewed clinical records of 46 patients who met their inclusion criteria. They were categorized into five subgroups according to abnormal vestibular function test findings. Results: In each subgroup, we hypothesized its clinical relevance, possible mechanism of dizz-iness and presumed diagnosis. Five categories are as below; visual dependency, imbalance of vestibular tones, chronic peripheral vestibulopathy, abnormality in the vestibulospinal tract and abnormality of oculomotor system. Conclusion: We suggest new classification of abnormal vestibular functional status in dizzy patients with normal caloric results. These are comparable according their clinical features and thought to be helpful in managing and counseling each patient.
Background and objectives: Vestibulo-ocular reflex and vestibulo-spinal reflex are induced by transmatoid galvanic stimulation of vestibular system. Nystagmus and body sway are result of each reflex. Recently, videooculograph possible to record a minute ocular movement was commonly used, vestibulo-ocular reflex induced by galvanic simualtion is easily documented. The purposes of this study are to evaluate the galvanic nystagmus in nomal persons in order to better understand the physiology of the vestibular system.
Materials and methods: Eye movement of 20 neurootologic normal subjects by both side transmstoid galvanic stimulation (40cases) were analyzing by videonystagmography.
Result The direction of nystagmus in fast phase was to the negative electrode. Galvanic nystagmus was occured all normal subjects when stimulus intensity was more than 2mA. There was positive correlation between slow phase velocity(SPV) and electric current but negative correlation was noted between asymmery of SPV and electric current.
Conclusion It is suggested that the galvanic nystagmus test could be a new diagnostic tool for evaluation of vestibular status.