Abstract
Objective: In the present study, we characterized the vestibulo-ocular reflex (VOR) gain and properties of corrective saccades (CS) in patients with posterior inferior cerebellar artery (PICA) stroke and determined the best parameter to differentiate PICA stroke from benign peripheral vestibular neuritis (VN). In particular, we studied CS amplitude and asymmetry in video head impulse tests (vHITs) to discriminate these two less-studied disease conditions.Methods: The vHITs were performed within 1 week from symptom onset in patients with PICA stroke (n = 17), patients with VN (n = 17), and healthy subjects (HS, n = 17).Results: PICA stroke patients had bilaterally reduced VOR gains in the horizontal semicircular canal (HC) and the posterior semicircular canal (PC) compared with HSs. When compared with VN patients, PICA stroke patients showed preserved gains in the HC and anterior semicircular canal (AC) bilaterally (i.e., symmetric VOR gain). Similar to VOR gain, smaller but bilaterally symmetric CS in the HC and AC were observed in PICA stroke patients compared with VN patients; the mean amplitude of CS for the ipsilesional HC was reduced (p < 0.001, Mann–Whitney U-test), but the mean amplitude of CS for the contralesional HC was increased (p < 0.03, Mann–Whitney U-test) in PICA stroke compared with VN. The receiver operating characteristic (ROC) curve showed that CS amplitude asymmetry (CSs) and VOR gain asymmetry (Gs) of HC are excellent parameters to distinguish PICA stroke from VN.Conclusion: In the current study, we quantitatively investigated the VOR gain and CS using vHITs for three semicircular canals in PICA stroke and VN patients. In addition to VOR gain, quantitative assessments of CS using vHITs can provide sensitive and objective parameters to distinguish between peripheral and central vestibulopathies.
Highlights
Acute vestibular syndrome (AVS) is characterized by the presence of acute continuous vertigo, motion intolerance, and gait unsteadiness lasting longer than 24 h [1]
This single-center study included 17 patients with posterior inferior cerebellar artery (PICA) stroke confirmed by magnetic resonance imaging (MRI) and 17 patients with Vestibular neuritis (VN) who were prospectively enrolled from March to August 2019 at Jeonbuk National University Hospital
The PICA stroke group had more patients with direction-changing nystagmus, negative clinical head impulse test (HIT) findings, and severe ataxia who could not stand unaided compared to the VN group (Table 1)
Summary
Acute vestibular syndrome (AVS) is characterized by the presence of acute continuous vertigo, motion intolerance, and gait unsteadiness lasting longer than 24 h [1]. Patients with vestibular nucleus, medial longitudinal fasciculus, or cerebellar lesions show decreased (hypoactive) or increased (hyperactive) VOR gains during vertical HITs [7]. In a prior search coil study, patients with PICA stroke showed bilateral mild gain reductions with small CS and minimal gain asymmetry in the horizontal semicircular canal (HC) plane [4], and the presence of large-amplitude CS with a profound right–left asymmetry indicated a peripheral vestibular lesion [4, 13]. Recent reports have evaluated the properties of CS including their latency, frequency, and amplitude as well as the presence of CS in peripheral vestibular disorders; these existing studies focused on elucidating HC VOR gain using clinical or quantitative HIT. VOR gain and CS properties for individual semicircular canals were investigated in a group of AVS patients (PICA stroke and VN), using the video HIT (vHIT) to supplement diagnostic characteristics and determine which parameters might optimally differentiate PICA from VN
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