Synchronized refixation saccades in enhanced VVOR test. A new application for PR score

Area of Science:

• Vestibular Neuroscience
• Ophthalmology
• Neurology

Background:

• The vestibular system's function is crucial for maintaining balance and gaze stability.
• Accurate assessment of vestibular-ocular reflex (VOR) function is essential for diagnosing and managing vestibular disorders.
• Current methods for quantifying VOR may have limitations in capturing all aspects of saccadic response synchronization.

Purpose of the Study:

• To develop a novel quantification method for calculating the Perez-Rey (PR) score specifically adapted for the vestibular-only water reactivity (VVOR) test.
• To evaluate the correlation between the newly developed PR score for quantified VVOR and the established PR score obtained from the video head impulse test (vHIT).

Main Methods:

• A new PR score calculation method for the VVOR test was developed using MATLAB, focusing on saccadic response time latency variability.
• A retrospective analysis was conducted correlating PR scores from VVOR and vHIT tests in patients with vestibular neuritis and vestibular neurectomy.
• The study included 30 patients: 11 post-neurectomy and 19 with subacute vestibular neuritis.

Main Results:

• Pearson's correlation coefficient (R²) between the PR scores from VVOR and vHIT tests was 0.92 (p < 0.001), with a 95% confidence interval of 0.85-0.96.
• A linear mixed-effects statistical model indicated a significant association between PR scores from both VVOR and vHIT tests (Wald X² test, p = 0.008).

Conclusions:

• The newly developed PR score for the VVOR test is a valid method for measuring saccadic response synchronization.
• This novel PR score for VVOR demonstrates a high degree of correlation with the established PR score derived from the vHIT test.
• The findings suggest that the quantified VVOR test with the new PR score can reliably complement vHIT in assessing vestibular function.