Background: Unapparent saccades in video head impulse test (vHIT) are usually present in Meniere's disease (MD) patients but tend to be ignored by the clinician. The result of vHIT is constantly questioned in MD patients due to a lack of uniform metrics. A more effective indicator is needed for indicating MD's pathological progress.
Objectives: To get a comprehensive understanding of the nature and usability of saccades in different MD stages.
Methods: 118 patients diagnosed with unilateral MD were recruited in this study. Patient history, audiological examination, caloric test, vHIT were performed. We proposed 'raw saccades' to represent all showed wave peaks behind the head peak and named saccades by their appearance sequence: 1st saccade, 2nd saccade and 3rd saccade. An exploratory saccade analysis was executed to investigate the effectiveness of saccade attributes in identifying MD stages.
Results: MD patients have greater detectable 1st saccade than PR score as well as 2nd saccade. The time and velocity of the 1st saccade show high interaural variability (p = 0.028, p = 0.000 respectively). No statistical difference concerning the vHIT gain, PR score and 2nd saccade among stages could be recognized on both affected and contralateral sides. Multiple comparisons show the affected 1st saccade velocity and affected 1st saccade absolute velocity have stage-difference. At late stages (3&4), the affected 1st saccade is manifested as a speed increase, and this measure shows a relatively high correlation with MD stages compared to other vestibular indicators.
Conclusion: The 1st saccade velocity on the affected side could indicate the MD disease process and severity.
Keywords: Meniere’s disease; PR score; caloric test; saccades; vHIT.