Objective:

To compare affected and unaffected ear responses of dynamic visual acuity (DVA), functional head impulse test (FHIT), and video head impulse test (vHIT) in interictal Ménière’s disease (MD) and to evaluate the clinical value of each measure.

Approach:

• Participants: Eleven interictal MD patients and twelve inferior vestibular neuritis (IVN) patients were enrolled. Tests were performed during the interictal phase.
• Testing Methods: Six-canal FHIT, six-canal vHIT, and DVA were measured. Comparisons were made using the Wilcoxon signed-rank test.

Key Findings:

• In MD, lesion-side FHIT-H CA% was significantly lower than intact-side (53.9 ± 33.5% vs. 77.3 ± 26.5%; p = 0.022).
• vHIT-H gain (p = 0.146) and DVA (p = 0.820) showed no significant laterality in MD.
• The FHIT laterality index (25.4 ± 31.4%) significantly exceeded the vHIT-H laterality index (4.2 ± 9.1%; p = 0.019).
• In IVN, lesion-side posterior canal vHIT gain was significantly reduced (p = 0.027), while FHIT-H showed no laterality (p = 0.413).

Interpretation:

MD exhibited selective lesion-side FHIT-H reduction with preserved vHIT, while IVN showed selective posterior canal vHIT reduction with normal FHIT-H laterality.

Limitations:

• Small sample size limits generalizability of the findings.
• Retrospective observational design may introduce bias in the results.

Conclusion:

FHIT may be a useful adjunct for detecting functional vestibular asymmetry in interictal MD.