Worldwide survey on laboratory testing of vestibular function.

Area of Science:

• Neuroscience
• Otolaryngology
• Audiology

Background:

• Peripheral vestibular system function can be quantified using tests like video head impulse test (vHIT), caloric irrigation, cervical vestibular evoked myogenic potentials (cVEMP), and ocular vestibular evoked myogenic potentials (oVEMP).
• Existing methods assess semicircular canals (vHIT, caloric irrigation), sacculus (cVEMP), and utriculus (oVEMP).
• Lack of consensus on normal and pathological values hinders consistent clinical interpretation and research.

Purpose of the Study:

• To conduct a worldwide survey to identify current reference and cutoff values used for vestibular function tests.
• To highlight the variability in these values across different international centers.
• To advocate for standardization in vestibular testing protocols and interpretation.

Main Methods:

• A web-based, standardized survey questionnaire was distributed to collect data on reference and cutoff values.
• Data were collected from 38 participating centers across multiple continents (excluding Africa).
• The survey focused on values for vHIT, caloric irrigation, and cVEMP.

Main Results:

• Significant variability was observed in reference values for vHIT gain, caloric irrigation slow phase velocity, and cVEMP amplitude.
• Reported cutoff values for diagnosing unilateral and bilateral vestibulopathy also showed considerable variation.
• Specific ranges for vHIT side difference, caloric irrigation side difference, and cVEMP asymmetry were documented, revealing inconsistencies.

Conclusions:

• The global survey revealed substantial variability in reference and pathological cutoff values for vestibular testing.
• Standardization of data acquisition and agreement on specific values are crucial.
• Standardization will enhance the quality of vestibular testing and the reliability of clinical and scientific outcomes.