What is VHIT?

The Video Head Impulse Test (VHIT) is a diagnostic tool used to assess the function of the vestibular system, specifically the semicircular canals. By measuring eye movements in response to rapid, unpredictable head movements, VHIT helps identify deficits in the vestibulo-ocular reflex (VOR). This test is critical for evaluating patients with dizziness, vertigo, or imbalance.

The Role of Compensation

Compensation refers to the brain's ability to adapt to a vestibular loss or impairment. After a vestibular injury, the central nervous system employs mechanisms such as sensory substitution, saccade adjustment, and recalibration of the VOR. Compensation is essential for reducing symptoms and improving stability, and it can be enhanced through targeted vestibular rehabilitation exercises.

Key Concepts

• VOR Gain: A measure of how well the eyes compensate for head movement. Low gain indicates a deficit.
• Catch-up Saccades: Quick eye movements that help maintain focus during head impulses; often present in compensated patients.
• Recovery: Compensation strategies can restore balance even with permanent vestibular damage.