Beyond vHIT: Introducing the Functional Vision Head Impulse Test

The Functional Vision Head Impulse Test (fvHIT™) is designed to evaluate the Vestibulo-Ocular Reflex (VOR), which is how the eyes stay focused when the head moves quickly.

Unlike standard vHIT, which measures eye movement gain, fvHIT assesses how clearly a patient can see during head movement. It presents quick visual targets (optotypes) that the patient identifies after each head impulse.

fvHIT gives clinicians a functional, real-world view of VOR performance, making it easier to understand what patients are experiencing and to provide care that directly improves their daily activities.

Key Benefits of fvHIT

• Objective and functional insight into how well a patient’s eyes and ears work together during head movements
• Tests all semicircular canal planes: lateral, LARP, and RALP
• Helps pinpoint VOR weakness to guide more targeted treatment
• Enable precise interventions that lead to better functionality and quality of life for the patient.

Performing the fvHIT

The test is similar in technique to the video Head Impulse Test (vHIT) and begins with lateral (side-to-side) head movements to assess the horizontal semicircular canals. While the clinician moves the patient’s head in quick, randomized directions, the patient identifies the direction of an optotype (symbol) briefly shown on a screen.

The test then progresses to vertical canal planes—first the LARP (left anterior-right posterior), followed by the RALP (right anterior-left posterior).

Throughout testing, head movement speeds and directions are varied to assess VOR function across different frequencies. The clinician uses software feedback to ensure correct head movement planes and records the patient’s responses via a remote control.

Watch Now: How to perform the Functional Vision Head Impulse Test (fvHIT™)

Equipment Requirements

To perform fvHIT, the following components are required:
• VORTEQ™ IMU head sensor, which is affixed to a headband to record head movement accurately
• A remote control used by the clinician to initiate and control stimulus presentation
• A secondary monitor for visual stimulus display and patient responses

The fvHIT can be conducted using the VORTEQ Functional Assessments bundle.