vHIT96da is a video head impulse test (vHIT) application for iPhone. A fixture is required to secure the iPhone, and instructions for making one are provided near the bottom of this page.
Successful recordings have been made with the iPod touch (7th generation), iPhone SE (1st generation), iPhone 12 mini, and iPhone 16.
1) The iPhone has been secured and the application started. Tap the camera button at the lower right of the screen to activate the camera.
2) Tap the Start button at the bottom center to begin recording.
3) At the beginning of recording, have the subject fixate on a single point straight ahead and move the head fairly quickly from side to side several times for calibration. Then perform the vHIT examination. Motion-sensor data are recorded together with the video. When recording is complete, tap the large Stop button at the bottom center.
4) The first frame of the recorded video is displayed. Tap the reflection of the LED light on the cornea to move the green frame close to the reflection, and then tap the Analyze button.
5) The application uses the eye video and the iPhone motion-sensor data to display vHIT waveforms. An image of the result can be saved under a chosen name or sent by email.
The video on the left, recorded with an iPhone 16, is a screen recording beginning at the end of the vHIT examination. The recorded video is played with the yellow Play button at the lower right. Perform the examination so that the reflected LED image remains properly within the dark pupil area, as shown in this example.
Return the video to the first frame and tap the reflected LED image. The green frame moves to that position. When the Analyze button is tapped, the frame is automatically fine-tuned to a suitable position and analysis begins.
During analysis, head rotational velocity is shown in black and eye rotational velocity in red in the lower waveform area. The vHIT waveforms are shown in the upper waveform area.
After analysis, the application automatically corrects the timing and amplitude differences between head and eye rotation using the calibration results, and then displays the final vHIT analysis.
The upper waveform area displays the portions identified as vHIT impulses after checking the head rotation. In the video on the left, recorded with an iPod touch 7th generation, the subject blinks during the examination. Eye movement cannot be analyzed during a blink, so the waveform is disturbed. Most disturbed waveforms are removed automatically, although some may still appear in the vHIT results.
Move the lower waveform area with the blue slider. The vHIT waveform at the center of the lower area is highlighted in the upper area. When a disturbed waveform is highlighted, tap the lower display area to hide that waveform.
If you are viewing this page on an iPhone, tap the QR code to open the download page. If you are viewing it on a computer, scan the QR code with the iPhone camera.
iPhone Mounting Fixture
3D-printable design files are available for download. The designs support devices ranging from the iPod touch (7th generation) to the iPhone 16. The photographs show the oral stabilization mount attached to an iPod touch (7th generation) and an iPhone 12 mini. The mount is attached to the iPhone, which can then be stabilized either directly by biting on it or by covering it with a disposable material such as cardboard or a silicone sheet before gently clenching it between the teeth.
hagata.stl: 3D-printable design file Download