An assembly of devices used to track changes in visual acuity during head movements primarily to quantify visual acuity loss due to vestibular pathology. The assembly typically includes a three-dimensional (3-D) integrating gyrometer (or equivalent) fastened to the patient's head, a connected personal computer used to track the patient's ability to correctly identify an image according to a specified head movement, a mounted monitor for image viewing, and operating system software. The system helps to identify patients most likely to benefit from vestibular rehabilitation exercises.