Continuous Ambulatory Vestibular Assessment (CAVA)
Reviewed by Richard (Wei Chern) Gan

This article presents initial test findings using a novel system called CAVA - Continuous Ambulatory Vestibular Assessment. Akin to the 24-hour ECG tape to identify cardiac arrhythmias, this system aims to continuously monitor the presence of a nystagmus pattern in dizzy patients in the community. It consists of a wearable device that detects horizontal and vertical eye movements via the corneo-retinal potential generated by the eyes. The device also contains an accelerometer, microcomputer, data storage, battery, and connection port. The CAVA device allows continuous recording of eye and head movements 23 hours a day for 30 days. It involves the patient removing the device each morning for one hour and then reapplying it. Initial test findings of this system on a group of healthy individuals showed a sensitivity and specificity of detecting nystagmus in both stationary and moving subjects of 99.1% and 98.6% respectively. The frequency and beat direction could also be identified. The device is small enough to be worn for 30 days, can store more than a month’s data, and requires a single battery change after 15 days. Quantifiable differences in the nystagmus pattern of different conditions have been found. Nystagmus during an attack of Meniere’s disease occurs in short episodes lasting several hours with the direction alternating in relation to the affected ear. Vestibular migraine gives rise to a pattern of nystagmus of shorter duration, while BPPV an even shorter duration, and is induced by head acceleration. They may have also discovered a prodromal phase to the Meniere’s attack and, thus, the device could possibly be used to warn patients of an impending attack. This novel system has the potential in aiding diagnosis and the understanding of vestibular and non-vestibular diseases, and I look forward to reading about further data on the system.

Clinical Techniques and Technology: Vestibular Telemetry.
Phillips JS, Newman JL, Cox SJ.
OTOLARYNG-HEAD AND NECK SURG
2021;165(5):751-3.