CPT® Code 92538

Caloric vestibular test with recording, bilateral; monothermal (ie, one irrigation in each ear for a total of two irrigations)

The caloric vestibular test, identified by CPT® Code 92538, is a specialized diagnostic procedure designed to assess the vestibulo-ocular reflex, which is crucial for maintaining balance and stable vision. This test is particularly useful in evaluating patients who experience dizziness or balance disorders, as it helps to determine if there is an asymmetrical functioning of the peripheral vestibular system. During the procedure, the patient is positioned supine at a 30-degree incline, which optimally aligns the horizontal semi-circular canals of the inner ear into a vertical orientation, enhancing the accuracy of the test results. The test involves the use of electrodes placed around the forehead and eyes to measure the corneo-retinal potential through electro-nystagmography (ENG), or alternatively, video-nystagmography (VNG) using infra-red goggles to track eye movements. The procedure includes the irrigation of each external auditory canal with water, which stimulates the vestibular system and induces eye movements that are recorded for analysis. In the case of monothermal testing, as specified by CPT® Code 92538, a single bolus of ice water is introduced into each ear sequentially, allowing for a focused assessment of the vestibular response without the variability introduced by temperature changes associated with bithermal testing.