Caloric Test

Temperature stimulation produces convection in the endolymph of the horizontal semicircular canal. This fluid movement activates the vestibular response associated with that ear and produces nystagmus, an involuntary eye movement. Observing this response gives clinicians a measurable indication of how the stimulated inner ear is functioning during the assessment.

Each ear is evaluated as a separate vestibular contributor, so clinicians compare the strength of the responses rather than interpreting one eye movement in isolation. A difference between sides can reveal reduced function in one vestibular system. This side-to-side comparison helps localize vestibular impairment and supports interpretation of dizziness or balance symptoms.

A reduced response may indicate diminished unilateral vestibular function on the less responsive side. The finding does not describe symptoms alone; it provides physiological evidence that one inner ear is contributing less strongly during stimulation. Clinicians can combine this result with the broader neurological and vestibular evaluation when investigating dizziness or balance disorders.

Warm or cool stimulation provides the temperature change needed to provoke the vestibular response, while water or air serves as the delivery method into the ear canal. The resulting eye movement is then observed and compared between ears. These options allow the same temperature-driven vestibular principle to be assessed through different forms of stimulation.

The clinician introduces warm or cool water or air into the ear canal, observes the resulting involuntary eye movement, and compares the response produced by each ear. The important outcome is not simply whether nystagmus appears, but how the two sides respond relative to one another. Those findings become part of the patient's vestibular assessment.

Clinicians may use this assessment when dizziness or balance problems require evaluation of inner-ear vestibular function. The test can help identify reduced function on one side and contribute to distinguishing peripheral vestibular findings from other possible sources of symptoms. Its results can also inform diagnostic decisions and planning for vestibular rehabilitation.

Within a comprehensive neurological and vestibular evaluation, the test supplies information about the functional contribution of each inner ear. That information can help clinicians interpret balance-related symptoms alongside other findings, rather than relying on the test alone. Identifying an asymmetric vestibular response may also help guide rehabilitation planning for patients with vestibular disorders.