Dizziness can be caused by a different underlying health problems, but identifying which is the culprit is not trivial. One technique is called a VEMP test (Vestibular Evoked Myogenic Potentials), which requires the patient to listen to exceedingly loud popping sounds. These sounds, via a natural reflex, trigger the muscles in the eyes and neck to contract momentarily, and these contractions and how quickly they come about can help form a diagnosis.

The problem is that the triggering sounds are so loud that they can cause hearing damage, in addition to causing quite a bit of discomfort for the patients. Researchers at Chalmers University of Technology in Sweden have now developed a VEMP device that works on the principle of bone conduction to trigger the vestibular system, avoiding unnecessary damage to the ears. It is a small, carefully tuned vibrator that causes the skull to resonate and generate audible sound in the ears.

The team’s new device is attached to the skull near the ear and it vibrates at 250 Hz, which is considerably lower and safer than frequencies in the thousands of Hertz. The maximum sound levels that the device can transmit go up to only 75 decibels, which is 40 decibels quieter (a huge difference because the decibel scale is logarithmic) than current VEMP tests.

This technology was already tested on three volunteers, demonstrating that it is able to trigger VEMP responses just the traditional test, but at much lower sound levels.