A New Test to Diagnose Dizziness without Deafening
Swedish researchers have developed a new way to diagnose dizziness problems in a simpler and less painful way than the old method. A bone conduction speaker, easily attached behind the ear, can make the diagnosis more efficient and safer – especially for patients with pre-existing hearing problems.
For patients with dizziness, the relationship of dizziness and hearing is used for diagnosis. Typically, a ‘VEMP’ test (Vestibular Evoked Myogenic Potentials) is performed. With loud sounds, the test evokes a muscle reflex contraction in the neck and eye muscles, triggered by the vestibular system. In their new approach, reported in Communications Medicine, researchers at Chalmers University instead made use of bone-conducted sounds to achieve better results.
“We have developed a new type of vibrating device called B250 that is placed behind the ear of the patient during the test,” said Bo Håkansson, a professor at Chalmers University. “The vibrating device is small and compact in size and optimised to provide an adequate sound level for triggering the reflex at frequencies as low as 250 Hz, which we have found to be optimal for VEMP stimulation. Previously, no vibrating device has been available that was directly adapted for this type of test of the balance system.”
In bone conduction transmission, sound waves are transformed into vibrations through the skull, stimulating the cochlea within the ear, in the same way as when sound waves normally go through the ear canal, the eardrum and the middle ear. This can be used in various technologies such as in hearing aids.
Half of over-65s suffer from dizziness, but the causes can be difficult to diagnose for several reasons. Dizziness in 50% of those cases results from vestibular system problems. But current VEMP methods have major shortcomings and can cause hearing loss and discomfort for patients. The VEMP test uses very high sound levels which can cause permanent hearing damage. Additionally, if certain types of hearing loss are already present, the test can be inconclusive.
“The previous test was like a machine gun going off next to the ear – with this bone-conduction method it will be much more comfortable. The sound levels to which patients are exposed can be minimised. The test can be performed at 40 decibels lower than today’s method, which uses air-conducted sounds through headphones. This eliminates the risk that the test itself could cause hearing damage,” said researcher Karl-Johan Fredén Jansson, who made all the measurements in the project.
“The benefits also include safer testing for children, and that patients with impaired hearing function due to chronic ear infections or congenital malformations in the ear canal and middle ear can still be diagnosed for the origin of their dizziness,” said Prof Håkansson.
The device has now been tested and developed in several patient studies that have been published internationally, both with healthy individuals to obtain normal data, and in patients suffering from various types of dizziness. The device is compatible with standardised equipment for balance diagnostics in healthcare, which makes it easy to use. In addition to the benefits for patients, the cost of the new technology is also judged to be lower than the corresponding equipment used today.
Source: News-Medical.Net
