Hearing and balance experts at Johns Hopkins report successful testing in animals of an electrical device that partly restores a damaged or impaired sense of balance.
Though human testing of the so-called multichannel vestibular prosthesis remains a few years away, the scientists say such a device, which is partially implanted in the inner ear, could aid the 30,000 Americans the experts own estimates show are coping with profound loss of inner ear balance. These people often suffer from unsteadiness, disequilibrium or wobbly vision. Problems with vestibular sensation can be inherited at birth or result from use of antibiotics, chemotherapy drugs, Mnires disease, viral infection, stroke or head trauma.
The Hopkins study, done in chinchillas because their inner ear function is well studied, is proof of concept that we can restore three-dimensional sensation of head movement with a multichannel vestibular prosthesis, says Charles C. Della Santina, M.D., Ph.D., director of the Vestibular Neuroengineering Laboratory at Hopkins.
While everyone knows about the five senses of sight, smell, taste, touch and hearing, few people think about a possible sixth sense - the sensation of head orientation and movement - until the system fails, says Della Santina, who has been working on this prosthesis since 2002.
In their report in the June 2007 edition of the journal I.E.E.E. Transactions on Biomedical Engineering, the Hopkins team showed that a matchbox-size prototype device, weighing less than 3 ounces, effectively mimics the workings of the inner ears three semicircular canals by sensing head rotation and transmitting that information to the brain.
Adapting the design of cochlear implants, which restore hearing through electrical stimulation of the cochlear nerve, researchers constructed a circuit that could measure and transmit 3-D balance information to the brain through multiple electrodes connected to the vestibul
Contact: David March
Johns Hopkins Medical Institutions