Problems in the cochlea (a hollow spiral in the inner ear) are the cause of most individuals’ hearing loss. However, the exact cause of such problems is almost always impossible to diagnose, because the inner ear cannot be safely accessed with existing techniques, and CT and MRI scans do not have sufficient resolution for diagnostic purposes.
This may soon change, however, as an international team of researchers recently identified a way to capture images of inner ear cells in mice without causing any tissue damage. This method may soon be used to advance research into hearing loss, and may even be used to enable more effective placement of cochlear implants and other hearing-assistance devices.
Most hearing loss begins around the so-called round window of the cochlea, one of the two natural openings into the inner ear that is covered with a membrane that responds to incoming vibrations through the other opening. This area of the ear is the intended target of cochlear implants, but the insertion of these is imprecise, which limits the effectiveness of the implants and can cause damage to the tiny hair-like cells of the inner ear. Because the cochlea is small, difficult to access, and encased with bone, it is difficult to examine for either research or clinical purposes.
The researchers were able to successfully capture high-resolution images of the inner ear cells of mice using two-photon microscopy, a technique that shoots photons at the targeted site. This technique allows for a high-resolution image of tissues that are otherwise difficult to access. The high sensitivity of these images may lead to significant developments in research on hearing loss, and possibly be used to more safely and effectively place cochlear implants.
Yang X, Pu Y, Hsieh C-L, et al. Two-photon microscopy of the mouse cochlea in situ for cellular diagnosis. Journal of Biomedical Optics (2013); 18(3), 031104 1-6.