It is estimated that one-quarter of today’s teens may have serious hearing damage and not even know it. It therefore becomes necessary that we find ways to diagnose hearing loss and treat it. Until recently, one common way of informally detecting hearing loss is to check for “tinnitus” (ringing in the ears), which has been associated with the loss of “hair cells” (sensory cells that convert sound vibrations into electrical signals that are sent to the brain). Researchers have now discovered that hearing loss is not only linked with the death of hair cells (which do not regenerate), but also with cochlear nerve cells that sustain damage to their synapses. This “hidden” hearing loss is known as “cochlear synaptopathy”.