Scientists have devised a noninvasive approach to offer relief from tinnitus - a persistent phantom perception of sound that afflicts as many as 15% of people in the United States. The intervention - 30 minutes of alternating audio and somatosensory stimulation, delivered as brief sound tones through headphones and mild pulses on the neck or cheek - alleviated tinnitus in a double-blind, sham-controlled crossover study with 20 participants. Tinnitus sometimes arises after excessive exposure to loud noises, which is one reason why it is the most common service-related disability among military personnel. Current treatments either involve invasive surgeries or merely adjust afflicted individuals' attitudes about hearing persistent noises instead of addressing the underlying neurological causes. Previous work suggests that tinnitus arises from the unprompted, simultaneous firing by networks of neurons in a brain region called the dorsal cochlear nucleus. Expanding further on such analyses, Kendra Marks and colleagues sought a method to disrupt spontaneous synchrony (or the synchronized firing of neurons). The researchers demonstrated that 20 minute treatments of alternating audio and somatosensory stimulation interrupted spontaneous synchrony and alleviated behavioral symptoms in a guinea pig model of tinnitus. Marks et al. went on to develop a take-home unit for people with tinnitus to self-administer the stimuli for 30 minutes each day over the course of four weeks. During the study, two individuals reported complete elimination of phantom sounds, and eleven participants noted reductions in the perceived volume or pitch, leading them to characterize their tinnitus as less "harsh" or "piercing." The authors note that alternating the two stimuli was crucial - neither animals nor humans had reduced tinnitus when they only heard pulses of sound.
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Journal
Science Translational Medicine