Tinnitus is a neurological disorder resulting in a phantom auditory percept in the absence of an external source (also known as “ringing in the ears”). In the U.S. alone, about 16 million people have sought medical attention for tinnitus with 2-3 million experiencing debilitating conditions. Tinnitus is also the highest service-connected disability for veterans and the top war-related health cost. Unfortunately, there is no consistent treatment for tinnitus. In recent years, various brain stimulation approaches have shown encouraging results for suppressing tinnitus by directly activating neural circuits involved with the phantom percept. However, the invasiveness of these neural stimulation approaches limits the number of eligible patients and the ability to optimize the treatment for each patient. We propose a new non-invasive approach, called Multimodal Synchronization Therapy (MST), for activating the brain to treat tinnitus. MST takes advantage of the dense interconnectivity between the central auditory system and other sensory, motor, limbic, and cognitive pathways to influence the brain’s state. Since tinnitus has been linked to abnormal brain coding within the auditory system, we propose to non-invasively activate these different pathways using artificial and synchronized patterns to then alter the coding behavior of the tinnitus-affected neurons within the auditory system.
In the first part of my talk, I will introduce the different types of brain stimulation approaches being used for tinnitus treatment and the justification for MST. In the second part, I will present initial findings from animal experiments showing that it is possible to electrically stimulate different regions across the body combined with acoustic stimulation to alter coding properties of neurons within the auditory system, including properties that have been linked to tinnitus. In the third part, I will present one potential approach for systematically targeting the specific neurons driving the tinnitus percept. In future studies, we will incorporate other inputs, such as visual and limbic pathways, to further enhance the neural effects caused by somatosensory and auditory activation. The success of MST for tinnitus could expand its use also for hyperacusis (i.e., over-sensitivity and pain to certain sounds).
Hubert Lim is an Assistant Professor in the Biomedical Engineering Department at the University of Minnesota and part of the Institute for Translational Neuroscience. He obtained his PhD in Biomedical Engineering at the University of Michigan in 2005 and performed postdoctoral research at Hannover Medical University in Germany from 2006-2009. His research focuses on neural engineering, auditory neuroscience, and brain plasticity with the aim of developing new neural treatments for hearing loss and tinnitus. Additional information can be found on his lab website: http://soniclab.umn.edu.