Overview of Laboratory of Tinnitus and Auditory Neuroscience Research

The Laboratory of Tinnitus and Auditory Neuroscience Research, located in the Lande Medical Research building, is under the direction of Dr. J.S. Zhang. This lab performs research in understanding mechanisms underlying tinnitus and electrical suppression of tinnitus, and in cochlear and auditory brainstem implants, development of prostheses in treating tinnitus and in improving hearing. The research approaches include multichannel electrical/acoustic stimulation, multichannel electrophysiology at single- and multi-unit levels, behavioral testing, engineering and fabrication, histology, neurochemistry, neuropharmacology, confocal microscopy, functional imaging with MEG, MEMRI and fMRI.

In tinnitus research, his group is interested in suppression of tinnitus and tinnitus related neural activity through electrical stimulation. Electrical stimulation has been used to suppress the percepts or reduce the loudness of tinnitus in patients when it is applied to certain structures including the somatosensory structures, cochlea, and auditory brain structures. Due to lack of understanding of the mechanisms underlying tinnitus and suppression of tinnitus, electrical stimulation has not been well established as a reliable therapy for treating tinnitus. In the animal research, his technical approaches combine surgical implantation, electrical stimulation, behavioral assays, electrophysiology at single- and multi-unit levels, and mapping of neural or neurotransmitter pathways. He is currently developing an animal model of Auditory Cortical Electrical Stimulation (ACES) to suppress tinnitus. The immediate goal of this research is to identify brain areas and neural pathways for stimulation and optimize the stimulation strategies in order to effectively suppress tinnitus and its neural correlates. He is collaborating with clinicians at the Henry Ford Hospital. The eventual goal is to translate the findings in the animal model to applications in patients through development of tinnitus prosthesis.

In addition, Dr. Zhang is collaborating with engineer colleagues to develop advanced neural implants to be used in central auditory prosthesis. The central auditory prosthesis currently includes both the auditory brainstem implants (ABI) and auditory midbrain implants (AMI). These implants have been developed to recover hearing for patients who cannot benefit from cochlear implantation. The problems of causing patients ineligible for cochlear implantation include Neurofibromatosis Type 2 (NF-2), cochlear ossification, aplasia and avulsion. Although the currently available central auditory prosthesis systems have demonstrated the benefits in hearing recovery, there is quite a large variability in speech performance. The low speech performance has been attributed to multiple factors including neural damage from surgery to the physiological processing pathway specialized for modulation and speech, channel interactions, low resolution of stimulation or inadequate target for stimulation. Dr. Zhang and Dr. Gregory Auner's group (www.ssim.eng.wayne.edu) are developing advanced neural implants to minimize trauma from insertion and reduce interactions among stimulation electrodes/channels in order to more effectively access and stimulate the tonotopic gradients in a brain structure. It is expected that knowledge acquired from the ABI research will further facilitate our tinnitus suppression research.