A
breakthrough study in Current Biology (4 May 2015) reveals a stunning new discovery about the behavior of neural pathways in the brain for those who experience Tinnitus. As
reported by WBUR on May 5, 2015, Tinnitus does not only occur in the auditory cortex (where it encompasses most of the region, which in and of itself is surprising, as it was theorized that Tinnitus was hyper-localized), but:
Contrary to expectation, these delta changes extended far beyond circumscribed auditory cortical regions to encompass almost all of auditory cortex, plus large parts of temporal, parietal, sensorimotor, and limbic cortex. In discrete auditory, parahippocampal, and inferior parietal "hub" regions, these delta oscillations interacted with middle-frequency (alpha) and high-frequency (beta and gamma) activity, resulting in a coherent system of tightly coupled oscillations associated with high-level functions including memory and perception.
Extensive intracranial recordings revealed rich cross-frequency interactions, clearly indicating that Tinnitus requires neural behavior that extends far beyond the auditory cortex but also involves memory, perception, and emotions.
The breakthrough, WBUR reports, means several things to scientists studying the phenomenon:
- The amount of brain activity has no impact on the perception (i.e., how "loud" the phantom sound is) of Tinnitus.
- Tinnitus brain-waves may be fixable using sound to retrain the brain. (Similar to notched music therapy or acoustic coordinated remodulation neurotherapy.)
- Neural plasticity offers the best hope for silencing Tinnitus given how complex and multivariate the corresponding brain activity is, suggesting that other therapies that address suspected underlying causes may ultimately be ineffective because brainwaves that misfire often become proactive and anticipatory ("hyperactive") behaviors, rather than responsive or reactive behaviors to a particular stimulus or condition. This is similar to the "centralization" effect that many people who have Tinnitus report.
The paper's author, the University of Iowa's
Dr. Phillip Gander, argues that most science on Tinnitus is fundamentally "wrong," and that a targeted solution may be ultimately fruitless since there appear to be innumerable points of hyperactivity disconnected from any single point of origin.