Ask someone with chronic tinnitus (ringing in the ears) to describe a typical episode and you will very quickly see their face succumb to a wave of frustration. Tinnitus is very common, affecting approximately one in five people. Irritatingly, as sufferers start to focus on the ringing more, they often become more agitated and anxious, which in turn makes the noise seem worse. Since the primary auditory cortex—region of the brain where auditory input is processed—has been implicated in tinnitus-related distress, researchers from Wright State University in Fairborn, OH, have begun using functional MRI (fMRI) to show that neurofeedback training has the potential to reduce the severity of tinnitus or even eliminate the condition entirely.
Findings from the new study will be presented today at the annual meeting of the Radiological Society of North America (RSNA) in a presentation entitled “Self-Regulation of the Primary Auditory Cortex Activity via Directed Attention Mediated by Real-Time fMRI Neurofeedback.”
“The idea is that in people with tinnitus there is an overattention drawn to the auditory cortex, making it more active than in a healthy person,” explained senior study investigator Matthew Sherwood, Ph.D., a research engineer and adjunct faculty in the department of biomedical, industrial & human factors engineering at Wright State University. “Our hope is that tinnitus sufferers could use neurofeedback to divert attention away from their tinnitus and possibly make it go away.”
In the current study, researchers looked at a novel way to potentially treat tinnitus by having people use neurofeedback training to turn their focus away from the sounds in their ears. Neurofeedback is a way of training the brain by allowing an individual to view some external indicator of brain activity and attempt to exert control over it.
To determine the potential efficacy of this approach, the researchers used 18 healthy volunteers with normal hearing and had them undergo five fMRI-neurofeedback training sessions. Study participants were given earplugs through which white noise could be introduced for periods of time. The earplugs also served to block out the scanner noise. To obtain fMRI results, the research team used single-shot echoplanar imaging, an MRI technique that is sensitive to blood oxygen levels, providing an indirect measure of brain activity.
“We started with alternating periods of sound and no sound in order to create a map of the brain and find areas that produced the highest activity during the sound phase,” Dr. Sherwood noted. “Then we selected the voxels that were heavily activated when sound was being played.”
Participants were then asked to attempt the fMRI-neurofeedback training phase while inside the MRI scanner. They received white noise through their earplugs and were able to view the activity in their primary auditory cortex as a bar on a screen. Each fMRI-neurofeedback training run contained eight blocks separated into a 30-second “relax” period followed by a 30-second “lower” period. Participants were instructed to watch the bar during the relax period and actively attempt to lower it by decreasing primary auditory cortex activity during the lower phase. The investigators gave the participants techniques to aid them in achieving their goals, such as trying to divert attention from sound to other sensations like touch and sight.
“Many focused on breathing because it gave them a feeling of control,” Dr. Sherwood remarked. “By diverting their attention away from sound, the participants' auditory cortex activity went down, and the signal we were measuring also went down.”
A control group of nine individuals performed the same tasks as the other group (sham), however the feedback came not from them but from a random participant. By performing the same procedures with both groups using either real or sham neurofeedback, the researchers were able to distinguish the effect of real neurofeedback on control of the primary auditory cortex.
Amazingly, this study represents the first time fMRI-neurofeedback training has been applied to demonstrate that there is a significant relationship between control of the primary auditory cortex and attentional processes. This is important to therapeutic development as the neural mechanisms of tinnitus are unknown but likely related to attention. The study results represent a promising avenue of research that could lead to improvements in other areas of health like pain management.
“Ultimately, we'd like to take what we learned from MRI and develop a neurofeedback program that doesn't require MRI to use, such as an app or home-based therapy that could apply to tinnitus and other conditions,” Dr. Sherwood concluded.