Andrea Soddu Tinnitus Eegs

A new study from an international team of researchers led by Andrea Soddu may provide a clearer picture of the levels of distress tinnitus sufferers are experiencing, according to a news release from Western University in Ontario, Canada. Soddu, a Western medical physicist, and his collaborators have developed a new classification procedure for tinnitus patients using data acquired by electroencephalography (EEG), a technique that measures electrical activity in the brain using small electrodes placed on the scalp.

The findings and new EEG testing procedure were published February 1 in the journal Brain Communications.

Western University professor Andrea Soddu holds a simulation head with an EEG cap. Photo by Jeff Renaud.
Western University professor Andrea Soddu holds a simulation head with an EEG cap. Photo by Jeff Renaud.

While it’s especially common in older adults, tinnitus—a potentially devastating ringing in the ears—can affect people of all ages. Tinnitus is experienced by about 1 in 5 people in North America and is usually caused by an underlying condition like age-related hearing loss, an ear injury, or heart disease. Because the noise an affected individual hears isn’t caused by an external sound and there are no discernible biomarkers, it’s extremely difficult for clinicians to assess, diagnose, and treat tinnitus.

EEG is easier to use, less expensive, and far more accessible than functional magnetic resonance imaging (fMRI) which is often considered the medical industry standard.

Phonak image

“Tinnitus is usually the result of external damage to the ear and some sound frequencies can no longer be properly transmitted,” said Soddu, physics professor and Western Institute for Neuroscience faculty member. “The brain tries to make sense of the lack of information and builds up its own interpretation, and that’s why you get this constant whistling in your ear. Your brain is trying to help, but it actually makes things worse.”

Simulation head with EEG cap. Photo by Jeff Renaud.
Simulation head with EEG cap. Photo by Jeff Renaud.

The new procedure, designed by University of Pisa (Italy) postdoctoral researcher Andrea Piarulli, required two classifiers based on brain electrophysical activity that can accurately distinguish tinnitus patients from healthy controls, as well as tinnitus patients with low and high distress levels.

“The classifiers, employed in recognizing the brain pathology of tinnitus, relied on very different electrophysiological parameters from the ones used to classify distress levels. We are convinced this new procedure will be applicable for other neurological conditions like post-traumatic stress disorder (PTSD), chronic pain, and disorders of consciousness as it can accurately pinpoint distress biomarkers,” said Western graduate student and study co-author Idan Nemirovsky.

An EEG cap being setup for recording by graduate student Idan Nemirovsky. The photo was taken at the Institute of Sant’Anna, a neurorehabilitation center in Crotone, Italy, where with Dr. Francesco Riganello, the same EEG classification technique will be applied to patients with severe brain injury who suffer from disorders of consciousness.
An EEG cap being setup for recording by graduate student Idan Nemirovsky. The photo was taken at the Institute of Sant’Anna, a neurorehabilitation center in Crotone, Italy, where with Dr. Francesco Riganello, the same EEG classification technique will be applied to patients with severe brain injury who suffer from disorders of consciousness.

For the study, EEG recordings were acquired from 129 tinnitus patients and 142 healthy controls. The classifier for healthy controls and tinnitus patients performed with an average accuracy of 96% and 94% for the training and test sets, respectively. For the distress classifier, these average accuracies were 89% and 84%.

This article was adapted from a news release by Western University's Senior Media Relations Officer Jeff Renaud.

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