Tinnitus Research: Unraveling How the Brain Adapts to Sound

When the Sound Stays: My Motivation for Tinnitus Research This month, Newcastle-based researcher Abishek Umashankar tells his story and shares his latest findings that could help uncover the truth behind tinnitus.

Like many researchers, my path to tinnitus was not a direct one, but accidental. My journey began with a strong desire to understand the neuroscience of sound processing, driven by my work with children using cochlear implants. I focused on how these devices influenced children’s sound perception and speech production. This led me to explore ways to shift my approach from a purely audiological perspective to one grounded in neuroscience. It was during my postgraduate studies that I started learning in detail about tinnitus, and it immediately sparked my curiosity. I couldn’t fully grasp what this constant sound people hear is, why they experience it, and why it never seems to go away. I struggled to understand the biology behind it, as if something didn’t quite add up right. That was why I decided to switch focus from cochlear implants to tinnitus.

While researching potential projects, I came across a funded PhD project by Dr Will Sedley of Newcastle University. This project was jointly funded by Tinnitus UK and RNID, and it was designed to investigate the biological differences between individuals who have recently developed tinnitus and those who have had it for an extended period. I was eager – here was my chance to comprehend the root causes of tinnitus.

The first steps to a breakthrough: My three years of research into tinnitus have been both insightful and thought-provoking, offering new directions for understanding and approaching the condition. We examined the neural and sound processing capabilities of individuals who had recently developed tinnitus, which is named the “acute stage”. We then followed up six months later to investigate the changes that had occurred, as after a condition that has been present for that long it is considered “chronic” or long lasting.

• Except for one person, the tinnitus had not disappeared for any of the participants who had recently developed it when we re-examined them six months later. This is consistent with the findings of numerous researchers who have observed that tinnitus continues to persist in approximately 80% of the population who have only recently developed the condition.
• This further contributes to the prevalence of tinnitus, which as reported by Tinnitus UK is approximately 1 in 7 adults in the country.
• When compared to people who have just developed the condition, tinnitus volume, intrusiveness and neural activity linked to tinnitus tend to improve gradually over time. This happens even without professional support for tinnitus, just a bit of self-education. This confirms that the brain tends to adapt to the tinnitus over time making it better (also called “habituation”).

We also observed a very interesting trend which could indicate the purpose of tinnitus, which we wish to investigate further. A shocking find: We looked at the brain’s ability to adapt to various sounds and combined that with data on the formation of tinnitus-related networks within the brain. Our preliminary investigation indicates that tinnitus correlates with a higher-than-usual ability to adapt to intense sounds and could therefore be helping the brain reduce excessive sound sensitivity. In the absence of hyperacusis, the tinnitus appears to regulate the sensitivity to external sounds, with the objective of preventing hyperacusis-like symptoms. If this is true, then tinnitus might be contributing to something protective, thereby helping us understand why it’s so persistent.

This may be a shock, so in the future we aim to investigate the tinnitus by tackling this question head-on: is tinnitus doing something beneficial? Currently, we are working on combined electric and acoustic stimulation for individuals who have recently developed tinnitus. This stimulation is intended to target the brain regions that we believe are part of a network that contributes to the persistence of tinnitus. We also intend to investigate the structural, functional, and neurochemical changes in individuals who have recently developed tinnitus and to follow them for an extended period in the future, provided that successful funding is secured. This will allow us to gain a more comprehensive understanding of the true nature of tinnitus – a massive step.

A huge thank you from Newcastle: Personally, I feel that we will see immediate progress in the field of tinnitus research if we focus on determining whether tinnitus can be reversed at the acute or early stage, before it transitions into a chronic condition. On behalf of everyone here at Newcastle University, I want to say thank you to everyone who supports Tinnitus UK, who in turn help fund our research. It’s your generous contributions that make ground-breaking research possible at Newcastle and at institutions across the globe, and each day bring us one step closer to understanding the truth about tinnitus.

If you would like to get involved in research at Newcastle, please visit the Tinnitus UK research pages to learn more. I hope I’ll be able to share many more exciting updates in the future, and I hope to meet some of you on a future study!