This is a Discovery Research Grant awarded to Dr Sharon Curhan at Brigham and Women’s Hospital, Harvard Medical School, USA, in 2021.
Background
Tinnitus is a persistent ringing, roaring or buzzing sound in the ears or head that’s perceived when no external sound is present.
Tinnitus:
- affects around 15% of the population
- causes considerable distress
- and can be disabling.
Although millions of people worldwide have tinnitus, the causes are not well understood and there is no cure.
A major challenge to understanding tinnitus and to finding effective treatments is that tinnitus is a complex condition with differing underlying causes and processes involved. People with tinnitus experience wide-ranging symptoms, including differences in what tinnitus ‘sounds’ like and how often it’s perceived.
People with tinnitus also differ with respect to many health, diet, lifestyle and environmental factors, such as:
- presence of hearing loss
- health conditions such as diabetes and high blood pressure
- their dietary intake
- and levels of physical activity.
Other factors, including exposure to loud noise and certain medications, also vary. Genetics may also play a role in a person’s likelihood of developing tinnitus. People with tinnitus often experience varying degrees of distress, anxiety, and depression, as well as differing effects on sleep and concentration.
Many people with tinnitus also have hearing loss, yet most people with hearing loss do not have tinnitus. Similarly, many who are exposed to loud noise develop tinnitus, but not all people with noise exposure develop tinnitus.
Although researchers have been working to discover effective ways to alleviate tinnitus, treatment options are limited and are not effective for everyone. People respond to the treatments that are available to differing degrees, and there’s no way to predict who is most likely to benefit.
Aims
The researchers aim to understand more about the underlying biology of tinnitus. They’ll study patterns of ‘metabolites’, small molecules found in the blood that reflect a person’s metabolism (all the chemical reactions taking place inside the body), and try to identify a characteristic ‘metabolomic signature’ of tinnitus.
They’ll then combine this tinnitus-related signature information with a wide array of individual, lifestyle, and environmental data to find objective indicators, or ‘biomarkers’, of tinnitus, and use them to identify distinctive types of tinnitus.
The researchers have access to 2 large cohorts of volunteers, the Nurses’ Health Studies I and II. Data from these volunteers include the metabolomic data described above, alongside information about:
- each individual’s tinnitus
- hearing
- genetics
- health
- diet
- lifestyle
- and environmental factors.
This information has been collected and continually updated over the course of several decades from tens of thousands of study participants.
Their ultimate goal is to identify the metabolic processes, genetic factors and environmental influences that differ between individuals who develop tinnitus and those who do not to better understand the biology of tinnitus.
Benefit
The findings from this project will help to address the gaps that exist in our understanding of tinnitus and reveal factors that cause tinnitus, and how these factors differ among people. This knowledge can then be used to direct the development of specific treatments that target these underlying causes to silence, or alleviate, tinnitus.
These findings could also help in the development of personalized treatment approaches for tinnitus, that consider each person’s individual characteristics, health, diet, lifestyle and environment.