Research update: Looking for tinnitus biomarkers

Professor Frances Williams’ chronic pain and hearing loss research group within TwinsUK at King’s College London has recently published another piece of the puzzle in the steps to understanding and treating tinnitus.

The large project – funded by Tinnitus UK as part of their Large Research Grants Programme – spanned Sweden and the UK, recruiting participants with tinnitus and matched controls firstly in over 1,000 participants in Sweden and then running a replication arm of the study in over 1,000 twins from Twins UK.

The aim of the research was to find a biomarker/s for tinnitus. A biomarker, or biological marker, is a measurable indicator of some biological state or condition – for example, blood pressure or cholesterol levels.

“It is difficult to establish biomarkers to detect or treat the disorder…” says co-author Max Freidn “…because tinnitus is heterogeneous”, meaning many different factors could determine whether a person gets tinnitus or not.

Perhaps surprisingly, tinnitus shares several signs and symptoms with chronic pain. Neuroimaging suggests there are similar disturbances in the prefrontal cortex of the brain which lead signals from sensory inputs such as sound being interpreted in a muddled way. A localised brain inflammatory response has been reported to occur with chronic pain and was detectable in the bloodstream. Williams’ team investigated to see if inflammatory biomarkers could be found in people with tinnitus, hypothesising “that chronic and constant tinnitus may also be associated with neuroinflammation”.

Importantly, factors unrelated to hearing difficulties that affect inflammatory marker levels, such as age, sex and body mass index were accounted for. Tinnitus tends to be accompanied by stress, anxiety, and depression, hyper-sensitivity to sound, face pain and headache, however none of these conditions were related to inflammatory marker levels. While a weak association of five inflammatory proteins was seen in the Swedish cohort, the finding was not replicated in the UK cohort, leaving researchers to conclude “there is a lack of association between plasma biomarkers and constant tinnitus…”. Other research has shown “…biomarkers can be derived from electrophysiological measures, this does not appear to be the case for blood biomarkers”.

Although the team didn’t find a tinnitus biomarker, negative results are progress and an important part of directing future research and treatment. Such steps forward are only made possible with the generous contribution of research investments made possible by Tinnitus UK, the participants belonging to the TwinsUK cohort and the generous support of individuals from both research institutions.

Link to article:

Screening for Circulating Inflammatory Proteins Does Not Reveal Plasma Biomarkers of Constant Tinnitus Journal of the Association for Research in Otolaryngology