Research Annick Gilles

Abstract

Transcranial direct current stimulation (tDCS) has been proposed as a non-invasive brain stimulation technique to alleviate tinnitus. Many trials target the right dorsolateral prefrontal cortex (rDLPFC), with the aim of strengthening deficient top-down mechanisms and interfering with the emotional response to tinnitus. This technique has a high theoretical potential, but the considerable number of trials investigating the effects of tDCS of the DLPFC on tinnitus are characterized by a high level of interindividual variability in treatment response, and attempts at replication often fail. A major reason for the variability observed in the literature is the known large interindividual variation in electric field strength and neurophysiological effects of tDCS. Moreover, there is a lack of insight into the underlying effects of the tDCS, as trials often only take clinical outcomes into account and not effects on cortical activity. The proposed research aims to optimise tDCS as a tinnitus treatment by delivering individualised paradigms and assessing its effects on evoked cortical activity alongside subjective tinnitus severity. We hypothesize that an individualised anodal tDCS paradigm, with the current optimum in the rDLPFC, will significantly decrease subjective tinnitus severity compared to a sham stimulation protocol. Moreover, we expect that tDCS effects on tinnitus severity will be mediated by its effects on evoked brain activity as measured via cortical auditory evoked potentials (CAEPs). Preliminary data from our centre have shown that active tDCS may elicit a measurable impact on CAEPs, and that these CAEPs may function as an objective neural marker of subjective tinnitus severity. Combining this prior knowledge in a prospective randomized controlled trial, we will elucidate the effects of optimised tDCS over the rDLPFC on tinnitus by taking the underlying effects on cortical activity into account. If successful, the results of this trial will have a tangible effect on the treatment of tinnitus.

Researcher(s)

• Promoter: Cardon Emilie
• Co-promoter: Gilles Annick
• Co-promoter: Van Rompaey Vincent

Research team(s)

• Translational Neurosciences (TNW)

Project type(s)

• Research Project

Abstract

Tinnitus is a highly prevalent disorder affecting 10 to 15% of adults. It has a high socioeconomic burden, because it affects patients' quality of life, is associated with depression, reduced productivity at work and sleeping difficulties. Many different risk factors for the development of tinnitus have been described, such as hearing loss. In about 25% of patients, tinnitus is influenced by neck or jaw related muscle tension or limitations in joint movement, then called somatic tinnitus (ST). Animal research has proposed that ST originates from brainstem connections between the areas that collect information from the neck and jaw and hearing related areas. One brain imaging study has shown that these connections also exist in humans. This, however, does not explain why some patients with tinnitus experience changes in their tinnitus when they are having neck pain while others don't. This is why we aim to use a unique multimodal medical imaging approach with the ultimate goal to identify how function, structure and neurochemistry of key nodes (somatosensory and auditory) in the brain are related to ST. By comparing the results of a group of patients with ST to patients with other types of tinnitus and patients with neck pain without tinnitus, we aim to better identify the mechanisms of ST. This will give us the tools to improve future assessment and treatment strategies for patients with tinnitus.

Researcher(s)

• Promoter: Gilles Annick
• Co-promoter: Jeurissen Ben

Research team(s)

Project type(s)

• Research Project