Objective assessment of tinnitus laterality.

Area of Science:

• Neuroscience
• Medical Imaging
• Auditory Science

Background:

• Tinnitus, characterized by phantom sounds, severely impacts quality of life with no current effective treatments.
• Identifying tinnitus subtypes with distinct neural activity is crucial for developing personalized therapies and monitoring treatment efficacy.
• Perceived laterality (unilateral vs. bilateral) is a proposed characteristic for tinnitus subtypes with differing neural underpinnings.

Purpose of the Study:

• To investigate the potential of functional near-infrared spectroscopy (fNIRS) and functional network analysis in differentiating unilateral and bilateral tinnitus.
• To explore if laterality of tinnitus perception correlates with specific patterns of brain activity.

Main Methods:

• fNIRS recordings were obtained from individuals with unilateral tinnitus, bilateral tinnitus, and healthy controls at rest and during auditory/visual stimulation.
• Functional network analysis was applied to fNIRS data to identify brain activity modules.
• Module Laterality and Modified Module Laterality metrics were calculated to quantify neural network asymmetry.

Main Results:

• A significant difference in Module Laterality was observed between unilateral tinnitus and both bilateral tinnitus and control groups.
• Within the unilateral tinnitus group, Modified Module Laterality distinguished between left-sided and right-sided tinnitus perception.
• These findings suggest distinct neural network differences based on tinnitus laterality.

Conclusions:

• fNIRS combined with network analysis can differentiate tinnitus subtypes based on laterality.
• This approach offers a potential tool for understanding the neural mechanisms underlying different tinnitus types.
• Identifying neural correlates of tinnitus laterality may facilitate the development and monitoring of targeted treatments.