A large-scale, multi-site examination of resting state functional connectivity in tinnitus

Resting state functional connectivity (RS-FC) studies of tinnitus are useful tools for identifying neural mechanisms and potential treatment options for patients. Building on our previous work demonstrating the replicability of RS-FCin individuals with tinnitus and controls, we attempted to investigate the factors leading to published inconsistent findings by examining resting state networks in participant groups across two different study sites: civilians recruited from the University of Illinois Urbana-Champaign; and military-affiliated participants recruited at the Hearig Center of Excellence at Lackland Airforce Base in San Antonio, Texas. Multiple analyses were performed: an overall analysis comparing tinnitus and control participants combined across the sites, and subgroup analyses based on hearing loss, severity, and site. In general, the tinnitus group at the military site exhibited a more profound effect of severity and less so of hearing, compared to their civilian counterparts. More specifically, while changes to the dorsal attention network were observed in the civilian group, the military tinnitus group exhibited alterations to the default mode, emotion processing, and sensory networks. Our study reiterates the impact of severity and hearing loss on neural networks of tinnitus and further supports the need to account for demographic variables such as age and profession.