Functional Connectivity Networks in Nonbothersome Tinnitus

Objective. To assess functional connectivity in cortical networks in patients with nonbothersome tinnitus compared with a normal healthy nontinnitus control group by measuring low-frequency (<0.1 Hz) spontaneous blood oxygenation level-dependent (BOLD) signals at rest. Design. Case-control. Setting. Academic medical center. Participants. Nonbothersome, idiopathic subjective tinnitus for at least 6 months (n = 18) and a normal healthy nontinnitus control group (n = 23). Main Outcome Measure. Functional connectivity differences in 58 a priori selected seed regions of interest encompassing cortical loci in the default mode, attention, auditory, visual, somatosensory, and cognitive networks. Results. The median age of the 18 subjects was 54 years (interquartile range [IQR], 52-57), 66% were male, 90% were white, median Tinnitus Handicap Inventory (THI) score was 8 (IQR, 4-14), and a median Beck Depression Index score was 1 (IQR, 0-5). The median age for the control group was 46 years (IQR, 39-54), and 52% were male. Of the 58 seeds analyzed, no regions had significantly different functional connectivity among the nonbothersome tinnitus group when compared with the control group. Conclusion. Among nonbothersome tinnitus patients, the tinnitus percept does not appear to alter the functional connectivity of the auditory cortex or other key cortical regions.