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. Trial Registration ClinicalTrials.gov Identifier: NCT01049828.