Changes in auditory cortex subregions and their prediction for sound therapy outcomes in patients with tinnitus

To examine structural and functional changes in auditory cortex(AC) subregions of patients with tinnitus and identify potential predictive indicators for sound therapy.

63 patients with tinnitus (29 in effective group[EG] and 34 in ineffective group[IG]) and 38 healthy controls(HCs) were included. High-resolution 3D T1-weighted images, diffusion tensor imaging, and resting-state functional magnetic resonance imaging were obtained before sound therapy. We compared gray matter volume, fractional anisotropy(FA), amplitude of low-frequency fluctuations(ALFF), fractional ALFF(fALFF), regional homogeneity(ReHo) within AC subregions, and functional connectivity(FC) between each subregion and other brain voxels, across the three groups. Spearman's correlation assessed the relationship between imaging and clinical data, while receiver operating characteristic(ROC) analyses identified sensitive imaging indicators for predicting sound therapy outcomes.

The EG and IG exhibited increased FA and decreased ALFF, fALFF, ReHo in AC subregions, especially in the higher subregion TE3.0. The EG showed a significantly higher FC between bilateral TE3.0 and the left inferior temporal gyrus(ITG) than the IG. FC values between bilateral TE3.0 and left ITG were positively correlated with improvements in Tinnitus Handicap Inventory scores following treatment. When the FC values between bilateral TE3.0 and left ITG combined as an indicator, the area under the curve(AUC) reaches the highest of 0.811.

Our findings demonstrate extensive AC changes in bilateral TE3.0, offering new insights into the mechanism of tinnitus. The sound therapy efficacy may be linked to individual differences in AC subregion reorganization, with combined FC values between bilateral TE3.0 and the left ITG serving as an effective predictor.