Neuroanatomic Volume Differences in Tinnitus and Hearing Loss

Abstract

Objectives: To investigate neuroanatomic volume differences in tinnitus and hearing loss.

Study design: Cross-sectional.

Methods: Sixteen regions of interest (ROIs) in adults (43 male, 29 female) were examined using 3Tesla structural magnetic resonance imaging in four cohorts: 1) tinnitus with moderate hearing loss (N = 31), 2) moderate hearing loss only (N = 15), 3) tinnitus with normal hearing (N = 17), and 4) normal hearing only (N = 13). ROI volumes were corrected for brain size, age, and sex variations. Analysis of covariance (ANCOVA) and post hoc Tukey's test were used to isolate the effects of tinnitus and hearing loss on volume differences. Effect sizes were calculated as the fraction of total variance (η² ) in ANCOVA models and percent of mean volume difference relative to mean total volume.

Results: The four cohort ANCOVA revealed tinnitus and hearing loss cohorts to have increased volume in the corona radiata (η² = 0.192; P = .0018) and decreased volume in the nucleus accumbens (η² = 0.252; P < .0001), caudate nucleus (η² = 0.188; P = .002), and inferior fronto-occipital fasciculus (η² = 0.250; P = .0001). Tinnitus with normal hearing showed decreased volume in the nucleus accumbens (22.0%; P = .001) and inferior fronto-occipital fasciculus (18.1%; P = .002), and hearing loss only showed increased volume in the corona radiata (10.7%; P = .01) and decreased volume in the nucleus accumbens (22.1%; P = .001), caudate nucleus (16.1%; P = .004), and inferior fronto-occipital fasciculus (18.3%; P = .003).

Conclusion: Tinnitus and hearing loss have overlapping effects on neurovolumetric alterations, especially impacting the nucleus accumbens and inferior fronto-occipital fasciculus. Neurovolumetric studies on tinnitus or hearing loss can be more complete by accounting for those two clinical dimensions separately and jointly.

Level of evidence: 3 Laryngoscope, 131:1863-1868, 2021.

Keywords: Caudate nucleus; corona radiata; inferior fronto-occipital fasciculus; neurovolumetric; nucleus accumbens; tinnitus.