Sensorineural hearing loss and cognitive impairments: Contributions of thalamus using multiparametric MRI

The thalamus is an integrative hub conveying sensory information between cortical areas and related to cognition. However, alterations of the thalamus following partial hearing deprivation remains unknown.

To investigate the modifications of the thalamus and its seven subdivisions in terms of structure, function, and perfusion in subjects with sensorineural hearing loss (SNHL), as well as their associations with SNHL-induced cognitive impairments.

Cross-sectional study.

Thirty-seven bilateral long-term SNHL patients and 38 well-matched controls.

3 T/BOLD, T₁ -weighted imaging, arterial spin labeling (ASL).

Quantitative measurements in the thalamus and subdivisions were obtained, including the relative volume, fractional amplitude of low-frequency fluctuation (fALFF) within slow 5 (0.01-0.027 Hz), slow 4 (0.027-0.073 Hz), and combined frequency (0.01-0.073 Hz), as well as the whole-brain functional connectivity. Twenty-five SNHL patients and 20 controls underwent ASL scanning. Then correlation analysis was computed between all significant changes and cognition tests.

Continuous and categorical variables were compared by independent-sample t-test and chi-square test, respectively. Quantitative MRI measurement comparisons were corrected for multiple comparison, and functional connectivity (FC) analysis used two-sample t-test with false-discovery rate correction. Area under the curve (AUC) in receiver operating characteristic curve analysis was applied to evaluate the power of alterations in differentiating SNHL and controls.

No significant difference in the relative volume and perfusion of seven thalamus subdivisions were observed, but a decrease in fALFF in SNHL. SNHL showed reduced thalamic connectivity with the cerebellum lobule VIII, ventral anterior cingulate cortex, insula, superior temporal gyrus, media temporal gyrus, medial frontal gyrus, Heschl's gyrus, and temporal pole. And some FC abnormalities exhibited positive correlations with cognitive tests and high discriminative power (0.8 < AUC < 1) in two groups.

SNHL led to decreased thalamic activity and widespread weakened connectivity with other brain areas.

2 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:787-797.