Reduced DTI-ALPS index in tinnitus patients: DTI-ALPS as a mediator of sleep on tinnitus.

Background: Sleep disturbance is a common comorbidity in tinnitus patients, which may be attributed to changes in brain structure and function. The aim of this study was to explore the potential role of the glymphatic system (GS), a recently discovered pathway for brain waste clearance, in tinnitus and the associated sleep disturbance.

Methods: The DTI-ALPS index of 22 tinnitus patients and 22 healthy controls (18-60 years old) were compared after controlling for age, sex, and handedness. Partial correlation and mediation analyses were performed to explore the association between the above parameters and clinical data.

Results: Significant differences were found between the right-side DTI-ALPS index and the DTI-ALPS index of the healthy group. Furthermore, the DTI-ALPS index in tinnitus patients was significantly lower than that of the healthy group (1.288 vs. 1.422, p = 0.009). After adjusting for age and sex, the DTI-ALPS index correlated significantly with the Tinnitus Handicap Inventory (THI) scores (r = -0.587, p < 0.001). The DTI-ALPS index was negatively correlated with Pittsburgh Sleep Quality Index (PSQI) scores (r = -0.457, p = 0.032). The mediation analysis of the ALPS index, PSQI, and THI revealed a significant indirect effect of PSQI on the association between ALPS index and THI (p < 0.0001).

Conclusion: The glymphatic system may influence sleep disturbance in tinnitus patients due to its role in brain waste clearance. We observed a decrease in DTI-ALPS in tinnitus patients, and our analyses suggest that sleep disturbances influence tinnitus through the mediation of DTI-ALPS. Thus, greater emphasis should be placed on averting sleep issues at Tinnitus.