Glymphatic system dysfunction in chronic tinnitus patients with sleep disturbance

Area of Science:

• Neuroimaging
• Sleep Medicine
• Otolaryngology

Background:

• Chronic tinnitus often co-occurs with sleep disturbances, but the underlying neural mechanisms remain unclear.
• The glymphatic system, responsible for waste clearance in the brain, plays a crucial role in maintaining brain homeostasis and may be implicated in sleep regulation.

Purpose of the Study:

• To investigate potential glymphatic system dysfunctions in patients with chronic tinnitus and sleep disturbance using multimodal magnetic resonance imaging (MRI).

Main Methods:

• A prospective study involving 30 tinnitus with sleep disturbance (TSD) patients, 30 tinnitus with no sleep disturbance (TNSD) patients, and 38 healthy controls (HCs).
• Multimodal MRI was employed to assess glymphatic system indices, including choroid plexus volume (CPV), enlarged perivascular spaces (EPVS), and diffusion tensor image analysis along the perivascular space (DTI-ALPS).
• Clinical assessments included the Pittsburgh Sleep Quality Index (PSQI) and Tinnitus Handicap Questionnaire (THQ).

Main Results:

• The TSD group showed significantly higher CPV and EPVS compared to HCs (p < 0.0001).
• The TNSD group exhibited significantly lower DTI-ALPS values than HCs (p = 0.044).
• In chronic tinnitus patients, decreased DTI-ALPS was negatively associated with PSQI scores (r = -0.428, p = 0.001), while increased CPV and EPVS positively correlated with PSQI scores (r = 0.374, p = 0.005; r = 0.335, p = 0.013). Reduced ALPS also correlated negatively with THQ scores (r = -0.378, p = 0.005).

Conclusions:

• This study suggests disrupted glymphatic function in chronic tinnitus patients, potentially linked to sleep disturbances.
• CPV, EPVS, and ALPS may serve as valuable neuroimaging markers for understanding the neuropathological mechanisms of chronic tinnitus comorbid with sleep disturbance.