Cerebral Blood Flow Changes in Tinnitus

A new study from Capital Medical University has identified a specific pattern of reduced blood flow in the brains of patients with non-auditory tinnitus (NAT) linked to cerebral venous congestion. The research, led by Dr. Lu Liu and Dr. Chen Zhou, found that these perfusion deficits correlate with symptom duration, poor sleep, and depression, offering a potential physiological explanation for a condition often considered idiopathic.

How Researchers Measured Brain Blood Flow in Tinnitus

The study, published in Brain Imaging and Behavior, involved 87 participants split into three groups: 34 patients with cerebral venous congestion (CVC) and NAT, 17 CVC patients without NAT, and 36 healthy controls. This design allowed the team to isolate changes specific to the tinnitus symptom, not just the underlying vascular condition.

To measure cerebral blood flow (CBF), the researchers used a non-invasive MRI technique called multi-delay pseudo-continuous arterial spin labeling (ASL). This method labels water molecules in arterial blood as an endogenous tracer, allowing for a quantitative map of blood perfusion without injections. A key advantage was its adjustment for arterial transit time, providing a more accurate picture of blood flow in patients where vascular flow dynamics might be altered.

Clinical assessments went beyond tinnitus, evaluating sleep quality, anxiety, depression, and cognitive function. This holistic approach aimed to connect the physiological data from the brain scans with the lived experience of the patients.

Left-Hemisphere Blood Flow Deficits Linked to Symptoms

The results revealed a clear and specific pattern. Patients in the NAT+ group had significantly lower cerebral blood flow compared to both the NAT- patients and healthy controls. The reductions were most pronounced in the left hemisphere, including key regions like the insula, paracentral lobule, and precentral gyrus.

Critically, these were not random findings. The lower the measured blood flow in these areas, the longer the patient’s tinnitus had persisted. Reduced perfusion also correlated strongly with poorer scores on sleep quality and depression scales. This creates a direct line from a measurable brain change—reduced blood flow—to the debilitating daily symptoms patients report.

Further network analysis showed the affected regions are hubs within major functional brain networks. These include the attention network, the sensorimotor network, the default mode network (active during rest and self-reflection), and cerebellar networks. This suggests venous congestion and its resulting hypoperfusion may disrupt integrated brain operations, not just a localized “hearing” area. This systemic view aligns with other research on how conditions like hyperacusis alters brain structure and function across networks.

Implications for Understanding and Treating Non-Auditory Tinnitus

The study provides strong evidence for cerebral venous congestion as a contributor to non-auditory tinnitus. The authors propose a pathophysiology where stenosis in veins like the internal jugular or cerebral venous sinuses impairs drainage. This backup of blood likely causes a secondary reduction in fresh arterial perfusion, starving critical brain regions of oxygen and nutrients. The resulting dysfunction in attention, sensorimotor, and default mode networks could generate the phantom sound perception and its associated emotional distress.

This shifts the focus. While much tinnitus research investigates the auditory cortex and limbic system, this work points to a vascular origin for a subset of patients. It suggests that for individuals with NAT, especially with certain risk factors, assessment could include evaluation of cerebral venous health.

Practically, these findings open a potential new avenue for management. If confirmed, treatments aimed at improving venous drainage or increasing cerebral perfusion might be explored for symptom relief. It also helps validate patient experiences, linking the subjective distress of tinnitus, sleep issues, and low mood to an objective, measurable biological change. Understanding such fundamental brain changes is a primary goal, similar to the aims of research on reversing tinnitus-related brain changes.

The study’s cross-sectional design means it cannot prove cause and effect. The authors note the need for larger, longitudinal studies to confirm if treating venous congestion directly improves blood flow and reduces tinnitus symptoms. However, by employing advanced ASL MRI, the research offers a new lens through which to view NAT. It moves the conversation forward by identifying a specific link between tinnitus and cerebral blood flow changes rooted in venous pathology.

Source: Liu L, Jia M, Li H, et al. Cerebral blood flow alterations in non-auditory tinnitus: implications for cerebral venous congestion pathophysiology. Brain Imaging Behav. 2026;20(2):72. doi:10.1007/s11682-026-01144-8. PMID: 41957332.