Cerebral Blood Flow in Tinnitus: Venous Congestion Link

Patients with non-auditory tinnitus (NAT) linked to cerebral venous congestion show significantly reduced blood flow in specific left-brain regions. A study published in *Brain Imaging and Behavior* used advanced MRI to measure cerebral blood flow (CBF) in 87 participants, identifying a distinct perfusion pattern that correlates with the severity of tinnitus, poor sleep, and depression.

Connecting Tinnitus to Blood Flow: The Venous Congestion Hypothesis

For many, tinnitus is considered a disorder of the auditory system. However, a growing body of research points to broader neurological and vascular factors. The 2026 study by Liu, Jia, Li, and colleagues at Capital Medical University focuses on a specific subtype: non-auditory tinnitus (NAT) in patients with cerebral venous congestion (CVC). CVC, which includes conditions like internal jugular vein stenosis, impedes blood drainage from the brain. The researchers hypothesized that this venous “traffic jam” could lead to secondary reductions in fresh arterial blood delivery, measured as cerebral blood flow (CBF), and that this perfusion deficit might drive neurological symptoms like tinnitus.

This work builds on existing evidence of cerebral blood flow changes in tinnitus, but narrows in on a specific vascular cause. It moves beyond the cochlea and auditory nerve to examine how global brain perfusion patterns are altered when venous drainage fails.

How Researchers Measured Brain Perfusion

The team conducted a cross-sectional study with three groups: 34 patients with CVC and NAT (NAT+), 17 patients with CVC but no tinnitus (NAT-), and 36 healthy controls. To quantify blood flow, they used a non-invasive MRI technique called multi-delay pseudo-continuous arterial spin labeling (ASL). This method labels arterial blood as an internal tracer, allowing for precise measurement of CBF across the entire brain without contrast agents.

Brain regions were defined using a detailed anatomical atlas (AAL3v1). Crucially, the analysis adjusted for arterial transit time—the time it takes for labeled blood to reach brain tissue—which improves accuracy, especially in pathologies that might slow blood delivery. The researchers then compared CBF maps between groups and analyzed correlations with clinical data like tinnitus duration, sleep scores (PSQI), and depression and anxiety scales (HAMD, HAMA).

Pinpointing the Affected Brain Networks

After identifying regions with altered CBF, the team took a further step. They mapped these areas onto known functional brain networks to understand what cognitive or sensory systems were being impacted. This network analysis helps explain why venous congestion might lead to more than just a phantom sound.

Left-Hemisphere Blood Flow Reductions Define NAT

The findings revealed a clear and specific pattern. Compared to both the healthy controls and the CVC patients without tinnitus, the NAT+ group showed significant CBF reductions in the left hemisphere overall. Key affected regions included the left insula, paracentral lobule, and precentral gyrus.

“Reduced CBF in NAT+ patients was correlated with longer tinnitus duration, poorer sleep quality, and worse depression scores,” the authors report. This triad of correlations is significant. It suggests that the reduced brain perfusion is not just an incidental finding but is linked to the core burdens of the condition: a chronic symptom, sleep disruption, and low mood.

The network analysis confirmed that the hypoperfused regions are hubs within major brain systems: the attention network, sensorimotor network, default mode network (active during rest and self-reflection), and cerebellar networks. This widespread involvement aligns with the complex, multi-symptom experience reported by many with severe tinnitus and related conditions, such as the brain alterations seen in hyperacusis.

Implications for Diagnosis and Treatment Pathways

This study has several practical implications. First, it provides a potential imaging biomarker. The distinct left-hemisphere perfusion pattern could help clinicians identify patients whose tinnitus may have a significant venous component, distinguishing them from those with primarily auditory-origin tinnitus.

Second, it strengthens the rationale for investigating venous health in intractable tinnitus cases. Diagnostic workups could consider assessments like MR venography to check for jugular or venous sinus stenosis, especially when tinnitus is accompanied by other symptoms like head pressure or exercise intolerance.

Finally, it opens new avenues for treatment. If confirmed, these findings suggest that improving cerebral venous drainage or addressing the resulting hypoperfusion could be a valid therapeutic target. This represents a different approach from standard sound therapies or strategies aimed at reversing tinnitus-related brain changes through habituation, focusing instead on a potential circulatory root cause.

The study, “Cerebral blood flow alterations in non-auditory tinnitus: implications for cerebral venous congestion pathophysiology” (DOI: 10.1007/s11682-026-01144-8; PMID: 41957332), calls for larger, longitudinal studies to confirm if treating venous congestion can normalize blood flow and alleviate symptoms. It marks an important step in understanding tinnitus not as a monolithic disorder, but as a symptom with diverse neurological origins.