Predicting TMS Success for Tinnitus with Brain Scans

A Brain Scan Can Now Predict Tinnitus Treatment Success

For many with chronic tinnitus, transcranial magnetic stimulation (rTMS) offers hope, but its results are frustratingly inconsistent. A new study by researchers Zhongling Ding, Bo Peng, and Mengfang Gong identifies a specific, measurable feature in the brain that predicts who will benefit. The work, published in Frontiers in Neurology, reveals that a larger volume of gray matter in a region linked to cognitive control and attention strongly predicts a positive response to rTMS treatment.

Finding a Needle in a Brain Scan

The team enrolled 64 patients with subjective tinnitus and 18 healthy controls. All patients underwent a two-week course of rTMS, a non-invasive procedure that uses magnetic pulses to modulate brain activity. Before treatment began, each participant received a high-resolution structural MRI scan.

The researchers extracted 242 distinct measurements of brain anatomy from these scans. They then compared the brain structures of patients who responded to rTMS—defined by a clinically meaningful reduction in tinnitus severity—to those who did not. Thirty-six patients, or 56.25% of the cohort, were classified as responders.

Using a machine learning approach called ExtraTrees, the scientists built a predictive model. It was trained to distinguish future responders from non-responders based solely on their pre-treatment brain scans. The model’s performance was validated using rigorous statistical methods to avoid overfitting.

The Right Inferior Frontal Gyrus Emerges as Top Predictor

The results were clear. The predictive model achieved an area under the curve (AUC) of 0.85, indicating high accuracy. Its precision was 0.71, and its recall—its ability to correctly identify true responders—was a striking 0.97.

Analysis identified ten brain regions that differed between groups, but one stood out. The volume of gray matter in the right pars triangularis of the inferior frontal gyrus (IFGtriang-R) was the single most important predictor in the model. A larger volume in this area was associated with a higher likelihood of treatment success.

Further analysis comparing responders, non-responders, and healthy controls revealed a specific pattern. The IFGtriang-R was significantly larger in responders (0.90 ± 0.08) than in both healthy controls (0.86 ± 0.06) and non-responders (0.86 ± 0.07). This suggests responders possess a unique structural signature, not merely a “healthier” or more typical brain.

Intriguingly, the size of this brain region did not correlate with the degree of improvement or with baseline tinnitus severity. This indicates it acts more as a threshold biomarker—a necessary pre-condition for neuroplastic change—rather than a gauge of symptom intensity. You can read more about the importance of baseline assessments in treatment outcomes in a related article on CBT-I Outcomes: Baseline Depression Predicts Long-Term Results.

Toward Precision Neuromodulation for Tinnitus

This study moves the field from a one-size-fits-all application of rTMS toward a precision medicine model. The practical implication is straightforward: a routine structural MRI scan could potentially stratify patients, identifying those with a high probability of success before they commit to an intensive treatment course.

The findings also deepen our understanding of why rTMS works for some and not others. The right inferior frontal gyrus is involved in executive control, attention regulation, and inhibitory processes. A larger volume in this area might indicate a greater inherent capacity for neuroplastic reorganization—a “reserve” that rTMS can effectively engage to disrupt the maladaptive brain networks sustaining tinnitus.

This aligns with a broader shift in auditory health research, which increasingly views conditions like tinnitus as integrated brain disorders rather than simple ear problems. For a wider perspective on this integrated approach, see our article on Integrated Auditory Health: From Hearing Loss to Brain.

Limitations and Future Directions

The study has limitations. The sample size, while respectable, requires replication in larger, independent groups. The rTMS protocol was specific, and results might vary with different stimulation parameters or treatment durations. Furthermore, while the biomarker is statistically powerful, it is not a perfect predictor; some with smaller IFGtriang-R volumes may still respond, and some with larger volumes may not.

Future research should explore whether this structural feature predicts response to other neuromodulation treatments for tinnitus, such as Lenire or different forms of brain stimulation. It also raises a compelling question: could targeted cognitive or behavioral therapies designed to engage the inferior frontal gyrus enhance treatment outcomes for a broader range of patients?

For now, the work by Ding and colleagues provides a concrete, data-driven path to improve clinical trials and patient care. By using an individual’s own brain structure as a guide, clinicians are one step closer to offering effective, personalized treatment for tinnitus.

Source: Ding Z, Peng B, Gong M. Pre-treatment brain structural biomarkers for predicting rTMS efficacy in subjective tinnitus. Front Neurol. 2026;17. doi:10.3389/fneur.2026.1808769.