Progressive supranuclear palsy, or PSP, typically develops in middle-aged and older adults. Patients experience increasing difficulty with balance, motor function, eye movements, and cognition as the disease advances. Although abnormal accumulation of tau protein has long been recognized as a hallmark of the disease, scientists have struggled to determine how changes in tau over time relate to the worsening of symptoms in living patients. Cross-sectional scans could reveal where tau had deposited, but they could not answer the crucial question of whether the dynamics of that deposition mirrored the pace at which a patient’s condition deteriorated.

To address this challenge, the QST team turned to florzolotau (18F), also known as [18F]PM-PBB3, a highly sensitive tau PET tracer developed by the institute. The researchers followed 26 people with PSP and 10 healthy volunteers over approximately one year. By comparing PET scans taken at two time points, the team examined how tau accumulation changed throughout the brain and whether those changes were associated with clinical decline measured over the same interval. This longitudinal design, rather than a single snapshot, is what allowed the researchers to connect the tempo of tau deposition to the tempo of symptom progression.

The imaging revealed that tau accumulation increased over time in several brain regions affected by PSP, including the basal ganglia, the frontal and parietal cortices, and the cerebellum. The pattern of change was not uniform, however, and the most clinically meaningful signal emerged in a specific deep brain structure. Among patients with Richardson’s syndrome, the most common and fastest-progressing form of PSP, greater increases in tau accumulation within the globus pallidus were strongly associated with greater worsening of symptoms. Patients whose tau burden increased more rapidly experienced faster disease progression.

The globus pallidus, a structure nestled deep within the basal ganglia, showed both prominent tau accumulation at the start of the study and a clear longitudinal increase over the one-year observation period. The relationship between tau change in this region and clinical status was captured using the PSP Rating Scale, a standardized measure of disease severity. Patients with greater increases in globus pallidus tau accumulation tended to show greater worsening of their clinical scores, tying a molecular measurement made by a scanner directly to the functional decline experienced by patients in their daily lives.

“Until now, we could see tau pathology in the brains of people with PSP, but we did not know whether changes in tau over time truly reflected the progression of symptoms,” said Hironobu Endo, Principal Researcher at the Advanced Neuroimaging Center, Institute for Quantum Medical Science, QST. “Our study demonstrates that patients with faster tau accumulation experience faster clinical decline. This provides important support for the development of treatments aimed at reducing tau pathology and offers a promising imaging biomarker for evaluating their effectiveness.”

The implications for drug development could be substantial. The QST researchers note that their imaging method can detect changes over time even in relatively small patient groups, which may help researchers evaluate new therapies more efficiently and objectively than has previously been possible.

If future therapies are designed to slow the accumulation of tau, the new findings suggest a concrete way to test whether they are working. A treatment that measurably reduced the rate of tau buildup in the globus pallidus, for example, could be assessed against the expectation that slower tau accumulation is associated with slower clinical decline. The researchers believe that imaging biomarkers such as this could accelerate the development of disease-modifying therapies, enable clinicians to monitor disease progression more precisely, and help patients maintain independence for longer while reducing the burden on caregivers.

The reach of the technique may extend well beyond PSP. The researchers believe the imaging approach could benefit studies of other neurological disorders in which tau plays a central role, including Alzheimer’s disease and related dementias. The QST tracer’s sensitivity to change over time is what distinguishes the approach from conventional single-scan imaging.

The study, titled “Spatiotemporal Tau Accumulation and Its Clinical Impact on Progressive Supranuclear Palsy: Longitudinal Florzolotau (18F) Positron Emission Tomography,” was published in Movement Disorders on September 4, 2026. As with any longitudinal imaging study, the observed association between tau accumulation and clinical worsening does not by itself prove that tau drives the disease process, and the modest sample size of 26 patients warrants replication in larger cohorts. Nevertheless, the work provides a template for how molecular imaging can be used to follow a rare neurodegenerative disease in real time, and it gives researchers pursuing anti-tau therapies a measurable target whose change over one year can be linked to the outcomes that matter most to patients.

Subject of Research: Longitudinal tau PET imaging linking tau accumulation speed to clinical progression in progressive supranuclear palsy

Article Title: Faster brain tau buildup linked to faster progression of rare neurological disease

Article References: Faster brain tau buildup linked to faster progression of rare neurological disease. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: progressive supranuclear palsy, tau protein, PET imaging, florzolotau, neurodegeneration, biomarker, globus pallidus, Richardson's syndrome, QST, Movement Disorders, drug development, brain imaging