Summary: A novel PET imaging study has identified unique patterns of neuroinflammation in patients with progressive apraxia of speech (PAOS), a rare disorder that impairs the brain’s ability to plan speech. Using TSPO PET scans, researchers found elevated inflammation in brain regions involved in movement and speech, particularly in patients who also showed signs of Parkinson-plus syndromes.
The findings link brain inflammation to tau pathology and disease severity, suggesting inflammation could serve as an early biomarker for PAOS progression. This insight opens new avenues for diagnosis, monitoring, and therapeutic targeting in tau-related neurodegenerative diseases.
Key Facts:
- Inflammation Hotspots: PET scans showed inflammation in speech and motor regions like the premotor cortex, frontal lobes, and midbrain.
- Parkinson-Plus Link: Patients with Parkinson-plus features had broader inflammation and stronger correlation with tau buildup.
- Biomarker Potential: Neuroinflammation may serve as a marker for PAOS progression and guide future treatment strategies.
Source: SNMMI
A novel PET imaging approach has revealed distinct patterns of brain inflammation in patients with progressive apraxia of speech (PAOS), a rare neurodegenerative disorder that affects speech planning.
These findings provide new insight into how neuroinflammation and tau pathology may drive disease progression in PAOS, opening potential avenues for earlier diagnosis and targeted treatments.
This research was presented at the Society of Nuclear Medicine and Molecular Imaging 2025 Annual Meeting.
PAOS is a neurodegenerative disorder that impairs the brain’s ability to plan and coordinate speech. It is marked by a slow speaking rate, distorted sounds, and effortful facial movements during speech.
Patients with PAOS are likely to have Parkinson-plus syndrome in the later stages, meeting criteria for progressive supranuclear palsy or corticobasal syndrome, and typically have a 4-repeat tauopathy at autopsy.
“Although previous neuroimaging studies have shown significant brain atrophy and tau buildup in the premotor cortex and subcortical regions of PAOS patients, the spatial patterns of neuroinflammation—and how they relate to Parkinson-plus syndromes and tau accumulation—remain poorly understood,” said Ryota Satoh, assistant professor at the Mayo Clinic in Rochester, Minnesota.
“Our study aimed to map the spatial patterns of neuroinflammation in PAOS—with and without Parkinson-plus features—and to explore how inflammation relates to tau deposition.”
The study included 25 PAOS patients (13 with Parkinson-plus syndrome) and 30 healthy controls, all of whom underwent 11C-ER176 TSPO PET scans to measure brain inflammation and tau buildup.
Researchers analyzed 84 brain regions to assess how inflammation and tau PET signals were related in each patient, using a standardized brain atlas for reference. They then compared these levels between patients and healthy controls and analyzed how inflammation and tau were related across different brain regions.
11C-ER176 TSPO PET scans revealed that patients with PAOS had more brain inflammation than healthy controls, especially in areas of the brain that control movement and speech, like the premotor cortex, frontal lobes, basal ganglia, and midbrain.
Patients with Parkinson-plus syndrome had broader uptake patterns and higher correlations than patients without the syndrome, suggesting that severe neuroinflammation is associated with the presence of Parkinson-plus syndrome.
“These results help contribute to our understanding of the neuroinflammatory process in PAOS and provide potential utility as a disease biomarker,” stated Satoh. “We believe that our findings could have a positive impact on research and development of neuroinflammatory PET techniques.”
About this neuroimaging research news
Author: Rebecca Maxey
Source: SNMMI
Contact: Rebecca Maxey – SNMMI
Image: The image is credited to Neuroscience News
Original Research: The findings will be presented at the Society of Nuclear Medicine and Molecular Imaging 2025 Annual Meeting