Brain agingHumans

Multimodal PET and MRI predict dementia with Lewy bodies

Combined occipito-parietal cortex pathology and striatal dopamine loss predicted conversion to dementia with Lewy bodies with a sub-distribution hazard ratio of 38.68.

Figure 1 from Journal of Neurology — Figure 1Baun et al.

Journal of Neurology4 Oct 2026, 07:35 BST

In 21 patients with isolated REM sleep behaviour disorder, researchers evaluated whether multimodal brain imaging could predict conversion to dementia with Lewy bodies. Participants underwent structural and perfusion MRI alongside PET scans targeting dopamine synthesis, cholinergic terminals, and neuroinflammation. Using a covariance analysis, the team identified a network combining neuroinflammation, cholinergic loss, microcirculatory dysfunction, and grey matter atrophy that converged in the medial occipito-parietal cortex. When paired with striatal dopamine impairment, this posterior cortical pathology specifically predicted conversion to dementia with Lewy bodies, yielding a sub-distribution hazard ratio of 38.68 (95% confidence interval: 7.545 to 198.3). The predictive association remained significant after adjusting for participant age and disease duration.

Why it matters

Isolated REM sleep behaviour disorder frequently precedes synucleinopathies, but predicting specific clinical trajectories has remained challenging. Mapping convergent posterior cortical and striatal pathologies provides insight into the distinct neurodegenerative pathways driving dementia versus pure motor syndromes during aging.

Caveats

The study was observational and evaluated a small cohort of 21 patients. Larger prospective studies are needed to validate the specific predictive power of this multimodal imaging network.