Blood Biomarkers Reveal Early Signs of Neurodegeneration in REM Sleep Disorder

Most people think vivid, restless sleep is harmless. But in isolated REM Sleep Behaviour Disorder (iRBD), it can be the earliest warning sign of something far more serious (Liguori C. et al., 2025). In my clinic, I often see patients thrashing in their sleep, acting out dreams, with no other symptoms. For years, iRBD was dismissed as a strange but benign sleep issue. But studies now show around 80% of these patients will develop Parkinson’s disease, dementia with Lewy bodies, or multiple system atrophy (Liguori C. et al., 2025). The real breakthrough? We can now detect early brain stress in the blood, years before it appears on a scan. Three biomarkers are proving especially powerful: NfL – signalling nerve fibre damage GFAP – indicating inflammation in the brain pTau181 – linked to Alzheimer’s-type changes (Liguori C. et al., 2025) Tracking these together not only helps identify who’s most at risk but also shows how quickly changes are happening. In some cases, these blood changes even match patterns seen on brain imaging, confirming they reflect real metabolic disruption (Li S. et al., 2025). And iRBD isn’t one-size-fits-all. Some patients have blood profiles closer to Alzheimer’s risk, while others show Parkinson’s-type patterns (Delva A. et al., 2025). This makes personal monitoring and early intervention even more important. In my own practice, I combine plasma biomarkers with gut microbiome, circadian, and metabolic assessments. This allows me to design personalised protocols, from anti-inflammatory nutrition to melatonin rhythm support, aimed at slowing progression and protecting function. iRBD is no longer “just” a sleep quirk. It’s a clinical window into the future of neurodegeneration, and the earlier we act, the better the outcome (Liguori C. et al., 2025). If you or someone you know experiences vivid, restless sleep, don’t ignore it. Speak to a specialist and explore early testing. If you want to learn more about this, check out my latest blog post.