Early Biomarkers of Neurodegeneration in Parkinsonian Syndromes

Parkinson's disease (PD) is the most common degenerative Parkinson's syndrome and is linked, among other things, to the excessive accumulation of an abnormally aggregating protein, alpha-synuclein. Progressive Supranuclear Palsy (PSP) is another Parkinson's syndrome, linked, among other things, to the abnormal accumulation of the protein Tau, and expressed clinically by falls, early cognitive impairment and oculomotor disorders, not present in PD. The onset of these disorders is so gradual that differential diagnosis between the two diseases is only possible at a late stage, on average 3 to 5 years after the onset of symptoms.

To date, there is a lack of validated imaging biomarkers for diagnosing and monitoring PD and PSP. There is therefore an urgent need for the development of robust biomarkers capable of detecting neurodegeneration at an early stage, in order to aid differential diagnosis as soon as symptoms appear, and to potentially enable these patients to be included in specific therapeutic trials (as these diseases are pathophysiologically different) with potential neuroprotective effects.

The development of cutting-edge technologies such as 7T MRI, combined with optimized image processing methods, now enable non-invasive in vivo exploration and analysis of these small structures in terms of ion homeostasis (sodium), microstructure (volumetry, amount of iron and neuromelanin) and connectivity.