Functional Neuroimaging Biomarkers in Parkinson's Disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the degeneration of dopaminergic neurons in the substantia nigra. It is characterised by the classical motor symptoms such as bradykinesia, rigidity, tremor, and/or postural instability as well as non-motor symptoms including olfactory dysfunction, cognitive decline and mood disturbances. There is currently no cure for the disorder and thus the identification of reliable biomarkers is essential for improving diagnostic accuracy, monitoring disease progression and evaluating therapeutic responses. Functional neuroimaging has emerged as an important technique for addressing this need. The present narrative review examined recent studies that applied various functional neuroimaging techniques to identify and evaluate potential functional biomarkers of PD. Findings from the reviewed literature showed that functional neuroimaging can detect alterations in brain networks and activity patterns that precede motor symptom onset, correlate with disease severity and change in response to therapeutic interventions. Future research should focus on combining imaging techniques with longitudinal clinical studies to develop translatable diagnostic and prognostic tools.