Neuromelanin hemispheric asymmetry in normal aging and early Parkinson’s disease with motor symptom laterality

The bilateral neuromelanin degeneration pattern in substantia nigra in normal aging and underlying mechanisms of asymmetric motor symptoms in early Parkinson’s disease (PD) are still unknown. Here we examined the neuromelanin hemispheric asymmetry in normal elderly people and early PD patients with motor symptoms laterality by short-echo-time magnitude images derived from QSM. We demonstrated hemispheric asymmetry of neuromelanin in normal aging, as well as a left-hemispheric preferential nigral dysfunction in early-stage PDR, but a different spatial neuromelanin loss pattern in PDL. This template-based neuromelanin measurement might help to detect aging-related change and deepen our understanding of PD with motor laterality.