Multiparametric imaging of dopaminergic, cholinergic and noradrenergic contribution in olfactory dysfunction in Parkinson’s disease

Motivation: Olfactory dysfunction is an early symptom of Parkinson’s disease (PD), involving impairments of cholinergic, dopaminergic, and noradrenergic networks. Patients with idiopathic REM sleep behavior disorder (iRBD), a prodromal phase of PD, are associated with anosmia and severe noradrenergic defects. Goal(s): This study aimed to decipher the contribution of cholinergic, dopaminergic, and noradrenergic alterations in olfactory impairments in the presence or absence of RBD. Approach: Multiparametric imaging highlighted specific alterations of the Locus Coeruleus (LC) and Nucleus Basalis of Meynert that correlated with olfactory scoreResults: Alterations were modulated by the presence of RBD, suggesting specific progression pattern. Impact: Our results show that olfactory dysfunction originates from different altered subcortical nodes in Parkinson’s disease patients depending on the presence of sleep disorder. This suggests that patients with sleep disorder display different progression pattern of Parkinson’s disease.