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The following is a summary of “Association of Relative Brain Hyperperfusion Independent of Dopamine Depletion With Motor Dysfunction in Patients With Parkinson Disease,” published in the November 2024 issue of Neurology by Yoo et al.   

Parkinson disease (PD) is a network disorder characterized by altered brain perfusion patterns and dopamine depletion. 

Researchers conducted a prospective study to investigate the association between brain perfusion and motor symptoms in PD, independent of dopamine depletion. 

They recruited 168 patients with de novo PD and 30 HCs, who underwent dual-phase ¹⁸F-FP-CIT PET, brain MRI, and the Unified Parkinson’s Disease Rating Scale (UPDRS). The early-phase images assessed brain perfusion, and the delayed-phase images evaluated dopamine transporter availability. Standardized residuals (SRs) of relative brain hyperperfusion in the regions showing relative hyperperfusion (SUVR_E -HYPER) were calculated and analyzed for their correlation with motor symptoms. 

The results showed that compared with HCs, patients with PD exhibited relative hyperperfusion in the primary motor cortex, thalamus, pons, hippocampus, and cerebellum, and hypoperfusion in the prefrontal and temporo-parieto-occipital cortices. Motor symptoms were negatively correlated with dopamine transporter availability in the posterior putamen (SUVR_D -PP) (standardized β = 0.402, P<0.001) and positively correlated with SUVR_E -HYPER (standardized β = 0.292, P<0.001), but not with SUVR_E in the hypoperfusion regions. SUVR_E -HYPER was independently associated with motor dysfunction, particularly rigidity (standardized β = 0.214, P=0.012). The SR of SUVR_E -HYPER was significantly linked to the UPDRS part III total score, with the baseline SR predicting a worsening of the UPDRS part III score (P=0.017) and a decrease in brain volume. 

They concluded that relative brain hyperperfusion, independent of dopamine depletion, was associated with motor dysfunction and disease progression in PD. 

Source: neurology.org/doi/10.1212/WNL.0000000000210077