Differences in myocardial sympathetic degeneration and the clinical features of the subtypes of Parkinson’s disease

Parkinson’s disease (PD) can be divided into the akinetic-rigid (ART), mixed (MT), and tremor-dominant (TDT) subtypes according to the clinically dominant symptoms. We analyzed the correlations between 123I-meta-iodobenzylguanidine (MIBG) uptake and the clinical features of patients with various PD subtypes. In addition, we evaluated the relationship between MIBG uptake and the severity of the cardinal motor symptoms among patients with PD subtypes. The mean Unified Parkinson’s Disease Rating Scale motor scores differed significantly among patients with different PD subtypes (± standard deviation [SD]) (ART, 34.6 ± 18.28; MT, 24.63 ± 7.78; TDT, 16.22 ± 4.15, p = 0.002), especially between the ART and TDT subtypes (p = 0.022). The mean MIBG uptake (± SD) was decreased in the TDT (1.69 ± 0.39), MT (1.35 ± 0.32), and ART (1.35 ± 0.22) subtypes (p = 0.049). The MIBG uptake values differed significantly between the ART and TDT subtypes (p = 0.02). The MIBG uptake was inversely correlated with the severity of hypokinesia in the ART subtype (r = −0.75; p = 0.01) and the MT subtype (r = −0.8; p = 0.02), but it was not correlated with the severity of any of the parkinsonian motor symptoms in the TDT subtype. These results imply that hypokinesia is strongly associated with sympathetic myocardial degeneration and that sympathetic myocardial degeneration can reflect the progression of the disease in patients with the ART and mixed MT subtypes of PD.