Background: In patients with Parkinson's disease (PD), myocardial (123)I-metaiodobenzylguanidine (MIBG) uptake is significantly reduced even without apparent autonomic abnormalities. Several studies have suggested that the disease duration, severity and specific phenotype influence MIBG uptake in PD. The objective of this study was to investigate prospectively the relationship between the myocardial MIBG uptake and the Parkinsonian motor handicap in patients with minimal to severe disability.
Methods: Sixty-nine patients with PD who underwent MIBG scintigraphy and clinical assessments off medication were included. MIBG uptake was assessed using the ratio of the heart to the upper mediastinum (H/M) according to planar scintigraphic data and correlated with the age, disease duration and severity as measured by the modified Hoehn and Yahr (H & Y) stage and Unified Parkinson's Disease Rating Scale (UPDRS).
Results: There was a significant negative correlation between the H/M ratio and midline symptoms such as speech, posture and gait. However, neither the severity measured by H & Y stage and UPDRS motor scores nor the non-midline symptoms were related to the degree of cardiac sympathetic denervation.
Conclusion: The results of this study suggest that the severity of midline motor symptoms is closely related to myocardial sympathetic dysfunction, although the implications of these findings require further study.