MIBG myocardial scintigraphy in pre-motor Parkinson's disease: A review

ObjectivesDetecting very early markers of neurodegeneration that predate the diagnosis of idiopathic Parkinson's disease (PD) is a crucial research topic for the development of disease-modifying therapeutic interventions. Recently ¹²³I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy has become widely used for this purpose, since this test shows high sensitivity and specificity in the diagnosis of PD, based on evidence that cardiac sympathetic nerve fibers are affected early and commonly in PD. We reviewed the literature to determine the role of MIBG myocardial scintigraphy for diagnosing pre-motor PD.MethodsWe performed a systematic review of the literature to identify the use of MIBG myocardial scintigraphy in relation to the constellation of pre-motor symptoms in PD.ResultsMild memory disorder, autonomic failure (constipation and postural hypotension), depression/anxiety, visual hallucination/psychosis (in the elderly), sleep disorder (REM sleep behavior disorder), and impaired olfaction are reported to appear as sole initial symptoms of PD. All clinical features except for impaired olfaction are accompanied by low MIBG uptake, suggestive of very early PD in situ.ConclusionIdentifying persons with mild memory disorder, constipation/postural hypotension, depression/anxiety, visual hallucination/psychosis (in the elderly), and REM sleep behavior disorder associated with low MIBG uptake may provide a unique opportunity to detect very early PD in situ within a pre-clinical window. Future prospective studies to investigate further the findings of these early cases are warranted.