Characterization of cerebral microbleeds in idiopathic Parkinson's disease

Cerebral microbleeds (CMBs) have been extensively studied in healthy controls and patients with cerebrovascular disease and Alzheimer's disease. Our aim was to characterize the clinical and radiological features of CMBs in idiopathic Parkinson's disease (IPD).

This cross-sectional study included consecutive parkinsonian patients who attended the authors' movement disorders clinic from March 2010 to February 2012 and underwent a standard magnetic resonance imaging (MRI) protocol with gradient recalled echo taken with a 3 T MRI machine.

Amongst parkinsonian disorders, CMBs were most common in vascular parkinsonism (VP) (56%) and least common in IPD (17.7%). In IPD, CMBs were significantly associated with white matter hyperintensities and concurrent lacunar infarctions. The presence of CMBs had no effect on various cognitive domains in IPD. IPD with CMBs was discriminated from VP by clinical and neuroimaging findings: frequencies of motor subtypes were similar between IPD with and without CMBs, whereas all VP patients were the postural-instability gait difficulty type. In 90.9% of the IPD cases with CMBs, the numbers of CMBs were three or less, whereas the numbers of CMBs exceeded three in 50% of the cases of VP and exceeded 10 in 31.3% of the cases (P < 0.001). The topography of the CMBs in IPD was also different from that in VP (P < 0.01).

Cerebral microbleeds are not rare in IPD, and IPD with CMBs does not appear to be a form of VP. Further studies in larger populations are needed to elucidate the clinical implications of CMBs in terms of prognoses and cognitive changes in IPD.