Cerebral microbleeds (CMB) are commonly seen in patients with dementia with Lewy bodies (DLB) but their pathophysiology and significance are not clearly understood, Victorian researchers say.

CMB were found in 30% (6 of 20) DLB patients investigated by MRI studies conducted by clinicians at the Royal Melbourne Hospital and the Florey Institute of Neuroscience and Mental Health.

There was a low burden of CMB, with all but one of the patients had a single CMB. Similarly all but one CMB were lobar, according to the findings published by Dr Kai Sin Chin and colleagues in the journal Parkinsonism and Related Disorders. (link here).

As in previous studies of CMB, the microbleeds were associated with traditional vascular risk factors, with patients more likely to have a history of hypertension and therefore hypertensive small vessel disease.

The presence of CMB was also associated with use of antiplatelets or anticoagulants.

However there were no differences in core clinical features of DLB such as cognition and neuropsychiatric features between the two groups, nor in the severity of motor parkinsonism.

And when amyloid-beta (Aβ) was assessed on PET scans, there was no association found between the presence of CMB and cortical Aβ deposition.

The report authors said CMB were already known to be common in patients with dementia (Alzheimer’s disease) and cerebral amyloid angiopathy, and the new findings suggested that CMB in DLB might possibly represent a separate process distinct to that seen in these two conditions.

“Further studies into the pathophysiology and clinical implications of CMB in DLB are needed,” they concluded.