Hippocampal atrophy in subcortical vascular dementia.

BACKGROUND AND PURPOSE: New research criteria for subcortical vascular dementia (SVaD) have been suggested to define a more homogeneous subgroup of vascular dementia. Hippocampal (Hc) atrophy is a hallmark of Alzheimer's disease (AD), but it also occurs in other dementia disorders including vascular dementias. So far, it is unknown to which extent Hc atrophy is present in SVaD.

METHODS

From a larger consecutive referral population in a memory clinic, 11 patients fulfilling the research criteria for SVaD were carefully matched with comparison groups of healthy controls and patients with AD. To estimate the extent of Hc atrophy in SVaD, both Hc volumetry and visual rating of medial temporal lobe atrophy (MTA) were applied.

RESULTS

In SVaD, significant Hc atrophy occurred. The extent was intermediate between controls and patients with AD both on Hc volumetry and visual MTA ratings. At the same level of global cognition, Hc volumes were reduced by 11.6% in SVaD and 16.6% in AD, relative to controls.

CONCLUSIONS

Patient groups with AD and SVaD as identified by current research criteria appear to overlap considerably with regard to the feature of Hc atrophy. While contamination with AD is a likely cause, other mechanisms of Hc atrophy in SVaD also deserve consideration. The findings have implications for the design of future clinical trials of SVaD.