To investigate patterns of cerebral atrophy associated with specific subtypes of mild cognitive impairment (MCI).
Community-based sample at a tertiary referral center
One hundred and forty-five subjects with MCI subjects and 145 age and gender-matched cognitively normal controls. MCI subjects were classified as amnestic single cognitive domain, amnestic multi-domain, non-amnestic single-domain and non-amnestic multi-domain MCI. The non-amnestic single-domain subjects were also divided into language, attention/executive, and visuospatial groups based on the specific cognitive impairment.
Main Outcome Measure
Patterns of grey matter loss in the MCI groups compared to controls assessed using voxel-based morphometry
The amnestic single and multi-domain groups both showed loss in the medial and inferior temporal lobes compared to controls, while the multi-domain group also showed involvement of the posterior temporal lobe, parietal association cortex and posterior cingulate. The non-amnestic single-domain subjects with language impairment showed loss in the left anterior inferior temporal lobe. The group with attention/executive deficits showed loss in the basal forebrain and hypothalamus. No coherent patterns of loss were observed in the other subgroups.
The pattern of atrophy in the amnestic groups is consistent with the concept that MCI in most of these subjects represents prodromal AD. However, the different patterns in the language and attention/executive groups suggest that these subjects may have a different underlying disorder.