The topography of grey matter involvement in early and late onset Alzheimer's disease.

Frisoni, Giovanni B; Pievani, Michela; Testa, Cristina; Sabattoli, Francesca; Bresciani, Lorena; Bonetti, Matteo; Beltramello, Alberto; Hayashi, Kiralee M; Toga, Arthur W; Thompson, Paul M

The topography of grey matter involvement in early and late onset Alzheimer's disease.

Date

2007-03-09

Authors

Abstract

Clinical observations have suggested that the neuropsychological profile of early and late onset forms of Alzheimer s disease EOAD and LOAD differ in that neocortical functions are more affected in the former and learning in the latter suggesting that they might be different diseases The aim of this study is to assess the brain structural basis of these observations and test whether neocortical areas are more heavily affected in EOAD and medial temporal areas in LOAD Fifteen patients with EOAD and 15 with LOAD onset before and after age 65 Mini Mental State Examination 19 8 SD 4 0 and 20 7 SD 4 2 were assessed with a neuropsychological battery and high resolution MRI together with 1 1 age and sex matched controls Cortical atrophy was assessed with cortical pattern matching and hippocampal atrophy with region of interest based analysis EOAD patients performed more poorly than LOAD on visuospatial frontal executive and learning tests EOAD patients had the largest atrophy in the occipital 25 grey matter GM loss in the left and 24 in the right hemisphere and parietal lobes 23 loss on both sides while LOAD patients were remarkably atrophic in the hippocampus 21 and 22 loss Hippocampal GM loss of EOAD 9 and 16 to the left and right and occipital 12 and 14 and parietal 13 and 12 loss of LOAD patients were less marked In EOAD GM loss of 25 or more was mapped to large neocortical areas and affected all lobes with relative sparing of primary sensory motor and visual cortex and anterior cingulate and orbital cortex In LOAD GM loss was diffusely milder below 15 losses of 15 20 were confined to temporoparietal and retrosplenial cortex and reached 25 in restricted areas of the medial temporal lobe and right superior temporal gyrus These findings indicate that EOAD and LOAD differ in their typical topographic patterns of brain atrophy suggesting different predisposing or aetiological factors