Differences between early and late-onset Alzheimer's disease.

Alzheimer's disease of early onset versus that of late onset represent different syndromes, with distinct neuropathologies. Patients with early onset disease exhibit a more severe and more widespread loss of neurons from cortical and sub-cortical regions and the neurochemical changes involve not only the cholinergic system, but also neurons containing GABA, somatostatin and norepinephrine.