Accelerated ageing or selective neuronal loss as an important cause of dementia?

Extensive biochemical analysis of whole temporal lobe from cases of dementia and controls suggests that Alzheimer's disease is a primary degenerative nerve-cell disorder and not the result of accelerated ageing. There is selective loss of neocortical cholinergic neurones. Transmitter systems apart from the cholinergic system appears to be affected, but to a lesser extent, and there are no significant changes in the caudate nucleus. The change in cholinergic neurones has been confirmed in biopsy samples.