Education and Dementia

Abstract

The very high prevalence of Alzheimer’s disease (AD) among the elderly is a cause of great concern. Unfortunately, there is still no unanimity concerning basic issues, going as far as even questioning whether AD is a single nosological entity. The clinical diagnosis entertains significance uncertainties (Korczyn, 1991), necessitating diagnostic criteria (American Psychiatric Association, 1995; McKhann et al., 1984). While these are of great importance in setting methodological unity, their validation against outside “gold standards” is difficult. The most commonly agreed upon criterion for validation of clinical criteria consists of a set of pathological changes that can be observed microscopically in the brains of deceased people (less frequently, biopsy material is available). These changes consist primarily of amyloid (senile) plaques (SP) and neuro-fibrillary tangles (NFT), although both can frequently be seen in other dementing diseases as well as in nondemented elderly people. Moreover, even among AD patients, there is only a poor correlation between the degree of dementia and the number of SP and NFT. It thus was suggested that SP are essentially tombstones, which result and accumulate during certain degenerative processes of the brain. Although obviously not all forms of brain degeneration lead to SP and NFT formation, there is at present no compelling reason to assume that the latter result from a highly specific process. Some data suggest that the cognitive decline in AD is more closely linked to loss of cortical synapses (Masliah, Miller, & Terry, 1993), although these changes are also not likely to be specific to AD.