A Prospective Study of Alzheimer Disease in Down Syndrome

A four year prospective study of age-related cognitive change in adults with Down's syndrome

“…The first is age and this confirms the findings of previous research (Hewitt et al 1985 ;Fenner et al 1987 ;Lai & Williams, 1989). However, it should be noted that 30 % of participants over the age of 50 showed no cognitive deterioration throughout the course of the study.…”

“…However, it should be noted that the majority of participants (71n7 %) experienced no cognitive deterioration. These estimates of cognitive deterioration are high in comparison to the range described by Aylward et al (1995) and those given by Lai & Williams (1989). This may be because the criteria employed in this study are not diagnostic for dementia but are operationalized in terms of cognitive impairment.…”

Alpha- and beta-secretase activity as a function of age and beta-amyloid in Down syndrome and normal brain

“…However, increased incidence of clinical signs of dementia in DS after the age of 50 years [29,54,63,66] appear to be at a later age than the first signs of significant insoluble Aβ accumulation or plaque accumulation and also after the first signs of neurofibrillary tangle pathology [35]. Thus, downstream events that may be directly or indirectly related to Aβ or tangle formation may lead to neuronal dysfunction and cognitive decline.…”

“…Individuals with Down syndrome (DS) develop Alzheimer disease (AD) pathology in a progressive age-dependent manner [26,34,35,68] and as such, are at high risk for the development of dementia [29,33]. Clinical signs of dementia are more commonly observed when individuals are over 50 years of age [4,29,49,63].…”

“…Clinical signs of dementia are more commonly observed when individuals are over 50 years of age [4,29,49,63]. By age 40 years, however, all individuals with DS have neuropathological changes including senile plaques and neurofibrillary tangles consistent with AD [35,67,68].…”