Severity of Symptoms and Rate of Progression in Alzheimer's Disease: A Comparison of Cases with Early and Late Onset

Abstract

Since first description of Alzheimer''s disease rapid symptom progression and relatively severe cognitive symptoms have been frequently associated with early age of onset, while slow symptom progression and relatively mild cognitive symptoms were often related to late age of onset. In a longitudinal study of 90 patients with mild to moderate Alzheimer''s disease, we investigated these hypotheses. We found that neither severity of cognitive symptoms nor symptom progression in Alzheimer''s disease were associated with age of onset. In addition, a comparison of extreme groups (group 1: < 60 years of age; group 2: > 75 years of age), taken from the study sample, showed similar results with respect to the independent variables. These results suggest that the interindividual variability of cognitive impairment as well as the large variation of symptom progression in Alzheimer''s disease cannot be explained by age of onset.

Neuropsychological Heterogeneity in Mild Alzheimer's Disease

“…The lack of consistent results in the literature, on the other hand, may be related to different methodological ap proaches. In agreement with this, most studies were based on the introduction of an artificial dichotomy in the patient sample, such as age at onset [9][10][11], rate of pro gression [12,13] and performance on selected cognitive measures [14,15]. We report the results of a pilot study on neuropsycho logical performance in mild AD, which supports the exis tence of two heterogeneous cognitive profiles in the early phase of the disease.…”

Clinically diagnosed presenile dementia of the Alzheimer type in the Northern Health Region: ascertainment, prevalence, incidence and survival

“…Differential rates of progression and survival in dementia of Alzheimer type (DAT) according to age of onset has been adduced as evidence that the disease may be heterogeneous (Heston, 1983;Seltzer & Sherwin, 1983). However, several recent studies have failed to show that age at onset predicts rate of progression (Haupt et al 1992), institutionalization or length of survival (Knopman et al 1988;Hier et al 1989), though older patients deteriorated faster than younger patients when rate of progression was measured by the Blessed Dementia Score (Huff et al 1987). But Heyman et al (1987) found a greater risk of death in younger patients with severe cognitive impairment as compared with older patients with the same degree of dysfunction.…”