Age at onset of Alzheimer's disease. Relation to language dysfunction
K. A. Bayles
Department of Speech and Hearing Sciences, University of Arizona, Tucson 85721.
A later age at onset of Alzheimer's disease (AD) was found to be related to
diminished language performance in 86 patients with probable AD. A
hierarchical linear model was constructed to assess effects of age at onset
and disease duration on the performance of patients with AD on four
language tasks (naming, reading, auditory comprehension, and writing to
dictation) after controlling for disease severity. Results of univariate
analysis, in which the dependent variable was the averaged language task
performances, revealed a significant effect for age at onset of AD, but not
for disease duration. To assess the possibility that the relationship
between the age at onset of AD and language performance reflects effects of
normal aging, the language tasks were given to 33 normal subjects of
similar ages who scored perfectly on dementia severity measures. A
convincing relationship was not found between test score and age.
