Spelling tasks and Alzheimer's disease staging.
Reading, writing and oral spelling were evaluated in 30 normal elderly individuals and 28 patients with probable Alzheimer's disease (AD). Significant differences between control and AD groups were found in all tasks. Oral spelling was the most impaired function in AD and the only one which differentiated mild and moderate dementia cases. This task is very sensitive to the disease's effects on working memory and may be included in batteries aimed at staging AD.