Prevalence and Malignancy of Alzheimer Disease

To the Editor.— Coblentz et al1reported detailed studies of 20 patients with presenile dementia classified as Alzheimer disease. Follow-up information on 18 of these patients has dramatically highlighted the malignancy of Alzheimer disease, 14 of them having died. Survival was related to the degree of dementia at the time of admission. Of the 11 most impaired patients with dementia rating scores (DRS) varying between 0 and 3, eight died within 30 months, whereas all five with higher scores (71 to 122) survived longer than 30 months. Of the four living patients, one has shown the expected loss of function over the past four years. This 56-year-old woman had a DRS of 100 and a two-year history of intellectual decline when her condition was first evaluated in 1971. She now has a DRS of 6, being echolalic but responding with appropriate effect to statements about herself and her family.