A study of the reliability of the family history method in genetic studies of Alzheimer disease.

The reliability between 2 raters conducting independent family history interviews for Alzheimer disease-like and other dementias was investigated. The interviews were conducted at least 1 year apart with the second rater blind to the data collected by the first rater. Raters agreed on the presence and type of dementia in 153 relatives age 45 or older of 30 AD probands, the age at onset in secondary cases, and the age of nonaffected relatives.