Preclinical prediction of AD using neuropsychological tests

Normals (N = 42) and patients with mild memory difficulty (N = 123) were gi ven a neuropsychological test battery, and then followed annually for 3 yea rs to determine which individuals developed sufficient functional change th at they met clinical criteria for AD. Twenty-three of the 123 participants with mild memory difficulty converted to a diagnosis of probable Alzheimer' s disease (AD) within 3 years of follow-up. Four of the 20 neuropsychologic al measures obtained at baseline, were useful in discriminating the groups on the basis of their status 3 years after the tests were given. The 4 disc riminating tests pertained to assessments of memory and executive function. When the controls were compared to the individuals with memory impairments who ultimately developed AD (the converters), the accuracy of discriminati on was 89%, based on the neuropsychological measures at baseline. The discr imination of the controls from the individuals with mild memory problems wh o did not progress to the point where they mel clinical criteria for probab le AD over the 3 years of follow-up (the Questionables) was 74% and the dis crimination of the questionables from the converters was 80%. The specific tests that contributed to these discriminations. in conjunction with recent neuropathological and neuroimaging data from preclinical cases, have impli cations for which brain regions may be affected during the prodromal phase of AD.