Overview

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) was funded by the National Institute on Aging (NIA) in 1986 to develop a battery of standardized instruments for the evaluation of patients with Alzheimer's disease (AD) enrolled in ongoing Alzheimer's Disease Research Centers and other major dementia research programs in the US. At that time, clinical investigation of AD was hampered by the absence of uniform diagnostic criteria and standardized measures for the severity of impairment. Comparison of research findings from individual research centers was not possible because of the variety of approaches to testing. The purpose of CERAD was to create uniformity in enrollment criteria and methods of assessment in clinical and neuropsychological studies of AD, permitting the pooling of information across sites.

Study onset. At the onset of the study, a battery of relatively brief but reliable instruments was selected to evaluate patients who had mild or moderate AD. These tests included the overall clinical assessment of the patient¹ and neuropsychological assessment of cognitive impairment or dementia.² These tests were selected for their value in assessment of the progression of the illness at annual intervals over the course of the disease. Once these primary assessments were applied and shown to be reliable, attention was given to standardization of neuropathologic measures of AD.³ The need for this assessment was particularly great because clinical diagnosis could be confirmed only through autopsy examination. The neuropathologic assessment instrument not only provided criteria for the neuropathologic spectrum of AD but also established the types and frequency of coexisting disorders (e.g., vascular disease, Parkinson's disease, diffuse Lewy body disease) at autopsy.

After the development of these three major components of the CERAD battery, several other assessments were developed: neuroimaging, frequency rating of behavioral abnormalities associated with AD, characterization of extrapyramidal …