Early detection of Alzheimer's disease using the Cambridge Cognitive Examination (CAMCOG)

Background. Dementia screening instruments, such as the Cambridge Cognitive Examination (CAMCOG), measure a variety of cognitive functions. However, m emory impairment generally is the first sign of Alzheimer's disease (AD). I t seems logical, therefore, to use only memory-related items for the early detection of AD. We divided the CAMCOG into a memory section and a non-memo ry section, and tested the hypothesis that the memory section predicts AD b etter than the non-memory section. We also provide normative data for both sections. Methods. Normal subjects (N = 169) and patients with incident AD (i.e. sati sfying AD criteria between 1 and 3 years from baseline; N = 25) were partic ipants in the Amsterdam Study of the Elderly (AMSTEL), a population-based l ongitudinal study on cognitive decline and dementia. Patients with prevalen t AD (i.e. satisfying AD criteria at baseline; N = 155) were either recruit ed in a memory clinic or came from AMSTEL. Normal subjects were cognitively intact at baseline and remained so for at least 3 years. The CAMCOG was ad ministered to all subjects. AD was diagnosed by DSM-III-R criteria. Results. Logistic regression analysis showed that the memory section was re lated to prevalent AD, whereas in multivariate analysis the non-memory sect ion was not (after correction for the memory score and demographic characte ristics). A similar analysis showed that the memory section predicted incid ent AD, as did a higher score on the non-memory section. The MMSE did not p redict incident AD better than age alone. Conclusion. For the early detection of AD it is best to use the memory and non-memory sections separately instead of the total CAMCOG score.