Psychometric properties of the CAMCOG and its efficacy in the diagnosis of dementia

The Cambridge Cognitive Examination (CAMCOG) is a concise neuropsychological test for the assessment of cognitive impairment in elderly people. It was designed specifically to assist in the diagnosis of dementia in an early stage. CAMCOG assesses a broad range of cognitive functions, as is required for the diagnosis of dementia, and it minimizes floor and ceiling effects by covering a range of item difficulty. We report here some psychometric properties of the CAMCOG in two stages of a population survey of people over the age of 75 years. Total score on the CAMCOG was found to have excellent internal reliability and test-retest reliability. The reliability of the individual subscales. which corresponded to different cognitive abilities, was also acceptable. Principal components analysis on the individual CAMCOG items revealed two easily interpretable factors, corresponding to general intelligence and memory. CAMCOG scores were very effective in differentiating between demented and nondemented individuals. The CAMCOG total score, as well as each subscale score, differed significantly between nondemented individuals and those with the diagnosis of mild dementia or minimal dementia. Regression analysis demonstrated that CAMCOG score alone was a strong predictor of dementia diagnosis. CAMCOG total scores showed high levels of sensitivity and specificity in differentiating between nondemented individuals and those with a diagnosis of mild dementia. The cut-point which produced the highest levels of both sensitivity and specificity was 80/81, with values of 93% and 87% respectively.