CALCULATION AND NUMBER PROCESSING IN MILD ALZHEIMERS-DISEASE

Calculation and number processing abilities in 17 patients suffering f rom a mild form of dementia of Alzheimer's a type (DAT) were studied b y means of a. standardized multitask assessment battery, the EC301 (De loche et al., 1994). Patients were selected from a larger sample by us ing a specific visuo-perceptive task to control the confounding effect s of deficits in analysing digit serial older. Language and memory ski lls were evaluated by means of standardized testing procedures. The EC 301 overall score: showed impaired performance in 12 cases. Calculatio n and number processing scores were highly correlated with Mini-Mental State Examination and language performance. However, multiple single- case analyses indicated heterogeneous patterns of preserved / impaired abilities with respect to the three cognitive areas under investigati on (calculation. memory, and language) and to the different components of the calculation and number processing system.