Calculation abilities in dementia of Alzheimer's type and in vascular dementia.

Calculation abilities tested by 12 additive and 12 multiplicative tasks were investigated in 19 patients suffering from vascular dementia and in 23 patients suffering from dementia of Alzheimer's type as well as in 17 age-matched controls. Arithmetic impairment expressed by the number of correct results showed a significant correlation with the degree of dementia, measured by the Mini-Mental State Examination. An error type analysis was performed, but was of no help in the differential diagnosis of dementia. Calculation abilities are similarly impaired in both vascular dementia and dementia of Alzheimer's type.