Psychometric discrimination of Alzheimer's disease and mild cognitive impairment

Mild Cognitive Impairment (MCI) refers to a boundary between normal ageing and dementia. People with MCI have a high risk of developing dementia, freq uently Alzheimer's disease (AD). In order to develop a reduced-length psych ometric battery, we performed an extended neuropsychological battery of tes ts on the classification of 94 individuals with AD, 90 individuals clinical ly diagnosed as MCI, and 79 normal elderly subjects. Using discriminant ana lysis techniques, it was possible to achieve a high rate of correspondence between clinical and present statistical classification of the three groups (85%). We found that specific ability domains, particularly episodic memor y, as well as semantic memory, visuospatial function and attention contribu ted to the two discriminant functions. The first and dominant discriminant function, which only included five tests, discriminated the three groups ac cording to a global cognitive function. These findings demonstrate the poss ibility of developing reduced-length cognitive batteries so as to identify MCI in subjects at risk of developing AD.