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, frequently Alzheimer's disease (AD). In order to develop a reduced-length psychometric battery, we performed an extended neuropsychological battery of tests on the classification of 94 individuals with AD, 90 individuals clinically diagnosed as MCI, and 79 normal elderly subjects. Using discriminant analysis 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 memory, as well as semantic memory, visuospatial function and attention contributed to the two discriminant functions. The first and dominant discriminant function, which only included five tests, discriminated the three groups according to a global cognitive function. These findings demonstrate the possibility of developing reduced-length cognitive batteries so as to identify MCI in subjects at risk of developing AD.