New Study Using Neuropsychological Testing Shows Signs of Cognitive Impairment Preceed
Alzheimer's Disease 

Swedish researchers at the Karolinska Institute, Stockholm, reviewed the findings of 47 studies published between 1985 and 2003. The studies included over 1,200 people with preclinical Alzheimer's disease who later developed the degenerative brain disease and over 9,000 people who did not develop the disease.

Their analysis revealed that people with preclinical Alzheimer's show warning signs in a number of cognitive areas years before they're officially diagnosed with the disease. These signs included marked deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning. They also display smaller deficits in verbal ability, visuospatial skill and attention. There was no sign of preclinical problems in terms of primary memory.

The review authors noted that many of the cognitive deficits observed in people with preclinical Alzheimer's disease are quite similar to signs of normal aging. However, these problems are more apparent in people who are later diagnosed with Alzheimer's.

The findings appear in the July issue of the journal Neuropsychology.