July 9, 2009

Tests can tell Alzheimer’s from dementia

Alzheimer's disease and dementia affect memory and behavior but have different causes and require different treatment, Australian researchers say.

Jane Mathias and Jennifer Burke, both from the University of Adelaide, analyzed 81 previously published studies that compared the cognitive testing of people diagnosed with dementia of the Alzheimer's and vascular type. The average age across participants was 75.

Of the 118 different tests that were used in more than one study, Mathias and Burke found only two were able adequately to differentiate between Alzheimer's and vascular dementia.

Emotional Recognition Task and Delayed Story Recall were the only tests that appeared to reliably tell the two groups apart.

People with Alzheimer's were better at the Emotional Recognition Task -- the ability to identify facial expressions in photographs and match emotional expressions to situations. People with vascular dementia were better at Delayed Story Recall.

Many commonly used tests -- repeating a set of numbers forward and backward, verbal fluency, drawing tasks -- were unable to distinguish between dementia types.

While these tests may assist in diagnosing dementia, they do not adequately discriminate between Alzheimer's disease and vascular dementia, the study authors said.

The findings are published in Neuropsychology.