Study: Testing one time is not enough

University of Virginia psychologist Timothy Salthouse said he wondered how accurate are tests used to diagnose learning disability, progressive brain disease or impairment from head injury. He found repeating tests over a short period may give a more accurate range of scores, improving diagnostic workups.

Salthouse gave 16 common cognitive and neuropsychological tests to groups of people ages 18-39, 50-59 and 60-97 years. He found the variation between scores on the same test given three times during a two-week period was as big as the variation between the scores of people in different age groups.

It's as if on the same test, someone acted like a 20-year-old on a Monday, a 45-year-old on Friday, and a 32-year-old the following Wednesday, he said, noting the inconsistency raises questions about the worth of single, one-time test scores.

The study is detailed in the July issue of Neuropsychology.

Copyright 2007 by United Press International