Frontal lobe damage and tests of executive processing: a meta-analysis of the category test, stroop test, and trail-making test.

The Category Test, Trails B, and the interference task of the Stroop Test are among the most commonly administered measures of frontal lobe functioning and are thought to tap different cognitive functions mediated by these brain regions. Two meta-analyses were conducted on these tests to determine their sensitivity to frontal and lateralized frontal brain damage. Study 1 compared participants with frontal lobe damage to those with damage to posterior brain regions, whereas Study 2 compared participants with left and right frontal lobe damage. For each study, effect sizes based on performance differences between the above groups were calculated for the Category Test, Trail-Making Test Parts A and B, and the Stroop Test, including Word, Color, and Color-Word subtests. In Study 1 significant differences between groups were found for Trails A and all Stroop tasks, but in Study 2 the only difference between left and right frontal participants was on the Stroop Color-Word task. Potential reasons why Trails A and the Stroop Test are sensitive to frontal lobe damage are discussed, such as novelty and processing speed, as are clinical implications of these findings. The challenges of research on assessment of frontal lobe functioning are discussed and new developments in this area are highlighted.