Is impaired executive function a single or multidimensional disability?

This study was undertaken to determine if certain logical relations might be found in two pairs of similar executive functioning tasks: (a) Design Fluency and Word Fluency, and (b) the Tinker Toy and Story Telling Tests. Overall, the results were "inconsistent," with there being no meaningful relations found between tests with regard to similarities in task demand, theoretical hierarchical relations, or whether the tasks were verbal or nonverbal (with the exception of a very close relation between Design Fluency and Tinker Toy Test.). Despite the apparent entropy of the findings, they have substantial clinical and theoretical importance given the simultaneously rigid and weak-minded definitions and measures of disexecutive disability in current use.