Constructional apraxia from the roots up: Kleist, Strauss, and their contemporaries.

The concept and the term of constructional apraxia have been proposed by Karl Kleist and described in his impressive book "Gehirnpathologie", published in 1934. However, the first ever paper under the heading of constructional apraxia was written by Hans Strauss, one of Kleist's pupils, and published in 1924. Nowadays, the term constructional apraxia is still in use to refer to all disorders observed in drawing and assembling activities; its assessment, performed as it was in early studies, is part of common practice in behavioral neurology and neuropsychology. Nonetheless, the concept and the neural underpinnings of constructional apraxia have been deeply revisited with respect to the original proposal. Modern studies demonstrated that drawing and assembling are based on very large and complex brain networks extending in both hemispheres, including the left angular gyrus (as hypothesized by Kleist) but well beyond the original ideas about localization of constructional apraxia. From a clinical point of view, constructional apraxia has poor localizing value but provides valuable diagnostic information for conditions of cognitive impairment.