Benton. A. "Constructional apraxia." In F. Boller and J. Grafman (eds.), Handbook of Neuropsychology. Elsevier Press, 1989, Vol.2, pp.387-394. Constructional apraxia Arthur Benton Department of Neurology, University of Iowa, College of Medicine, Iowa City, I.A 52242, U.S.A. Introduction Visuoconstructional disabilities, as reflected in failure in drawing or assembling tasks, were of some interest to neurologists and psychologists as early as the 1880s, at which time they were usually interpreted as evidence of either 'loss of the spatial sense' or impairment of the capacity for 'com- binatory activity'. When the German neurologist, Karl Kleist (Fig. 1), introduced the term and con- cept of 'constructional apraxia' in the 1920s to designate a specific defect in spatial-organizational or constructional activity, these disabilities became a topic of major concern in clinical neuropsycho- logy. Kleist's (1923, 1934) definition of constructional apraxia was fairly precise and restrictive. He con- ceived of the disorder as being what is now called a disconnection symptom (Geschwind, 1965), in which there is failure to integrate the visual and kinesthetic information required for successful constructional activity. On the one hand, construc- tional apraxia was to be distinguished from other constructional deficits that were clearly the results of impaired visuoperceptive capacity; on the other hand, although akin to the classical apraxias of Liepmann (1900, 1908), it was sufficiently distinc- tive to warrant a separate designation. The pure case of constructional apraxia shows adequate visual form perception, preserved capacity to localize objects in visual space and no signs of ideomotor apraxia. Thus the disorder is one of 'ex- ecution' or 'praxis' and not merely a behavioral ex- pression of either perceptual impairment or motor disability. Up to that time constructional apraxis generally had been viewed as a sign of bilateral oc- cipitoparietal disease. In contrast, Kleist maintain- ed that the visuomotor integrative process underly- Fig. 1. Karl Kleist (1879 - 1960). (Reprinted from Archiv für Psychiatrie und Nervenkrankheiten, Vol. 202, 1961, by permis- sion of Springer-Verlag.) 387 215
Ch. 20 A. Benton ing constructional performances took place in the left hemisphere and was conducted by way of the corpus callosum to the right hemisphere in order to mediate bilateral constructional activity. Follow- ing the reasoning of Liepmann with respect to unilateral ideomotor apraxia, he further maintain- ed that a strategically placed callosal lesion which interrupted the pathways from the dominant to the subordinate hemisphere would produce a unilateral constructional apraxia confined to the left hand. The disability which Kleist and his student, Hans Strauss (1924), described was readily accepted as a distinctive type of behavioral deficit associated with cerebral disease, and by the late 1920s the term 'constructional apraxia' had become part of the lexicon of clinical neurology. However, Kleist's precise definition of constructional apraxia as an executive type of disorder rather than as the motoric expression of visuoperceptual impairment was largely ignored, the term being applied to visuoconstructional failure whether or not it was associated with visuoperceptual impairment. . Types of defective performance Kleist defined constructional apraxia as a distur- bance 'in