Objectives. Copying of the Rey-Osterrieth Complex Figure is used for the neuropsychological assessment of visual perception and visual-constructional abilities. However, a poor performance on this test may also result from impaired planning and organization of complex activity. No method has been developed so far that would allow to differentiate accurately between the two causes ofperformance deterioration. The aims of the study were to devise a procedure enabling such a differentiation and to examine its validity.
Method. For the purposes of this study a modification of the original method was devised involving firstly, an appropriate organizational help provision (effective only in cases of planning impairment) and secondly, observation of qualitative changes in the produced copy. Two groups of neurological patients were examined using the new procedure: 1) patients sufferingfrom damage to the occipital lobes and adjacent cortex (whereperceptual and visual-constructional deficits were expected), and 2) those sufferingfrom damage to the frontal lobes (where an impairment of planning and organization was expected).
Results. The new procedure was found to differentiate accurately between the two compared groups, and therefore, between the mechanisms underlying their disorders.
Conclusions. The proposed procedure may be useful for the neuropsychological assessment of a wide range of disorders, especially for the differential diagnosis of various forms of dementia and specific developmental learning disabilities in children.