Gerstmann's syndrome as a deficit of mental imagery manipulation

Abstract

    We reported a case of Gerstmann's syndrome and discussed one of four points at issue concerning Gerstmann's syndrome as summarized by Benton (1992) : whether the combination of the syndrome's four symptoms is behavioral expression of a single underlying basic deficit (Grundstorung). The reported case was a 47-year-old right-handed male afflicted with left parietal hemorrhage who exhibited finger agnosia and right-left disorientation for others and himself, acalculia accompanied by deficit of understanding numerical conceptions, and agraphia mainly in the form of disturbed reminiscence of kanji. Moreover, he was unable either to draw pictures of objects from visual memory or to describe their features verbally, though he could copy pictures and letters and recite long sentences (imitation). In addition, he complained that he was unable to use a Japanese dictionary because he could not recall the order of the Japanese syllabary. On subtests of standardized batteries, he was poor at picture completion, picture arrangement, block design and word similarities on the WAIS-R, and poor at paired associations on the WMS-R. These findings suggest the following. First, the patient is unable either to understand the order and correlation of objects in series, or to manipulate their arrangement mentally. Second, he cannot describe objects without visual stimuli. These traits include the four symptoms composing Gerstmann's syndrome, and they correspond to the process of arranging parts of an object into their proper configuration of mental imagery as described by Kosslyn (1988). We concluded that deficit of mental imagery manipulation is the “Grundstorung” of Gerstmann's syndrome.