Conceptual Apraxia in Alzheimer's Disease

Abstract

Theoretical models of praxis have two major components, a praxis conceptual system that includes knowledge of tool use and mechanical knowledge and a praxis production system that includes the information needed to program skilled motor acts. Because patients with Alzheimer's disease may have an impairment of the central conceptual system, we wanted to learn if they had a conceptual apraxia by testing their knowledge of the type of actions associated with tool use, their ability to associate tools with objects that receive their action, their ability to understand the mechanical nature of problems and the mechanical advantages tools may afford. We studied 32 subjects with probable Alzheimer's disease and 32 controls by examining tool-action relationships and tool-object associations. We tested mechanical knowledge by having subjects select alternative tools and solve mechanical puzzles by developing new tools. The Alzheimer's group was subdivided into four groups based on the presence or absence of ideomotor apraxia and a lexical-semantic deficit. Results indicated that each of the four Alzheimer's groups differed from normal controls on at least some measures of conceptual apraxia, suggesting that Alzheimer's patients do have a disturbance of the praxis conceptual system and that impairment of this system is not directly related to language impairment or ideomotor apraxia.

Imaging a cognitive model of apraxia: The neural substrate of gesture‐specific cognitive processes

“…Subsequently, Ochipa et al [1989] proposed the term conceptual apraxia to qualify disturbances of the action semantic system except action-sequencing disorders. Conceptual apraxia was reported in patients suffering from Alzheimer's disease [Dumont and Ska, 2000;Foundas et al, 1999;Greenwald et al, 1992;Ochipa et al, 1992;Schwartz et al, 2000] in which the temporal cerebral structures are often early damaged. However, a high correlation exists between ᭜ Peigneux et al ᭜ ᭜ 136 ᭜ performance in pantomime to verbal command and verbal comprehension deficit [Dumont and Ska, 1998; but see Ochipa et al, 1992, for divergent results].…”

“…Conceptual apraxia was reported in patients suffering from Alzheimer's disease [Dumont and Ska, 2000;Foundas et al, 1999;Greenwald et al, 1992;Ochipa et al, 1992;Schwartz et al, 2000] in which the temporal cerebral structures are often early damaged. However, a high correlation exists between ᭜ Peigneux et al ᭜ ᭜ 136 ᭜ performance in pantomime to verbal command and verbal comprehension deficit [Dumont and Ska, 1998; but see Ochipa et al, 1992, for divergent results]. It is, therefore, not clear whether conceptual apraxia in Alzheimer's disease reflects the disruption of a specific action semantic subsystem rather than a global conceptual impairment.…”

When objects lose their meaning: What happens to their use?

“…The patients were assessed on single-object use with and without a recipient (see below), to investigate whether the presence of the recipient provides clues as to the goal (the object's function), thereby enabling better problem solving. We also included a more difficult assessment of mechanical problem solving: mechanical puzzles (based on those designed by Ochipa, Rothi, & Heilman, 1992), which cannot be accomplished simply on the basis of visual matching.…”

Activation of left intraparietal sulcus using a fMRI conceptual praxis paradigm

“…We believe that the findings of the present investigation contribute an important piece to this conundrum by calling attention to the possible role of the left intraparietal sulcus as a critical area involved in the genesis of apraxia for tool use. The hypothesis that the distinct domains of conceptual praxis described by Ochipa et al 3 are differentially distributed in spatially discrete cortical areas can be put to test in the foreseeable future.…”

“…Conceptual apraxia (CA) is the inability to select and use tools and utensils despite normal sensation, motor power, and coordination [1][2][3][4] . Patients with CA are at a loss when they attempt to use a screwdriver, unlock a padlock, or cut bread with a knife.…”