Two forms of ideomotor apraxia

TLDR

Destruction of parietal visuokinesthetic motor engram areas impairs the ability to distinguish well‑performed from poorly performed movements, whereas disconnection from frontal motor areas does not. The study employed movement and act‑discrimination tasks on patients with anterior lesions or nonfluent aphasia and on patients with posterior lesions or fluent aphasia to investigate ideomotor apraxia. Posterior/fluent patients performed worse on both tasks, supporting the existence of two distinct types of ideomotor apraxia.

Abstract

Destruction of parietal areas containing visuokinesthetic motor engrams, where motor acts may be programmed, should be distinguishable from apraxia induced by disconnection of these parietal areas from frontal motor areas. Destruction should result in inability to distinguish well-performed from poorly performed movements, whereas disconnection should not. We gave movement and act-discrimination tasks to apraxic and nonapraxic patients with anterior lesions or nonfluent aphasia, and to patients with posterior lesions or fluent aphasia. On both tasks, the performance of posterior/fluent patients was worse than that of all other patients. Our results suggest that there are two types of patients with ideomotor apraxia.