Effects of ideomotor apraxia on functional outcomes in patients with right hemiplegia.

The aim of this study was to investigate the effect of ideomotor apraxia on activities of daily living and to determine if the presence of apraxia interferes with rehabilitation. This study was conducted on 47 patients with right hemiplegia. All the patients were assessed at their admission and discharge, respectively, for apraxia by Ideomotor Apraxia Test, for daily living activities by Functional Independence Measure (FIM, Santa Clara Valley Medical Center, San Jose, California, USA), for cognitive functions by Mini Mental State Examination (MMSE), and for language components by Gulhane Aphasia Test (GAT). The effects of apraxia presence and time course on FIM, MMSE, and GAT scores were investigated. Presence of apraxia was found to have significant effect on all test scores (P<0.05). Time course had the main significant effect on FIM, MMSE, and GAT scores (P<0.05). Interaction effect of both presence of apraxia and time course on the test scores was not significant either. In other words, apraxic and nonapraxic patients seemed to gain benefits from the neurological rehabilitation. However, mean FIM scores of apraxic patients during discharge have failed to reach the mean FIM scores of nonapraxic patients during admission. Apraxia is considered as an important determinant in the dependence of patients with stroke in their activities of daily living. For this reason, during the initial assessment of patients with right hemiplegia, apraxia should be tested, and the presence of apraxia as well as its severity should be determined.

Ideomotor apraxia and functional ability.

The impact of ideomotor apraxia (IMA) on functional ability has been a relatively neglected topic in research. This has been due to the continued focus on performance on gesture imitation and pantomime of tool-use, together with widespread acceptance of anecdotal evidence that IMA has no effect when directly manipulating objects. An increasing number of studies have shown that IMA does in fact result in increased clumsiness when handling objects and may contribute to disability in everyday life. However the effect seems relatively mild compared to the stark abnormalities on gesture imitation and pantomime. The conventional explanation for this is that the cues provided by naturalistic contexts improve retrieval of action representations, but an alternative account concerns task-specific cognitive demands. Performance on simple prehensile tasks can be successfully guided by physical affordances whereas motor tasks may be failed if they require the support of memory or problem solving ability. A central deficit in IMA may be impaired postural representation causing inability to solve the problem of how to manipulate objects where neither affordance nor memory can dictate action. However, this account still fails to explain fully the patterns of error seen on complex naturalistic tasks such as dressing. Future research needs to further our understanding of how IMA maps on to disability, which will have implications for theory building and for therapeutic intervention.

A new classification of higher level gait disorders in patients with cerebral multi-infarct states.

BACKGROUND: cerebral multi-infarct states may lead to gait disorders in the absence of cognitive impairment. Where these gait disorders occur in the absence of neurological signs they have been termed gait apraxia or more recently higher-level gait disorders. In this paper we hypothesise three main types based on presumptive sites of anatomical damage: (a) Ignition Apraxia, where damage is predominantly in the supplementary motor area and its connections, with good responses to external clues; (b) Equilibrium Apraxia, where damage is predominantly in the pre-motor area in its connections, with poor responses to external cues and (c) Mixed Gait Apraxia. SUBJECTS: the clinical features and measured gait parameters of 13 patients with cerebral multi-infarct states and higher-level gait disorder are described (7 with Ignition Apraxia and 6 with Equilibrium Apraxia) along with those of 6 healthy elderly control subjects. METHODS: baseline gait characteristics were assessed on a walkway, which measured the following: step lengths, width of base and velocity. RESULTS: measured baseline gait parameters support the above hypothesis. CONCLUSIONS: it is suggested, though not proven, that patients with Ignition Apraxia could have problems with internal cueing due to lesions in the supplementary motor area or its connections whereas those with Equilibrium Apraxia could have dysfunction predominantly in the pre-motor area and its connections.

Limb apraxias: higher-order disorders of sensorimotor integration.

Limb apraxia comprises a wide spectrum of higher-order motor disorders that result from acquired brain disease affecting the performance of skilled, learned movements. At present, limb apraxia is primarily classified by the nature of the errors made by the patient and the pathways through which these errors are elicited, based on a two-system model for the organization of action: a conceptual system and a production system. Dysfunction of the former would cause ideational (or conceptual) apraxia, whereas impairment of the latter would induce ideomotor and limb-kinetic apraxia. Currently, it is possible to approach several types of limb apraxia within the framework of our knowledge of the modular organization of the brain. Multiple parallel parietofrontal circuits, devoted to specific sensorimotor transformations, have been described in monkeys: visual and somatosensory transformations for reaching; transformation of information about the location of body parts necessary for the control of movements; somatosensory transformation for posture; visual transformation for grasping; and internal representation of actions. Evidence from anatomical and functional brain imaging studies suggests that the organization of the cortical motor system in humans is based on the same principles. Imitation of postures and movements also seems to be subserved by dedicated neural systems, according to the content of the gesture (meaningful versus meaningless) to be imitated. Damage to these systems would produce different types of ideomotor and limb-kinetic praxic deficits depending on the context in which the movement is performed and the cognitive demands of the action. On the other hand, ideational (or conceptual) apraxia would reflect an inability to select and use objects due to the disruption of normal integration between systems subserving the functional knowledge of actions and those involved in object knowledge.