Affordances are meaningful relations between the features of observed objects and the observer’s action systems with its proper abilities. The notion of affordance integrates perceptual, cognitive and motor functions, so that perceiving an object, conducting cognitive operations on it, and executing motor actions with it cannot be considered as independent functions. Limb apraxia is a higher-or...

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 s...

Apraxia of speech is a disorder of speech motor planning and/or programming that is distinguishable from aphasia and dysarthria. It most commonly results from vascular insults but can occur in degenerative diseases where it has typically been subsumed under aphasia, or it occurs in the context of more widespread neurodegeneration. The aim of this study was to determine whether apraxia of speech...

Corticobasal degeneration is a neurodegenerative disease characterized, by cortical dysfunction and extrapyramidal signs. The most consistent symptom is a unilateral limb apraxia, which consists of an isolated disorder of gestural production involving primarily the upper limb. The objective of this study is to investigate the functional abnormalities that may underlie motor dysfunction, and tho...

BACKGROUND Data on white matter changes in corticobasal degeneration syndrome (CBDS) are not yet available, whereas cortical gray matter loss is a feature of this condition. The structural abnormalities related to a key feature of CBDS (limb apraxia) are unknown. OBJECTIVES To measure selective structural changes in early CBDS using diffusion tensor imaging and voxel-based morphometry and to ...

There exist few clinical assessments for limb apraxia, a disorder of learned, purposeful action, that enable clinicians to distinguish pathological from normal variance in limb praxis performance. We describe a theoretically motivated, comprehensive assessment battery for limb apraxia and present control comparison scores for 16 older healthy normal individuals on subtests designed to distingui...