Le Gall, Didier <br/><br/>
Apraxia in neurodegenerative diseases 

 -  2016.<br/>							 
<br/><br/> 14 
<br/><br/> From its beginning, at the end of the nineteenth century, apraxia has been associated with neurodegenerative diseases. However, very little work has been done in this area; this is particularly relevant for tool use disorders. This lack of interest might be surprising given that the diagnosis of neurodegenerative diseases also requires additional deficits such as apraxia. For example, limb apraxia or conceptual apraxia are quite common in patients with Alzheimer's disease and limb-kinetic, asymmetrical apraxia is one of the most frequent signs in corticobasal degeneration. Another important issue is that of tool use disorders and its definite impact on patients’ lives, but there are still very few studies in this field. Moreover, several theoretical questions arise regarding the nature of apraxia in these diseases. Are disorders of skilled movement in these pathologies qualitatively similar to the apraxic syndromes that follow left parietal damage? Are they due to global deterioration and inability to access knowledge? First, this presentation will provide a synthetic review of works on apraxia in Alzheimer's disease and an analysis of their methodological and theoretical limits. Then, we will present preliminary data from our research on apraxia in patients with mild to moderate Alzheimer's disease. The performances of these patients on our “apraxia and tool use battery” confirm the reality and heterogeneity of tool use disorders in this disease and highlight the importance of individual analysis. In order to explore more precisely the role of conceptual knowledge in object use, we will also provide evidence from semantic dementia and fronto-temporal dementia. Finally, we discuss future research directions.