title: Mechanical problem-solving strategies in Alzheimer's disease and semantic dementia.
abstract: The goal of this study was to explore whether the tool-use disorders observed in Alzheimer's disease (AD) and semantic dementia (SD) are of the same nature as those observed in left brain-damaged (LBD) patients. Recent evidence indicates that LBD patients with apraxia of tool use encounter difficulties in solving mechanical problems, characterized by the absence of specific strategies. This pattern may show the presence of impaired mechanical knowledge, critical for both familiar and novel tool use. So, we explored the strategies followed by AD and SD patients in mechanical problem-solving tasks in order to determine whether mechanical knowledge is also impaired in these patients.
  
  
  
  We used a mechanical problem-solving task in both choice (i.e., several tools were proposed) and no-choice (i.e., only 1 tool was proposed) conditions. We analyzed quantitative data and strategy profiles.
  
  
  
  AD patients but not SD patients met difficulties in solving mechanical problem-solving tasks. However, the key finding is that AD patients, despite their difficulties, showed strategy profiles that are similar to that of SD patients or controls. Moreover, AD patients exhibited a strategy profile distinct from the one previously observed in LBD patients.
  
  
  
  Those observations lead us to consider that difficulties met by AD patients to solve mechanical problems or even to use familiar tools may not be caused by mechanical knowledge impairment per se. In broad terms, what we call apraxia of tool use in AD is certainly not the same as apraxia of tool use observed in LBD patients. (PsycINFO Database Record
authors.affiliation: Laboratoire d'Etude des Mécanismes Cognitifs (EA 3082), Université de Lyon.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Lesourd
authors.affiliation: Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université d'Angers.
authors.forename: Josselin
authors.initials: J
authors.lastname: Baumard
authors.affiliation: Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université d'Angers.
authors.forename: Christophe
authors.initials: C
authors.lastname: Jarry
authors.affiliation: Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université d'Angers.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Etcharry-Bouyx
authors.affiliation: Service de Neurologie, Centre Hospitalier Universitaire and Laboratoire de Neuropsychologie, Unité INSERM U 1077.
authors.forename: Serge
authors.initials: S
authors.lastname: Belliard
authors.affiliation: CMRR Grenoble Arc Alpin, Pôle de Psychiatrie et Neurologie, Centre Hospitalier Universitaire de Grenoble.
authors.forename: Olivier
authors.initials: O
authors.lastname: Moreaud
authors.affiliation: Service de Neuropsychologie, Hôpital Neurologique Pierre Wertheimer.
authors.forename: Bernard
authors.initials: B
authors.lastname: Croisile
authors.affiliation: Département de Neurologie, Centre Hospitalier Universitaire d'Angers.
authors.forename: Valérie
authors.initials: V
authors.lastname: Chauviré
authors.affiliation: Laboratoire d'Etude des Mécanismes Cognitifs (EA 3082), Université de Lyon.
authors.forename: Marine
authors.initials: M
authors.lastname: Granjon
authors.affiliation: Laboratoire de Psychologie des Pays de la Loire (EA 4638), Université d'Angers.
authors.forename: Didier
authors.initials: D
authors.lastname: Le Gall
authors.affiliation: Laboratoire d'Etude des Mécanismes Cognitifs (EA 3082), Université de Lyon.
authors.forename: François
authors.initials: F
authors.lastname: Osiurak
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000150:complications / Q000503:physiopathology*; D001072:Apraxias / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D057180:Frontotemporal Dementia / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011340:Problem Solving / Q000502:physiology*