Apraxia of tool use: more evidence for the technical reasoning hypothesis

Various distinct cognitive processes such as semantic memory, executive planning or technical reasoning have been shown to support tool use. The aim of this study is to investigate the relationship between these processes. To do so, a large apraxia battery was submitted to 16 patients with left brain-damage (LBD) and aphasia and 19 healthy controls. The battery included: classical apraxia tests (Pantomime of Tool Use and Single Tool Use), familiar and novel tool use tests (Tool-Object Pairs and Sequential Mechanical Problem-Solving), semantic memory tests (Recognition of tool utilization gestures and Functional and Categorical Associations) as well as the Tower Of London. The Sequential Mechanical Problem-Solving task is a new task which permits the evaluation of pre-planning in unusual tool use situations. In this task as well as in the Tool-Object Pairs task, participants solved a tool use problem in a Choice and a No-Choice condition to examine the effect of tool selection. Globally, left brain damaged patients were impaired as compared to controls. We found high correlations in left brain damaged patients between performances on classical apraxia tests, familiar and novel tool use tests and Functional and Categorical Associations but no significant association between these performances and Tower Of London or Recognition of tool utilization gestures. Furthermore, the two conditions (Choice and No-Choice) of Tool-Object Pairs and Sequential Mechanical Problem-Solving were associated. In sum, all tasks involving tool use are strongly associated in LBD patients. Moreover, the ability to solve sequential mechanical problems does not depend on executive planning. Also, tool use appears to be associated with knowledge about object function but not with knowledge about tool manipulation. Taken together, these findings indicate that technical reasoning and, to a lesser extent, semantic memory may both play an important role in tool use

Detecting everyday action deficits in Alzheimer’s disease using a non-immersive virtual reality kitchen

Alzheimer’s disease (AD) causes impairments affecting instrumental activities of daily living (IADL). Transdisciplinary research in neuropsychology and virtual reality has fostered the development of ecologically valid virtual tools for the assessment of IADL, using simulations of real life activities. Few studies have examined the benefits of this approach in AD patients. Our aim was to examine the utility of a non-immersive virtual coffee task (NI-VCT) for assessment of IADL in these patients. We focus on the assessment results obtained from a group of 24 AD patients on a task designed to assess their ability to prepare a virtual cup of coffee, using a virtual coffee machine. We compared performance on the virtual task to an identical daily living task involving the actual preparation of a cup of coffee, as well as to global cognitive, executive, and caregiver-reported IADL functioning. Relative to 32 comparable, healthy elderly (HE) controls, AD patients performed worse than HE controls on all tasks. Correlation analyses revealed that NI-VCT measures were related to all other neuropsychological measures. Moreover, regression analyses demonstrated that performance on the NI-VCT predicted actual task performance and caregiver-reported IADL functioning. Our results provide initial support for the utility of our virtual kitchen for assessment of IADL in AD patients. (JINS, 2014, 20, 1–10

Different constraints on grip selection in brain-damaged patients: Object use versus object transport

The present study discusses the presence of different constraints on action selection during object use versus object transport. Sixteen left brain-damaged (LBD) patients, 10 right brain-damaged (RBD) and 35 healthy controls were examined on a grip preference test consisting of a grasping-to-transport and a grasping-to-use condition. Assessment included a general praxis testing (pantomime production, object utilization gesture recognition and object use). We also reported the case of a close-head injury patient (DR) with an atypical behavioural pattern. Our results supported the different constraint hypothesis. While several LBD and RBD patients performed inappropriate grips in the grasping-to-transport condition, only two patients (L2 and DR) used inappropriate grips in the grasping-to-use condition. No correlation was found between the two conditions of the grip preference test and measures of the general praxis testing. The discussion focuses on the nature of constraints on grip selection during object use and object transport

Les apraxies : synthèse et nouvelles perspectives

L’étude de l’apraxie a été, et est toujours, sujette à un débat intense, notamment en ce qui concerne l’autonomie du trouble par rapport aux déficits sensorimoteurs élémentaires et aux déficits cognitifs de plus haut niveau. Ces controverses conduisent généralement les cliniciens à s’interroger sur la bonne façon d’évaluer et d’interpréter les phénomènes apraxiques. Dans cet article, nous proposons une lecture des troubles qui s’inspire des développements les plus récents effectués dans le domaine. Après quelques rappels historiques utiles à la compréhension des modèles cognitivistes qui ont émergé au début des années quatre-vingt, nous discuterons l’apport d’études conduites ces quinze dernières années. Les résultats de ces travaux nous invitent à réexaminer les interprétations issues des modèles cognitifs. Par souci de clarté, nous traiterons uniquement des phénomènes apraxiques évalués lors de situations d’imitation de postures non significatives, d’utilisation effective d’outils et de production de pantomimes. Nous espérons que la discussion présentée dans cet article sera utile aux cliniciens mais aussi aux étudiants en neuropsychologie

Unusual use of objects after unilateral brain damage. The technical reasoning model.

International audienceIt has been suggested that gesture engrams, conceptual knowledge and/or the ability to infer function from structure can support object use. The present paper proposes an alternative view which is based upon the idea that object use requires solely the ability to reason about technical means provided by objects. Technical means are abstract principles which are not linked with any object representation (e.g., cutting involves the opposition between dense and permeable material). The technical reasoning model predicts that the inability to perform technical reasoning should impair performance in any situation requiring the use of objects (in a conventional way or not). Twenty left brain-damaged (LBD) patients, 11 right brain-damaged (RBD) patients and 41 healthy controls were examined on experimental tests assessing the conventional use of objects (e.g., screwing a screw with a screwdriver), conceptual knowledge about object function, pantomime of object use and recognition of object utilization gestures. We also designed the Unusual Use of Objects test, which demands unusual applications of objects to achieve a purpose for which the usually applied object is not provided (e.g., screwing a screw with a knife). The key findings are that only LBD patients have more difficulties on the Unusual Use of Objects Test than controls or RBD patients, and that the severity of their impairment is correlated with that on conventional use of objects. Correlations with tests assessing conceptual knowledge as well as with tests of pantomime of object use and recognition of object utilization gestures were weaker. These results support the technical reasoning model and question the role of conceptual knowledge and gesture engrams in object use. Since the technical reasoning model also predicts two distinct technical disorders, the discussion focuses on the existence of these disorders in regard to individual performance profiles obtained in the Unusual Use of Objects test

Executive functions in clinical and preclinical Alzheimer's disease

Executive functions is an umbrella term describing a wide range of higher order processes that allow the flexible modification of thought and behaviour in response to changing cognitive or environmental contexts. Impairment of executive functions is common in neurodegenerative disorders such as Alzheimer\u27s disease. These deficits negatively affect everyday activities and hamper the ability to cope with other cognitive or behavioural disorders. In this paper, we propose a synthesis of the knowledge on executive impairments in clinical and preclinical Alzheimer\u27s disease, mostly leaning on the current studies made in this domain. We made some propositions for neuropsychological assessment of executive functions in preclinical and clinical phases of Alzheimer\u27s disease. We hope that this overview will provide a useful insight into an area that is still insufficiently explored in the field of the neuropsychology of Alzheimer\u27s disease

Gestural apraxia

Gestural apraxia was first described in 1905 by Hugo Karl Liepmann. While his description is still used, the actual terms are often confusing. The cognitive approach using models proposes thinking of the condition in terms of production and conceptual knowledge. The underlying cognitive processes are still being debated, as are also the optimal ways to assess them. Several neuroimaging studies have revealed the involvement of a left-lateralized frontoparietal network, with preferential activation of the superior parietal lobe, intraparietal sulcus and inferior parietal cortex. The presence of apraxia after a stroke is prevalent, and the incidence is sufficient to propose rehabilitation