Limb apraxia is a heterogeneous disorder of skilled action and tool use that has long perplexed clinicians and researchers. It occurs after damage to various loci in a densely interconnected network of regions in the left temporal, parietal, and frontal lobes. Historically, a highly classificatory approach to the study of apraxia documented numerous patterns of performance related to two major apraxia subtypes: ideational and ideomotor apraxia. More recently, there have been advances in our understanding of the functional neuroanatomy and connectivity of the left-hemisphere "tool use network," and the patterns of performance that emerge from lesions to different loci within this network. This chapter focuses on the left inferior parietal lobe, and its role in tool and body representation, action prediction, and action selection, and how these functions relate to the deficits seen in patients with apraxia subsequent to parietal lesions. Finally, suggestions are offered for several future directions that will benefit the study of apraxia, including increased attention to research on rehabilitation of this disabling disorder.

Limb apraxia and the left parietal lobe.

Selection and application of familiar and novel tools in patients with left and right hemispheric stroke : Psychometrics and normative data

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS; the most common phenotype of corticobasal degeneration) are tauopathies with a relentless course, usually starting in the mid-60s and leading to death after an average of 7 years. There is as yet no specific or disease-modifying treatment. Clinical deficits in PSP are numerous, involve the entire neuraxis, and present as several discrete phenotypes. They center on rigidity, bradykinesia, postural instability, gait freezing, supranuclear ocular motor impairment, dysarthria, dysphagia, incontinence, sleep disorders, frontal cognitive dysfunction, and a variety of behavioral changes. CBS presents with prominent and usually asymmetric dystonia, apraxia, myoclonus, pyramidal signs, and cortical sensory loss. The symptoms and deficits of PSP and CBS are amenable to a variety of treatment strategies but most physicians, including many neurologists, are reluctant to care for patients with these conditions because of unfamiliarity with their multiplicity of interacting symptoms and deficits. CurePSP, the organization devoted to support, research, and education for PSP and CBS, created its CurePSP Centers of Care network in North America in 2017 to improve patient access to clinical expertise and develop collaborations. The directors of the 25 centers have created this consensus document outlining best practices in the management of PSP and CBS. They formed a writing committee for each of 12 sub-topics. A 4-member Steering Committee collated and edited the contributions. The result was returned to the entire cohort of authors for further comments, which were considered for incorporation by the Steering Committee. The authors hope that this publication will serve as a convenient guide for all clinicians caring for patients with PSP and CBS and that it will improve care for patients with these devastating but manageable disorders.

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Best Practices in the Clinical Management of Progressive Supranuclear Palsy and Corticobasal Syndrome: A Consensus Statement of the CurePSP Centers of Care

PURPOSE OF REVIEWIn part because of their striking clinical presentations, disorders of higher nervous system function figured prominently in the early history of neurology. These disorders are not merely historical curiosities, however. As apraxia, neglect, and agnosia have important clinic

Apraxia, Neglect, and Agnosia.

Introduction: Apraxia is defined as a disorder of learned skilled movements, in the absence of elementary motor or sensory deficits and general cognitive impairment, such as inattention to commands, object-recognition deficits or poor oral comprehension. Limb apraxia has long been a challenge for clinical assessment and understanding and covers a wide spectrum of disorders, all involving motor cognition and the inability to perform previously learned actions. Demographic variables such as gender, age, and education can influence the performance of individuals on different neuropsychological tests. Objective: The present study aimed to evaluate the performance of healthy subjects on a limb apraxia battery and to determine the influence of gender, age, and education on the praxis skills assessed. Methods: Forty-four subjects underwent a limb apraxia battery, which was composed of numerous subtests for assessing both the semantic aspects of gestural production as well as motor performance itself. The tasks encompassed lexical-semantic aspects related to gestural production and motor activity in response to verbal commands and imitation. Results: We observed no gender effects on any of the subtests. Only the subtest involving visual recognition of transitive gestures showed a correlation between performance and age. However, we observed that education level influenced subject performance for all sub tests involving motor actions, and for most of these, moderate correlations were observed between education level and performance of the praxis tasks. Conclusion: We conclude that the education level of participants can have an important influence on the outcome of limb apraxia tests.

/pdf/the-influence-of-age-gender-and-education-on-the-performance-4vi2pul842.pdf

The influence of age, gender and education on the performance of healthy individuals on a battery for assessing limb apraxia.

Background: Limb apraxia comprises many different and common disorders, which are largely unrecognized essentially because there is no easy-to-use screening test sensitive enough to identify all types of limb praxis deficits. Method: We evaluated 70 right-handed patients with limb apraxia due to a single focal lesion of the left hemisphere and 40 normal controls, using a new apraxia screening test. The test covered 12 items including: intransitive gestures, transitive gestures elicited under verbal, visual, and tactile modalities, imitation of meaningful and meaningless postures and movements, and a multiple object test. Results: Interrater reliability was maximum for a cutoff of >2 positive items identifying apraxia on the short battery (Cohen’s kappa .918, p 3 items (Cohen’s kappa .768, p 2 was higher, indicating greater apraxia diagnosis agreement between raters at this cutoff value. Conclusions: The scree...

Florencia Clarens

Papers

Short apraxia screening test.