Objectives: Recent evidence indicates that some left brain-damaged (LBD) patients have difficulties to use familiar tools because of the inability to reason about physical object properties. A fundamental issue is to understand the residual capacity of those LBD patients in tool selection. Methods: Three LBD patients with tool use disorders, three right brain-damaged (RBD) patients, and six matched healthy controls performed a novel tool selection task, consisting in extracting a target out from a box by selecting the relevant tool among eight, four, or two tools. Three criteria were manipulated to make relevant and irrelevant tools (size, rigidity, shape). Results: LBD patients selected a greater number of irrelevant tools and had more difficulties to solve the task compared to RBD patients and controls. All participants committed more errors for selecting relevant tools based on rigidity and shape than size. In some LBD patients, the difficulties persisted even in the 2-Choice condition. Conclusions: Our findings confirm that tool use disorders result from impaired technical reasoning, leading patients to meet difficulties in selecting tools based on their physical properties. We also go further by showing that these difficulties can decrease as the choice is reduced, at least for some properties, opening new avenues for rehabilitation programs. (JINS, 2018, 24, 524–529)

Objectives: Two theories of tool use, namely the gesture engram and the technical reasoning theories, make distinct predictions about the involvement of the left inferior parietal lobe (IPL) in manipulation judgement tasks. The objective here is to test these alternative predictions based on previous studies on manipulation judgment tasks using transcranial magnetic stimulations (TMS) targeting the left supramarginal gyrus (SMG). Methods: We review recent TMS studies on manipulation judgement tasks and confront these data with predictions made by both tool use theories. Results: The left SMG is a highly intertwined region, organized following several functionally distinct areas and TMS may have disrupted a cortical network involved in the ability to use tools rather than only one functional area supporting manipulation knowledge. Moreover, manipulation judgement tasks may be impaired following virtual lesions outside the IPL. Conclusions: These data are more in line with the technical reasoning hypothesis, which assumes that the left IPL does not store manipulation knowledge per se. (JINS, 2017, 23, 685–691)

Gaucher disease is an autosomal-recessive lysosomal storage disease characterised by the accumulation of glucocerebroside in macrophages; it is caused by mutations in glucocerebrosidase gene-1 in many organ tissues such as the liver, spleen, and bone marrow. Its different clinical subtypes, according to the presence and severity of neurological symptoms, are as follows: type I, non-neuronopathic (95%); type II, acute neuronopathic; and type III, chronic neuronopathic. Type IIIC is a rare subgroup characterised by cardiovascular involvement as well as eye-movement disorders and late-onset neurological symptoms. In such cases, homozygous D409H is the most frequently detected mutation. In this article, we report the case of a patient, aged 15 years and 8 months, with complaints of syncope and a diagnosis of type IIIC Gaucher disease.

Objectives: Pantomiming the use of familiar tools is a central test in the assessment of apraxia. However, surprisingly, the nature of the underlying cognitive mechanisms remains an unresolved issue. The aim of this study is to shed a new light on this issue by exploring the role of functional, mechanical, and manipulation knowledge in patients with Alzheimer’s disease and semantic dementia and apraxia of tool use. Methods: We performed multiple regression analyses with the global performance and the nature of errors (i.e., production and conception) made during a pantomime of tool use task in patients and control participants as dependent variables and tasks investigating functional, mechanical, and manipulation knowledge as predictors. Results: We found that mechanical problem solving, assessing mechanical knowledge, was a good predictor of the global performance of pantomime of tool use. We also found that occurrence of conception errors was robustly predicted by the task assessing functional knowledge whereas that of production errors was not explained by only one predictor. Conclusions: Our results suggest that both functional and mechanical knowledge are important to pantomime the use of tools. To our knowledge, this is the first demonstration that mechanical knowledge plays a role in pantomime of tool use. Although impairment in pantomime of tool use tasks (i.e., apraxia) is widely explained by the disruption of manipulation knowledge, we propose that pantomime of tool use is a complex problem-solving task. (JINS, 2017, 23, 128–138)

Objectives: Exploring the nature of defective pantomime in apraxia. Methods: Critical review of behavioral associations and dissociations between defective pantomime, imitation of gestures, and real tool use. Analysis of congruencies between crucial lesions for pantomime, imitation, and tool use. Results: There are behavioral double dissociations between pantomime and imitation, and their cerebral substrates show very little overlap. Whereas defective pantomime is bound to temporal and inferior frontal lesions, imitation is mainly affected by parietal lesions. Pantomime usually replicates the motor actions of real use but on scrutiny there are important differences between the movements of real use and of pantomime that cast doubt on the assumption that pantomime is produced by the same motor programs as actual use. A more plausible proposal posits that pantomime is a communicative gesture that uses manual actions for conveying information about objects and their use. The manual actions are constructed by selection and combination of distinctive features of tools and actions. They frequently include replications of characteristic motor actions of real use, but the main criterion for selection and modification of features is the comprehensibility of the gestures rather than the accurate replication of the motor actions of real use. Conclusions: Pantomime of tool use is a communicative gesture rather than a replication of the motor actions of real use. (JINS, 2017, 23, 121–127)

A review is given of the neuropsychological conceptualizations of aphasia and apraxia in SDAT. In the beginning of this century localisationism was prevailing. Later, developmental and cognitive psychology gave an important impetus to reconsider these symptoms in an holistic framework. More recently, since the application of new brain imaging techniques, there is a revival of localizing conceptualizations.

Motor theories of perception posit that motor information is necessary for successful recognition of actions. Perhaps the most well known of this class of proposals is the motor theory of speech perception, which argues that speech recognition is fundamentally a process of identifying the articulatory gestures (i.e. motor representations) that were used to produce the speech signal. Here we review neuropsychological evidence from patients with damage to the motor system, in the context of motor theories of perception applied to both manual actions and speech. Motor theories of perception predict that patients with motor impairments will have impairments for action recognition. Contrary to that prediction, the available neuropsychological evidence indicates that recognition can be spared despite profound impairments to production. These data falsify strong forms of the motor theory of perception, and frame new questions about the dynamical interactions that govern how information is exchanged between input and output systems.

The present article responds to commentaries from experts in anthropology, apraxia, archeology, linguistics, neuroanatomy, neuroimaging, neurophysiology, neuropsychology, primatology, sign language emergence and sign language neurolinguistics on the book How the brain got language: The mirror system hypothesis (Arbib 2012). The role of complex imitation is discussed, and the distinction between protolanguage and language is emphasized. Issues debated include the role of protosign in scaffolding protospeech, the interplay between biological evolution of the brain and cultural evolution of the social interactions within groups, the relations brain mechanisms for action and language, and the question of when language first emerged.

In this article, I will comment on recent advances in the research on the intersection between language and action. On the basis of the argument proposed by Arbib, I will consider an evolutionary scenario according to which language emerged from a basic imitation mechanism devoted to action representation. I will review more appropriate data in patients who present with gesture and language disorders and add it to behavioral, neurophysiological, and neuroimaging evidence that suggests that specialized sensorimotor circuits underlie action processing and may ultimately even ground complex aspects of language. Finally, in the last part of the article, I will discuss some of the future research on the interwoven processes of production and comprehension that are involved in the predictive mechanisms of action and language.

Acoustic analysis provides objective quantitative measures of speech that enable a comprehensive and accurate understanding of motor disorders and complement the traditional measures. This paper aims to distinguish between normal and pathological speech, more specifically between apraxia of speech and spastic dysarthria in native Spanish speaking patients using acoustic parameters. Participants (4 aphasic with apraxia of speech, 4 with spastic dysarthria, and 15 without speech disorders) performed three different tasks: repeating the syllable sequence [pa-ta-ka], repeating the isolated syllable [pa] and repeating the vowel sequence [i-u]. The results showed that the normative values of motor control, in general, coincide with those obtained in previous research on native English speakers. They also show that damage to motor control processes results in a decrease in the rate of alternating and sequential movements and an increase in the inter-syllabic time for both types of movements. A subset of the acoustic parameters analyzed, those that measure motor planning processes, enable differentiation between normal population and apraxic and dysarthric patients, and between the latter. The differences between the pathological groups support the distinction between motor planning and motor programming as described by van der Merwe's model of sensorimotor processing (1997).

Though its existence has been known for well over 30 years, only recently has the supplementary motor area (SMA) and its role in the cortical organization of movement come to be examined in detail by neuroscientists. Evidence from a wide variety of investigational perspectives is reviewed in an attempt to synthesize a conceptual framework for understanding SMA function. It is suggested that the SMA has an important role to play in the intentional process whereby internal context influences the elaboration of action. It may be viewed as phylogenetically older motor cortex, derived from anterior cingulate periarchicortical limbic cortex, which, as a key part of a medial premotor system, is crucial in the “programming” and fluent execution of extended action sequences which are “projectional” in that they rely on model-based prediction. This medial system can be distinguished from a lateral premotor system postulated to have evolved over phylogeny from a different neural source. An anatomico-physiologic model of the medial premotor system is proposed which embodies the principles of cyclicity and reentrance in the process of selecting those neural components to become active in conjunction with the performance of a particular action. The postulated dynamic action of this model in the microgenesis of a discrete action is outlined. It is concluded that although there is a great deal to be learned about the SMA, a convergence of current evidence can be identified. Such evidence suggests that the SMA plays an important role in the development of the intention-to-act and the specification and elaboration of action through its mediation between medial limbic cortex and primary motor cortex.

Patients with corticobasal degeneration (CBG) often demonstrate agraphesthesia in the same hand they demonstrate apraxia. To recognize letters written in their hand subjects can develop a spatial representation and access graphemic representations. Alternatively, people can use movement working memory and match movement patterns to stored letter movement representations. To learn the method normally used without vision, normal subjects (12) had letters written on their palm either in the normal manner or in a reverse direction. If letters written on the hand are recognized by their spatial features (as when visually reading) direction should not influence letter recognition, but if letters written on the hand are recognized by movement patterns, then in the reverse condition recognition should be impaired. When letters were written normally there were no differences in error between the tactile and visual modality. When letters were written in reverse, however, normal subjects made more errors in the tactile than visual condition. Normally, people identify letters written on their hand by covertly copying (mirroring) the examiner and then access letter movement representations. This might explain why patients with CBG often have agraphesthesia associated with apraxia. (JINS, 2010, 16, 190–193.)

Limb praxis can be influenced by age, gender, and education. The present study investigated the influence of these variables on gesture production by healthy elderly subjects. We evaluated 96 individuals divided into two age groups (60–74 and 75–88 years). Each group contained 48 men and 48 women and was subdivided into four groups according to education: illiterates and 1–3, 4–7, and 8 or more years of education. Individuals were requested to carry out tasks on verbal command and imitation. There were no differences between the performance of men and women, while older individuals performed worse than their younger counterparts. Regarding educational level, three major groups emerged: illiterates, individuals with 1–7 years of education, and those with 8 or more years of education. In conclusion, age and education significantly influenced the performance of individuals in limb praxis tests. (JINS, 2009, 15, 618–622.)

Humans learn skilled acts in order to effectively interact with their environment. A loss of the ability to perform skilled acts is termed apraxia. Apraxia has been thought to be of theoretical interest, but the ecological implications of apraxia are controversial and have not been fully studied. We examined ten patients with unilateral left hemisphere cerebral infarctions (eight of whom were apraxic) and compared their mealtime eating behavior to a group of neurologically normal, age-matched controls. The stroke patients were less efficient in completing the meal. They made more action errors and were less organized in the sequencing of mealtime activities. Because the patients made more errors while using tools than when performing nontool actions, their deficit could not be accounted for by an elemental motor deficit. A positive relationship was found between mealtime action errors and the severity of apraxia. These findings suggest that limb apraxia may adversely influence activities of daily living. (JINS, 1995, I, 62–66.)

Impaired imitation of skilled gestures is commonly reported in autism. Questions, however, remain as to whether impaired imitation is associated with a more generalized deficit in performance of gestures consistent with a dyspraxia and whether the pattern of errors differs from that observed in typically developing children. To address these questions, praxis in 21 high-functioning children with autism spectrum disorders (ASD) was compared with 24 typically developing controls using a traditional approach in which performance was evaluated through detailed examination of error types. Children with ASD produced significantly fewer correct responses not only during Gesture to Imitation, but also during Gesture to Command and with Tool Use. The pattern of errors in ASD was similar to that of controls with spatial errors being most common in both groups; however, body-part-for-tool errors were more common in children with ASD, suggesting dyspraxia is not entirely attributable to motor deficits. The findings suggest that autism is associated with a generalized praxis deficit, rather than a deficit specific to imitation. In a developmental disorder such as autism, the findings may reflect abnormalities in frontal/parietal–subcortical circuits important for acquisition (i.e., learning) of sensory representations of movement and/or the motor sequence programs necessary to execute them. (JINS, 2006, 12, 314–326.)