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It has now been 100 years since Hugo Liepmann, in his classic 1920 paper described limb kinetic, ideomotor, and ideational apraxia. There are now several rating scales used to assess and grade the signs and symptoms associated with Parkinson’s disease; however, none of these assesses patients for the presence of these disabling forms of upper limb apraxia. This paper, reviews the four types of apraxia that can be associated with Parkinson’s disease, how they can be tested, the disabilities associated with these disorders and possible treatments.

Apraxia is a disorder of the skilled movements that are needed successfully perform transitive or intransitive movements, when this disorder is not caused by failures of comprehension, weakness, sensory loss, or involuntary movements. The following forms of upper limb apraxia have been reported to be associated with Parkinson's disease: (1) limb-kinetic apraxia, a loss of the ability to make precise, independent but coordinated finger-hand movements; (2) ideomotor apraxia, a failure to make the correct joint movements, to coordinate these movements with the correct timing, speed, and force; and (3) ideational apraxia, the incorrect sequencing of a series of actions required to complete a goal. This chapter summarizes the means of testing for these different forms of apraxia, the types of errors made by patients with these forms of apraxia, and the pathophysiology and treatment of these disorders.

A previous exposition of apraxia in Practical Neurology 1 offered an account of underlying impairment and accompanying clinical assessment based on a distinction between ideational, ideomotor and limb-kinetic apraxia. This conceptualisation stems from 19th-century models of higher cortical motor, language and visual function, revived by Geschwind2 3 in the 1960s. Liepmann in 19004 had posited a hierarchical model of action control over three discrete levels. At the top, movement formulae (‘visual engrams’ of the action) provided overall targets, which activate innervatory patterns to stimulate the appropriate muscles, coordinated contraction of muscles then led to execution of the action. (1) Ideational apraxia arose when movement formulae were either impaired or disconnected from the innervatory patterns. (2) Ideomotor apraxia resulted from disruption to innervatory patterns. (3) Limb-kinetic apraxia , assumed to be a disruption to the smooth neural transmission of the motor commands, was, even for Liepmann, not a full apraxia. It existed between apraxia and paresis only within a broader view of dysfunction. Liepmann’s model proved valuable in studying apraxia. However, despite surviving in several neurology textbooks, the ideational–ideomotor dichotomy has now been replaced as a way of understanding and classifying apraxias,5–8 similar to the disbandment of Broca’s versus Wernicke’s aphasia, or the dichotomy of associative versus apperceptive agnosia9 (although these distinctions, too, still persist in some areas of clinical practice). A radical rethink was needed, owing to issues with the underlying theoretical model of apraxia and difficulties in distinguishing between ideational and ideomotor clinically. Goldenberg7 made the plea to ‘relegate the dichotomy of ideational …

Aside from being measured in the context of producing facial expressions of emotion, the ability to voluntarily control a range of facial muscles in Parkinson's disease (PD) has not been systematically measured. We used in three enrollment phases an adaptation of the Upper and Lower Face Apraxia test, a measure of the ability to make voluntary movements of the upper and lower face in PD patients and healthy controls. Errors were scored due to (1) pauses prior to movement initiation, (2) loss of individuation, (3) impoverished movement, (4) no movement at all, or (5) content errors (likened to ideational apraxia errors). The results show impaired voluntary control of facial musculature in most but not all with PD (with large effect sizes) which correlated positively and highly with disease severity. Errors by PD patients were predominantly due to impoverished movement and individuation loss whereas those made by controls were predominantly due to individuation loss. Patients committed more errors than controls due to impoverishment and no movement, with negligible differences between groups in other errors. In summary, similarly to spontaneous and voluntary emotional expressions, voluntary non-emotional facial movements are impoverished in PD; impoverishment of all movement types will likely contribute to the mask-like facial appearance that is seen with disease progression. These findings also illustrate the utility of an adapted Face Apraxia test as a practical and sensitive measure of voluntary facial musculature control in PD. The test can be used to supplement clinical observations and as a research tool.

Neuropsychological studies showed that manipulatory and semantic knowledge can be independently impaired in patients with upper-limb apraxia, leading to different tool use disorders. The present study aimed to dissociate the brain regions involved in judging the hand configuration or the context associated to tool use. We focussed on the left supramarginalis gyrus (SMG) and left middle temporal gyrus (MTG), whose activation, as evidenced by functional magnetic resonance imaging (fMRI) studies, suggests that they may play a critical role in tool use. The distinctive location of SMG in the dorsal visual stream led us to postulate that this parietal region could play a role in processing incoming information about tools to shape hand posture. In contrast, we hypothesized that MTG, because of its interconnections with several cortical areas involved in semantic memory, could contribute to retrieving semantic information necessary to create a contextual representation of tool use. To test these hypotheses, we used neuronavigated transcranial magnetic stimulation (TMS) to interfere transiently with the function of either left SMG or left MTG in healthy participants performing judgement tasks about either hand configuration or context of tool use. We found that SMG virtual lesions impaired hand configuration but not contextual judgements, whereas MTG lesions selectively interfered with judgements about the context of tool use while leaving hand configuration judgements unaffected. This double dissociation demonstrates that the ability to infer a context of use or a hand posture from tool perception relies on distinct processes, performed in the temporal and parietal regions. The present findings suggest that tool use disorders caused by SMG lesions will be characterized by difficulties in selecting the appropriate hand posture for tool use, whereas MTG lesions will yield difficulties in using tools in the appropriate context.

To successfully interact with the environment, goal-oriented movements made by human limbs must be guided by instructions from the brain. Loss of the ability to program purposeful skilled movements, in the absence of any motor, sensory, or cognitive deficit that could fully account for this disability, is called apraxia. Several types of apraxia were described by Hugo Liepmann in the beginning of the 20th century: ideomotor apraxia, where patients make spatial movement and postural errors as well as temporal errors, limb-kinetic apraxia, where patients are unable to perform precise independend and coordinated finger movements and ideational apraxia, where patients fail to correctly sequence a series of action. More recently, three other types of apraxia have been described: conceptual apraxia, where patients have a loss of mechanical knowledge; dissociation apraxia, where patients are impaired at performing a skilled act in response to stimuli in one modality but can perform normally when the stimulus is given in another modality; and conduction apraxia, where patients are impaired at action imitation. This chapter, using an historical approach, reviews the signs associated with each of these forms of apraxia, as well as their pathophysiology.

We report data from a group of patients with mild Alzheimer's disease on a range of tasks requiring either stored semantic knowledge about objects (e.g., naming object use) or the execution of action to objects (e.g., miming and using objects). We found that the patients were impaired at miming in response to objects, even when they could describe the object's function. On the other hand, copying gestures was not impaired relative to naming gestures, indicating that an ideomotor deficit in action execution, per se, was unlikely to explain the impairments in object use. We suggest instead that the patients had an impairment in stored motor programmes for action, over and above their deficits in semantic knowledge. Despite this, the patients were better at using than at miming to objects, consistent with the view that proprioceptive input (when using objects) can directly constrain selection of the appropriate motor programme for action.

Neurologists are familiar with the standard definition of apraxia: ‘an inability to perform a motor task that cannot be adequately explained by motor weakness, sensory loss or a lack of understanding’. Being a definition of exclusion, this has led to a bewildering number of motor disorders being described as forms of apraxia, despite many of these failing to capture the essence of what apraxia really is: a disorder of motor cognition. Apraxia reflects an impairment of the storage and transformation of motor representations in the brain, either through degradation of the semantic knowledge of gestures and tool use or through inability to translate the neural representations of higher level goals accurately into lower level patterns of muscle activation and inhibition. Our current clinical approach to apraxia is similar to that proposed by Liepman in the early 20th century.1 He recognised that left hemispheric lesions tend to cause bilateral upper limb apraxia and suggested a model of motor control in which the left parietal lobe stores a ‘space–time form picture’ of a movement. For a movement to be executed, its picture must be retrieved and activated and then be associated via cortical projections with the relevant motor engrams in the prefrontal regions. From here the information passes to the primary motor cortex before being fed down the corticospinal tracts. For the right upper limb to move the information remains contained within the left hemisphere, but for the left upper limb to move the information from the left parietal lobe must first be sent to the right prefrontal and frontal regions through the corpus callosum. Using this scheme, Liepman delineated three forms of apraxia. He described ideational apraxia as a disruption of the space–time picture, in which the idea of the movement itself is lost or degraded. In ideomotor apraxia , …

A large left hemisphere porencephalic cyst was incidentally found in a 48-year-old woman (MS) with a Diagnostic and Statistical Manual (DSM)-5 diagnosis of schizophrenia. The encephaloclastic characteristics of the cyst indicated that it was acquired between the 22nd and 24th gestational weeks, after the major waves of neuronal migration had tapered off. The cyst destroyed the left temporal and occipital lobes, and the inferior parietal lobule. Surprisingly, MS had no evidence of aphasia, alexia, agraphia, or ideational apraxia; in contrast, cognitive functions dependent on the integrity of the right hemisphere were severely impaired. To test the hypothesis that the development of language in MS took place at the expense of functions that are normally carried out by the right hemisphere, we investigated MS’s correlates of oral comprehension with fMRI as a proxy for auditory comprehension and other cognitive functions strongly lateralized to the posterior left hemisphere, such as ideational praxis and reading. Comprehension of spoken language engaged the homologous of Wernicke’s area in the right planum temporale. Porencephaly may represent a natural model of neuroplasticity supervening at predictable epochs of prenatal development.

Apraxia refers to an impairment in the performance of skilled motor acts. This is in the context of normal or near-normal elementary neurological function such as motor power and sensation. In addition a long list of specific exclusions and conditions that may masquerade as apraxia need to be excluded. These include the domains of attention, cognition, motor deficits, and movement disorders

Background and purpose: Although apraxia is a typical consequence of Alzheimer’s disease (AD), the profile of apraxic impairments is still subject to debate. Here, we analysed apraxia components in patients with AD with mild-to-moderate or moderately severe dementia. Methods: Thirty-one patients were included. We first evaluated simple gestures, that is, the imitation of finger and hand configurations, symbolic gestures (recognition, production on verbal command and imitation), pantomimes (recognition, production on verbal command, imitation and production with the object), general knowledge and complex gestures (tool–object association, function–tool association, production of complex actions and knowledge about action sequences). Tests for dementia (Mini Mental State Examination and the Dementia Rating Scale), language disorders, visual agnosia and executive function were also administered. Results: Compared with controls, patients showed significant difficulties (P ≤ 0.01) in subtests relating to simple gestures (except for the recognition and imitation of symbolic gestures). General knowledge about tools, objects and action sequences was less severely impaired. Performance was frequently correlated with the severity of dementia. Multiple-case analyses revealed that (i) the frequency of apraxia depended on the definition used, (ii) ideomotor apraxia was more frequent than ideational apraxia, (iii) conceptual difficulties were slightly more frequent than production difficulties in the early stage of AD and (iv) difficulties in gesture recognition were frequent (especially for pantomimes). Conclusion: Patients with AD can clearly show gesture apraxia from the mild–moderate stage of dementia onwards. Recognition and imitation disorders are relatively frequent (especially for pantomimes). We did not find conceptual difficulties to be the main problem in early-stage AD.

The objective of the study was to determine whether ideational apraxia (IA), a loss of ability to plan the sequence of actions needed to achieve a goal, is associated with Parkinson disease (PD).: The frontal lobes play an important role in planning and sequencing, and many patients with PD have frontal lobe dysfunction.: Ten right-handed patients with PD and 10 right-handed neurologically and psychiatrically healthy people participated. To assess for IA, participants were given sets of pictures that showed the steps in completing a task, but the steps were shown out of order. The participants were required to point to the pictures in the correct sequence to complete each task. The participants also performed a control task of sequencing randomly arranged printed single words to create a sentence that described an accompanying picture.: The patients with PD performed more poorly than the controls on the action-sequencing tasks (P0.05). Errors were predominantly in sequencing rather than repetition or omission, indicating that the poor performance was not caused by perseveration. There were no group differences in the task of sequencing words to make a sentence.: These results indicate that patients with PD do have IA, an action-sequence planning deficit. Further research is needed to better understand mechanisms, ecological implications, and potential treatments.

This study evaluated the impact of distractor objects and their similarity to target objects on everyday task performance in dementia. Twenty participants with dementia due to Alzheimer’s disease (n = 12) or subcortical vascular disease (n = 8) were videotaped while they performed 3 discrete tasks: (1) make a cup of coffee, (2) wrap a gift, and (3) pack a lunch under two conditions that were counterbalanced across participants. The conditions differed in terms of the type of distractor objects included in the workspace: (1) Target-Related Distractor Condition - distractor objects were functionally and visually similar to target objects (e.g., salt for sugar) (2) Unrelated Distractor Condition - distractors were neither visually nor functionally similar to targets (e.g., glue for sugar). Participants touched (t = 4.19; p < .01) and used (z = 3.00; p < .01) significantly more distractors, made more distractor errors (i.e., substitutions; t = 2.93; p < .01), and took longer to complete tasks (t = 2.27; p < .05) in the Target-Related Distractor condition. The percent of steps accomplished and non-distractor errors did not differ across conditions (t < 1.26; p > .05 for both). In summary, distractors that were similar to targets elicited significant interference effects circumscribed to object selection. (JINS, 2010, 16, 484–494.)

Apraxias are disorders of motor cognition that cannot be explained by basic sensorimotor deficits or aphasia. The relatively high frequency of apraxia (approximately half of all patients with left-hemispheric stroke suffer from apraxia during the acute phase) as well as its prognostic value for determining the outcome of rehabilitative therapy clearly convey the necessity of more comprehensive research into the pathophysiology of apraxia in order to develop new therapeutic strategies. In recent years, functional imaging (PET and fMRI) has helped to provide important new insights into the pathophysiology of ideomotor apraxia (defective movement plan) and ideational apraxia (defective action concept). In this review, the neural bases for the clinically observed dissociations between the imitation of abstract and symbolic movements (as in ideomotor apraxia) and for the object-trigger system (which is disturbed in ideational apraxia) will be exemplified. Furthermore, we will recapitulate recent studies that provide evidence for the complementary functions of the right and left parietal cortices in the spatial and temporal organization of complex, object-related actions. The particular importance of the left parietal cortex for motor cognition is further supported by studies examining the integration of spatial and temporal movement information during the generation of a movement plan as well as by the generation of such movement plans in the left parietal cortex independent from the hand that executes the movement.

Relative to our understanding of the memory and language deficits associated with Alzheimer's disease (AD), little is known about problems with everyday action performance (i.e., meal preparation, grooming). The resource theory proposes that everyday action problems are best explained by a unitary deficit in general cognitive resources. However, recent research suggests that omission and commission errors may reflect dissociable aspects of action impairment, with only omissions associated with resource limitations. This study examined everyday action performance in 70 participants with AD who also underwent a neuropsychological evaluation. First, correlation and principal component analyses were performed to examine the construct(s) that might explain everyday action impairment. Second, relations between everyday task component(s) and neuropsychological tests were examined by using correlation and regression analyses. Third, differences in everyday action error patterns were examined among participants of comparable overall impairment levels. Results showed omission and commission errors were uncorrelated and distinct components of everyday action performance, predicted by different neuropsychological tests, and differentially distributed even among participants with comparable overall impairment.

Apraxic phenomena occur in various neurological conditions. Selective motion control is viewed as the basic capacity to make fine and precise, isolated or independent face or limb movements. Its deficit can indicate limb-kinetic apraxia if it is not explained by paresis, somatosensory deafferentation, or ataxia. The core deficit in ideomotor apraxia could be deficient movement representations, i.e. the combination of invariant features of intrinsic and extrinsic coding for a given movement, which are most important when movements have to be performed outside their typical context. Ideational apraxia would be defined by a semantic deficit related to action. Frontal apraxia is characterised by an action-sequencing deficit. A detailed model is proposed regarding processes relevant to praxis.

In the present study we analysed the perseverative behaviour of three apraxic patients (FG, CEO, and VCR) while they were pantomiming the use of common objects and during their real use. The three patients were found to perseverate from one trial to later ones aspects of a given action in the pantomiming and in real use tasks. In particular, our main result was a striking double dissociation between patients in perseverating hand and arm movements. Patients FG and CEO made more perseveration errors involving the hand than VCR did, whereas the perseverative errors made by VCR involving the arm were more numerous than those made by FG and CEO. The patients differed also in other aspects of the perseverations, e.g., their median lags. Results are used to exend previous theories developed in the linguistic domain to that of actions.

Contains fulltext : 54642.pdf (Publisher’s version ) (Closed access) The present study compared imitation performance in patients with ideomotor apraxia (IMA), eight right hemispheric-damaged patients, and eight control participants without neurological damage in three experiments. Experiment 1 confirmed in the Goldenberg test that IMA patients were particularly impaired in hand gestures and combined finger and hand gestures, but not in the imitation of finger gestures, compared to the other two groups. Experiment 2, however, demonstrated that finger selection is not per se preserved in imitative behaviour in patients with IMA. Experiment 3 confirmed this finding in an experiment under visual control. Together, the results add evidence to the idea that imitation should be viewed from a goal-directed rather than a body-mapping perspective, and that highest priority is given to more distal aspects of imitation as reaching for the correct object, rather than the means used to achieve the goal of a modelled action.

We report three PET experiments that examine the neural substrates of the conceptual components of action retrieval. In all three experiments, subjects made action or screen-size decisions to familiar objects presented either as pictures or written words (the names ofthe objects). In Experiment 1, a third task was included, requiring a decision on the real-life size of the stimuli. In Experiment 2, a third stimulus type was included, with action and size decisions also performed on pictures of meaningless novel objects. Finally, in Experiment 3, we changed the response mode from a button press to a more explicit movement made with a lsquo;lsquo;manipulandumlsquo;lsquo;. Based on neuropsychological findings, we predicted that when action responses were made to pictures of familiar or novel objects, relative to words, there would be less activation in semantic regions but greater activation in visual, motor, and perhaps parietal cor tices. We found that, action relative to screen-size decisions on both pictures and words activated the left hemisphere temporo-frontal semantic system with activation in the left posterior middle temporal cortex specific to action retrieval (Experiment 1). In addition, action retrieval elicited more activation for (1) words than pictures in areas associated with semantics; and (2) novel objects than words or familiar objects in areas associated with pre-semantic object processing. These results are discussed in the context of semantic and visual routes to action retrieval.

Objective: To describe the prevalence rate of ideational apraxia (IA) affecting self-feeding in people with dementia, confirm the stage of dementia at which IA most commonly occurs, and compare mealtime performance and nutritional status between people with dementia (PWD) with and without IA. Method: A cross-sectional design with between-subject comparison was used. Among the 395 potential participants recruited from dementia special care units at nine long-term care facilities in central and northern Taiwan, 98 met the operational definition of IA and were included in the PWD with IA group. From the remaining pool, 98 participants, matched for age and sex with the PWD with IA group, were randomly allocated to the PWD without IA group. Eating Behavior Scale (EBS) scores, food intake, total eating time, meal assistance, body mass index, Mini-Nutritional Assessment (MNA), and Mini-Mental State Examination scores were collected. Results: The prevalence rate of IA affecting self-feeding in our study population of PWD was 24.8%. PWD with IA had significantly lower EBS scores, had more food intake ( p < .001), spent more time being fed by caregivers, needed more verbal and feeding assistance, and had lower MNA scores than PWD without IA. Decline in the self-feeding ability of PWD affected by IA most commonly occurred in the severe stage of dementia. Conclusion: When dementia progresses to the late stage, staff should pay special attention to residents’ mealtime performance and nutritional status. For PWD with IA, reassigning staff at mealtimes based on eating ability and providing memory training are recommended.

The paper entitled The relationship between performances on single and multiple-object tasks by left-hemisphere damaged aphasic patients (Nieman, Duffy, Belanger, & Coelho, 2000) focuses upon the issue of task complexity in apraxia by comparing single and multiple-object tests. In this study Neiman and colleagues discuss “complexity” and “disconnection” explanations as rival hypotheses about the potential explanations for performance variance on these two tasks. However, their findings fail fully to support either hypothesis and in turn provide the opportunity to discuss what might be a longstanding ambiguity about the relevance of these task variables under study. Specifically, in this paper we discuss our proposal that although the practice of testing multistage and multi-tool/object commands is longstanding and emanates from Liepmann's original descriptions of praxis assessment, the hypotheses and rationale for such assessment in the current study and related investigations are elusive, and that the la...

In this paper we studied three brain-damaged patients: the first two, DR and FG, had limb apraxia whilst the third was a control patient (WH2) with an executive function disorder but without limb apraxia. DR and FG were impaired in carrying out everyday actions, whilst they maintained the ability to sequence photographs representing those same activities. The failure in the action production task was not caused by visual agnosia for objects, as the patients could recognise them from sight. Nor was it produced by a loss of knowledge about their functions (De Renzi & Lucchelli, 1988), as DR and FG could identify objects from descriptions of their use. WH2's pattern of performance doubly dissociated from that of the apraxic patients, namely spared action production on the multiple object test, but faulty sequencing of photographs. WH2's difficulties in sequencing photographs were not due to a failure to understand the task, as she could sequence stimuli other than actions (e.g., shapes and numbers). Nor were the differences due to a loss of knowledge about the actions, since she could perform and identify them from photographs. These results show that the kind of apraxia observed in DR and FG is not produced by a degraded action sequence representation (Lehmkuhl & Poeck, 1981; Poeck & Lehmkuhl, 1980). We interpreted our results within a contention scheduling model (Cooper & Shallice, 2000; Norman & Shallice, 1986).

Although ideomotor apraxia (IM) has been a topic of investigation since the early 20th century, progress in studying the disorder has been hindered by important (and sometimes unarticulated) differences in the underlying theoretical models of various investigative groups. As a result, it is difficult to draw conclusions about the expected performance of IM patients on various tests of praxis (e.g. pantomime, single object use, gesture imitation, and naturalistic action); the relationship of IM to ideational apraxia (IA); the degree to which specific error types are diagnostic of one or the other disorder; the relationship of semantic knowledge to gesture representations; and the role of spatiomotor systems external to the stored gesture representation system. Here an updated model of IM is presented, informed by recent physiological and functional neuroimaging literature, as a step towards resolving some of these concerns. The model is intended to lay the groundwork for future investigations of specific performance patterns in different subtypes of IM.

観念失行は道具の認知や使用法は理解しているものと定義されているが,左脳損傷患者では失語のためその検討は不十分である.今回,左脳損傷で失語を伴う患者53名について,すべて絵や写真を用いて,図形,道具の視覚的認知と道具の使用法,課題の洞察力等を検討した.53名中,観念失行のある者は25名で,課題内容の洞察力は低かったが,全例単一道具の視覚認知と道具の使用法の知識は保たれていた.一方,複数の道具の使用法の知識は20名で誤りが見られたが,生活環境の中では道具使用の誤りが減少した.結局,失語を伴う観念失行患者でも道具の認知や使用法はほぼ理解しており,観念失行は運動プログラムの立ち上げに到る経路の障害が示唆された.

Limb apraxia comprises a wide spectrum of higher-order motor disorders that result from acquired brain disease affecting the performance of skilled, learned movements. At present, limb apraxia is primarily classified by the nature of the errors made by the patient and the pathways through which these errors are elicited, based on a two-system model for the organization of action: a conceptual system and a production system. Dysfunction of the former would cause ideational (or conceptual) apraxia, whereas impairment of the latter would induce ideomotor and limb-kinetic apraxia. Currently, it is possible to approach several types of limb apraxia within the framework of our knowledge of the modular organization of the brain. Multiple parallel parietofrontal circuits, devoted to specific sensorimotor transformations, have been described in monkeys: visual and somatosensory transformations for reaching; transformation of information about the location of body parts necessary for the control of movements; somatosensory transformation for posture; visual transformation for grasping; and internal representation of actions. Evidence from anatomical and functional brain imaging studies suggests that the organization of the cortical motor system in humans is based on the same principles. Imitation of postures and movements also seems to be subserved by dedicated neural systems, according to the content of the gesture (meaningful versus meaningless) to be imitated. Damage to these systems would produce different types of ideomotor and limb-kinetic praxic deficits depending on the context in which the movement is performed and the cognitive demands of the action. On the other hand, ideational (or conceptual) apraxia would reflect an inability to select and use objects due to the disruption of normal integration between systems subserving the functional knowledge of actions and those involved in object knowledge.

Patients with probable Alzheimer's disease (AD) often have difficulties associated with semantic knowledge. Therefore, conceptual apraxia, a defect of action semantics and mechanical knowledge, may be an early sign of this disease. The Florida Action Recall Test (FLART), developed to assess conceptual apraxia, consists of 45 line drawings of objects or scenes. The subject must imagine the proper tool to apply to each pictured object or scene and then pantomime its use. Twelve participants with Alzheimer's disease (NINCDS–ADRDA criteria) and 21 age- and education-matched controls were tested. Nine Alzheimer's disease participants scored below a 2-standarddeviation cutoff on conceptual accuracy, and the three who scored above the cutoff were beyond a 2-standard-deviation cutoff on completion time. The FLART appears to be a sensitive measure of conceptual apraxia in the early stages of Alzheimer's disease. (JINS, 2000, 6, 265–270.)

検査場面と実際の日常場面での神経心理症状の解離はよく観察される現象である。本研究は解離現象の一例として単一物品の使用における観念失行を取り上げ，道具使用時における患者を取り巻く状況が，観念失行に及ぼす影響を検討した。検査室で単一物品のみを使用する状況から，日常的環境までさまざまな状況を設定し観察した結果，全症例とも日常的状況と切り離された単一物品のみの使用で失行を示す一方，その物品と意味連想の高い物品が加わり，より日常場面に類似するに従い観念失行が消失し，検査室においても正常な道具操作が可能になった。以上より，観念失行患者の道具使用は状況依存的であり，被験者を取り巻く行為関連情報多寡が行為の実現に強く影響すると示唆された。解離現象に対して，神経系の意図性と自動性の解離という Jackson の古典的理論に加え，認知心理学における状況論の立場も取り入れ，患者の状況的認知という新たな視点で考察した。

The corticospinal tract (CST) is an essential motor pathway in the human brain: particularly, it is essential for fine hand movements (Jang, 2014). Stroke patients can show more severe weakness when a partial injury of the CST is combined with apraxia. Therefore, a thorough estimation of the CST injury degree at the beginning of stroke rehabilitation would be mandatory for a successful rehabilitation. In this study, we report on a case in whom partially injured CST had been neglected due to accompanying apraxia for 10 months. A 71-year-old female patient was transferred for rehabilitation of hemiplegia after cranioplasty. The patient had undergone decompressive craniectomy for brain swelling due to a left middle cerebral artery (MCA) territory infarct which occurred after clipping of a ruptured left MCA bifurcation aneurysm 10 months ago at the same hospital. The patient had presented with complete paralysis (manual muscle test (Wadsworth et al., 1987): 0) of the right side (upper and lower extremities) for 10 months since the onset of cerebral infarct, although she had undergone rehabilitation at a local rehabilitation hospital for 10 months. Brain CT and brain MRI (2 days and 10 months after onset, respectively) showed a large infarct in the left MCA territory except for some portion of the left precentral gyrus (Figure 1A). The ideomotor apraxia test scores were 40 points (cut-off score < 32 points) (De Renzi et al., 1980). The patient was involved in a comprehensive rehabilitative therapy, including dopaminergic drugs for improvement of apraxia (pramipexole 1.5 mg; ropinorole 0.75 mg; amantadine 300 mg; levodopa, 750 mg) (Jang, 2013). During 3 weeks of rehabilitation treatment, the patient exhibited significant motor improvement in the right side (upper and lower extremities) to the extent that she was able to move against gravity (manual muscle test: 3). The patient provided signed, informed consent and our hospital review board approved the study protocol. Figure 1 CT, T2-weighted MRI and diffusion tensor tractography (DTT) images in a stroke patient. Diffusion tensor imaging (DTI) data were acquired once (10 months after onset) using a 6-channel head coil on a 1.5 T Philips Gyroscan Intera (Philips Healthcare, Best, the Netherlands) with single-shot echo-planar imaging. Seventy contiguous slices (acquisition matrix = 96 × 96, reconstructed to matrix = 192 × 192, field of view (FOV) = 240 × 240 mm2, repetition time (TR)/echo time (TE) = 10,398/72 ms, SENSE factor = 2, echo planar imaging (EPI) factor = 59, b = 1,000 s/mm2, number of excitations = 1, thickness = 2.5 mm) were acquired. Fiber assignment continuous tracking (FACT) algorithm was used for fiber tracking. The CST was reconstructed using fibers passing through two regions of interest (ROIs) on the color map. The first ROI and second ROI were given on the blue portion (anterior) of the upper and lower pons, respectively on the axial image of the color map (threshold fractional anisotropy = 0.15, angle = 27). The left CST was narrowed compared with the right CST; however, the integrity was preserved from the cerebral cortex to the medulla (Figure 1B). Transcranial magnetic stimulation (TMS) was carried out using a Magstim Novametrix 200 magnetic stimulator (Novametrix Inc., Wallingford, CT, USA) at 10 months after onset. Cortical stimulation was performed (left hemisphere: a counterclockwise direction; right hemisphere: a clockwise direction). Motor-evoked potentials (MEPs) were recorded from the right thumb muscle (abductor pollicis brevis) upon stimulation of the left hemisphere with 90% of maximal output (the MEP of shortest latency; latency: 23.7 ms, amplitude: 100 µV, excitatory threshold: 70%). In this patient, some portion of the left precentral gyrus, which is the essential origin of the CST, was preserved on 2-day brain CT and 10-month brain MRI, thus it appeared that the left CST integrity had been preserved since the left MCA infarct (Jang, 2014). In addition, MEP, which has the characteristics of the CST, was evoked at the right hand muscle on 10-month TMS (Rossini et al., 1994). Therefore, we believe that the left CST, which was partially damaged by the MCA infarction, had been in limb apraxia state for 10 months since the onset. Limb apraxia is a common disorder of skilled purposive movement; three types of limb apraxia have been reported: ideational apraxia, ideomotor apraxia, and limb-kinetic apraxia (Leiguarda and Marsden, 2000; Ochipa and Gonzalez Rothi, 2000; Hong et al., 2012; Jang, 2013). Limb-kinetic apraxia is attributable to injury of the premotor cortex with preservation of CST integrity (Leiguarda and Marsden, 2000; Ochipa and Gonzalez Rothi, 2000; Hong et al., 2012; Jang, 2013). Precise diagnosis of limb-kinetic apraxia is difficult because it is made by clinical observation of movements without use of specific evaluation tools (Hong et al., 2012; Jang, 2013). In this patient, brain MRI findings involving the fronto-parietal cortex suggested the possibility of limb-kinetic apraxia and ideomotor apraxia; however, because the patient showed an intact ideational plan for motor performance in the ideomotor apraxia test, we think that the motor improvement for 3 weeks since 10 months after onset was mainly attributed to the resolution of limb-kinetic apraxia (De Renzi et al., 1980). Our results suggest the importance of thorough evaluation of the damage degree of the tracts at the beginning of stroke rehabilitation. However, limitation of using DTI in this study should be taken into account. Fiber tracking is an analyzer dependent method. In addition, DTI might underestimate the neural fibers due to the fiber-crossing effect (Lee et al., 2005; Yamada et al., 2009). This work was supported by the DGIST R&D Program of the Ministry of Science, ICT and Future Planning (15-BD-0401). SHJ designed this study, collected and analyzed data, and revised the paper. CHC participated in study design and data collection. WHJ participated in data collection and analysis and wrote the paper. All authors approved the final version of this paper.

This paper considers the characteristics of apraxia and presents a case study which explores the effectiveness of tactile and kinaesthetic stimulation as an intervention strategy, in addition to visual and verbal mediation input, in the rehabilitation of a man with ideomotor and ideational apraxia following a head injury. Using an ABA design, quantitative measures were used to monitor change in motor performance. The results indicated some significant differences in measured performances between baseline and intervention phases and provided limited evidence of the effectiveness of additional sensory input. The implications for occupational therapy are discussed as are the limitations of the study.

Does semantic knowledge of objects mediate object selection and use? We present data from two patients that speak to this question. The first, DM, is a semantic dementia patient previously reported by Breedin, Saffran, and Coslett (1994) who, despite moderate to severe loss of functional and associative object knowledge, was nevertheless able to perform almost normally on single-object use and on more complex tests of naturalistic action. The second, HB, is a dementia patient who exhibited an executive disorder but performed as well as controls on a detailed battery of semantic memory and single-object use tests. Unlike DM, he made numerous errors on the naturalistic action tests, among which were errors of object selection and usage. Taken together, these data suggestthatintactsemantic memory forobjects is neithernecessary norsufficient to ensure good object utilisation in naturalistic action. The data cannot be accommodated by accounts postulating that action with objects is performed exclusively via no...

Motor theories of action comprehension claim that comprehending the meaning of an action performed by a conspecific relies on the perceiver's own motor representation of the same action. According to this view, whether an action belongs to the motor repertoire of the perceiver should impact the ease by which this action is comprehended. We tested this prediction by assessing the ability of an individual (D.C.) born without upper limbs to comprehend actions involving hands (e.g., throwing) or other body parts (e.g., jumping). The tests used a range of different visual stimuli differing in the kind of information provided. The results showed that D.C. was as accurate and fast as control participants in comprehending natural video and photographic presentations of both manual and nonmanual actions, as well as pantomimes. However, he was selectively impaired at identifying point-light animations of manual actions. This impairment was not due to a difficulty in processing kinematic information per se. D.C. was indeed as accurate as control participants in two additional tests requiring a fine-grained analysis of an actor's arm or whole-body movements. These results challenge motor theories of action comprehension by showing that the visual analysis of body shape and motion provides sufficient input for comprehending observed actions. However, when body shape information is sparsely available, motor involvement becomes critical to interpret observed actions. We suggest that, with natural human movement stimuli, motor representations contribute to action comprehension each time visual information is incomplete or ambiguous.

This chapter focuses on apraxia of the upper limbs. Hugo Liepmann described three major forms of apraxia: ideomotor apraxia, which was also called ideo-kinetic apraxia in Liepmann's terminology; ideational apraxia; and limb-kinetic apraxia, also referred to by some investigators as melokinetic or innervatory apraxia. The chapter discusses the signs and pathophysiology of the apraxic disorders but use a processing approach. The Florida Action Recall Test (FLART), developed to assess conceptual apraxia, consists of 45 line drawings of objects or scenes for which an action with a tool is required. Conceptual apraxia is reported among persons with degenerative dementias such as Alzheimer's disease (AD) and in the semantic dementia subtype of frontotemporal lobar degeneration. Limb-kinetic apraxia is characterized by a loss of dexterity or deftness such that patients with this disorder are impaired at making precise, independent but coordinated finger movements.

Apraxia is a cognitive-motor disorder that impacts the performance of learned, skilled movements. Limb apraxia, which is the topic of this chapter, is specific to disordered movements of the upper limb that cannot be explained by weakness, sensory loss, abnormalities of posture/tone/movement, or a lack of understanding/cooperation. Patients with limb apraxia have deficits in the control or programming of the spatial-temporal organization and sequencing of goal-directed movements. People with limb apraxia can have difficulty manipulating and using tools including cutting with scissors or making a cup of coffee. Two praxis systems have been identified including a production system (action plan and production) and a conceptual system (action knowledge). Dysfunction of the former produces ideomotor apraxia (e.g., difficulty using scissors), and dysfunction of the latter induces ideational apraxia (e.g., difficulty making a cup of coffee). Neural mechanisms, including how to evaluate apraxia, will be presented in the context of these two praxis systems. Information about these praxis systems, including the nature of the disordered limb movement, is important for rehabilitation clinicians to understand for several reasons. First, limb apraxia is a common disorder. It is common in patients who have had a stroke, in neurodegenerative disorders like Alzheimer disease, in traumatic brain injury, and in developmental disorders. Second, limb apraxia has real world consequences. Patients with limb apraxia have difficulty managing activities of daily living. This factor impacts healthcare costs and contributes to increased caregiver burden. Unfortunately, very few treatments have been systematically studied in large numbers of patients with limb apraxia. This overview of limb apraxia should help rehabilitation clinicians to educate patients and caregivers about this debilitating problem, and should facilitate the development of better treatments that could benefit many people in the future.

観念運動失行と観念失行の定義，検査法および問題点について述べた。まず，観念運動失行と観念失行の定義，分類および検査法については，本稿では山鳥に従った。山鳥の分類では，観念運動失行では自動詞的運動と他動詞的運動が混在し，下位分類の可能性も示唆された。また，観念失行については，ほかの道具の使用障害をきたす病態との鑑別が必要になる場合があり，そのなかでも意味記憶障害と多感覚様式失認との鑑別は注意深い臨床観察により可能であると考えられた。

We report a subject who, subsequent to closed head injury, demonstrated a severe left hand ideational apraxia and apraxic agraphia, consistent with callosal disconnection syndrome. In contrast to the left hand, performance of the right hand was unimpaired on traditional tests of gesture to command, sight of object, and with actual object use, but proved deficient on tests of spatial and constructional ability. We examined the consequences of these hand-specific deficits for the performance of naturalistic action tasks. The patient made errors with each hand; however, the right hand performed more poorly than the left hand. In addition, the types of errors made by each hand differed in a manner consistent with the results of neuropsychological testing and indicative of disconnection phenomena. We suggest that unlike gesture, naturalistic action requires the contribution of the specialized abilities of each hemisphere, integrated across callosal structures. Traditional testing of gesture may undere...

This study examined everyday action impairment in participants with Parkinson's disease dementia (PDD) by comparison with participants with Parkinson's disease-no dementia (PD) or Alzheimer's disease (AD) and in reference to a neuropsychological model. Participants with PDD (n = 20), PD (n = 20), or AD (n = 20) were administered performance-based measures of everyday functioning that allowed for the quantification of overall performance and error types. Also, caregiver ratings of functional independence were obtained. On performance-based tests, the PDD group exhibited greater functional impairment than the PD group but comparable overall impairment relative to the AD group. Error patterns did not differ between PDD and PD participants but the PDD group demonstrated a higher proportion of commission errors and lower proportion of omission errors relative to the AD group. Hierarchical regression analyses showed omission errors were significantly predicted by neuropsychological measures of episodic memory, whereas commission errors were predicted by both measures of general dementia severity (MMSE) and executive control. Everyday action impairment in PDD differs quantitatively from PD but qualitatively from AD and may be characterized by a relatively high proportion of commission errors—an error type associated with executive control deficits. (JINS, 2012, 18, 1–12)

It is frequently claimed that ideational apraxia, an impairm ent of the performance of complex actions with objects, is a left-hemisphere syndrome. We assessed the consequences of lefthemisphere damage for naturalistic action performance in two studies. In Study 1, we compared the action errors of left-hemisphere stroke patients (LCVA) to previously reported patients with right-hemisphere stroke (RCVA) and closed head injury (CHI), and found that LCVA were no more vulnerable to errors of action than the other patient groups once differences in severity were controlled. In Study 2, we compared the naturalistic action performance of a patient with severe ideational apraxia and left-hemisphere damage to that of two RCVA patients of equal clinical severity. There was considerable quantitative and qualitative similarity in the errors of the three patients. From these and other findings, we argue that deficits in left-hem isphere systems do not compromise com plex action in a unique or transparent manner. We offer an alternative account based on nonspecific resource limitations that accommodates the data from all patient groups.

Apraxia is a higher level motor deficit that occurs when processing a goal-directed action. The apraxic deficit can manifest itself in absence of sensory input deficits or motor output deficits, neglect, frontal inertia or dementia. According to a clinical classification still largely in use, there are two main forms of limb apraxia: ideomotor (IMA) and ideational (IA), observed when a patient is required to imitate a gesture or use an object, respectively. In the present review, we examined only the cognitive treatments of both types of limb apraxia of a vascular aetiology. Despite the high prevalence of limb apraxia caused by left brain damage, and the fact that apraxia has been known for over a century, the literature regarding its rehabilitation is still very limited. This is partly due to the nature of the recovery from the deficit, and in part to the automatic-voluntary dissociation. Here we review those treatments that have proved most successful in helping patients to recover from limb apraxia.

The parietal lobes are involved in integrating sensory information to form a body-centered representation of external space necessary for movement control. They are also important for language comprehension and mathematical skills. Impairment of the parietal lobes can lead to clinical features such as cortical sensory loss, apraxia, aphasia, or neglect of body and extrapersonal space.

Limb apraxia, the inability to correctly perform skilled purposeful movements, has several forms. Patients with these disorders can lose dexterity, fail to move the limb in the correct spatial pattern, being unable to correctly sequence acts, and do not know the mechanical advantages that tools afford.

Theoretical models of praxis have two major components, a praxis conceptual system that includes knowledge of tool use and mechanical knowledge and a praxis production system that includes the information needed to program skilled motor acts. Because patients with Alzheimer's disease may have an impairment of the central conceptual system, we wanted to learn if they had a conceptual apraxia by testing their knowledge of the type of actions associated with tool use, their ability to associate tools with objects that receive their action, their ability to understand the mechanical nature of problems and the mechanical advantages tools may afford. We studied 32 subjects with probable Alzheimer's disease and 32 controls by examining tool-action relationships and tool-object associations. We tested mechanical knowledge by having subjects select alternative tools and solve mechanical puzzles by developing new tools. The Alzheimer's group was subdivided into four groups based on the presence or absence of ideomotor apraxia and a lexical-semantic deficit. Results indicated that each of the four Alzheimer's groups differed from normal controls on at least some measures of conceptual apraxia, suggesting that Alzheimer's patients do have a disturbance of the praxis conceptual system and that impairment of this system is not directly related to language impairment or ideomotor apraxia.

Apraxia is clinically separable from other cognitive dysfunctions and has the potential to interfere with motor performance in everyday living. To determine its prevalence and severity at each stage of senile dementia of the Alzheimer type (SDAT), a quantitative apraxia battery was used in conjunction with comprehensive quantitative cognitive assessments of 142 SDAT subjects who fell into four stages of dementia severity, and 113 elderly persons determined to be intellectually healthy by the same cognitive assessment. Thirty-five percent of the mildly, 58% of moderately, and 98% of severely demented SDAT subjects showed apraxia. When ideomotor and ideational apraxia were considered separately, ideomotor apraxia was apparent in mild dementia, while ideational apraxia was found only in moderate and severe dementia. When a covariate analysis was employed to test the influence of aphasia that is known to occur in SDAT, ideomotor (but not ideational) deficits were found to be statistically distinct from language impairment. Taken together the findings suggest that ideomotor apraxia may be tied to loss of functional independence in individuals with SDAT.

We studied five patients with semantic memory disorders, four with semantic dementia and one with herpes simplex virus encephalitis, to investigate the involvement of semantic conceptual knowledge in object use. Comparisons between patients who had semantic deficits of different severity, as well as the follow-up, showed that the ability to use objects was largely preserved when the deficit was mild but progressively decayed as the deficit became more severe. Naming was generally more impaired than object use. Production tasks (pantomime execution and actual object use) and comprehension tasks (pantomime recognition and action recognition) as well as functional knowledge about objects were impaired when the semantic deficit was severe. Semantic and unrelated errors were produced during object use, but actions were always fluent and patients performed normally on a novel tools task in which the semantic demand was minimal. Patients with severe semantic deficits scored borderline on ideational apraxia tasks. Our data indicate that functional semantic knowledge is crucial for using objects in a conventional way and suggest that non-semantic factors, mainly non-declarative components of memory, might compensate to some extent for semantic disorders and guarantee some residual ability to use very common objects independently of semantic knowledge.

Associative agnosias are traditionally regarded as perceptual, and ideational apraxia as motor, deficits, but they can be understood as amnesias for generic knowledge, caused by bilateral or unilateral left-hemispheric cortical lesions. Current theories of hemispheric specialization explain these syndromes' mandatory link with left-hemispheric damage, and are validated by this link. This link reflects the multiple nature of generic, categorical representational systems, not all reducible to natural language, and the left hemisphere's principal role as their substrate, regardless of their dependence on language. The distinction between processing novel information, and processing based on well-established, routinized representations, captures a fundamental difference between the functions of the right and left hemispheres. The complementary link of apperceptive agnosias with right-and associative agnosias with left-hemisphere lesions is an expression of this general principle in the posterior cortex. Future studies of the neuroanatomy of agnosias in animals may offer insights into the evolutionary continuities of hemispheric specialization.

The purpose of this study was to devise quantitative methods for the assessment of praxic skills of the upper limbs by developing a computerised task which permits each component of a sequence of actions to be timed precisely. Furthermore, two versions of such a quantitative measure were developed to investigate the relationship between meaningful and meaningless movements. The praxic skills of 35 patients with Alzheimer's disease (AD) and 75 healthy controls were assessed on two 3-item sequential movement tasks involving either meaningful or meaningless actions. A qualitative rating scale assessment of gesture imitation and pantomime was also administered. AD patients were significantly slower than controls on both the sequential movement tasks. Indeed, the correlation between AD patients' abilities on the novel and traditional tasks provided evidence that the sequential movement tasks constitute valid measures of praxis. Within the AD population, disease severity was also found to have a minimal and inconsistent influence upon praxis. The apraxia assessment results are considered in relation to the debate over whether apraxia constitutes an early or late feature of AD, and also to theoretical claims about the cognitive neuropsychological deficit underlying ideational apraxia.