Diagnosis and treatment of upper limb apraxia

Authors: A Dovern G R Fink P H Weiss

Publish Date: 2012/01/04

Volume: 259, Issue: 7, Pages: 1269-1283

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Abstract

Upper limb apraxia a disorder of higher motor cognition is a common consequence of lefthemispheric stroke Contrary to common assumption apraxic deficits not only manifest themselves during clinical testing but also have delirious effects on the patients’ everyday life and rehabilitation Thus a reliable diagnosis and efficient treatment of upper limb apraxia is important to improve the patients’ prognosis after stroke Nevertheless to date upper limb apraxia is still an underdiagnosed and illtreated entity Based on a systematic literature search this review summarizes the current tools of diagnosis and treatment strategies for upper limb apraxia It furthermore provides clinicians with graded recommendations In particular a short screening test for apraxia and a more comprehensive diagnostic apraxia test for clinical use are recommended Although currently only a few randomized controlled studies investigate the efficacy of different apraxia treatments the gesture training suggested by Smania and colleagues can be recommended for the therapy of apraxia the effects of which were shown to extend to activities of daily living and to persist for at least 2 months after completion of the training This review aims at directing the reader’s attention to the ecological relevance of apraxia Moreover it provides clinicians with appropriate tools for the reliable diagnosis and effective treatment of apraxia Nevertheless this review also highlights the need for further research into how to improve diagnosis of apraxia based on neuropsychological models and to develop new therapeutic strategiesOne of the major causes for persistent handicaps and early unemployment in the Western civilization is stroke about half of the patients surviving a stroke do not fully recover from their stroke but rather suffer from persistent strokerelated sequela 7 Besides primary sensorymotor deficits eg paresis deafferentation a stroke is often accompanied by persistent cognitive deficits one common cognitive deficit after left hemispheric stroke is apraxia 74 a disorder of higher motor cognition Apraxic impairments are classified as higher motor deficits since they cannot be fully accounted for by primary sensory and motor deficits disturbed communication or lack of motivation The current article focuses on upper limb apraxia ie deficits when carrying out purposeful movements with the arms and/or hands Frequently observed clinical symptoms of upper limb apraxia are impairments in imitating abstract and symbolic gestures deficits in pantomiming the use of objects and tools as well as deficits in actual object use in particular when complex sequential actions including multiple objects are required Note that we purposely refrain from using terms like ideomotor apraxia or ideational apraxia as the different apraxia classifications are currently under debate 31 32 Instead we describe the various clinical motor deficits of the patients impaired gesture imitation pantomiming and object use so that the reader can classify the apraxic patients to her/his favored classification schemeContrary to a widely held notion apraxic deficits not only manifest themselves during clinical testing but also have delirious effects on the patients’ everyday lives and rehabilitation As some of the neuropsychological tests used for the diagnosis of apraxia eg pantomiming the use of objects and tools seem to have no direct bearing on the actual affordances of daily life apraxia is often considered to have little impact on the patients’ everyday lives However McDonald et al 48 reported that apraxic patients make similar errors when actually using objects as compared to pantomiming the use of these objects to verbal command We are aware that exclusion of bodypartasobject BPO errors constitutes a limitation of this study and that other studies showed that the kinematics of pantomimed and actual objectrelated actions may differ considerably eg 41 However we would like to stress the fact that apraxic patients ‘diagnosed’ by their errors in pantomime tasks also make errors when actually using objects and hence deficits in pantomime performance should not be considered irrelevant for activities of daily living Moreover gesture deficits are also of practical significance for the apraxic patient gesture deficits compromise the patient’s communication as they can no longer be used to compensate for the often concomitant aphasic deficits For example apraxia has a negative impact on the quality of communicative gestures 25 and patients affected by apraxia rarely use spontaneous communicative gestures in the natural setting 8 Furthermore several studies directly demonstrated the ecological relevance of apraxia by showing that clinical measures of apraxia correlated significantly with the patients’ ability to perform several activities of daily living ADLs including mealtime behavior 26 bathing toileting and grooming 40 as well as dressing and brushing one’s teeth 35 Consistently apraxia significantly impacts upon neurorehabilitation with respect to several ADLs the severity of apraxia determined the dependency of stroke patients on their caregivers after discharge from the rehabilitation clinic 6 29 63 Likewise stroke patients suffering from apraxia less frequently return to work than stroke patients without apraxia 59 It is important to note that nearly all studies dealing with the ecological relevance of apraxia used apraxia measures including both meaningful and meaningless items ie measures that assess apraxic impairments of the semantic as well as the structural processing route see below Although these studies do not provide any insight into which apraxic deficits and hence which apraxia tests predict performance of which specific aspects of everyday life they clearly demonstrate that apraxia has a more pronounced clinical relevance than is commonly assumed Thus the diagnosis of and effective treatment strategies for apraxia are of great clinical importance With respect to the latter issue only a few studies with an adequate study design and a sufficiently large patient sample have been published Nevertheless these studies indicate that a successful treatment of upper limb apraxia is feasible Existing treatment options for apraxia in turn trigger the clinical need to correctly identify patients suffering from apraxia so that the patients can undergo adequate neurorehabilitation programs accounting for apraxia Thus reliable and valid clinical tests for the diagnosis of apraxia are required To date apraxia is underdiagnosed and the diagnosis of apraxia is often based on the qualitative not quantitative judgment of apraxia experts However such an approach cannot provide us with quantifiable data eg test scores and cutoffs which are especially essential when clinicians and researchers plan to undertake clinical studies in apraxia Moreover quantitative assessments with good psychometric properties taking into account the different apraxic symptoms would also allow to resolve the question of which specific apraxic deficits would predict performance of which specific aspects of everyday life Although numerous neuropsychological tests for the diagnosis of apraxia have been published only a few of these assessments can be considered appropriate for clinical use For many of these no psychometric characteristics are available 2 16 17 30 39 43 45 49 Furthermore many assessments do not account for the different aspects of apraxia but focus on only a single apraxic deficit eg disturbed imitation or impaired object use 16 19 24 30 52 53 57 Finally some test batteries are very timeconsuming which seriously limits their applicability in everyday clinical routines 1 4 24 46 50 60 These important limitations are likely to contribute to the fact that none of these todate published assessments have become widely accepted as a standard tool for the assessment of upper limb apraxia The heterogeneity of tools and their limitations also probably account for the variable prevalence rates of apraxia that have been reported in patients with lefthemisphere stroke ranging from 28 20 to 54 42 As many of the tests merely examine single aspects of apraxia it might occur that a given patient may be considered apraxic according to a test that only assesses meaningless gestures but shows no signs of apraxia in another test that assesses the ability to perform meaningful gestures 34With this review we would like to raise the interest of both clinicians and neuroscientists for the syndrome of upper limb apraxia and its clinical relevance The aim of the current review is to provide an overview on the published tests developed for the diagnosis of limb apraxia This shall help the reader to select a diagnostic tool appropriate for his/her own needs eg short screening clinical diagnosis scientific study In the second part of the review different approaches for the treatment of upper limb apraxia will be presented and critically evaluated Here the focus is on therapeutic interventions that have been examined in randomized controlled trials RCTs and thus can be recommended based on strong evidencebased criteria Note that we do not restrict our review to these evidencebased therapies for apraxia but also describe further published therapeutic approaches 10 as these might have implications for the development of new therapeutic strategies for upper limb apraxia 72During the last four decades more than 20 assessments for upper limb apraxia have been published While some of the assessments were developed as a diagnostic tool within the clinical setting other assessments were primarily developed for scientific purposes One reason for the high number of different assessments is that apraxia is a very heterogeneous syndrome and many assessments capture merely single aspects of apraxia eg either imitation of gestures or object use that can be affected differentially 3 34 52 55 58 This especially applies to assessments primarily developed for research purposes which are often focused on the specific apraxic impairment under investigation In contrast apraxia assessments used for the daily clinical routine need to provide a high diagnostic sensitivity which can usually only be achieved when many apraxic symptoms are concurrently assessed Taking into account that apraxia is often accompanied by aphasia 17 44 tests for clinical application should focus on test items that use objects or gestures rather than language as the trigger for actions because in patients with comorbid aphasia it is difficult to differentiate whether the motor deficits observed after verbal instructions are primarily due to the apraxic or aphasic eg reduced language comprehension impairment Moreover a tool used in a clinical environment to test for upper limb apraxia often necessitates a quick and easy application and should hence require as few test items as possible Finally it is important that the psychometric properties of clinical apraxia tests are available with reliable cutoff valuesLines highlighted in dark grey indicate apraxia tests that are described in more detail in the text as these tests fulfill our predefined selection criteria ie provide cutoff scores and assess both the structural and the semantic processing routeExamined patient populations according to the categorization by the authors LHD left hemisphere damage RHD right hemisphere damage HC healthy controls TBI traumatic brain injury AD Alzheimer’s disease NDD neurodegenerative diseases eg Alzheimer’s disease Parkinson’s disease etc

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