IDEATIONAL APRAXIA AND NATURALISTIC ACTION

The impact of visual and motor skills on ideational apraxia and transcortical sensory aphasia

BACKGROUND

Patients with extensive left hemisphere damage frequently have ideational apraxia (IA) and transcortical sensory aphasia (TSA). Difficulty with action coordination, phonological processing, and complex motor planning may not be indicative of higher-order motor programming or higher-order complex formation. We report on the effects of IA and TSA on the visual and motor skill of stroke patients.

PURPOSE

The study aims to address the question of whether IA and TSA in bilingual individuals are the results of an error of motor function alone or due to a combined motor plus and cognitive dysfunction effect.

METHOD

Twelve bilingual patients (seven males, and five females) were diagnosed with IA and TSA, and are divided into two groups of six patients. Then, 12 healthy bilingual controls were evaluated for comparing with both groups. Bilingual aphasia testing (BAT) and appropriate behavioral evaluation were used to assess motor skills, including coordination, visual-motor testing, and phonological processing.

RESULTS

Findings (pointing skills) show that the performance of the L1 and L2 languages are consistently significant (p < 0.001) in healthy individuals compared to the IA and TSA groups. Command skills for L1 and L2 languages were significantly higher in healthy individuals compared to IA and TSA controls (p < 0.001). Further, the orthographic skills of IA and TSA vs controls in both groups were significantly reduced (p < 0.01). Visual skills in the L1 language were significantly improved (p < 0.05) in IA and TSA patients compared to healthy controls after 2 months. Unlike orthographic skills which were improved in IA and TSA patients, languages in bilingual patients did not simultaneously improve.

CONCLUSION

Dyspraxia is a condition that affects both motor and visual cognitive functions, and patients who have it often have less referred motor skills. The current dataset shows that accurate visual cognition requires both cognitive-linguistic and sensory-motor processes. Motor issues should be highlighted, and skills and functionality should be reinforced along with the significance of treatment between IA and TSA corresponding to age and education. This can be a good indicator for treating semantic disorders.

Kinematic analysis of activities of daily living performance in frail elderly

Background

Frailty is accompanied by limitations of activities of daily living (ADL) and frequently associated with reduced quality of life, institutionalization, and higher health care costs. Despite the importance of ADL performance for the consequence of frailty, movement analyses based on kinematic markers during the performance of complex upper extremity-based manual ADL tasks in frail elderly is still pending.

The main objective of this study was to evaluate if ADL task performance of two different tasks in frail elderlies can be assessed by an activity measurement based on an acceleration sensor integrated into a smartwatch, and further to what degree kinematic parameters would be task independent.

Methods

ADL data was obtained from twenty-seven elderly participants (mean age 81.6 ± 7.0 years) who performed two ADL tasks. Acceleration data of the dominant hand was collected using a smartwatch. Participants were split up in three groups, F (frail, n = 6), P (pre-frail, n = 13) and R (robust, n = 8) according to a frailty screening. A variety of kinematic measures were calculated from the vector product reflecting activity, agility, smoothness, energy, and intensity.

Results

Measures of agility, smoothness, and intensity revealed significant differences between the groups (effect sizes combined over tasks η²_p = 0.18 – 0.26). Smoothness was particularly affected by frailty in the tea making task, while activity, agility, a different smoothness parameter and two intensity measures were related to frailty in the gardening task. Four of nine parameters revealed good reliability over both tasks (r = 0.44 – 0.69). Multiple linear regression for the data combined across tasks showed that only the variability of the magnitude of acceleration peaks (agility) contributed to the prediction of the frailty score (R² = 0.25).

Conclusion

The results demonstrate that ADL task performance can be assessed by smartwatch-based measures and further shows task-independent differences between the three levels of frailty. From the pattern of impaired and preserved performance parameters across the tested tasks, we concluded that in persons with frailty ADL performance was more impaired by physiological deficiencies, i.e., physical power and endurance, than by cognitive functioning or sensorimotor control.

The goal-control model: An integrated neuropsychological framework to explain impaired performance of everyday activities

OBJECTIVE

This review describes the relatively small body of neuropsychological and cognitive research conducted over the past 100 years focused on theoretical models explaining the neurocognitive processes that support everyday functioning and the breakdown of functional abilities in the face of neurological damage or disease.

METHOD

The historical roots of the theories of everyday activities based on direct observation of behavior in neurology and diary reports of everyday errors in cognitive psychology are presented, followed by a review of the empirical findings and resulting theoretical conceptualizations from case studies and group studies of various clinical populations in neuropsychology.

RESULTS

We conclude with a new framework (the goal-control model) that integrates the most recent empirical findings in neuropsychology with mechanisms proposed by cognitive models.

CONCLUSIONS

The goal-control model offers empirically supported solutions to understanding and predicting functioning in the real world. This new model generates testable predictions for future research and provides guidance for clinical assessment and interventions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

On Simulating Neural Damage in Connectionist Networks

A key strength of connectionist modelling is its ability to simulate both intact cognition and the behavioural effects of neural damage. We survey the literature, showing that models have been damaged in a variety of ways, e.g. by removing connections, by adding noise to connection weights, by scaling weights, by removing units and by adding noise to unit activations. While these different implementations of damage have often been assumed to be behaviourally equivalent, some theorists have made aetiological claims that rest on nonequivalence. They suggest that related deficits with different aetiologies might be accounted for by different forms of damage within a single model. We present two case studies that explore the effects of different forms of damage in two influential connectionist models, each of which has been applied to explain neuropsychological deficits. Our results indicate that the effect of simulated damage can indeed be sensitive to the way in which damage is implemented, particularly when the environment comprises subsets of items that differ in their statistical properties, but such effects are sensitive to relatively subtle aspects of the model's training environment. We argue that, as a consequence, substantial methodological care is required if aetiological claims about simulated neural damage are to be justified, and conclude more generally that implementation assumptions, including those concerning simulated damage, must be fully explored when evaluating models of neurological deficits, both to avoid over-extending the explanatory power of specific implementations and to ensure that reported results are replicable.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (10.1007/s42113-020-00081-z) contains supplementary material, which is available to authorized users.

Heterogeneity of Informant-Reported Functional Performance in Mild Cognitive Impairment: A Latent Profile Analysis of the Functional Activities Questionnaire

Heterogeneity of subtle functional difficulties in mild cognitive impairment (MCI) remains poorly understood. We characterized patterns of informant reports of functional abilities among participants with MCI and the relation between functional ability pattern and cognitive abilities and subsequent decline. Data from 4,273 MCI participants from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set (UDS) were included in latent profile analyses (LPA) of informant responses on the Functional Activities Questionnaire (FAQ). Profiles from the best fitting model were compared on demographic, clinical, and cognitive variables. The best fitting model supported three profiles varying by level and type of difficulty: intact function (n = 3,299), intermediate (n = 769), and high ratings of difficulty (n = 205). For the Intermediate profile, items related to finances, remembering dates, and travel were rated as most difficult. The High Ratings profile also had elevated ratings on the meal preparation item. Participants with either the Intermediate or High Ratings profile demonstrated a three-fold increase in conversion to dementia as compared to participants with the Intact profile. Demographically, the Intact profile was younger and consisted of a higher proportion of minorities. On cognitive tests, the Intact profile showed the best performance, and the Intermediate profile performed comparably to or better than the High Ratings profile. There is meaningful heterogeneity in informant ratings of function in MCI, though individuals with MCI whose informants report even intermediate-level functional difficulties are more likely to progress to dementia, suggesting that even subtle functional difficulties place individuals at higher risk for future decline.

Smoothness Metrics in Complex Movement Tasks

Smoothness is a main characteristic of goal-directed human movements. The suitability of approaches quantifying movement smoothness is dependent on the analyzed signal's structure. Recently, activities of daily living (ADL) received strong interest in research on aging and neurorehabilitation. Such tasks have complex signal structures and kinematic parameters need to be adapted. In the present study we examined four different approaches to quantify movement smoothness in ADL. We tested the appropriateness of these approaches, namely the number of velocity peaks per meter (NoP), the spectral arc length (SAL), the speed metric (SM) and the log dimensionless jerk (LDJ), by comparing movement signals from eight healthy elderly (67.1a ± 7.1a) with eight healthy young (26.9a ± 2.1a) participants performing an activity of daily living (making a cup of tea). All approaches were able to identify group differences in smoothness (Cohen's d NoP = 2.53, SAL = 1.95, SM = 1.69, LDJ = 4.19), three revealed high to very high sensitivity (z-scores: NoP = 1.96 ± 0.55, SAL = 1.60 ± 0.64, SM = 3.41 ± 3.03, LDJ = 5.28 ± 1.52), three showed low within-group variance (NoP = 0.72, SAL = 0.60, SM = 0.11, LDJ = 0.71), two showed strong correlations between the first and the second half of the task execution (intra-trial R2s: NoP = 0.22 n.s., SAL = 0.33, SM = 0.36, LDJ = 0.91), and one was independent of other kinematic parameters (SM), while three showed strong models of multiple linear regression (R2s: NoP = 0.61, SAL = 0.48, LDJ = 0.70). Based on our results we make suggestion toward use examined smoothness measures. In total the log dimensionless jerk proved to be the most appropriate in ADL, as long as trial durations are controlled.

Evolution of Cognitive Rehabilitation After Stroke From Traditional Techniques to Smart and Personalized Home-Based Information and Communication Technology Systems: Literature Review

Background

Neurological patients after stroke usually present cognitive deficits that cause dependencies in their daily living. These deficits mainly affect the performance of some of their daily activities. For that reason, stroke patients need long-term processes for their cognitive rehabilitation. Considering that classical techniques are focused on acting as guides and are dependent on help from therapists, significant efforts are being made to improve current methodologies and to use eHealth and Web-based architectures to implement information and communication technology (ICT) systems that achieve reliable, personalized, and home-based platforms to increase efficiency and level of attractiveness for patients and carers.

Objective

The goal of this work was to provide an overview of the practices implemented for the assessment of stroke patients and cognitive rehabilitation. This study puts together traditional methods and the most recent personalized platforms based on ICT technologies and Internet of Things.

Methods

A literature review has been distributed to a multidisciplinary team of researchers from engineering, psychology, and sport science fields. The systematic review has been focused on published scientific research, other European projects, and the most current innovative large-scale initiatives in the area. A total of 3469 results were retrieved from Web of Science, 284 studies from Journal of Medical Internet Research, and 15 European research projects from Community Research and Development Information Service from the last 15 years were reviewed for classification and selection regarding their relevance.

Results

A total of 7 relevant studies on the screening of stroke patients have been presented with 6 additional methods for the analysis of kinematics and 9 studies on the execution of goal-oriented activities. Meanwhile, the classical methods to provide cognitive rehabilitation have been classified in the 5 main techniques implemented. Finally, the review has been finalized with the selection of 8 different ICT–based approaches found in scientific-technical studies, 9 European projects funded by the European Commission that offer eHealth architectures, and other large-scale activities such as smart houses and the initiative City4Age.

Conclusions

Stroke is one of the main causes that most negatively affect countries in the socioeconomic aspect. The design of new ICT-based systems should provide 4 main features for an efficient and personalized cognitive rehabilitation: support in the execution of complex daily tasks, automatic error detection, home-based performance, and accessibility. Only 33% of the European projects presented fulfilled those requirements at the same time. For this reason, current and future large-scale initiatives focused on eHealth and smart environments should try to solve this situation by providing more complete and sophisticated platforms.

Limb apraxia and the left parietal lobe

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.

Positive and Negative Consequences of Making Coffee among Breakfast Related Irrelevant Objects: Evidence from MCI, Dementia, and Healthy Ageing

OBJECTIVES

Previous studies have reported impairments in activities of daily living (ADL) performance in the presence of irrelevant but physically/functionally related objects in dementia patients. The aim of the present study was to increase our knowledge about the impact of the presence of contextually related non-target objects on ADL execution in patients with multi-domain mild cognitive impairment (MCI) and dementia.

METHODS

We compared ADL execution in patients with MCI, dementia, and healthy elderly participants under two experimental conditions: One in which the target objects were embedded with contextually related non-target items that constituted the object set necessary to complete two additional (but unrequired) ADL tasks related to the target task, and a second, control condition where target objects were surrounded by isolated objects (they never constituted a whole set needed to complete an alternative ADL task).

RESULTS

Separate analysis of ADL errors associated with the target task versus errors involving the non-target objects revealed that, although the presence of contextually related objects facilitated the accomplishment of the target task, such a condition also led to errors involving the use of irrelevant objects in dementia and MCI.

CONCLUSIONS

The presence of contextually related non-target items produces both positive and negative effects on ADL performance. These types of non-target objects might help to cue the retrieval of the action schema related to the target task, particularly in patients with MCI. In contrast, the presence of these objects might also lead to distraction in dementia and MCI. (JINS, 2017, 23, 481-492).

Treatments and technologies in the rehabilitation of apraxia and action disorganisation syndrome: A review

BACKGROUND: Apraxia and Action Disorganisation Syndrome are characterised by an inability to use tools and carry out ordered sequences of movements in the absence of motor or sensory impairment. To date treatment for these complex but debilitating conditions has received little attention.

OBJECTIVES: To provide an overview of apraxia and action disorganisation syndrome and its treatment, providing a state of the art summary for practitioners including likely future therapeutic directions.

METHOD: Review of apraxia literature and treatment studies collated from internet searches involving MEDLINE, PubMed, PyscINFO and Google Scholar as well as the author’s own catalogue.

RESULTS: Evidence for current restitution and compensatory approaches is critically reviewed, with limited evidence to date in support of either method. Strategy training is the most promising intervention type with no support for sensory and exploratory interventions, practice effects only for direct task-specific training, and modest support for gestural training.

CONCLUSIONS: Larger controlled studies are needed but evidence is sufficient to indicate certain approaches over others. Advances in assistive technology have not translated into mainstream therapy but future interventions are likely to require a model-based approach which embraces current technologies in order to provide a more accessible, effective and cost-efficient approach to rehabilitation.

Early diagnosis of mild cognitive impairment and mild dementia through basic and instrumental activities of daily living: Development of a new evaluation tool

BACKGROUND

Assessment of activities of daily living (ADL) is paramount to determine impairment in everyday functioning and to ensure accurate early diagnosis of neurocognitive disorders. Unfortunately, most common ADL tools are limited in their use in a diagnostic process. This study developed a new evaluation by adopting the items of the Katz Index (basic [b-] ADL) and Lawton Scale (instrumental [i-] ADL), defining them with the terminology of the International Classification of Human Functioning, Disability and Health (ICF), adding the scoring system of the ICF, and adding the possibility to identify underlying causes of limitations in ADL.

METHODS AND FINDINGS

The construct validity, interrater reliability, and discriminative validity of this new evaluation were determined. From 2015 until 2016, older persons (65-93 y) with normal cognitive ageing (healthy comparison [HC]) (n = 79), mild cognitive impairment (MCI) (n = 73), and Alzheimer disease (AD) (n = 71) underwent a diagnostic procedure for neurocognitive disorders at the geriatric day hospital of the Universitair Ziekenhuis Brussel (Brussels, Belgium). Additionally, the ICF-based evaluation for b- and i-ADL was carried out. A global disability index (DI), a cognitive DI (CDI), and a physical DI (PDI) were calculated. The i-ADL-CDI showed high accuracy and higher discriminative power than the Lawton Scale in differentiating HC and MCI (area under the curve [AUC] = 0.895, 95% CI .840-.950, p = .002), MCI and AD (AUC = 0.805, 95% CI .805-.734, p = .010), and HC and AD (AUC = 0.990, 95% CI .978-1.000, p < .001). The b-ADL-DI showed significantly better discriminative accuracy than the Katz Index in differentiating HC and AD (AUC = 0.828, 95% CI .759-.897, p = .039). This study was conducted in a clinically relevant sample. However, heterogeneity between HC, MCI, and AD and the use of different methods of reporting ADL might limit this study.

CONCLUSIONS

This evaluation of b- and i-ADL can contribute to the diagnostic differentiation between cognitively healthy ageing and neurocognitive disorders in older age. This evaluation provides more clarity and nuance in assessing everyday functioning by using an ICF-based terminology and scoring system. Also, the possibility to take underlying causes of limitations into account seems to be valuable since it is crucial to determine the extent to which cognitive decline is responsible for functional impairment in diagnosing neurocognitive disorders. Though further prospective validation is still required, the i-ADL-CDI might be useful in clinical practice since it identifies impairment in i-ADL exclusively because of cognitive limitations.

Effects of Stroke on Ipsilesional End-Effector Kinematics in a Multi-Step Activity of Daily Living

Background: Stroke frequently impairs activities of daily living (ADL) and deteriorates the function of the contra- as well as the ipsilesional limbs. In order to analyze alterations of higher motor control unaffected by paresis or sensory loss, the kinematics of ipsilesional upper limb movements in patients with stroke has previously been analyzed during prehensile movements and simple tool use actions. By contrast, motion recording of multi-step ADL is rare and patient-control comparisons for movement kinematics are largely lacking. Especially in clinical research, objective quantification of complex externally valid tasks can improve the assessment of neurological impairments. Methods: In this preliminary study we employed three-dimensional motion recording and applied kinematic analysis in a multi-step ADL (tea-making). The trials were examined with respect to errors and sub-action structure, durations, path lengths (PLs), peak velocities, relative activity (RA) and smoothness. In order to check for specific burdens the sub-actions of the task were extracted and compared. To examine the feasibility of the approach, we determined the behavioral and kinematic metrics of the (ipsilesional) unimanual performance of seven chronic stroke patients (64a ± 11a, 3 with right/4 with left brain damage (LBD), 2 with signs of apraxia, variable severity of paresis) and compared the results with data of 14 neurologically healthy age-matched control participants (70a ± 7a). Results: T-tests revealed that while the quantity and structure of sub-actions of the task were similar. The analysis of end-effector kinematics was able to detect clear group differences in the associated parameters. Specifically, trial duration (TD) was increased (Cohen's d = 1.77); the RA (Cohen's d = 1.72) and the parameters of peak velocities (Cohen's d = 1.49/1.97) were decreased in the patient group. Analysis of the task's sub-actions repeated measures analysis of variance (rmANOVA) revealed no impact of the different demands of the sub-actions on the relative performance of the patient group. Conclusion: The analyses revealed kinematic peculiarities in the performance with the ipsilesional hand. These deficits apparently arose from the cognitive demands like sequencing rather than motor constraints. End-effector kinematics proved as a sensitive method to detect and quantify aspects of disturbed multi-step ADL performance after stroke. If standardized, the examination and the analysis are quick and deliver objective data supporting clinical research.

How do assessments of activities of daily living address executive functions: A scoping review

Executive functions (EF) allow persons to adapt to situations arising in daily life and can be affected following acquired brain injury (ABI). Measuring the impact of EF impairments on the accomplishment of activities of daily living (ADL) requires specific assessment tools, but choosing the right tool may be difficult.

PURPOSE

To conduct a scoping review on how assessments of ADL address EF and EF impairments in persons with ABI.

METHOD

A scoping review of literature (peer-reviewed and grey literature) published until August 2014 was conducted. Using a systematic procedure, literature was selected, results were charted, and tools were analysed with respect to their goals, underlying models, psychometric properties and applicability. The analysis also included how tools considered components of EF according to Lezak's model.

RESULTS

12 tools, developed either to assess EF in ADL, independence in ADL considering EF or ADL capacities, were identified and analysed according to multiple criteria.

CONCLUSIONS

This review provides important information about existing tools to assist in tool selection and clinical decision-making related to ABI and EF.

Forward Prediction in the Posterior Parietal Cortex and Dynamic Brain-Machine Interface

While remarkable progress has been made in brain-machine interfaces (BMIs) over the past two decades, it is still difficult to utilize neural signals to drive artificial actuators to produce predictive movements in response to dynamic stimuli. In contrast to naturalistic limb movements largely based on forward planning, brain-controlled neuroprosthetics mainly rely on feedback without prior trajectory formation. As an important sensorimotor interface integrating multisensory inputs and efference copy, the posterior parietal cortex (PPC) might play a proactive role in predictive motor control. Here it is proposed that predictive neural activity in PPC could be decoded to provide prosthetic control signals for guiding BMI systems in dynamic environments.

The complexity of the relationship between neuropsychological deficits and impairment in everyday tasks after stroke

BACKGROUND AND PURPOSE

A large body of research reports that stroke patients are debilitated in terms of daily independence after dismissal from the hospital unit. Patients struggle with the use of daily objects or performing complex actions. Differences between individual deficits of patients are often associated with the site of the brain damage. However, clinical studies suggest that patients exhibit varied constellations of action-associated difficulties and neuropsychological deficits. There is a lack of conclusive evidence indicating how different neuropsychological symptoms link to the impaired ability to perform activities of daily living (ADL).

MATERIALS AND METHODS

To further address this matter, in this study we compared the behavior of patients with left brain damage (LBD) and right brain damage (RBD) following stroke in two naturalistic task scenarios (tea making and document filing), and compared the committed action errors to the neuropsychological screening results.

RESULTS

We observed mild to severe impairments in both the LBD and RBD groups amounting to 37-55% of failure rate in attainment of action goal. Interestingly, the performance on both tasks was not correlated to each other, suggesting that the tasks involved a different set of higher cognitive functions. Despite similar behavioral manifestations, in the LBD group poor task performance was related to deficits in praxis performance and unilateral tactile and visual extinction. The presence of aphasia did not correlate with task performance, except for a link between low scores in Aachen aphasia test scales and misestimation error in the tea making task. In the RBD group, difficulties with performance were primarily linked to deficit in praxis and unilateral visual extinction.

CONCLUSIONS

Despite similar behavior, the underlying mechanisms of the deficits after stroke might be different (in patients with LBD and RBD) and reveal complex interlinks of cognitive networks involved in the ability to carry on everyday tasks.

Patient Mood and Instrumental Activities of Daily Living in Alzheimer Disease: Relationship Between Patient and Caregiver Reports

This retrospective study investigated the relationship between self-reports and caregiver perceptions of patients' depressive symptoms and the respective ability of these reports to predict instrumental activities of daily living (IADLs) beyond what is accounted for by cognitive abilities in 71 patients with mild Alzheimer disease. Patients completed the Geriatric Depression Scale-Short Form, and caregivers completed the Behavior Rating Scale for Dementia assessing their perception of patients' depressive symptoms. Caregivers also completed IADL items from the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory. Cognitive measures included the Mini-Mental State Examination, Logical Memory from the Wechsler Memory Scale III, and Trail Making Test, Part B. The relationship between self-reported depressive symptoms and caregiver report of patients' depressive symptoms showed a trend toward significance (r = .22, P = .06). Measures of depressive symptoms significantly predicted 12.5% of the variance in IADLs performance, beyond that accounted for by patient demographics and cognitive functioning. Interestingly, patients' reports, rather than caregivers', were particularly useful in this prediction.

From Intention to Action: Hierarchical Sensorimotor Transformation in the Posterior Parietal Cortex(12)

While there is a large body of evidence in favor of a clustering of representations of body effectors in the posterior parietal cortex, recent advances have revealed a hierarchical organization beyond a flat intentional map composed of functionally distinct subdivisions operating in parallel at same level. In particular, the parietal reach region (PRR) and dorsal area 5 (area 5d) have been found to play distinct roles in visually-guided reach.

Cover Figure

The application of SHERPA (Systematic Human Error Reduction and Prediction Approach) in the development of compensatory cognitive rehabilitation strategies for stroke patients with left and right brain damage

Approximately 33% of stroke patients have difficulty performing activities of daily living, often committing errors during the planning and execution of such activities. The objective of this study was to evaluate the ability of the human error identification (HEI) technique SHERPA (Systematic Human Error Reduction and Prediction Approach) to predict errors during the performance of daily activities in stroke patients with left and right hemisphere lesions. Using SHERPA we successfully predicted 36 of the 38 observed errors, with analysis indicating that the proportion of predicted and observed errors was similar for all sub-tasks and severity levels. HEI results were used to develop compensatory cognitive strategies that clinicians could employ to reduce or prevent errors from occurring. This study provides evidence for the reliability and validity of SHERPA in the design of cognitive rehabilitation strategies in stroke populations.

Commissions and omissions are dissociable aspects of everyday action impairment in schizophrenia

Prior research using performance-based assessment of functional impairment has informed a novel neuropsychological model of everyday action impairment in dementia in which omission errors (i.e., failure to complete task steps) dissociate from commission errors (i.e., inaccurate performance of task steps) and have unique neuropsychological correlates. However, this model has not been tested in other populations. The present study examined whether this model extends to schizophrenia. Fifty-four individuals with schizophrenia or schizoaffective disorder were administered a neuropsychological protocol and the Naturalistic Action Test (NAT), a performance-based measure of everyday action. A principal component analysis (PCA) was performed to examine the construct(s) comprising everyday action impairment, and correlations between the resultant component(s) and neuropsychological tests were examined. Results showed that omissions and a subset of commissions were distinct components of everyday action. However, results did not support unique associations between these components and specific neuropsychological measures. These findings extend the omission-commission model to schizophrenia and may have important implications for efficient assessment and effective rehabilitation of functional impairment, such as the potential efficacy of targeted interventions for the rehabilitation of omission and commission deficits in everyday functioning. Larger studies with prospective designs are needed to replicate the present preliminary findings.

The tool in the brain: apraxia in ADL. Behavioral and neurological correlates of apraxia in daily living

Humans differ from other animals in the way they can skilfully and precisely operate or invent tools to facilitate their everyday life. Tools have dominated our home, travel and work environment, becoming an integral step for our motor skills development. What happens when the part of the brain responsible for tool use is damaged in our adult life due to a cerebrovascular accident? How does daily life change when we lose the previously mastered ability to make use of the objects around us? How do patients suffering from compromised tool use cope with food preparation, personal hygiene, grooming, housework, or use of home appliances? In this literature review we present a state of the art for single and multiple tool use research, with a focus on the impact that apraxia (impaired ability to perform tool-based actions) and action disorganization syndrome (ADS; impaired ability to carry out multi-step actions) have on activities of daily living (ADL). Firstly, we summarize the behavioral studies investigating the impact of apraxia and other comorbidity syndromes, such as neglect or visual extinction, on ADL. We discuss the hallmarks of the compromised tool use in terms of the sequencing of action steps, conceptual errors committed, spatial motor control, and temporal organization of the movement. In addition, we present an up-to-date overview of the neuroimaging and lesion analyses studies that provide an insight into neural correlates of tool use in the human brain and functional changes in the neural organization following a stroke, in the context of ADL. Finally we discuss the current practice in neurorehabilitation of ADL in apraxia and ADS aiming at increasing patients' independence.

Dorsal parietal area 5 encodes immediate reach in sequential arm movements

To generate a coherent action sequence, it is essential to integrate all component movements beforehand, and such sequence-related information has been observed in numerous brain regions. However, this high-level sequential plan encompassing multiple motor elements in parallel ultimately must be decomposed into serial motor commands to be executed by the musculoskeletal system. In the present study, we recorded single-neuron activity from dorsal parietal area 5 (area 5d) while monkeys performed a double-reach task, and found that area 5d conveys the immediate upcoming reach, but not the subsequent movement, as opposed to the entire movement sequence being encoded as in other cortical sensorimotor areas. The elementary movement coded in area 5d suggests that unfolding of the motor sequence begins in the parietal-frontal cortex, instead of being exclusively implemented by downstream subcortical and spinal circuits.

Neuroimaging correlates of everyday action in dementia

The everyday, functional impairments associated with dementia remain poorly understood from a neuropsychological perspective. This study investigated relations between brain structure volumes and two measures of everyday action-caregiver questionnaire and direct assessment-in 57 participants with dementia. Results showed that caregiver ratings reflecting more functional impairment were strongly associated with smaller volumes of deep white matter. Direct assessment of everyday task performance in a subsample revealed relations between unique neurological substrates and discrete everyday action error types. Findings emphasize differences in functional assessment methods and highlight the role of white matter in functional deficits in dementia.

Action perception predicts action performance

Everyday action impairments often are observed in demented older adults, and they are common potential barriers to functional independence. We evaluated whether the ability to segment and efficiently encode activities is related to the ability to execute activities. Further, we evaluated whether brain regions important for segmentation also were important for action performance. Cognitively healthy older adults and those with very mild or mild dementia of the Alzheimer's type watched and segmented movies of everyday activities and then completed the Naturalistic Action Test. Structural MRI was used to measure volume in the dorsolateral prefrontal cortex (DLPFC), medial temporal lobes (MTL), posterior cortex, and anterior cingulate cortex (ACC). Dementia status and the ability to segment everyday activities strongly predicted naturalistic action performance, and MTL volume largely accounted for this relationship. In addition, the current results supported the Omission-Commission Model: Different cognitive and neurological mechanisms predicted different types of action error. Segmentation, dementia severity, and MTL volume predicted everyday omission errors, DLPFC volume predicted commission errors, and ACC volume predicted action additions. These findings suggest that event segmentation may be critical for effective action production, and that the segmentation and production of activities may recruit the same event representation system.

Age-related changes in error monitoring of an everyday task

The process of checking in an everyday task to ensure error prevention/error correction, has not been systematically documented in relation to everyday action errors. This is surprising, given that studies of everyday task performance in people with dementia suggest poor error monitoring (error detection/correction). The present study documented age-related changes in errors and error monitoring behaviors, including the novel variable of checking (verbal/non-verbal gestures indicating active task monitoring), in an everyday task. In a 2 × 2 mixed-subjects design (n = 57), young and older adults performed a tea-making task under standard and dual-task conditions. Error rates were similar across age-groups and conditions. The dual-task condition reduced verbal checking and increased microslips (initiation and termination of an error before the error is completed) for both age-groups, when compared to the standard condition. In the standard condition, older adults engaged in more verbal checks than young adults, but this was not associated with improved task accuracy. Thus, both age-groups do engage in checking during an everyday task, but this checking had little impact on task accuracy. Consequently, checking may not be a necessary part of performance accuracy. Future studies should investigate whether enhanced awareness would make monitoring more effective.

Dissociations of action means and outcome processing in left-hemisphere stroke

Previous evidence suggests that distinct fronto-parietal regions may be involved in representing action kinematics (means) and action results (outcome) during action observation. However, the evidence is contradictory with respect to the precise regions that are critical for each type of representation. Additionally unknown is the degree to which ability to detect action means and outcome during observation is related to action production performance. We used a behavioral task to evaluate the ability of healthy and left-hemisphere stroke participants to detect differences between pairs of videos that dissociated object-related action means (e.g., wiping with circular or straight movement) and/or outcome (e.g., applying or removing detergent). We expected that deficits in detecting action means would be associated with spatiomotor gesture production deficits, whereas deficits in detecting action outcome would predict impairments in complex naturalistic action. We also hypothesized a posterior to anterior gradient in the regions critical for each type of representation, disproportionately affecting means and outcome encoding, respectively. Results indicated that outcome--but not means--detection predicted naturalistic action performance in stroke participants. Regression and voxel lesion-symptom mapping analyses of lesion data revealed that means--but not outcome--coding relies on the integrity of the left inferior parietal lobe, whereas no selective critical brain region could be identified for outcome detection. Thus, means and outcome representations are dissociable at both the behavioral and neuroanatomical levels. Furthermore, the data are consistent with a degree of parallelism between action perception and production tasks. Finally, they reinforce the evidence for a critical role of the left inferior parietal lobule in the representation of action means, whereas action outcome may rely on a more distributed neural circuit.

Cognitive profiles in Parkinson's disease and their relation to dementia: a data-driven approach

Parkinson's disease is characterized by a substantial cognitive heterogeneity, which is apparent in different profiles and levels of severity. To date, a distinct clinical profile for patients with a potential risk of developing dementia still has to be identified. We introduce a data-driven approach to detect different cognitive profiles and stages. Comprehensive neuropsychological data sets from a cohort of 121 Parkinson's disease patients with and without dementia were explored by a factor analysis to characterize different cognitive domains. Based on the factor scores that represent individual performance in each domain, hierarchical cluster analyses determined whether subgroups of Parkinson's disease patients show varying cognitive profiles. A six-factor solution accounting for 65.2% of total variance fitted best to our data and revealed high internal consistencies (Cronbach's alpha coefficients >0.6). The cluster analyses suggested two independent patient clusters with different cognitive profiles. They differed only in severity of cognitive impairment and self-reported limitation of activities of daily living function but not in motor performance, disease duration, or dopaminergic medication. Based on a data-driven approach, divers cognitive profiles were identified, which separated early and more advanced stages of cognitive impairment in Parkinson's disease without dementia. Importantly, these profiles were independent of motor progression.

The cognitive neuropsychology of everyday action and planning

Today's cognitive neuropsychology of everyday action had its inception in studies of ADS-action disorganisation syndrome-that were inspired by the Norman-Shallice theory of controlled and automatic action selection. It is now known that errors in everyday action and planning are commonplace with many types of brain damage, and that effects associated with gradations in severity, and with the presence of distractor objects, are surprisingly uniform across clinically diverse patient samples. The Norman-Shallice model of automatic action selection, having been implemented for two everyday tasks, has had some success in explaining these facts. This paper reviews the patient and modelling studies and discusses some unanswered questions and methodological challenges that confront future research in this area.

Everyday action impairment in Parkinson's disease dementia

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).

Cerebrovascular disease and cognition in older adults

The well-established association between advanced age, cerebrovascular pathology, and cognitive decline is receiving greater attention as the population attains new levels of longevity. This chapter will provide an overview of vascular anatomy and age-related cerebrovascular disorders and diseases, including stroke and degenerative dementia. The cognitive and functional sequellae of these cerebrovascular disorders will also be described in detail. Throughout this review, we will emphasize topics that have been relatively underrepresented in the literature, including age-related diseases of the cerebral small vessels, nuanced characterization of cognitive impairment associated with insidious small-vessel vascular dementia, and the real-life functional consequences of cerebrovascular changes in older adults.

Neurological principles and rehabilitation of action disorders: common clinical deficits

In this chapter, the authors use the computation, anatomy, and physiology (CAP) principles to consider the impact of common clinical problems on action. They focus on 3 major syndromes: paresis, apraxia, and ataxia. They also review mechanisms that could account for spontaneous recovery, using what is known about the best-studied clinical dysfunction--paresis--and also ataxia. Together, this and the previous chapter lay the groundwork for the third chapter in this series, which reviews the relevant rehabilitative interventions.

Performance-based everyday functioning after stroke: relationship with IADL questionnaire and neurocognitive performance

Neuropsychologists frequently are asked to comment on everyday functioning, but the research relies mostly on questionnaire-based assessment of daily functioning. While performance-based assessment of everyday functioning has many advantages over commonly used questionnaires, there are few empirically validated comprehensive performance-based measures. We present data here on a performance-based battery of daily living skills, the Functional Impact Assessment (FIA) in 47 unilateral stroke patients and 37 matched healthy controls. The FIA was validated by comparing it to performance on the self- and informant-report version of the Functional Activities Questionnaire (FAQ). We also examined the relationship between the FIA and cognitive functioning using the Neuropsychological Assessment Battery (NAB). The stroke group's performance on the FIA, FAQ (self and informant), and NAB (total and domain scores) was significantly (d's ≥ .80) lower than the control group. The NAB total score and all domain scores were highly correlated with the FIA in the stroke group (r's > .7), and only one NAB domain score (visuospatial) was a unique predictor. This may be due to the fact that most of the NAB domains have a statistical problem of multicollinearity, which may explain why only the spatial domain was a unique predictor. While the informant FAQ was significantly correlated with FIA total score (r = .48, p < .01), the NAB total score was a significantly better predictor (r = .83, p < .001) than the informant FAQ. NAB total scaled score of less than 86 predicted impairment on the FIA with 92% sensitivity and 84% specificity. Our findings argue that the FIA is sensitive to deficits associated with stroke and is highly associated with all neuropsychological domains (attention, executive functions, language and spatial skills, and memory).

Apraxia impairs intentional retrieval of incidentally acquired motor knowledge

Apraxia caused by left hemispheric stroke typically impairs skilled sequential movements. After stroke, apraxic patients need to reacquire motor skills by motor learning. The current study assessed for the first time incidental motor sequence learning in apraxic patients. Forty-eight human subjects (henceforth called "patients") with left hemispheric stroke affecting the middle cerebral artery territory (18 with apraxia and 30 without apraxia) and 17 age-matched healthy controls were tested on a visuomanual serial reaction time task. Subjects performed four blocks consisting of repetitions of a complex six element sequence containing ambiguous pairwise transitions before a new and unfamiliar sequence was introduced in block 5. Reaction time (RT) disadvantages in this fifth block indicated incidental sequence-specific motor learning. The intentional retrieval of the learned motor knowledge was assessed subsequently with a free recall task. Voxel-based lesion-symptom mapping (VLSM) was performed to investigate for the first time the lesion correlates of deficits in learning and retrieving sequential motor knowledge. Despite generally prolonged RTs, apraxic patients showed sequence-specific motor learning as could be observed in nonapraxic patients and healthy controls. However, apraxic patients showed reduced intentional retrieval of the learned sequence. VLSM revealed that impaired intentional retrieval of motor sequence knowledge resulted from dorsal premotor cortex lesions. Apraxic patients showed a dissociation of preserved incidental motor (sequence) learning and deficient intentional retrieval of this incidentally learned motor knowledge. The data suggest that novel approaches for treating apraxia should focus on incidental motor learning, but that automatic rather than intentional retrieval strategies should be enforced.

Meal preparation abilities after left or right hemisphere stroke

OBJECTIVE

To examine meal preparation ability after right or left hemisphere damage (RHD, LHD) caused by stroke and whether cognitive (spatial abilities, aphasia, limb apraxia) and motor deficits are differentially associated with meal preparation.

DESIGN

Observational cohort design.

SETTING

Primary care Veterans Affair Medical Center and private medical center.

PARTICIPANTS

Volunteer right-handed sample of adults with LHD (n=30) or RHD (n=16) caused by stroke and healthy demographically matched adults (n=63) (N=109).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Total completion time, number and type of errors, and level of independence for a meal preparation task consisting of making a hot beverage and toast, eating part of the meal, and clean-up.

RESULTS

Both stroke groups took significantly more time to complete the meal preparation task than the control group. Total errors and level of independence were worse in the group with LHD than other groups, but individual errors did not significantly differ between the 2 stroke groups. While correlations should be interpreted cautiously, especially in the relatively small RHD group, poorer ipsilesional motor performance was associated with longer completion time in the RHD group, and poorer contralesional motor performance and greater aphasia were associated with less independence in the LHD group.

CONCLUSIONS

These findings demonstrate impaired meal preparation after LHD or RHD but greater impairment after LHD. Poorer meal preparation is associated with different cognitive and motor deficits in the 2 stroke groups.

Script Generation Following Frontal and Parietal Lesions

The purpose of this investigation was to distinguish putative effects of parietal lobe lesions on script generation, in distinction from the better known and established effects of frontal lobe lesions. Nine patients, most with excised parietal lesions, were compared to nine age, gender and education matched normal participants. Eleven patients with excised tumors of the frontal lobe were compared to twelve age, gender and education matched normal subjects. Participants were requested to generate, out loud, scripts corresponding to everyday activities. Half the scripts were relatively more demanding with respect to temporal representation (understanding the time line of events) and the other half with respect to spatial representation (understanding the layout of the actions in space). These two conditions were further broken down into conditions of high and low demands on working memory (reciting the scripts backwards versus forward). The frontal lobe patients enunciated significantly fewer actions overall. They were also significantly more impaired than the normal participants on all tasks with high demands on working memory, and more often, high temporal demands (sequencing and perseverative errors). The parietal lobe patients had significant difficulty in sequencing in all conditions, and manifested no perseveration. Though script generation tasks have been primarily associated with frontal lobe function until now, consideration should be given to the type of activity being scripted as a function of relative demands on spatial or temporal representation, as well as working memory, and the contributions of other lobes ought to be taken into consideration.

The impact of goal cues on everyday action performance in dementia

Everyday action performance is impaired as a consequence of dementia. Omissions (i.e., not performing task steps) are a frequent source of error in everyday tasks among dementia patients. External cues or notes are often suggested to improve everyday functioning and might specifically address omission errors; however, the efficacy of such strategies has not been evaluated. Thus, the primary aim of this study was to assess the efficacy of goal cues (i.e., reminders of everyday task objectives) for improving dementia patients' everyday action performance. Forty-four participants with mild to moderate dementia were administered the Naturalistic Action Test (NAT), a performance-based test that includes three everyday tasks. After participants indicated that they had completed each task, they were presented with a cue card restating the task goals. Videotapes were used to code task performance as well as responses to the cues. Most participants checked their work and showed significant improvement in task accomplishment/omission errors, but not commission errors, after the cues. However, effect sizes for the differences were small, and the proportion of cases in the impaired range did not differ before versus after the cues. Therefore, although statistically significant, we concluded that the goal cues did not meaningfully or clinically improve everyday functioning.

Target-related distractors disrupt object selection in everyday action: evidence from participants with dementia

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.