Testing for neglect in right-hemispheric stroke patients using a new assessment battery based upon standardized activities of daily living (ADL)

A parcellation-based connectomic model of hemispatial neglect

BACKGROUND AND PURPOSE

Hemispatial neglect is characterized by a reduced awareness to stimuli on the contralateral side. Current literature suggesting that damage to the right parietal lobe and attention networks may cause hemispatial neglect is conflicting and can be improved by investigating a connectomic model of the "neglect system" and the anatomical specificity of regions involved in it.

METHODS

A meta-analysis of voxel-based morphometry magnetic resonance imaging (MRI) studies of hemispatial neglect was used to identify regions associated with neglect. We applied parcellation schemes to these regions and performed diffusion spectrum imaging (DSI) tractography to determine their connectivity. By overlaying neglect areas and maps of the attention networks, we studied the relationship between them.

RESULTS

The meta-analysis generated a list of 13 right hemisphere parcellations. These 13 neglect-related parcellations were predominantly linked by the superior longitudinal fasciculus (SLF) throughout a fronto-parietal-temporal network. We found that the dorsal and ventral attention networks showed partial overlap with the neglect system and included various other higher-order networks.

CONCLUSIONS

We provide an anatomically specific connectomic model of the neurobehavioral substrates underlying hemispatial neglect. Our model suggests a fronto-parietal-temporal network linked via the SLF supports the functions impaired in neglect and implicates various higher-order networks which are not limited to the attention networks.

Measurement properties of performance-based instruments for assessing mental function during activity and participation in persons with stroke: A systematic review

BACKGROUND

Various performance-based instruments exist to assess mental function after stroke and users have to select one for research or clinical practice.

OBJECTIVES

To evaluate the measurement properties of performance-based instruments to assess (any aspect of) mental function during activity and participation in persons after stroke.

MATERIAL AND METHODS

We searched in five electronic databases. COSMIN methodology was used to conduct the review. The strength of evidence was assessed using a modified GRADE approach.

RESULTS

Fifty articles were included reporting on 20 instruments assessing (1) multiple mental functions including ≥ four subdomains (2) attention, memory and executive functions, or single subdomains (3) executive functions, (4) perception, and (5) mental function of language. Highest quality evidence for sufficient results was found for some measurement properties in seven instruments. These instruments included: FIM + FAM, MPAI-4 and EFPT, MET, CBS/KF-NAP, BIT and the Scenario Test.

CONCLUSIONS

Further studies of high methodological quality are needed that evaluate the measurement properties of instruments to allow clinicians and researchers to select the most suitable performance-based measures for purpose.

SIGNIFICANCE

Results may be used to select the most suitable performance-based instrument to measure mental function during activity and participation in persons with stroke.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42018086744.

The neuroanatomy of visuospatial neglect: A systematic review and analysis of lesion-mapping methodology

While visuospatial neglect is commonly associated with damage to the right posterior parietal cortex, neglect is an anatomically heterogenous syndrome. This project presents a systematic review of 34 lesion-mapping studies reporting on the anatomical correlates of neglect. Specifically, the reported correlates of egocentric versus allocentric, acute versus chronic, personal versus extra-personal, and left versus right hemisphere neglect are summarised. The quality of each included lesion-mapping analysis was then evaluated to identify methodological factors which may help account for the reported variance in correlates of neglect. Overall, the existing literature strongly suggests that egocentric and allocentric neglect represent anatomically dissociable conditions and that the anatomy of these conditions may not be entirely homologous across hemispheres. Studies which have compared the anatomy of acute versus chronic neglect have found that these conditions are associated with distinct lesion loci, while studies comparing the correlates of peripersonal/extrapersonal neglect are split as to whether these neglect subtypes are anatomically dissociable. The included studies employed a wide range of lesion-mapping analysis techniques, each producing results of varying quality and generalisability. This review concludes that the reported underlying anatomical correlates of heterogeneous visuospatial neglect vary considerably. Future, high quality studies are needed to investigate patterns of disconnection associated with clearly defined forms of visuospatial neglect in large and representative samples.

The impact of apraxia and neglect on early rehabilitation outcome after stroke

Background

This study aims to characterize the impact of apraxia and visuospatial neglect on stroke patients’ cognitive and functional outcomes during early rehabilitation. Prior work implies an unfavorable effect of visuospatial neglect on rehabilitation; however, previous findings remain ambiguous and primarily considered long-term effects. Even less is known about the impact of apraxia on rehabilitation outcomes. Although clinicians agree on the significance of the first few weeks after stroke for the course of rehabilitation, studies exploring the impact of neglect and apraxia in this early rehabilitation period remain scarce.

Methods

Based on a screening of 515 hospitalized stroke patients from an early rehabilitation ward, 150 stroke patients (75 left-hemispheric strokes, 75 right hemispheric strokes) fulfilled the inclusion criteria and were enrolled in this observational, longitudinal study. The patients’ cognitive and functional statuses were documented at admission to the early rehabilitation ward and discharge. Also, detailed apraxia and neglect assessments were performed at midterm. The predictive values of age and apraxia and neglect severity (as reflected in two components from a principal component analysis of the neglect and apraxia assessments) for cognitive and functional outcomes at discharge were evaluated by multiple regression analyses.

Results

Besides the expected influence of the respective variables at admission, we observed a significant effect of apraxia severity on the cognitive outcome at discharge. Moreover, neglect severity predicted the Early Rehabilitation Barthel Index (Frühreha-Barthel-Index) at discharge. Supplementary moderator analysis revealed a differential effect of neglect severity on the cognitive outcome depending on the affected hemisphere.

Conclusion

Data indicate a strong association between apraxia and visuospatial neglect and early rehabilitation outcomes after stroke.

Impact of visuospatial neglect post-stroke on daily activities, participation and informal caregiver burden: A systematic review

OBJECTIVES

Visuospatial neglect (VSN) is a common cognitive disorder after stroke. The primary aim of this systematic review was to provide an overview of the impact of VSN in 3 aspects: (1) activities of daily living (ADL), (2) participation, and (3) caregiver burden. The second aim was to investigate the differences in studies focusing on populations with mean age<65 versus≥65 years.

METHODS

PubMed, EMBASE, Web of Science, Cochrane Library, Emcare, PsychINFO, Academic Search Premier and CENTRAL were searched systematically. Quality was assessed with the Mixed Methods Appraisal Tool.

RESULTS

Of the 115 included studies, 104 provided outcomes on ADL, 15 on participation (4 studies with mean age≥65), and 2 on caregiver burden (1 study with mean age≥65). Quality assessment yielded scores ranging from 0 to 100%. VSN had a negative impact on ADL (i.e., independence during ADL and performance in self-care, household tasks, reading, writing, walking, wheelchair navigation) and participation (i.e., driving, community mobility, orientation, work). The impact of VSN on fulfilling social roles was unclear. VSN had a negative effect on caregiver burden. We found no clear age-related differences.

CONCLUSIONS AND IMPLICATIONS

VSN has a negative impact not only on patients' independence but particularly on the performance of ADL. Despite the far fewer studies of VSN as compared with ADL, VSN also seems to hamper participation and increase caregiver burden, but further research is needed. Because of the large impact, VSN should be systematically and carefully assessed during rehabilitation. A considerable number of different instruments were used to diagnose VSN. Diagnosing VSN at more than one level [function (i.e., pen-and-paper test), activities, and participation] is strongly recommended. Consensus is needed on how to assess VSN and its negative impact for research and rehabilitation practice.

SYSTEMATIC REVIEW REGISTRATION NO

PROSPERPO Registration No. CRD42018087483.

Development of the Halifax Visual Scanning Test: A New Measure of Visual-Spatial Neglect for Personal, Peripersonal, and Extrapersonal Space

OBJECTIVES

Visual-spatial neglect is a common attentional disorder after right-hemisphere stroke and is associated with poor rehabilitation outcomes. The presence of neglect symptoms has been reported to vary across personal, peripersonal, and extrapersonal space. Currently, no measure is available to assess neglect severity equally across these spatial regions and may be missing subsets of symptoms or patients with neglect entirely. We sought to provide initial construct validity for a novel assessment tool that measures neglect symptoms equally for these spatial regions: the Halifax Visual Scanning Test (HVST).

METHODS

In Study I, the HVST was compared to conventional measures of neglect and functional outcome scores (wheelchair navigation) in 15 stroke inpatients and 14 healthy controls. In Study II, 19 additional controls were combined with the control data from Study I to establish cutoffs for impairment. Patterns of neglect in the stroke group were examined.

RESULTS

In Study I, performance on all HVST subtests were correlated with the majority of conventional subtests and wheelchair navigation outcomes. In Study II, neglect-related deficits in visual scanning showed dissociations across spatial regions. Four inpatients exhibited symptoms of neglect on the HVST that were not detected on conventional measures, one of which showed symptoms in personal and extrapersonal space exclusively.

CONCLUSIONS

The HVST appears a useful measure of neglect symptoms in different spatial regions that may not be detected with conventional measures and that correlates with functional wheelchair performance. Preliminary control data are presented and further research to add to this normative database appears warranted.

Preserved but Less Efficient Control of Response Interference After Unilateral Lesions of the Striatum

Previous research on the neural basis of cognitive control processes has mainly focused on cortical areas, while the role of subcortical structures in cognitive control is less clear. Models of basal ganglia function as well as clinical studies in neurodegenerative diseases suggest that the striatum (putamen and caudate nucleus) modulates the inhibition of interfering responses and thereby contributes to an important aspect of cognitive control, namely response interference control. To further investigate the putative role of the striatum in the control of response interference, 23 patients with stroke-induced lesions of the striatum and 32 age-matched neurologically healthy controls performed a unimanual version of the Simon task. In the Simon task, the correspondence between stimulus location and response location is manipulated so that control over response interference can be inferred from the reaction time costs in incongruent trials. Results showed that stroke patients responded overall slower and more erroneous than controls. The difference in response times (RTs) between incongruent and congruent trials (known as the Simon effect) was smaller in the ipsilesional/-lateral hemifield, but did not differ significantly between groups. However, in contrast to controls, stroke patients exhibited an abnormally stable Simon effect across the reaction time distribution indicating a reduced efficiency of the inhibition process. Thus, in stroke patients unilateral lesions of the striatum did not significantly impair the general ability to control response interference, but led to less efficient selective inhibition of interfering responses.

Unilateral spatial neglect after posterior parietal damage

Unilateral spatial neglect is a disabling neurologic deficit, most frequent and severe after right-hemispheric lesions. In most patients neglect involves the left side of space, contralateral to a right-hemispheric lesion. About 50% of stroke patients exhibit neglect in the acute phase. Patients fail to orient, respond to, and report sensory events occurring in the contralateral sides of space and of the body, to explore these portions of space through movements by action effectors (eye, limbs), and to move the contralateral limbs. Neglect is a multicomponent higher-level disorder of spatial awareness, cognition, and attention. Spatial neglect may occur independently of elementary sensory and motor neurologic deficits, but it can mimic and make them more severe. Diagnostic tests include: motor exploratory target cancellation; setting the midpoint of a horizontal line (bisection), that requires the estimation of lateral extent; drawing by copy and from memory; reading, assessing neglect dyslexia; and exploring the side of the body contralateral to the lesion. Activities of daily living scales are also used. Patients are typically not aware of neglect, although they may exhibit varying degrees of awareness toward different components of the deficit. The neural correlates include lesions to the inferior parietal lobule of the posterior parietal cortex, which was long considered the unique neuropathologic correlate of neglect, to the premotor and to the dorsolateral prefrontal cortices, to the posterior superior temporal gyrus, at the temporoparietal junction, to subcortical gray nuclei (thalamus, basal ganglia), and to parietofrontal white-matter fiber tracts, such as the superior longitudinal fascicle. Damage to the inferior parietal lobule of the posterior parietal cortex is specifically associated with the mainly egocentric, perceptual, and exploratory extrapersonal, and with the personal, bodily components of neglect. Productive manifestations, such as perseveration, are not a correlate of posterior parietal cortex damage.

The Mobility Assessment Course for the Diagnosis of Spatial Neglect: Taking a Step Forward?

Spatial neglect after stroke can be a challenging syndrome to diagnose under standard neuropsychological assessment. There is now sufficient evidence that those affected might demonstrate neglect behavior in everyday settings despite showing no signs of neglect during common neglect tasks. This discrepancy is attributed to the simplified and unrealistic nature of common pen and paper based tasks that do not match the demanding, novel, and complex environment of everyday life. As such, increasing task demands under more ecologically valid scenarios has become an important method of increasing test sensitivity. The main aim of the current study was to evaluate the diagnostic utility of the Mobility Assessment Course (MAC), an ecological task, for the assessment of neglect. If neglect becomes more apparent under more challenging task demands the MAC could prove to be more diagnostically accurate at detecting neglect than conventional methods, particularly as the time from initial brain damage increases. Data collected by Guide Dogs of SA/NT were retrospectively analyzed. The Receiver Operating Characteristic (ROC) curve, a measure of sensitivity and specificity, was used to investigate the diagnostic utility of the MAC and a series of paper and pencil tests in 67 right hemisphere stroke survivors. While the MAC proved to be a more sensitive neglect test (74.2%) when compared to the Star Cancellation (43.3%) and Line Bisection (35.7%) tests, this was at the expense of relatively low specificity. As a result, the ROC curve analysis showed no statistically discernable differences between tasks (p > 0.12), or between subacute and chronic groups for individual tasks (p > 0.45). It is concluded that, while the MAC is an ecologically valid alternative for assessing neglect, regarding its diagnostic accuracy, there is currently not enough evidence to suggest that it is a big step forward in comparison to the accuracy of conventional tests.

Assessment of unilateral neglect in stroke: Simplification and structuring of test items

Statement of context

Unilateral neglect is a complex impairment that is common after stroke and limits occupational performance. Sensitive assessment of unilateral neglect is critical for planning treatment and ensuring safe community discharge.

Critical reflection on practice

This reflection describes unexpected findings in the assessment of neglect with two individuals in the acute phase of recovery post stroke. When trialing a new activity based test battery, we observed few neglect behaviors during test tasks despite observation of multiple neglect behaviors outside of the testing situation. Upon reflection, we better understood how simplification and structuring of test items and environments could impact the observation and assessment of neglect behaviors.

Implications for practice

This practice analysis further supports the use of multiple assessments when evaluating unilateral neglect and specifically encourages the inclusion of assessment methods that maintain the complexity of everyday tasks and environments.

The ecological assessment of unilateral neglect

Conventional paper-and-pencil tests of unilateral neglect are of limited ecological validity. To address this issue, a number of assessment procedures have been proposed to provide clinicians and researchers with more ecologically valid assessments of unilateral neglect, which may be useful to plan rehabilitation and to measure the generalization of the effects of rehabilitation to daily life. We present here an overview of the different assessment measures available in the literature. The most widely used scales are the Behavioural Inattention Test (BIT), the semi-structured scales for assessment of personal and extra-personal neglect, the Subjective Neglect Questionnaire, the Baking Tray Task, the wheelchair obstacle course, the ADL-based neglect battery, and the Catherine Bergego Scale (CBS). The CBS is probably, to date, the most widely used behavioural assessment instrument for unilateral neglect. It has been found to be reliable, valid, and sensitive to change during rehabilitation. It also enables the assessment of awareness of the consequences of unilateral neglect in daily life skills.

Anatomical and psychometric relationships of behavioral neglect in daily living

Spatial neglect has been related to both cortical (predominantly at the temporal-parietal junction) and subcortical (predominantly of the superior longitudinal fasciculus) lesions. The objectives of this observational study were to specify the anatomical relationships of behavioral neglect in activities of daily living (N-ADLs), and the anatomical and psychometric relationships of N-ADLs on one hand and components of neglect (peripersonal neglect and personal neglect) and anosognosia on the other. Forty five patients were analyzed for behavioral difficulties in daily living (on the Catherine Bergego scale) and the main components of neglect (using conventional clinical assessments) during the first months post right hemisphere stroke. Voxel-based lesion-symptom mapping was used to identify brain areas within which lesions explained the severity of bias in each assessment (non-parametric permutation test; p<0.01, one tailed). N-ADLs was associated with lesions centered on the posterior part of the superior temporal gyrus and extending to the temporo-parietal junction, temporo-occipital junction and subcortical white matter (including the superior longitudinal fasciculus). Peripersonal neglect resulted from extended cortical lesions centered on the superior temporal gyrus and the inferior parietal gyrus, with subcortical extension. Personal neglect resulted predominantly from lesions centered on the somatosensory cortex and at a lesser degree on the superior temporal sulcus. Anosognosia resulted from lesions of the posterior inferior temporal gyrus and superior temporal gyrus. In anatomic terms, N-ADLs was strongly related to peripersonal neglect, and those relationships were also shown by the psychometric analysis. In conclusions, superior temporal gyrus and superior longitudinal fasciculus lesions have a pivotal role in N-ADLs. N-ADLs is principally related (anatomically and psychometrically) to peripersonal neglect, and at a lesser degree to anosognosia and personal neglect.

Spatial attention can transfer to the contralateral hemisphere in neonatal stroke patients: a case report following hemispherectomy

Patients suffer hemispatial neglect after stroke. However, whether the function of spatial attention is reorganized to the contralateral brain remains poorly understood. Here we present a case report of neonatal stroke to demonstrate the reorganization of spatial attention in the contralateral hemisphere using a series of tests including star cancellation task, line bisection test, the bells test, letter cancellation test, and drawing tests. The patient underwent right hemispherectomy for treatment of refractory epilepsy and did not have hemispatial neglect after surgery, supporting transfer of function prior to the operation. After analyzing the literature in this field, we proposed that the function of spatial attention may transfer to the contralateral side in childhood. Thus, this study sheds new light on the preserved function of spatial attention in neonatal stroke patients even when hemispherectomy is performed.

Neuroanatomical Dissections of Unilateral Visual Neglect Symptoms: ALE Meta-Analysis of Lesion-Symptom Mapping

Unilateral visual neglect is commonly defined as impaired ability to attend to stimuli presented on the side of visual space contralateral to the brain lesion. However, behavioral analyses indicate that different neglect symptoms can dissociate. The neuroanatomy of the syndrome has been hotly debated. Some groups have argued that the syndrome is linked to posterior parietal cortex lesions, while others report damage within regions including the superior temporal gyrus, insula, and basal ganglia. Several recent neuroimaging studies provide evidence that heterogeneity in the behavioral symptoms of neglect can be matched by variations in the brain lesions, and that some of the discrepancies across earlier findings might have resulted from the use of different neuropsychological tests and/or varied measures within the same task for diagnosing neglect. In this paper, we review the evidence for dissociations between both the symptoms and the neural substrates of unilateral visual neglect, drawing on ALE (anatomic likelihood estimation) meta-analyses of lesion-symptom mapping studies. Specifically, we examine dissociations between neglect symptoms associated with impaired control of attention across space (in an egocentric frame of reference) and within objects (in an allocentric frame of reference). Results of ALE meta-analyses indicated that, while egocentric symptoms are associated with damage within perisylvian network (pre- and postcentral, supramarginal, and superior temporal gyri) and damage within sub-cortical structures, more posterior lesions including the angular, middle temporal, and middle occipital gyri are associated with allocentric symptoms. Furthermore, there was high concurrence in deficits associated with white matter lesions within long association (superior longitudinal, inferior fronto-occipital, and inferior longitudinal fasciculi) and projection (corona radiata and thalamic radiation) pathways, supporting a disconnection account of the syndrome. Using this evidence we argue that different forms of neglect link to both distinct and common patterns of gray and white matter lesions. The findings are discussed in terms of functional accounts of neglect and theoretical models based on computational studies of both normal and impaired attention functions.

Neglect and extinction depend greatly on task demands: a review

This review illustrates how, after unilateral brain damage, the presence and severity of spatial awareness deficits for the contralesional hemispace depend greatly on the quantity of attentional resources available for performance. After a brief description of neglect and extinction, different frameworks accounting for spatial and non-spatial attentional processes will be outlined. The central part of the review describes how the performance of brain-damaged patients is negatively affected by increased task demands, which can result in the emergence of severe awareness deficits for contralesional space even in patients who perform normally on paper-and-pencil tests. Throughout the review neglect is described as a spatial syndrome that can be exacerbated in the presence and severity by both spatial and non-spatial tasks. The take-home message is that the presence and degree of contralesional neglect and extinction can be dramatically overlooked based on standard clinical (paper-and-pencil) testing, where patients can easily compensate for their deficits. Only tasks where compensation is made impossible represent an appropriate approach to detect these disabling contralesional deficits of awareness when they become subtle in post-acute stroke phases.

Is there a critical lesion site for unilateral spatial neglect? A meta-analysis using activation likelihood estimation

The critical lesion site responsible for the syndrome of unilateral spatial neglect has been debated for more than a decade. Here we performed an activation likelihood estimation (ALE) to provide for the first time an objective quantitative index of the consistency of lesion sites across anatomical group studies of spatial neglect. The analysis revealed several distinct regions in which damage has consistently been associated with spatial neglect symptoms. Lesioned clusters were located in several cortical and subcortical regions of the right hemisphere, including the middle and superior temporal gyrus, inferior parietal lobule, intraparietal sulcus, precuneus, middle occipital gyrus, caudate nucleus, and posterior insula, as well as in the white matter pathway corresponding to the posterior part of the superior longitudinal fasciculus. Further analyses suggested that separate lesion sites are associated with impairments in different behavioral tests, such as line bisection and target cancellation. Similarly, specific subcomponents of the heterogeneous neglect syndrome, such as extinction and allocentric and personal neglect, are associated with distinct lesion sites. Future progress in delineating the neuropathological correlates of spatial neglect will depend upon the development of more refined measures of perceptual and cognitive functions than those currently available in the clinical setting.