Egocentric Neglect Research Articles

Comprehensive voxel-wise, tract-based, and network lesion mapping reveals unique architectures of right and left visuospatial neglect

Visuospatial neglect is a common, post-stroke cognitive impairment which is widely considered to be a disconnection syndrome. However, the patterns of disconnectivity associated with visuospatial neglect remain unclear. Here, we had 480 acute stroke survivors [age = 72.8 (SD = 13.3), 44.3% female, 7.5 days post-stroke (SD = 11.3)] undertake routine clinical imaging and standardised visuospatial neglect testing. The data were used to conduct voxel-wise, tract-level, and network-level lesion-mapping analyses aimed at localising the neural correlates of left and right egocentric (body-centred) and allocentric (object-centred) visuospatial neglect. Only minimal anatomical homogeneity was present between the correlates of right and left egocentric neglect across all analysis types. This finding challenges previous work suggesting that right and left visuospatial neglect are anatomically homologous, and instead suggests that egocentric neglect may involve damage to a shared, but hemispherically asymmetric attention network. By contrast, egocentric and allocentric neglect was associated with disconnectivity in a distinct but overlapping set of network edges, with both deficits related to damage across the dorsal and ventral attention networks. Critically, this finding suggests that the distinction between egocentric and allocentric neglect is unlikely to reflect a simple dichotomy between dorsal versus ventral networks dysfunction, as is commonly asserted. Taken together, the current findings provide a fresh perspective on the neural circuitry involved in regulating visuospatial attention, and provide important clues to understanding the cognitive and perceptual processes involved in this common and debilitating neuropsychological syndrome.

Prevalence, Severity and Impact of Visuospatial Neglect in Geriatric Stroke Rehabilitation, a Cross-Sectional Study

ObjectivesVisuospatial neglect (VSN) is a common cognitive deficit of lateralized attention after stroke and can have a negative influence on patients’ daily activities, community participation, and caregiver burden. VSN prevalence has been investigated in several mixed-age populations, but rarely in only an older population. As the population in geriatric rehabilitation (GR) is understudied and VSN may influence rehabilitation goals in GR (return home), we examined the prevalence of VSN as well as associations between VSN (severity) and population characteristics and the impact of VSN on functioning, length of stay, and discharge destination after GR. DesignMulticenter cross-sectional study. Setting and ParticipantsStroke patients admitted to GR. MethodsThree VSN tests (Star cancelation task, Line bisection task, and Catherine Bergego Scale) were administered in the first 2 weeks of GR admission. To examine VSN severity, a composite score was calculated based on scores of the 3 tests. ResultsA total of 114 stroke patients were included [55.3% female; mean age 80.2 (SD 8.0) years]. VSN prevalence was 47.4%, in which allocentric and egocentric neglect were more prevalent than VSN during activities of daily living. Participants with VSN spent more days in GR compared to participants without VSN (median 68.5 vs 35.5 days) and had fewer home returns. In addition, VSN participants showed less mobility, lower cognitive functioning, and less independence during self-care compared to participants without VSN. Mobility, self-care, cognition, duration of rehabilitation, and home return were negatively associated with VSN severity. Conclusions and ImplicationsVSN is very prevalent in the GR stroke population. VSN severely hampers older people during daily activities and their rehabilitation process and, therefore, has a major personal and societal impact. Accordingly, systematic assessment of VSN in the early phase of geriatric rehabilitation with multiple VSN screening tests is recommended.

Standardization of apple cancellation test for neglect patients in Korea: An observational study.

Neglect can be divided into two types using apple cancellation test (apple test): Egocentric neglect (EN) and allocentric neglect (AN). However, in South Korea, apple test results and decision criteria are still largely dependent on tests by foreign countries. To establish a new South Korea standard and improve the accuracy of neglect assessment, the apple experiment was standardized in this study. This study was conducted on 223 healthy subjects for a total of 7 mo from August 2021 to February 2022. Standardization was carried out using the original apple test developed by Bickerton in 2011. In scoring for the apple test, total omission error refers to the number of missed targets (full apple) in the entire test sheet (left, middle, and right area). The score for EN is the difference between the cor-rect number of right area and the correct number of left area (excluding the middle area). For AN, the score is difference between the number of left opening apples and number of right opening apples (including the middle area). Linear regression analysis was used for standardization using the general characteristics of subjects and the results of the apple test. The cut-off score, which is the standard value indicating the pathological condition by combining the results of all subjects, is as follows: Total omission error (5), error for EN (2), and error for AN (2). Also, differences in cut-off score according to age were found. This study will be helpful in facilitating a more accurate differential diagnosis of neglect.

Digital Therapeutics for the Egocentric and Allocentric Neglects in Patients with Brain Injury: A Mini Review.

Various therapeutic approaches have been developed for neglect. Many studies have demonstrated the effect of digital therapeutics (DTx) on neglect. However, few studies have reported the effects of DTx on egocentric and allocentric neglect. The differentiation of types of neglect and separate interventions is crucial in the rehabilitation process. In this article, seven studies on DTx on egocentric and allocentric neglect were reviewed. DTx, which was employed in these studies, could be classified as follows: (1) software adaptation in traditional treatment, (2) VR game using the head-mount display as treatment, and (3) the development of a new digital program like ReMoVES. In addition, more studies and more effective results were reported for egocentric neglect than for allocentric neglect. In future studies, each effect on egocentric and allocentric neglect should be identified in detail with the appropriate use of differential evaluation and long-term application of independent DTx.

Effects of Twins Therapy on Egocentric and Allocentric Neglect in Stroke Patients: A Feasibility Study.

(1) Background: Existing treatment methods for neglect are concentrated on egocentric neglect and may lead to various problems such as cost/space constraints and portability. Therefore, this study seeks to determine how a new treatment (also known as twins therapy, TT) for stroke patients can improve an existing problem associated with neglect. (2) Method: A pre/post-test control group research design was used and both groups continued to receive existing rehabilitation treatment, whilst TT intervention was only added to the experimental group. TT intervention was conducted for a total of 20 sessions (1 session for 30 min/day, 5 days/week, for 4 weeks). (3) Result: There was no significant difference in the manual function test (MFT) and the Korean version of the Modified Barthel Index (K-MBI) items (p > 0.05) before and after the TT intervention. However, the score and execution time of the apple cancellation test showed a significant reduction only in the experimental group (p < 0.05). (4) Conclusion: TT not only improved egocentric neglect, but also allocentric neglect symptoms in stroke patients.

Word-centred neglect dyslexia as an inhibitional deficit: A single case study

Word-centred neglect dyslexia is most commonly characterised as consequence of visuospatial neglect rather than an independent condition. However, recent research has suggested that this deficit may be dissociable from spatial attentional biases. This study aims to provide preliminary evidence investigating alternative mechanisms which could account for cases of word-centred neglect dyslexia which cannot be explained by visuospatial neglect.Patient EF is a chronic stroke survivor who presented with clear right-lateralised word-centred neglect dyslexia in conjunction with severe left egocentric neglect and left hemianopia following a right PCA stroke. The severity of EF's neglect dyslexia was not found to be affected by factors which modulate the severity of visuospatial neglect. EF demonstrated an intact ability to identify all letters in words, but reliably committed neglect dyslexia errors when subsequently reading the same words as a whole. EF did not exhibit neglect dyslexic impairment in standardised spelling, word-meaning matching, and word-picture matching tasks. Critically, EF exhibited marked cognitive inhibition impairment and committed neglect dyslexia errors which were characterised by misreading less familiar target words as more familiar responses.This behavioural pattern cannot be clearly accounted for by theories which characterize word-centred neglect dyslexia as a consequence of neglect. Instead, this data suggests that this case of word-centred neglect dyslexia may be related to a deficit of cognitive inhibition. Overall, these novel findings call for reevaluation of the dominant model of word-centred neglect dyslexia.

Linguistic structure modulates attention in reading: Evidence from negative concord in Italian

ABSTRACT We report the reading performance of an Italian speaker with egocentric Neglect Dyslexia on sentences with Negative Concord structures, which contain a linguistic cue to the presence of a preceding negative marker and compare it to sentences with no such cue. As predicted, the frequency of reading the whole sentence, including the initial negative marker non, was higher in Negative Concord structures than in sentences which also started with non, but crucially, lacked the medially positioned linguistic cue to the presence of non. These data support the claim that the presence of linguistic cues to sentence structure modulates attention during reading in Neglect Dyslexia.

Assessment tools for differential diagnosis of neglect: Focusing on egocentric neglect and allocentric neglect.

BACKGROUNDThere are very few studies on the differential diagnosis between egocentric neglect (EN) and allocentric neglect (AN). AIMTo investigate the overall trend of the previously developed assessment tools by conducting a descriptive review of the studies on assessment tools that can perform a differential diagnosis of EN and AN. METHODSThe data were collected by using databases such as Google Scholar, PubMed, and ScienceDirect. The most commonly used search terms were “neglect”, “stroke”, “egocentric neglect”, and “allocentric neglect”.RESULTSA total of seven studies that met the inclusion criteria were selected and analyzed. We were able to confirm the research process, test method, and differential diagnosis criteria of the seven presented assessment tools from four studies on paper-based tests and three studies on computerized tests. The majority of the tests were carried out via the cancellation method using stimuli such as everyday objects or numbers. EN distinguished the left from right based on the test paper, while AN distinguished the left from right based on stimuli. In order to perform differential diagnosis, the difference in the number of left and right responses or non-responses was used based on the EN and AN criteria.CONCLUSIONIt was confirmed that all the seven assessment tools can effectively perform differential diagnosis of EN and AN. This study may provide important data that can be used in clinical practice for differential diagnosis and future intervention planning for neglect patients.

Abstract 50: Testing Procedures Influence Allocentric And Egocentric Neglect Associations

Testing Procedures Influence Allocentric and Egocentric Neglect Associations Hemispatial visual neglect is common after right hemisphere (RH) stroke and can impact attention to the left side of view (egocentric) or the left side of objects irrespective of location (allocentric). Allocentric and egocentric neglect correlations have been reported as high as 0.80; however, others report low correlations and dissociations between them using the same task but with different administration procedures. To determine if divergent results are due to distinct procedures, we compared allocentric and egocentric neglect presence and severity between the two. Thirty-eight adults (21 female, age 65±15 years, 14±2 years education, 21 black/16 white) completed neglect testing within 10 days of RH stroke. Neglect testing comprised circling 10 complete circles (egocentric task) and crossing out 20 circles with gaps (10 left gaps, 10 right gaps; allocentric task). All participants completed testing once with allocentric and egocentric tasks on separate pages and once with both tasks on the same page. We used paired t -tests, Pearson correlations, and Fisher’s Exact test for analyses. Neglect severity did not differ across single- and separate-page conditions ( allocentric : t (32)=0.68, p =0.50; egocentric : t (36)=-1.27, p =0.21). Single- and separate-page severity scores were strongly associated ( allocentric : r =0.65, p &lt;0.001; egocentric : r =0.52, p =0.004). Allocentric and egocentric neglect severity were moderately associated for single-page ( r =0.45, p =0.008) but not separate-page ( r =0.10, p =0.60) conditions. Diagnosis of allocentric ( single-page : 6%, separate-page : 3%), egocentric ( single-page : 12%, separate-page : 9%), or allocentric and egocentric ( single-page : 27%, separate-page : 39%) neglect was not dependent on page condition ( p =0.75). To conclude, assessment procedures influenced association of allocentric and egocentric neglect severity but not categorical diagnosis, and presence of both appeared more common than either alone. Studies that reported high correlations between the allocentric and egocentric neglect on the same task may have included participants with lesions causing both types of neglect due to their size and/or location.

Right and left neglect are not anatomically homologous: A voxel-lesion symptom mapping study

Visuospatial neglect is a heterogenous syndrome which can occur following damage to either right or left hemisphere areas. This study employs voxel-lesion symptom mapping to identify the neural correlates of left and right egocentric and allocentric neglect in a large acute stroke cohort.A cohort of 446 acute stroke survivors (age = 26–95, 44% female) completed neuropsychological neglect assessment and routine clinical imaging. Similar to previous investigations, left egocentric and left allocentric neglect were associated with damage to distinct clusters of voxels within the posterior parietal and temporo-parietal junction areas. Unlike previous investigations, right egocentric neglect was found to most strongly associated with damage to more posterior voxels within left occipital cortical areas. Right allocentric neglect was found to be most strongly associated with damage to the anterior limb of the left internal capsule. Interestingly, the right hemisphere homologues of the areas implicated in right-lateralised neglect were not overlapping with those associated with left neglect impairment. This dissociation was present across both egocentric and allocentric neglect impairment.The results of this investigation suggest that right egocentric/allocentric neglect should not be characterised as a consequence of damage to left-hemisphere homologues of the right hemisphere attentional systems. These findings support the characterisation of visuospatial neglect as a heterogenous cluster of impairments rather than a unitary syndrome and provide novel insight into the neural correlates of spatial attention.

Aligning formal and functional assessments of Visuospatial Neglect: A mixed-methods study

ABSTRACT The occurrence of visuospatial neglect acts as a key predictor of recovery outcome following stroke. However, the specific behavioural profiles associated with various neglect subtypes are not well understood. This study aims to identify real-world functional impairments associated with neglect, to determine whether functional impairment profiles differ across patients with egocentric and allocentric neglect, and to investigate how neglect severity predicts functional impairments. Notes from 290 stroke patients’ occupational therapy functional assessments were qualitatively and quantitatively analysed in the context of neglect type and severity as reported by the OCS Cancellation Task. Overall, neglect patients had more references to having difficulty initiating tasks, finding items, exhibiting spatial inattention, and having difficulty using both arms than patients without neglect. The proportion of theme references did not differ significantly across patients with egocentric and allocentric neglect. The quantitative severity of egocentric neglect was acted as a significant predictor of reference occurrence over and above stroke severity within difficulty finding items, spatial inattention, body inattention, and upper limb use. This study expands on previous findings by identifying real-world functional impairments differentiating patients with and without neglect. This data provides novel insight into the impact of neglect on functional abilities.

Left egocentric neglect in early subacute right-stroke patients is related to damage of the superior longitudinal fasciculus

A typical consequence of stroke in the right hemisphere is unilateral spatial neglect. Distinct forms of neglect have been described, such as space-based (egocentric) and object-based (allocentric) neglect. However, the relationship between these two forms of neglect is still far from being understood, as well as their neural substrates. Here, we further explore this issue by using voxel lesion symptoms mapping (VLSM) analyses on a large sample of early subacute right-stroke patients assessed with the Apples Cancellation Test. This is a sensitive test that simultaneously measures both egocentric and allocentric neglect. Behaviourally, we found no correlation between egocentric and allocentric performance, indicating independent mechanisms supporting the two forms of neglect. This was confirmed by the VLSM analysis that pointed out a link between a damage in the superior longitudinal fasciculus and left egocentric neglect. By contrast, no association was found between brain damage and left allocentric neglect. These results indicate a higher probability to observe egocentric neglect as a consequence of white matter damages in the superior longitudinal fasciculus, while allocentric neglect appears more “globally” related to the whole lesion map. Overall, these findings on early subacute right-stroke patients highlight the role played by white matter integrity in sustaining attention-related operations within an egocentric frame of reference.

Left egocentric neglect in early subacute right‑stroke patients is related to damage of the superior longitudinal fasciculus

Left egocentric neglect in early subacute right‑stroke patients is related to damage of the superior longitudinal fasciculus

Recovery of Visuospatial Neglect Subtypes and Relationship to Functional Outcome Six Months After Stroke

Background/Objective. This study aims to investigate how complex visuospatial neglect behavioural phenotypes predict long-term outcomes, both in terms of neglect recovery and broader functional outcomes after 6 months post-stroke. Methods. This study presents a secondary cohort study of acute and 6-month follow-up data from 400 stroke survivors who completed the Oxford Cognitive Screen’s Cancellation Task. At follow-up, patients also completed the Stroke Impact Scale questionnaire. These data were analysed to identify whether any specific combination of neglect symptoms is more likely to result in long-lasting neglect or higher levels of functional impairment, therefore warranting more targeted rehabilitation. Results. Overall, 98/142 (69%) neglect cases recovered by follow-up, and there was no significant difference in the persistence of egocentric/allocentric (X2 [1] = .66 and P = .418) or left/right neglect (X2 [2] = .781 and P = .677). Egocentric neglect was found to follow a proportional recovery pattern with all patients demonstrating a similar level of improvement over time. Conversely, allocentric neglect followed a non-proportional recovery pattern with chronic neglect patients exhibiting a slower rate of improvement than those who recovered. A multiple regression analysis revealed that the initial severity of acute allocentric, but not egocentric, neglect impairment acted as a significant predictor of poor long-term functional outcomes (F [9,300] = 4.742, P < .001 and adjusted R2 = .098). Conclusions. Our findings call for systematic neuropsychological assessment of both egocentric and allocentric neglect following stroke, as the occurrence and severity of these conditions may help predict recovery outcomes over and above stroke severity alone.

The 3s Spreadsheet Test version 2 for assessing egocentric viewer-centered and allocentric stimulus-centered spatial neglect

The present study established the norms of the 3 s Spreadsheet Test version 2 (3S-v2 Test) with 186 healthy adults, compared performance of 23 individuals with spatial neglect after right brain stroke to the norms, and examined the extent that allocentric neglect is independent from egocentric neglect. The task required in the 3S-v2 Test is to cross out the target digit “3” in a spreadsheet that contained 10 columns and 14 rows of digit strings, including 120 target digits and 720 non-target digits. Each target is categorized with respect to its location on the page (egocentric viewer-centered) and its position within the digit string (allocentric stimulus-centered). Patients completed the 3S-v2 Test, the Apples Test, and Scene Copying Test (a five-object figure copying test). Based on the neglect classification criteria of these three tests, 18 patients (78.3%) were identified with both forms of neglect, three patients (13.0%) had isolated egocentric neglect, and two (8.7%) had isolated allocentric neglect. Among patients who were determined as having allocentric neglect by a given test, we found no significant correlation between severity of allocentric neglect and stimulus location in the egocentric reference frame. Based on the present findings, we suggest that including the 3S-v2 Test, a functionally relevant task and different from the currently available tests, may increase the comprehensiveness of neglect assessment. In addition, allocentric neglect symptoms are independent of egocentric locations.

Non-Spatial Impairments Affect False-Positive Neglect Diagnosis Based on Cancellation Tasks.

To diagnose egocentric neglect after stroke, the spatial bias of performance on cancellation tasks is typically compared to a single cutoff. This standard procedure relies on the assumption that the measurement error of cancellation performance does not depend on non-spatial impairments affecting the total number of cancelled targets. Here we assessed the impact of this assumption on false-positive diagnoses. We estimated false positives by simulating cancellation data using a binomial model. Performance was summarised by the difference in left and right cancelled targets (R-L) and the Centre of Cancellation (CoC). Diagnosis was based on a fixed cutoff versus cutoffs adjusted for the total number of cancelled targets and on single test performance versus unanimous or proportional agreement across multiple tests. Finally, we compared the simulation findings to empirical cancellation data acquired from 651 stroke patients. Using a fixed cutoff, the rate of false positives depended on the total number of cancelled targets and ranged from 10% to 30% for R-L scores and from 10% to 90% for CoC scores. The rate of false positives increased even further when diagnosis was based on proportional agreement across multiple tests. Adjusted cutoffs and unanimous agreement across multiple tests were effective at controlling false positives. For empirical data, fixed versus adjusted cutoffs differ in estimation of neglect prevalence by 13%, and this difference was largest for patients with non-spatial impairments. Our findings demonstrate the importance of considering non-spatial impairments when diagnosing neglect based on cancellation performance.

Can auditory cues improve visuo-spatial neglect? Results of two pilot studies

ABSTRACT Although neglect is known to be a multimodal deficit, current interventions often address the visual modality only. Experimental studies, however, found that neglect patients can partially overcome their spatial inattention temporarily when being exposed to auditory cues that move towards the neglected side of space. Two pilot studies investigated the impact of dynamic auditory cueing on egocentric neglect severity in a clinical-therapeutic setting. In both studies, the patient groups received 15 sessions of intervention. Study 1, designed as double-blinded trial with a historical control group, targeted severely impaired early-acute patients who listened to music or audio books which were presented as moving dynamically from right to left. Results showed a reduction in egocentric neglect severity that persisted after therapy termination in the intervention but not in the historical control group. In study 2, based on the comparison with reported effect sizes of previous studies, dynamic meaningful auditory cues and optokinetic stimulation were combined in a computer-based training. Both studies found a significant reduction of neglect severity. Results provide evidence for the reduction of egocentric neglect severity after repetitive auditory cueing therapy in both severely and moderately impaired patients. Our promising findings should be verified thoroughly in randomized-controlled trials.

Dissociations within neglect-related reading impairments: Egocentric and allocentric neglect dyslexia

ABSTRACTConsistently lateralized reading errors are commonly understood as side-effects of visuospatial neglect impairment. There is however a qualitative difference between systematically omitting full words presented on one side of passages (egocentric neglect dyslexia) and lateralized errors when reading single words (allocentric neglect dyslexia). This study aims to investigate the relationship between egocentric and allocentric neglect dyslexia and visuospatial neglect.1209 stroke survivors completed standardized reading and cancellation tests. Stringent criteria identified unambiguous cases of allocentric neglect dyslexia (N = 17) and egocentric neglect dyslexia (N = 35). These conditions were found to be doubly dissociated with all cases of egocentric and allocentric neglect dyslexia occurring independently. Allocentric neglect dyslexia was dissociated from both egocentric and allocentric visuospatial neglect. Additionally, two cases of allocentric neglect dyslexia which co-occurred with oppositely lateralized domain-general visuospatial neglect were identified. Conversely, all cases of egocentric neglect dyslexia were found in the presence of domain-general visuospatial neglect. These findings suggest that allocentric neglect dyslexia cannot be fully understood as a consequence of visuospatial neglect. In contrast, we found no evidence for a dissociation between egocentric neglect dyslexia and visuospatial neglect. These findings highlight the need for new, neglect dyslexia specific rehabilitation strategies to be designed and tested.

Effects of Prism Adaptation on Reference Systems for Extrapersonal Space in Neglect Patients.

Up to now, rehabilitation of unilateral spatial neglect has focused on egocentric forms of neglect, whereas less is known about the possibility to improve allocentric deficits. The present study aimed to examine the efficacy of prism adaptation (PA) training on patients with different forms of neglect: egocentric, allocentric, or mixed. Twenty-eight patients were assessed with specific neglect tests before (T0) and after (T1) 10 sessions of PA training. Performance in the Apples Cancellation test was used to identify patients with egocentric (n = 6), allocentric (n = 5), or mixed (n = 17) forms of neglect. In the overall group of patients, PA training produced significant improvements in performance across different neglect tests. In terms of the egocentric–allocentric distinction, the training was effective in reducing omissions in the left part of space in the Apples Cancellation test both for patients with egocentric neglect and mixed neglect. By contrast, errors of commissions (marking the inability to detect the left part of the target stimulus, i.e., allocentric neglect) remained unchanged after PA in patients with allocentric neglect and actually increased marginally in patients with mixed neglect. The PA training is effective in improving egocentric neglect, while it is ineffective on the allocentric form of the disturbance. Notably, the allocentric component of neglect is frequently impaired, although this is most often in conjunction with the egocentric impairment, yielding the mixed form of neglect. This stresses the importance of developing exercises tuned to improving allocentric neglect.

Ego- and allocentric visuospatial neglect: Dissociations, prevalence, and laterality in acute stroke.

Objective: Visuospatial neglect, whereby patients are unable to attend to stimuli on their contralesional side, is a neuropsychological condition commonly experienced after stroke. We aimed to investigate whether egocentric and allocentric neglect are functionally dissociable and differ in prevalence and laterality in the early poststroke period. Method: A consecutive sample of 366 acute stroke patients completed the Broken Hearts test from the Oxford Cognitive Screen. We evaluated the association between egocentric and allocentric neglect and contrasted the prevalence and severity of left-sided versus right-sided neglect. Results: Clinically, we found a double dissociation between ego- and allocentric neglect, with 50% of the neglect patients showing only egocentric neglect and 25% only allocentric neglect. Left-sided egocentric neglect was more prevalent and more severe than was right-sided egocentric neglect, though right-sided neglect was still highly prevalent in the acute stroke sample (35%). Left-sided allocentric neglect was more severe but not more prevalent than was right-sided allocentric neglect. At 6 months, in a representative subsample of 160 patients, we found neglect recovery rates to be 81% and 74% for egocentric and allocentric neglect, respectively. Conclusion: Dissociable ego- and allocentric neglect symptoms support a heterogeneous account of visuospatial neglect, which was shown to be highly prevalent for both the left and the right hemifields.