Presence of Motor-Intentional Aiming Deficit Predicts Functional Improvement of Spatial Neglect With Prism Adaptation

Does prism adaptation treatment reduce spatial neglect and improve function?

The potential of using prism adaptation for treating spatial neglect (SN) was questioned when recent meta-analyses found inconsistent evidence. However, analyses of clinical datasets support the use of prism adaptation treatment (PAT) in reducing SN and improving function. The main objective of this review is to evaluate the current state of the evidence of PAT therapeutic effects, identify knowledge gaps, and make suggestions to guide further research and support clinical decision-making. We used the framework of the National Institutes of Health (NIH) Stage Model for Behavioral Intervention Development which provides guidance on best practices for developing effective behavioral interventions that can be implemented in real-world settings. This model emphasizes the interplay between mechanisms underlying therapeutic effects ("who" should receive the treatment and "how" best does it work?) and considerations of adaptability and feasibility in real-world settings. The present critical review led to the following conclusion: the use of the NIH Stage Model reveals the heterogeneity of PAT studies and challenges in advancing PAT as an effective intervention. The key mechanisms such as prism strength, treatment intensity, arm visibility and activities during treatment, and evaluation methods lack consensus. Therefore, clinical research teams must continue to collect evidence to determine critical mechanisms and the optimal protocol. Further research identifying the optimal PAT protocol is needed before another meta-analysis on PAT's clinical efficacy should be conducted again.

Effect of stimulation-driven attention in virtual reality balloon search training of patients with left unilateral spatial neglect after stroke: A randomized crossover study

Patients with unilateral spatial neglect (USN) commonly experiences stimulus-driven attention deficit characterized by unexpected stimuli detection. We investigated whether virtual reality (VR) balloon search training with the screen background shifted to left space could improve stimulus-driven attention in patients with USN. The participants were divided into two groups: immediate VR group (n = 14) and delayed VR group (n = 14). The immediate VR group first received VR balloon search training, followed by control training, for two weeks each. Delayed VR group received the same training in reverse order. Outcomes were changes in scores on Catherine Bergego Scale (CBS) and reaction time on the modified Posner task (MPT). There was significant improvement in CBS score change after VR balloon retrieval training (all F > 2.71; P < 0.002). In the invalid condition of MPT, significant improvements were shown after VR balloon search training in left-sided reaction time (improvement of stimulation-driven attention). This study shows that VR balloon search training can improve neglect symptoms by using an intensive intervention lasting 2 weeks.

Investigating premotor reaching biases after prism adaptation

Prism adaptation (PA) is both a visuomotor learning task and potential treatment for spatial neglect after stroke. While PA's aftereffects can improve neglect symptoms, therapeutic benefits vary across individuals, possibly due to differences in neglect subtypes. Neglect symptoms can be described along an information processing pathway, yielding perceptual (input) and premotor (output) neglect subtypes. There is some evidence that PA mainly benefits persons with premotor neglect. We investigated whether PA modulates the premotor stage of information processing by examining whether PA could induce a premotor bias in healthy adults. We measured perceptual and premotor biases using a speeded reach task that compares the initiation time of leftward and rightward reaches to lateralized targets from different hand start positions. Using a randomized mixed experimental design, 30 right-handed healthy adults completed this speeded reach task before and after either left-shifting (n = 15) or right-shifting (n = 15) PA. As hypothesized, left-shifting PA speeded initiation time specifically for reaches in the rightward direction, regardless of target location (p = .02, ηp2 = .18), suggesting that PA induced a premotor bias in the direction of the prism aftereffect. These findings have implications for PA's underlying mechanisms, which can inform visuomotor learning theories and PA's use as a treatment for spatial neglect.

A scoping review and critique of the Input-Output subtyping dimension of spatial neglect

Spatial neglect is a common and debilitating disorder after stroke whereby individuals have difficulty reporting, orienting, and/or responding to the contralesional side of space. Given the heterogeneity of neglect symptom presentation, various neglect subtypes have been proposed to better characterize the disorder. This review focuses on the distinction between Input neglect (i.e., difficulty perceiving and/or attending to contralesional stimuli) and Output neglect (i.e., difficulty planning and/or executing movements toward contralesional stimuli). Conceptualizations of Input and Output neglect have varied considerably. We provide a novel summary of the terminology, measurement approaches, and neural correlates of these subtypes. A protocol detailing our systematic scoping review strategy is registered on the Open Science Framework (https://osf.io/bvtxf/). For feasibility and greater comparability across studies, we limited our inclusion criteria to tasks focused on visual stimuli and upper-limb movements. A total of 110 articles were included in the review. Subtyping tasks were categorized based on whether they mainly manipulated aspects of the input (i.e., congruence of visual input with motor output, presence of visual input) or the output (i.e., modality, goal, or direction of output) to produce an Input-Output subtype dissociation. We used our review results to identify four main critiques of this literature: 1) lack of consistency/clarity in conceptual models; 2) methodological issues of dissociating Input and Output subtypes; 3) a need for updated neural theories; and 4) barriers to clinical application. We discuss the lessons learned from this subtyping dimension that can be applied to future research on neglect subtype assessment and treatment.

The effect of offline anosognosia for hemispatial neglect on neglect rehabilitation in patients with subacute and chronic right hemispheric brain injury. A retrospective cohort study

CLINICAL TRIALS REGISTRATION NUMBER

NCT05145855.

Effects of prism adaptation and visual scanning training on perceptual and response bias in unilateral spatial neglect

In some patients with unilateral spatial neglect, symptoms reflect impaired lateralized spatial attention and representation (perceptual bias) whereas in others the inability to respond to stimuli located in contralesional space (response bias). Here, we investigated whether prismatic adaptation (PA) and visual scanning training (VST) differentially affect perceptual and response bias and whether rehabilitation outcome depends on the type of bias underlying symptoms. Two groups of neglect patients in the subacute phase were evaluated before, immediately after, and two weeks following 10 days of PA (n = 9) or VST (n = 9). Standard neuropsychological tests (i.e., Behavioural Inattentional Test, Diller cancellation test, and Line Bisection test) were administered to assess neglect symptoms, while the Landmark task was used to disentangle perceptual and response biases. Performance on the Landmark task revealed that PA was more effective in improving the perceptual bias, while VST mainly modulated the response bias. Neuropsychological tests performance suggested that VST is better suited to modulate neglect in patients with response bias, while PA may be effective in patients with both types of bias. These findings may offer novel insights into the efficacy of PA and VST in the rehabilitation of perceptual and response biases in patients with neglect.

Clinical and demographic predictors of unilateral spatial neglect recovery after prism therapy among stroke survivors in the sub-acute phase of recovery

BACKGROUND AND AIMS: Unilateral Spatial Neglect (USN) affects the rehabilitation process and leads to poor outcomes after stroke. Factors that influence USN recovery following prism adaptation therapy have not been investigated. This study investigated predictors of USN recovery after prism therapy at the sub-acute phase of recovery. METHODS: This study was a randomized controlled trial. USN was assessed with the Behavioural Inattention Test and Catherine Bergego scale. Seventy-four patients with USN were divided into control and intervention group (prism). The prism group used 20 dioptre prism lenses for repeated aiming for 12 sessions while the control group used neutral lenses for aiming training. Regression analysis was conducted to establish clinical and sociodemographic factors that influence USN recovery. RESULTS: Gender, age, years of education, race, employment status, handedness, type of stroke, time since stroke and site of stroke (p > 0.005) showed no significant influence on USN recovery following PA treatment. Higher Cognitive function (OR  = 1.52, CI = 1.08-2.14, p =  0.016) and group allocationng (being in the prism group) (OR = 63.10, CI =  9.70-410.59, P < 0.001) were found to significantly influence USN recovery following PA treatment session. CONCLUSIONS: A significant modulating effect on general cognitive ability was found in this study. This suggests that prism adaptation therapy's effect on neural activity and spatial neglect depends on the cognitive function of stroke survivors.Trial registration: Pan African Clinical Trial Registry identifier: PACTR201903732473573.

Recent advances in treatment of spatial neglect: networks and neuropsychology

INTRODUCTION

Spatial neglect remains an underdiagnosed and undertreated consequence of stroke that imposes significant disability. A growing appreciation of brain networks involved in spatial cognition is helping us to develop a mechanistic understanding of different therapies under development.

AREAS COVERED

This review focuses on neuromodulation of brain networks for the treatment of spatial neglect after stroke, using evidence-based approaches including 1) Cognitive strategies that are more likely to impact frontal lobe executive function networks; 2) Visuomotor adaptation, which may depend on the integrity of parietal and parieto- and subcortical-frontal connections and the presence of a particular subtype of neglect labeled Aiming neglect; 3) Non-invasive brain stimulation that may modulate relative levels of activity of the two hemispheres and depend on corpus callosum connectivity; and 4) Pharmacological modulation that may exert its effect primarily via right-lateralized networks more closely involved in arousal.

EXPERT OPINION

Despite promising results from individual studies, significant methodological heterogeneity between trials weakened conclusions drawn from meta-analyses. Improved classification of spatial neglect subtypes will benefit research and clinical care. Understanding the brain network mechanisms of different treatments and different types of spatial neglect will make possible a precision medicine treatment approach.

Feasibility of hemispatial neglect rehabilitation with virtual reality-based visual exploration therapy among patients with stroke: randomised controlled trial

Background

Hemispatial neglect (HSN) was diagnosed using a virtual reality-based test (FOPR test) that explores the field of perception (FOP) and field of regard (FOR). Here, we developed virtual reality-visual exploration therapy (VR-VET) combining elements from the FOPR test and visual exploration therapy (VET) and examined its efficacy for HSN rehabilitation following stroke.

Methods

Eleven participants were randomly assigned to different groups, training with VR-VET first then waiting without VR-VET training (TW), or vice versa (WT). The TW group completed 20 sessions of a VR-VET program using a head-mounted display followed by 4 weeks of waiting, while the WT group completed the opposite regimen. Clinical HSN measurements [line bisection test (LBT), star cancellation test (SCT), Catherine Bergego Scale (CBS), CBS perceptual-attentional (CBS-PA), and CBS motor-explanatory (CBS-ME)] and FOPR tests [response time (RT), success rate (SR), and head movement (HM) for both FOP and FOR] were assessed by blinded face-to-face assessments.

Results

Five and six participants were allocated to the TW and WT groups, respectively, and no dropout occurred throughout the study. VR-VET considerably improved LBT scores, FOR variables (FOR-RT, FOR-SR), FOP-LEFT variables (FOP-LEFT-RT, FOP-LEFT-SR), and FOR-LEFT variables (FOR-LEFT-RT, FOR-LEFT-SR) compared to waiting without VR-VET. Additionally, VR-VET extensively improved FOP-SR, CBS, and CBS-PA, where waiting failed to make a significant change. The VR-VET made more improvements in the left hemispace than in the right hemispace in FOP-RT, FOP-SR, FOR-RT, and FOR-SR.

Conclusion

The observed improvements in clinical assessments and FOPR tests represent the translatability of these improvements to real-world function and the multi-dimensional effects of VR-VET training.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03463122, identifier NCT03463122.

Prism adaptation treatment improves spatial neglect after severe traumatic brain injury: A case series

BACKROUND

Spatial neglect (SN) after traumatic brain injury (TBI) is common, hindering rehabilitation progress and functional outcomes. Most research has focused on SN treatment after stroke with few published instances of post-TBI SN treated using prism adaptation treatment (PAT) in inpatient rehabilitation.

OBJECTIVE

This case series characterizes the dose, after-effect, and treatment response of PAT in patients with SN after severe TBI.

METHODS

Six patients exhibiting severe (n = 2), moderate (n = 2), or mild (n = 2) SN after severe TBI received 5 to 10 PAT sessions during their inpatient rehabilitation stay. Functional improvement in SN was measured by the Catherine Bergego Scale (CBS).

RESULTS

Patients presented with a mean initial CBS score of 16.8 (range: 8.8-24.3). Prism after-effect was present after PAT. Following 5-10 sessions, the mean CBS score improved by 11.6 points to 5.2 (range: 7.8-21.8); the change in initial versus final CBS scores was significant (P = 0.031).

CONCLUSION

This study is the first to demonstrate prism after-effect and functional SN improvement in individual patients with TBI. Patients showed a clinically meaningful improvement in mild, moderate, and severe SN following 5 to 10 PAT sessions. Additional studies are needed to assess tolerability, benefit, and optimal PAT dose for SN after TBI.

Effects of standing and walking training using a laser pointer based on stimulus-driven attention for behavioural outcome in spatial neglect: A single-case study

The therapy for unilateral spatial neglect (USN) is unclear. This case report investigated the effect of standing and walking training using a laser pointer based on stimulus-driven attention for USN. The patient was a right-handed 79-year-old man with cardiogenic cerebral embolism in the right middle and posterior cerebral arteries. Initially, we evaluated the absence of hemiparalysis in the lower limb and sensory disorder; almost all daily activities were performed independently. Intervention effects were verified using the BABA method. The course of the four phases (B1, A1, B2, A2) was conducted for 5 days. In the B1 and B2 phases, standing and walking training using a laser pointer was performed additionally to conventional physical therapy. Outcomes were measured using the Behavioural Inattention Test conventional subtest (BIT-c), Catherine Bergego Scale (CBS), and modified Posner task (MPT). The BIT-c remained unchanged in each phase. CBS scores improved after B1 and B2. In the MPT, the reaction time in the left space reduced after B1 and B2 compared with those in the A1 and A2 control phases. In this case, training may have contributed to the improvement in the response to the neglected space and behavioural assessment of USN.

Spatial neglect treatment: The brain's spatial-motor Aiming systems

Animal and human literature supports spatial-motor "Aiming" bias, a frontal-subcortical syndrome, as a core deficit in spatial neglect. However, spatial neglect treatment studies rarely assess Aiming errors. Two knowledge gaps result: spatial neglect rehabilitation studies fail to capture the impact on motor-exploratory aspects of functional disability. Also, across spatial neglect treatment studies, discrepant treatment effects may also result from sampling different proportions of patients with Aiming bias. We review behavioural evidence for Aiming spatial neglect, and demonstrate the importance of measuring and targeting Aiming bias for treatment, by reviewing literature on Aiming spatial neglect and prism adaptation treatment, and presenting new preliminary data on bromocriptine treatment. Finally, we review neuroanatomical and network disruption that may give rise to Aiming spatial neglect. Because Aiming spatial neglect predicts prism adaptation treatment response, assessment may broaden the ability of rehabilitation research to capture functionally-relevant disability. Frontal brain lesions predict both the presence of Aiming spatial neglect, and a robust response to some spatial neglect interventions. Research is needed that co-stratifies spatial neglect patients by lesion location and Aiming spatial neglect, to personalize spatial neglect rehabilitation and perhaps even open a path to spatial retraining as a means of promoting better mobility after stroke.

Prism Adaptation Treatment of Spatial Neglect: Feasibility During Inpatient Rehabilitation and Identification of Patients Most Likely to Benefit

Objective

Spatial Neglect is prevalent among stroke survivors, yet few treatments have evidence supporting efficacy. This study examines the feasibility of Prism Adaptation Treatment (PAT) within an inpatient rehabilitation facility and the degree by which PAT improves symptoms of spatial neglect and functional independence among sub-acute survivors of right hemispheric stroke.

Design

In this retrospective cohort study, 37 right hemispheric stroke patients were identified as having received at least 4 PAT sessions during their inpatient stay. Spatial neglect and functional independence levels of patients in the PAT cohort were compared to a matched active control group comprised of rehabilitation patients receiving alternative therapies to address neglect admitted during the same time period.

Results

Most patients received the full recommended 10 sessions of PAT (average sessions completed = 8.6). A higher percentage of severe neglect patients receiving PAT (69%) displayed clinically significant gains on FIM (≥22 points) compared to those receiving alternative treatments (6%). Patients with mild or moderate neglect in the PAT cohort did not exhibit greater benefit than controls.

Conclusion

Provision of PAT for treatment of spatial neglect in right hemispheric stroke patients was feasible during the inpatient rehabilitation admission. Patients with severe neglect showed the most benefit from PAT.

Clinical Trial Registration

This study was registered as a retrospective observational study on Itab Clinical Trials.gov. NCT04977219.

Effects of visual-motor illusion in stroke hemiplegic patients with left-side personal neglect: A report of two cases

Personal neglect is the neglect of self-body space, which often occurs in patients with unilateral spatial neglect (USN), but lacks a dedicated rehabilitation. The purpose of this study was to investigate the effects of visual-motor illusion (VMI) on two-stroke hemiplegic patients with left-side personal neglect. Case 1 was a 53-year-old man diagnosed with a right lenticulostriate artery infarction. Case 2 was a 76-year-old woman diagnosed with a right middle cerebral artery infarction. USN symptoms were not observed in either patient in the desk USN assessment, but personal neglect and USN symptoms in daily life were observed in both patients. Intervention effects were verified using an ABA design, comprising a 5-day three-phase (A1, B, A2). In phase B, VMI was performed on the paralyzed upper limb for 10 min in addition to conventional physical therapy. Outcomes measures were the Fluff test, Catherine Bergego Scale (CBS), Fugl-Meyer Assessment (FMA), and Functional Independence Measure (FIM). In both patients, no improvements were noted in FMA, but improvements were observed in the Fluff test, CBS, and FIM in phase B; these effects were retained in phase A2. Therefore, VMI may have contributed to improvements in Personal neglect and USN symptoms in daily life.

Spatial Neglect and Anosognosia After Right Brain Stroke

PURPOSE OF REVIEW

Up to 80% of survivors of right brain stroke leave acute care without being diagnosed with a major invisible disability. Studies indicate that a generic cognitive neurologic evaluation does not reliably detect spatial neglect, nor does it identify unawareness of deficit after right brain stroke; this article reviews the symptoms, clinical presentation, and management of these two cognitive disorders occurring after right brain stroke.

RECENT FINDINGS

Stroke and occupational therapy practice guidelines stress a quality standard for spatial neglect assessment and treatment to reduce adverse outcomes for patients, their families, and society. Neurologists may attribute poor outcomes associated with spatial neglect to stroke severity. However, people with spatial neglect are half as likely to return to home and community, have one-third the community mobility, and require 3 times as much caregiver supervision compared with similar stroke survivors. Multiple randomized trials support a feasible first-line rehabilitation approach for spatial neglect: prism adaptation therapy; more than 20 studies reported that this treatment improves daily life independence. Evidence-based treatment of anosognosia is not as developed; however, treatment for this problem is also available.

SUMMARY

This article guides neurologists' assessment of right brain cognitive disorders and describes how to efficiently assemble and direct a treatment team to address spatial neglect and unawareness of deficit.

Visual but Not Auditory-Verbal Feedback Induces Aftereffects Following Adaptation to Virtual Prisms

Visuo-motor adaptation with optical prisms that displace the visual scene (prism adaptation, PA) has been widely used to study visuo-motor plasticity in healthy individuals and to decrease the lateralized bias of brain-damaged patients suffering from spatial neglect. Several factors may influence PA aftereffects, such as the degree of optical deviation (generally measured in dioptres of wedge prisms) or the direction of the prismatic shift (leftward vs. rightward). However, the mechanisms through which aftereffects of adaptation in healthy individuals and in neglect affect performance in tasks probing spatial cognition remain controversial. For example, some studies have reported positive effects of PA on auditory neglect, while other studies failed to obtain any changes of performance even in the visual modality. We here tested a new adaptation method in virtual reality to evaluate how sensory parameters influence PA aftereffects. Visual vs. auditory-verbal feedback of optical deviations were contrasted to assess whether rightward deviations influence manual and perceptual judgments in healthy individuals. Our results revealed that altered visual, but not altered auditory-verbal feedback induces aftereffects following adaptation to virtual prisms after 30-degrees of deviation. These findings refine current models of the mechanisms underlying the cognitive effects of virtual PA in emphasizing the importance of visual vs. auditory-verbal feedback during the adaptation phase on visuospatial judgments. Our study also specifies parameters which influence virtual PA and its aftereffect, such as the sensory modality used for the feedback.

Prism Adaptation and Optokinetic Stimulation Comparison in the Rehabilitation of Unilateral Spatial Neglect

Prism adaptation (PA) is one of the most effective treatments for the rehabilitation of unilateral spatial neglect. Optokinetic stimulation (OKS) has also been demonstrated to be effective in ameliorating symptoms of neglect. The aim of this study is to compare the effectiveness of these two methods in a group of neglect patients using a crossover design. A group of 13 post-acute brain-damaged patients with unilateral spatial neglect, who had never been rehabilitated, were treated using PA and OKS. Each treatment was applied for 10 sessions, twice a day, to all patients with both treatments in crossed order (i.e., PA followed by OKS or vice versa). Neuropsychological assessments were performed: before the first (T1), at the end of the first/beginning of the second (T2) and at the end of the second training sessions (T3), and two weeks after the end of treatment (T4). Both procedures produced a significant improvement in clinical tests at T2, independent of the type of training. The results suggest that either PA or OKS induces a significant amelioration of neglect in right brain-damaged patients, mainly in the first block of treatment. Since no differences between treatments were found, they could be applied in clinical practice, according to the requirements of the individual patient.

FOPR test: a virtual reality-based technique to assess field of perception and field of regard in hemispatial neglect

BACKGROUND

We previously proposed a novel virtual reality-based method to assess human field of perception (FOP) and field of regard (FOR), termed the FOPR test. This study assessed the diagnostic validity of the FOPR test for hemispatial neglect (HSN).

METHODS

We included 19 stroke patients with a lesion in the right hemisphere and with HSN (HSN+SS), 22 stroke patients with a lesion in the right hemisphere and without HSN (HSN-SS), and 22 healthy controls aged 19-65 years. The success rate (SR) and response time (RT) in the FOPR test for both FOP and FOR were assessed (FOP-SR, FOR-SR, FOP-RT, and FOR-RT, respectively). Using a Bland-Altman plot, agreements between the FOPR test and conventional tests were confirmed, and the FOPR test accuracy was verified using the support vector machine (SVM). Measured values were analysed using ANOVA and Kruskall-Wallis tests for group comparison.

RESULTS

The Bland-Altman plot showed good agreement between FOPR test and conventional tests; individuals within 95% agreement limits were within the range of 94.8-100.0%. The SVM classification accuracy, using FOP and FOR variables from the left hemispace, ranged from 83.3 to 100.0% in a binary classification (HSN vs non-HSN). The FOPR test demonstrated differences in SR and RT for both FOP and FOR across the groups.

CONCLUSION

The FOPR test was valid for the HSN diagnosis and provided quantitative and intuitive information regarding visuospatial function. Furthermore, it might enhance our understanding of visuospatial function including HSN by applying the time relative component and concepts of perception and exploration, FOP and FOR.

TRIAL REGISTRATION

NCT03463122. Registered 13 March 2018, retrospectively registered.

Prism adaptation treatment to address spatial neglect in an intensive rehabilitation program: A randomized pilot and feasibility trial

Spatial neglect (SN) is a common cognitive disorder after brain injury. Prism adaptation treatment (PAT) is one of the promising interventions for SN albeit inconsistent results from previous studies. We carried out a comparison intervention (PAT vs. Sham) and aimed to evaluate the efficacy of PAT on visuospatial symptoms of SN in an inpatient rehabilitation setting that offered a highly intensive comprehensive brain injury rehabilitation program. A total of 34 patients with moderate-to-severe SN secondary to stroke or traumatic brain injury were randomized to the PAT group and the Sham group (an active control group). Both groups received 10 sessions of treatment, over two weeks, in addition to the rehabilitation therapies provided by their rehabilitation care teams. Outcomes were measured using an ecological instrument (the Catherine Bergego Scale) and paper-and-pencil tests (the Bells Test, the Line Bisection Test and the Scene Copying Test). Patients were assessed at baseline, immediately after treatment, two weeks after treatment, and four weeks after treatment. 23 (67.6%) patients completed treatment and all the assessment sessions and were included in the final analyses using mixed linear modeling. While SN symptoms reduced in both groups, we found no difference between the two groups in the degree of improvement. In addition, the average SN recovery rates were 39.1% and 28.6% in the PAT and Sham groups, respectively, but this discrepancy did not reach statistical significance. Thus, the present study suggests that PAT may contribute little to SN care in the context of a highly intensive inpatient rehabilitation program. Further large-scale investigation is required to uncover the mechanisms underlying PAT and Sham in order to refine the treatment or create new interventions.

Improved stability of long-duration sitting in spatial neglect after a single session of prism adaptation

Spatial neglect after right brain stroke affects balance, and improvements in sitting balance after prism adaptation have been demonstrated using short-duration center of pressure (CoP) data. We present long-duration (5 min) CoP and trunk muscles electromyography recordings of a 61-year-old man with left-sided spatial neglect, before and after a single session of prism adaptation. His CoP-derived measures showed improved balance and postural stability in both the anterior-posterior and medial-lateral directions after prism adaptation. Concurrently, asymmetry in neuromuscular activations was reduced. The findings suggest that improved sitting balance may be associated with more symmetrical activation of trunk muscles after prism adaptation.

Assessment of spatial neglect in clinical practice: A nationwide survey

This study was part of a nationwide, anonymous, open Internet survey conducted amongst healthcare professionals in Denmark on the assessment and treatment of spatial neglect (SN). The objective was to describe knowledge and practices in the assessment of SN in current clinical practice across different healthcare sectors and professions. Data included the perceived prevalence, assessment methods and observations, subtypes and differential diagnostics of SN. A total of 525 professionals participated in the survey. The vast majority (81.5%) reported that assessment of SN was provided by their workplace. The median of perceived prevalence of SN was 35% (IQR 22-51) but major differences were found between professions. Occupational therapists and psychologists appeared to be most involved in assessment, whilst nursing staff and speech therapists were least involved. Subjective observations were the most common assessment method (90%). Conversely, systematic ADL observations, paper-and-pencil tests, confrontational tests and computerized tests were less common. The survey revealed large differences in the assessment methods and awareness of various aspects of SN symptoms (subtypes and differential diagnostics) between different healthcare professions. The results emphasize the need for international multidisciplinary clinical guidelines on how to assess SN and distinguish between different subtypes and differential diagnoses.

Acupuncture plus Rehabilitation for Unilateral Neglect after Stroke: A Systematic Review and Meta-Analysis

OBJECTIVES

To systematically assess the efficacy of acupuncture combined with rehabilitation on unilateral neglect after stroke.

METHODS

The Cochrane Library, PubMed, Excerpt Medical Database (EMBASE), China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), Chinese Biomedical Literature Database (CBM), and Wan Fang databases were searched online for randomised controlled trials (RCTs) of acupuncture and its effects on unilateral neglect after stroke from their inception to September 2019. RCTs on acupuncture combined with rehabilitation in the experimental group for unilateral neglect compared with rehabilitation alone or rehabilitation plus sham acupuncture in the control group were included. Two authors separately screened the literature, extracted the data, and evaluated the quality of the included studies. Review Manager 5.3 software was used for the data analysis.

RESULTS

A total of 542 patients from nine RCTs were included. The meta-analysis showed that the experimental groups could significantly improve Fugl-Meyer Assessment (FMA) (MD = 11.54, 95% CI [9.54, 13.54], P < 0.00001) and the ability of daily living (SMD = 1.35, 95% CI [0.64, 2.07], P < 0.00001) and the ability of daily living (SMD = 1.35, 95% CI [0.64, 2.07], P < 0.00001) when compared with the control groups. However, there was no significant difference in the drop of Catherine Bergego Scale (CBS) and Behavioural Inattention Test-conventional (BIT-C) between the two groups.

CONCLUSIONS

Acupuncture combined with rehabilitation was more effective in improving the motor function and the ability of daily living. Because of the limitations regarding the quantity and quality of the studies in this meta-analysis, high-quality and well-designed RCTs are necessary to validate the above conclusions.

Frontal lesions predict response to prism adaptation treatment in spatial neglect: A randomised controlled study

Spatial neglect commonly follows right hemisphere stroke. It is defined as impaired contralesional stimulus detection, response, or action, causing functional disability. While prism adaptation treatment is highly promising to promote functional recovery of spatial neglect, not all individuals respond. Consistent with a primary effect of prism adaptation on spatial movements, we previously demonstrated that functional improvement after prism adaptation treatment is linked to frontal lobe lesions. However, that study was a treatment-only study with no randomised control group. The current study randomised individuals with spatial neglect to receive 10 days of prism adaptation treatment or to receive only standard care (control group). Replicating our earlier results, we found that the presence of frontal lesions moderated response to prism adaptation treatment: among prism-treated patients, only those with frontal lesions demonstrated functional improvements in their neglect symptoms. Conversely, among individuals in the standard care control group, the presence of frontal lesions did not modify recovery. These results suggest that further research is needed on how frontal lesions may predict response to prism adaptation treatment. Additionally, the results help elucidate the neural network involved in spatial movement and could be used to aid decisions about treatment.

Update on the Clinical Approach to Spatial Neglect

PURPOSE OF REVIEW

Spatial neglect is asymmetric orienting and action after a brain lesion, causing functional disability. It is common after a stroke; however, it is vastly underdocumented and undertreated. This article addresses the implementation gap in identifying and treating spatial neglect, to reduce disability and improve healthcare costs and burden.

RECENT FINDINGS

Professional organizations published recommendations to implement spatial neglect care. Physicians can lead an interdisciplinary team: functionally relevant spatial neglect assessment, evidence-based spatial retraining, and integrated spatial and vision interventions can optimize outcomes. Research also strongly suggests spatial neglect adversely affects motor systems. Spatial neglect therapy might thus "kick-start" rehabilitation and improve paralysis recovery. Clinicians can implement new techniques to detect spatial neglect and lead interdisciplinary teams to promote better, integrated spatial neglect care. Future studies of brain imaging biomarkers to detect spatial neglect, and real-world applicability of prism adaptation treatment, are needed.

Ventral attention and motor network connectivity is relevant to functional impairment in spatial neglect after right brain stroke

Emerging research suggests spatial neglect after right stroke is linked to dysfunctional attention and motor networks. Advanced functional connectivity analysis clarified brain network recovery, however we need to know how networks participate in adaptive motor performance. We need to verify network changes associated with validated functional measures and spatial-motor performance in spatial neglect, especially in patients with large brain lesions and significant disability. This study tested whether disability-relevant spatial neglect associates with different patterns of resting state functional connectivity between motor, dorsal and ventral attention networks (MN, DAN and VAN). Right stroke patients had spatial neglect (n = 8) or not (n = 10) on the Behavioural Inattention Test-conventional. Spatial neglect patients had weaker intranetwork VAN connectivity, and reduced internetwork connectivity between VAN and left frontal eye field (DAN), and between VAN and the left primary motor area (MN). These network impairments might explain the co-occurrence of attention and motor deficits in spatial neglect, and open a path to assessing functional connectivity in clinical trials of combined spatial retraining and motor rehabilitation after stroke.

Neuroanatomical and behavioural factors associated with the effectiveness of two weekly sessions of prism adaptation in the treatment of unilateral neglect

Among the different interventions to alleviate the symptoms of unilateral neglect, prism adaptation (PA) appears especially promising. To elucidate the contribution of some neuroanatomical and behavioural factors to PA's effectiveness, we conducted a study combining neuropsychological and lesion mapping methods on a group of 19 neglect patients who underwent two sessions of PA during one week and assessed their improvement relative to the baseline until the following week (7-8 days later). Correlation analyses revealed a significant positive relationship between the magnitude of the proprioceptive after-effect and the improvement at the follow-up session in two perceptual tasks requiring motor responses. Conversely, no correlation was found between the proprioceptive after-effect and the improvement in a perceptual task with no motor involvement. This finding suggests that patients' potential to show a prism-related improvement in motor-related tasks might be indicated by the strength of their proprioceptive response (proprioceptive after-effect). As for the neuroanatomical basis of this relationship, subtraction analyses suggested that patients' improvement in perceptual tasks with high motor involvement might be facilitated by the integrity of temporo-parietal areas and the damage of frontal and subcortical areas.

Illustrating where spatial perception versus memory-based representation: spatial neglect in a distinguished artist; a case report

Spatial neglect is a disorder of attention, perception, and processing of stimuli in contralesional space. The heterogeneous behaviors involve diverse neuroanatomical mechanisms. Anecdotal evidence suggests that neural circuitry of active spatial perception may differ from that used to encode spatial memory. These differences can escape detection by conventional assessments, thereby leading to missed diagnoses. We present a case, in an artist who demonstrates selective impairment in a contralesional space during active Where spatial perception. His performance is better when asked to draw entirely from memory. This case highlights the variability in neglect, importance for comprehensive testing, and encourages further investigation.

Prism Adaptation in Rehabilitation? No Additional Effects of Prism Adaptation on Neglect Recovery in the Subacute Phase Poststroke: A Randomized Controlled Trial

Background. Patients with neglect ignore or respond slower to contralesional stimuli. Neglect negatively influences independence in activities of daily living (ADL). Prism adaptation (PA) is one of the most frequently studied treatments, yet there is little evidence regarding positive effects on neglect behavior in ADL. Objective. To assess whether PA in the subacute phase ameliorates neglect in situations of varying complexity. Methods. A total of 70 neglect patients admitted for inpatient stroke rehabilitation received either PA or sham adaptation (SA) for 2 weeks, with full access to standard treatment. There were 7 time-dependent measurements (baseline and 1-4, 6, and 14 weeks after start of treatment). The primary outcome was change of neglect as observed during basic ADL with the Catherine Bergego Scale (CBS). Secondary outcomes were changes in performance on a dynamic multitask (ie, the Mobility Assessment Course [MAC]) and a static paper-and-pencil task (ie, a shape cancellation task [SC]). Results. In all, 34 patients received PA and 35 SA. There were significant time-dependent improvements in performance as measured with the CBS, MAC, and SC (all F > 15.57; P < .001). There was no significant difference in magnitude of improvement between groups on the CBS, MAC, and SC (all F < 2.54; P > .113]. Conclusions. No beneficial effects of PA over SA in the subacute phase poststroke were observed, which was comparable for situations of varying complexity. Heterogeneity of the syndrome, time post–stroke onset, and the content of treatment as usual are discussed. Basic knowledge on subtypes and recovery patterns would aid the development of tailored treatment.

What role for prism adaptation in the rehabilitation of pure neglect dyslexia?

Prism adaptation (PA) has been successfully applied in the rehabilitation of spatial neglect, with significant transfer to classic neglect tests and activities of daily living. However, well-controlled studies were unable to replicate these findings, and recent reports suggest that PA may affect selectively visuo-motor symptoms. Here, a patient with pure left neglect dyslexia was tested before, immediately after, and 24 h after PA. Despite a significant adaptation aftereffect adaptation had no effect omissions, substitutions and letter-based errors. PA does not affect pure neglect dyslexia and should therefore be reserved for the rehabilitation of motor-intentional, rather than visual-attentional symptoms.

Which perseverative behaviors are symptoms of spatial neglect?

Spatial neglect is a characterized by a failure to attend or make movements towards left-sided stimuli. Common paper-and-pencil tasks to diagnose spatial neglect are sensitive to perseverative errors, including additional marks over already cancelled targets and "scribbling" out a target. Here, we examine whether functionally distinct perseverative behaviors are related to spatial neglect. Line cancellation tasks of 45 healthy controls and 220 right-hemisphere stroke survivors were examined for recurrent marks (RM) and continuous marks (CM) perseverations. We found that RM perseveration correlated with neglect severity, while CM perseveration did not. Examination of lesion profiles for the two groups indicated distinct anatomical correlates, with RM lesions overlapping regions implicated in spatial neglect including the rolandic operculum, superior temporal gyrus, and inferior parietal lobule.

Rehabilitation of visuospatial neglect by prism adaptation: effects of a mild treatment regime. A randomised controlled trial

Closely examining the effects, optimal regime and time window of prism adaptation (PA) promotes guidelines for effective rehabilitation practice. The effects of short-term repetitive PA on spatial neglect manifestations were evaluated in patients with heterogeneous post-stroke delays, using a digital Visuospatial Neglect Test Battery. Subsequently, potential differences in PA effects between acute, subacute or chronic neglect were explored. A multicentre randomised controlled trial was conducted in 43 right-hemisphere neglect patients. They were treated with a mild PA regime: seven sessions of experimental or placebo prism training over 7-12 days. The outcome measures were diverse neglect variables related to peripersonal navigation, visual extinction, visuospatial memory, bisection, cancellation, drawing and visual search. The treatment effects were assessed after a short and a long time interval. Two to 24 hours after PA, conventional effects were found for drawing and centred bisection, and novel effects for peripersonal visuospatial navigation, visual extinction, and non-motor memory (with caution). No effects were found for visual search times and cancellation. The assessments after three months were still indicative of PA benefits for navigational, drawing and memory functions. PA did not prove to be more effective in acute, subacute or chronic patients. The extension of effects is theoretically framed within the debate about the levels of cognitive processing that are impacted by PA. Clinical suggestions are formulated regarding PA implementation in neglect treatment.

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.

Asymmetry in the Collision Judgments of People With Homonymous Field Defects and Left Hemispatial Neglect

PURPOSE

Although the impact of homonymous visual field defects (HFDs) on mobility has been investigated previously, the emphasis has been on obstacle detection. Relatively little is known about HFD patients' ability to judge collisions once an obstacle is detected. We investigated this using a walking simulator.

METHODS

Patients with HFDs (n = 29) and subjects with normal vision (NV; n = 21) were seated in front of a large screen on which a visual simulation of walking was displayed. They made collision judgments for a human figure that appeared for 1 second at lateral offsets from the virtual walking path. A perceived-collision threshold was calculated for right and left sides.

RESULTS

Symmetrical collision thresholds (same on left and right sides) were measured for participants with NV (n = 21), and right (n = 9) and left (n = 7) HFD without hemispatial neglect. Participants with left neglect (n = 10) showed significant asymmetry with thresholds smaller (compared to the NV group and other HFD groups) on the blind (P < 0.001) and larger on the seeing (P = 0.05) sides. Despite the asymmetry, the overall width of the zone of perceived collision risk was not different, suggesting a relatively uniform rightward deviation in judgments of the left neglect group.

CONCLUSIONS

Left neglect was associated with rightward asymmetry in collision judgments, which may cause collisions on the left side even when an obstacle is detected. These behaviors may represent the spatial misperceptions in body midline described previously in patients with left neglect.

Midline Body Actions and Leftward Spatial "Aiming" in Patients with Spatial Neglect

Spatial motor–intentional “Aiming” bias is a dysfunction in initiation/execution of motor–intentional behavior, resulting in hypokinetic and hypometric leftward movements. Aiming bias may contribute to posture, balance, and movement problems and uniquely account for disability in post-stroke spatial neglect. Body movement may modify and even worsen Aiming errors, but therapy techniques, such as visual scanning training, do not take this into account. Here, we evaluated (1) whether instructing neglect patients to move midline body parts improves their ability to explore left space and (2) whether this has a different impact on different patients. A 68-year-old woman with spatial neglect after a right basal ganglia infarct had difficulty orienting to and identifying left-sided objects. She was prompted with four instructions: “look to the left,” “point with your nose to the left,” “point with your [right] hand to the left,” and “stick out your tongue and point it to the left.” She oriented leftward dramatically better when pointing with the tongue/nose, than she did when pointing with the hand. We then tested nine more consecutive patients with spatial neglect using the same instructions. Only four of them made any orienting errors. Only one patient made >50% errors when pointing with the hand, and she did not benefit from pointing with the tongue/nose. We observed that pointing with the tongue could facilitate left-sided orientation in a stroke survivor with spatial neglect. If midline structures are represented more bilaterally, they may be less affected by Aiming bias. Alternatively, moving the body midline may be more permissive for leftward orienting than moving right body parts. We were not able to replicate this effect in another patient; we suspect that the magnitude of this effect may depend upon the degree to which patients have directional akinesia, spatial Where deficits, or cerebellar/frontal cortical lesions. Future research could examine these hypotheses.

Spatial cognitive rehabilitation and motor recovery after stroke

PURPOSE OF REVIEW

Stroke rehabilitation needs to take major steps forward to reduce functional disability for survivors. In this article, we suggest that spatial retraining might greatly increase the efficiency and efficacy of motor rehabilitation, directly addressing the burden and cost of paralysis after stroke.

RECENT FINDINGS

Combining motor and cognitive treatment may be practical, as well as addressing the needs after moderate-to-severe stroke. Spatial neglect could suppress motor recovery and reduce motor learning, even when patients receive appropriate rehabilitation to build strength, dexterity, and endurance. Spatial neglect rehabilitation acts to promote motor as well as visual-perceptual recovery. These findings, and the previous underemphasized studies, make a strong case for combining spatial neglect treatment with traditional exercise training. Spatial neglect therapies might also provide motor stimulation if people cannot participate in intensive movement therapies because of limited strength and endurance after stroke.

SUMMARY

Spatial retraining, currently used selectively after right-brain stroke, may be broadly useful after stroke to promote rapid motor recovery.

Prism adaptation and spatial neglect: the need for dose-finding studies

Spatial neglect is a devastating disorder in 50–70% of right-brain stroke survivors, who have problems attending to, or making movements towards, left-sided stimuli, and experience a high risk of chronic dependence. Prism adaptation is a promising treatment for neglect that involves brief, daily visuo-motor training sessions while wearing optical prisms. Its benefits extend to functional behaviors such as dressing, with effects lasting 6 months or longer. Because one to two sessions of prism adaptation induce adaptive changes in both spatial-motor behavior (Fortis et al., 2011) and brain function (Saj et al., 2013), it is possible stroke patients may benefit from treatment periods shorter than the standard, intensive protocol of ten sessions over two weeks—a protocol that is impractical for either US inpatient or outpatient rehabilitation. Demonstrating the effectiveness of a lower dose will maximize the availability of neglect treatment. We present preliminary data suggesting that four to six sessions of prism treatment may induce a large treatment effect, maintained three to four weeks post-treatment. We call for a systematic, randomized clinical trial to establish the minimal effective dose suitable for stroke intervention.

Ipsilesional neglect: behavioral and anatomical correlates

[Correction Notice: An Erratum for this article was reported in Vol 29(2) of Neuropsychology (see record 2014-42242-001). The funding source information was missing from the author note, and A. M. Barrett's institutional affiliation was incorrect. The funding source information and Barrett's correct institutional affiliation are provided in the erratum.]

OBJECTIVE

The sparse existing research on ipsilesional neglect supports an association of this disorder with damage to the right frontal and subcortical brain networks. It is believed that dysfunction in these networks may result in primarily "aiming" motor-intentional spatial errors. The purpose of this study was to confirm whether frontal-subcortical circuits are indeed commonly affected in ipsilesional neglect and to determine the relative presence of "aiming" motor-intentional versus "where" perceptual-attentional spatial errors in these individuals.

METHODS

We identified 12 participants with ipsilesional neglect based on a computerized line bisection task and used the line bisection data to quantify participants' perceptual-attentional and motor-intentional errors. We were able to discriminate between these 2 biases using the algebraic solutions for 2 separate equations, one for "aiming" and one for "where" biases. Lesion mapping was conducted for all participants using MRIcron software; lesion checklist and overlap analysis were created from these images.

RESULTS

A greater percentage of participants with ipsilesional neglect had frontal/subcortical damage (83%) compared with the expected percentage (27%) observed in published patient samples with contralesional neglect. We observed the greatest area of lesion overlap in frontal lobe white matter pathways. Nevertheless, participants with ipsilesional neglect made primarily "where" rather than "aiming" spatial errors.

CONCLUSION

Our data confirm previous research suggesting that ipsilesional neglect may result from lesions to the right frontal-subcortical networks. Furthermore, in our group, ipsilesional neglect was also strongly associated with primarily "where" perceptual-attentional bias, and less so with "aiming" motor-intentional spatial bias.