The line bisection bias as a deficit of proportional reasoning - evidence from number line estimation in neglect.

This study aimed to investigate whether neurological patients presenting with a bias in line bisection show specific problems in bisecting a line into two equal parts or their line bisection bias rather reflects a special case of a deficit in proportional reasoning more generally. In the latter case, the bias should also be observed for segmentations into thirds or quarters. To address this question, six neglect patients with a line bisection bias were administered additional tasks involving horizontal lines (e.g., segmentation into thirds and quarters, number line estimation, etc.). Their performance was compared to five neglect patients without a line bisection bias, 10 patients with right hemispheric lesions without neglect, and 32 healthy controls. Most interestingly, results indicated that neglect patients with a line bisection bias also overestimated segments on the left of the line (e.g., one third, one quarter) when dissecting lines into parts smaller than halves. In contrast, such segmentation biases were more nuanced when the required line segmentation was framed as a number line estimation task with either fractions or whole numbers. Taken together, this suggests a generalization of line bisection bias towards a segmentation or proportional processing bias, which is congruent with attentional weighting accounts of line bisection/neglect. As such, patients with a line bisection bias do not seem to have specific problems bisecting a line, but seem to suffer from a more general deficit processing proportions.

Disengagement of attention with spatial neglect: A systematic review of behavioral and anatomical findings.

The present review examined the consequences of focal brain injury on spatial attention studied with cueing paradigms, with a particular focus on the disengagement deficit, which refers to the abnormal slowing of reactions following an ipsilesional cue. Our review supports the established notion that the disengagement deficit is a functional marker of spatial neglect and is particularly pronounced when elicited by peripheral cues. Recent research has revealed that this deficit critically depends on cues that have task-relevant characteristics or are associated with negative reinforcement. Attentional capture by task-relevant cues is contingent on damage to the right temporo-parietal junction (TPJ) and is modulated by functional connections between the TPJ and the right insular cortex. Furthermore, damage to the dorsal premotor or prefrontal cortex (dPMC/dPFC) reduces the effect of task-relevant cues. These findings support an interactive model of the disengagement deficit, involving the right TPJ, the insula, and the dPMC/dPFC. These interconnected regions play a crucial role in regulating and adapting spatial attention to changing intrinsic values of stimuli in the environment.

Spatial Neglect: An Exploration of Clinical Assessment Behaviour in Stroke Rehabilitation.

OBJECTIVE: There is a large gap between evidence-based recommendations for spatial neglect assessment and clinical practice in stroke rehabilitation. We aimed to describe factors that may contribute to this gap, clinician perceptions of an ideal assessment tool, and potential implementation strategies to change clinical practice in this area. DESIGN: Qualitative focus group investigation. Focus group questions were mapped to the Theoretical Domains Framework and asked participants to describe their experiences and perceptions of spatial neglect assessment. SETTING: Online stroke rehabilitation educational bootcamp. PARTICIPANTS: A sample of 23 occupational therapists, three physiotherapists, and one orthoptist that attended the bootcamp. INTERVENTION: Prior to their focus group, participants watched an hour-long educational session about spatial neglect. MAIN MEASURES: A deductive analysis with the Theoretical Domains Framework was used to describe perceived determinants of clinical spatial neglect assessment. An inductive thematic analysis was used to describe perceptions of an ideal assessment tool and practice-change strategies in this area. RESULTS: Participants reported that their choice of spatial neglect assessment was influenced by a belief that it would positively impact the function of people with stroke. However, a lack of knowledge about spatial neglect assessment appeared to drive low clinical use of standardised functional assessments. Participants recommended open-source online education involving a multidisciplinary team, with live-skill practice for the implementation of spatial neglect assessment tools. CONCLUSIONS: Our results suggest that clinicians prefer functional assessments of spatial neglect, but multiple factors such as knowledge, training, and policy change are required to enable their translation to clinical practice.

Unilateral Spatial Neglect May Not Be Detected by Performance-Based Functional Neglect Assessment.

IMPORTANCE: Unilateral spatial neglect (neglect) poststroke is disabling. It is critical that people with neglect are identified so that treatment can be provided to maximize independence. However, there is some evidence to suggest that existing assessments may not adequately measure neglect. It is unclear whether assessments also fail to identify people with neglect entirely. OBJECTIVE: To determine whether there are stroke survivors who self-report neglect symptoms that are not detected by therapist-rated assessments and to compare self-report and therapist-ratings. DESIGN: Cross-sectional study. SETTING: U.S. university research center. PARTICIPANTS: Unilateral stroke survivors (N = 133). INTERVENTION: Not applicable. OUTCOMES AND MEASURES: The Catherine Bergego Scale (CBS) was administered to participants and scored by a trained occupational therapist. The parallel self-evaluation anosognosia form was also administered to participants to self-report and rate neglect symptoms. RESULTS: Forty-eight participants (36.1%) were classified as without neglect on the basis of therapist-rated total CBS scores, yet 30 (62.5%) of these 48 participants reported symptoms of neglect on the CBS self-evaluation anosognosia form. There was a significant difference (p < .001) between therapist-rated and self-rated total CBS scores. CONCLUSIONS AND RELEVANCE: Our results indicate that many stroke survivors report some level of disability associated with neglect yet do not meet the criteria to be classified as having neglect according to a commonly used therapist-rated performance-based measure. Plain-Language Summary: The findings of this study contribute to the evidence that existing assessments used by occupational therapists to measure performance-based neglect may not always detect neglect symptoms comprehensively in people poststroke. The finding also suggest that we may be missing neglect symptoms entirely. Occupational therapists should consider using various methods to assess for neglect, including patient self-report and comprehensive occupational profiles. Clinicians should also thoroughly screen all clients with stroke for neglect, regardless of lesion location.

Understanding Occupational Therapists' Knowledge and Confidence When Assessing for Spatial Neglect: A Special Issue Review.

IMPORTANCE: Spatial neglect (SN)-failure to respond to stimuli on the side of the body contralateral to a poststroke lesion-is one of the most disabling impairments for stroke survivors, and 80% of stroke survivors may have undetected SN. Occupational therapists' evaluations should include determining the impact of poststroke SN. OBJECTIVE: To investigate occupational therapists' confidence, knowledge, current practices, barriers, and facilitators when assessing for SN in adult stroke survivors. DESIGN: A 30-item survey was created with guidance from stroke rehabilitation occupational therapists who reviewed the survey for face and content validity. SETTING: Online survey. PARTICIPANTS: Occupational therapist survey responders (N = 76). OUTCOMES AND MEASURES: Self-report assessments were used to measure occupational therapists' confidence in identifying SN, SN assessment practices, and barriers to and facilitators of SN assessment. Knowledge of SN signs and symptoms, neuroanatomy, and clinical presentation were measured with a three-question quiz. RESULTS: Eighty-one percent of the respondents reported a high level of confidence in identifying SN, and 70% reported routinely assessing for SN, with 81% using clinical observation rather than standardized tools as the primary assessment method. Barriers to SN assessment included time and resources. CONCLUSIONS AND RELEVANCE: Most respondents, despite reporting high levels of confidence with routine SN assessments, did not use standardized SN measures and demonstrated suboptimal knowledge of SN. These results emphasize the need to increase clinical education about SN and its assessments. Plain-Language Summary: This study gathered baseline information on an underinvestigated topic-occupational therapists' education, confidence, current practices, barriers, and facilitators when assessing for spatial neglect in adult stroke survivors. The study results also contribute to future research on occupational therapists' current confidence and knowledge when assessing for spatial neglect.

Persistent aura, visual snow, and other visual symptoms.

In neurology practice, it is common to encounter a variety of visual complaints. Historically, in the absence of known ocular pathology, epilepsy, or insult to the central nervous system, positive symptoms were assumed to be migrainous in origin. This assumption was sometimes made even in the absence of a history of migraine. In the past decade, there has been considerable effort to better delineate and study nonmigrainous visual phenomena, with the most extensive focus on a newly defined syndrome, visual snow syndrome (VSS). The heightened awareness of visual snow as a symptom and syndrome has greatly enhanced the understanding of this visual phenomenon; however, in the last few years, there has been an almost pendulous swing in clinic, with patients now being given the diagnosis of VSS for any dots or flickering they may have in their vision. To avoid clinical misdiagnosis, it is critical that we expand our understanding not just of VSS but also of underlying pathologies that may present similarly. This chapter will review classical migraine aura, persistent migraine aura, visual snow and a number of positive and negative visual complaints that are on the differential when seeing patients with suspected aura or visual snow. This is followed by an in-depth discussion on the current understanding of the presenting symptoms, pathophysiology, evaluation and management of VSS. We also outline secondary causes of visual snow.

Task-based and Magnified Mirror Therapy for Unilateral Spatial Neglect among post-stroke subjects: Study protocol for a randomized controlled trial.

BACKGROUND: Unilateral spatial neglect (USN) is a commonly occurring neurocognitive disability after a stroke. The neglect may affect the motor recovery of the upper and lower limbs and functional performances. Mirror therapy, a simple and economical approach has the potential to reduce the USN and related impairments. AIM: The primary objective of this study is to determine the effectiveness of task-based and magnified mirror therapy on the USN and on the motor recovery of the post-stroke subjects. The secondary objective is to investigate the effectiveness of the intervention on the function and disability of the subjects. METHODS: In this randomized controlled, assessor-blinded trial, 86 post-stroke subjects will be recruited from the neuro-rehabilitation laboratory of a rehabilitation institute, located in northern India. The participants,aged20 to 80 years, with 1 to 36 months of stroke onset, hemiparesis, and the USN, will be considered eligible for the study. In addition to the conventional rehabilitation, the experimental group(n = 43) will receive 40 sessions (8 weeks) of Task-based and MAGnified Mirror Therapy for Unilateral Spatial Neglect (T-MAGUSN). The control group (n = 43) will undergo a dose-matched conventional program only. The participants will be assessed at baseline, post-intervention and 4-week follow-up using primary (Line Bisection Test, Letter Cancellation Test, and Fugl-Myer Assessment) and secondary (Catherine Bergego Scale, Berg Balance Scale, Functional Ambulation Classification, Modified Rankin Scale) outcome measures. DISCUSSION: This proposed study will lead to the development of a novel rehabilitation protocol for the management of USN, aiming to enhance motor and functional recovery. The investigation will consider both the upper and lower limbs for the intervention, reducing the impact of cognitive disability in stroke. TRIAL REGISTRATION: Clinical Trial Registry of India (CTRI) as CTRI/2023/05/053184 (www.ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=74659).

Zooming in on abnormal local and global processing biases after stroke: Frequency, lateralization, and associations with cognitive functions.

OBJECTIVES: The 'attentional spotlight' can be adjusted depending on the task requirements, resulting in processing information at either the local or global level. Stroke can lead to local or global processing biases, or the inability to simultaneously attend both levels. In this study, we assessed the (1) prevalence of abnormal local and global biases following stroke, (2) differences between left- and right-sided brain damaged patients, and (3) relations between local and global interference, the ability to attend local and global levels simultaneously, and lateralized attention, search organization, search speed, visuo-construction, executive functioning, and verbal (working) memory. METHODS: Stroke patients admitted for inpatient rehabilitation completed directed (N = 192 total; N = 46 left-sided/N = 48 right-sided lesion) and divided (N = 258 total; N = 67 left-sided/N = 66 right-sided lesion) local-global processing tasks, as well as a conventional neuropsychological assessment. Processing biases and interference effects were separately computed for directed and divided tasks. RESULTS: On the local-global tasks, 7.8-10.9% of patients showed an abnormal local bias and 6.3-8.3% an abnormal global bias for directed attention, and 5.4-10.1% an abnormal local bias and 6.6-15.9% an abnormal global bias for divided attention. There was no significant difference between patients with left- and right-sided brain damage. There was a moderate positive relation between local interference and search speed, and a small positive relation between global interference and neglect. CONCLUSIONS: Abnormal local and global biases can occur after stroke and might relate to a range of cognitive functions. A specific bias might require a different approach in assessment, psycho-education, and treatment.

Impact of Spatial Neglect on Activity and Participation: A Mixed-Methods Study.

Post-stroke neglect is disabling, yet it is unclear whether existing assessments capture the extent neglect affects activity and participation. The objective of the study is to explore stroke survivor and caregiver perspectives on how neglect affects activity and participation and to compare their experiences to neglect assessments items. We conducted an explanatory sequential mixed-methods study by conducting semi-structured interviews with stroke survivors (n = 7) and caregivers (n = 7) analyzed using thematic analysis. Stroke survivors completed the Catherine Bergego Scale (CBS) and Behavioral Inattention Test (BIT). Descriptive analyses characterized participant's neglect. The standardized CBS and BIT tests indicated that stroke survivors demonstrated mild-to-moderate (CBS) or no-to-mild (BIT) neglect. In contrast, the qualitative data revealed serious safety concerns and significant ongoing difficulties participating in school, work, and family activities because of neglect. Current assessments may not measure the impact of neglect on activity or participation in life for stroke survivors.

Individuals with neglect after stroke experience disability. This study interviewed individuals with neglect and their caregivers to understand whether clinical assessments capture the impact that neglect has on their daily life. Results show that existing assessments may not fully measure the challenges that individuals experience.

Unilateral spatial neglect affected by right-sided stimuli in a three-dimensional virtual environment: A preliminary proof-of-concept study.

Unilateral spatial neglect (USN) is defined as the inability to attend and see on one side, which seriously interferes with daily life. Clinically, patients with left USN commonly demonstrate a striking immediate capture of attention from ipsilesional, right-sided items as soon as a visual scene unfolds (i.e., magnetic attraction [MA]). Therefore, this preliminary study utilized a three-dimensional (3D) virtual environment to evaluate the effects of eliminating stimuli in the rightward space and directing attention to the left on neglect symptoms. METHODS: Seven patients with USN participated in this study, and two types of visual stimuli were created: the numbers and objects in the 3D virtual environment. To eliminate the visual stimuli on the right side, a moving slit was introduced in the virtual environment. During the experiment, patients were required to orally identify each object and number both in moving and nonmoving slit conditions. RESULTS: A statistical comparison of scores with and without the moving slit in the 3D virtual space indicated significant changes in the object stimuli condition; however, no statistically significant difference was observed in the number stimuli condition. CONCLUSIONS: Masking the right side within the 3D virtual space increased the number of objects that can be recognized on the left side by patients with USN. The results may allow interventions in a virtual reality environment that closely resembles the patient's real-life space.Clinical Relevance-Magnetic attraction is a symptom seen in patients in clinical practice, but there is no method of rehabilitation. The proposed moving slit method is expected to be effective because it enables attention guidance in a three-dimensional space.

Immersive virtual reality gameplay detects visuospatial atypicality, including unilateral spatial neglect, following brain injury: a pilot study.

BACKGROUND: In neurorehabilitation, problems with visuospatial attention, including unilateral spatial neglect, are prevalent and routinely assessed by pen-and-paper tests, which are limited in accuracy and sensitivity. Immersive virtual reality (VR), which motivates a much wider (more intuitive) spatial behaviour, promises new futures for identifying visuospatial atypicality in multiple measures, which reflects cognitive and motor diversity across individuals with brain injuries. METHODS: In this pilot study, we had 9 clinician controls (mean age 43 years; 4 males) and 13 neurorehabilitation inpatients (mean age 59 years; 9 males) recruited a mean of 41 days post-injury play a VR visual search game. Primary injuries included 7 stroke, 4 traumatic brain injury, 2 other acquired brain injury. Three patients were identified as having left sided neglect prior to taking part in the VR. Response accuracy, reaction time, and headset and controller raycast orientation quantified gameplay. Normative modelling identified the typical gameplay bounds, and visuospatial atypicality was defined as gameplay beyond these bounds. RESULTS: The study found VR to be feasible, with only minor instances of motion sickness, positive user experiences, and satisfactory system usability. Crucially, the analytical method, which emphasized identifying 'visuospatial atypicality,' proved effective. Visuospatial atypicality was more commonly observed in patients compared to controls and was prevalent in both groups of patients-those with and without neglect. CONCLUSION: Our research indicates that normative modelling of VR gameplay is a promising tool for identifying visuospatial atypicality after acute brain injury. This approach holds potential for a detailed examination of neglect.

[Simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions].

A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions. Although his overall cognitive function was almost normal, he exhibited reduced visual sensitivity in the homonymous lower left quadrant of the visual field, left unilateral spatial neglect (USN), and simultanagnosia. Left USN improved 4 months after the onset of infarction; however, simultanagnosia persisted. To the best of our knowledge, this is the first case of simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions.

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.

Spatial Neglect Therapy With the Augmented Reality App "Negami" for Active Exploration Training: A Randomized Controlled Trial on 20 Stroke Patients With Spatial Neglect.

OBJECTIVE: To investigate the efficacy of the augmented reality (AR) app "Negami" as an active exploration training for the treatment of spatial neglect. Improvements of the ipsilesional attention and orientation bias (and resulting contralesional neglect) will be examined in stroke patients with spatial neglect and compared with a control group. DESIGN: Randomized controlled trial with an experimental Negami group, consisting of patients with spatial neglect, and a group of neglect patients receiving standard neglect therapy. SETTING: Three rehabilitation hospitals. PARTICIPANTS: Twenty right hemispheric stroke patients with spatial neglect (N=20). INTERVENTION: Over a period of 2 weeks, both groups received 5 training sessions per week (à 25 minutes). Neglect behavior was assessed weekly over a 5-week period, with the Negami therapy group receiving a second follow-up assessment at 1-to-2-month intervals after completion of training. MAIN OUTCOME MEASURES: Letter Cancellation, Bells Test, Copying Task, Line Bisection Task, and a self-developed "Exploration Test". RESULTS: Both groups improved significantly. While the Negami therapy group improved in 4 of 5 neglect tests used, the standard therapy group improved in only 1 of these tests. We observed significantly better improvement in the Negami group already after the first week of training. This difference was also significant after the end of the training as well as 1 week after the end of training and remained stable 1-2 months after the end of treatment. CONCLUSION: Negami can be used as an effective alternative or addition to current standard neglect therapy, and may even be superior to it.

Optokinetic stimulation effects in the management of unilateral spatial neglect in patients with chronic stroke: study protocol for a randomised controlled trial.

INTRODUCTION: Unilateral spatial neglect (USN) is a stroke complication of stroke. Optokinetic stimulation (OKS) is one of the treatments, but its effects on motor symptoms, such as poverty or alterations in movements on the affected side, are not clear yet. The aim of this study will be to evaluate the OKS effects on the perceptual and postural complications of patients with USN. METHODS AND ANALYSIS: Randomised double-blinded clinical trial, with an intervention group that will undergo OKS and a control placebo group. The research will take place at the Faculty of Nursing and Physiotherapy, University of Salamanca, 102 patients older than 18 years with diagnosed USN will participate. The intervention group will receive 2 weekly OKS session for 10 weeks. Virtual reality glasses will be used for the application of a video. The video will project OKS at a preset speed and will request the participant's attention throughout the session. The control group will receive a placebo treatment, through a virtual reality video. The measurement variables will be posturography, Fluff test, line bisection, Fullerton Advance Balance Scale and Diller's cancellation test. ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee University of Salamanca on February 2020 (registration number: 584). All patients in the study will be informed about the objective of the study and will give their written informed consent to participate in the study. The anonymised database will be available from the publication of the results for 10 years in the repository of the University of Salamanca GREDOS (https://gredos.usal.es/). The trial results will be shared with the scientific community at international conferences and by publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04663646.

Prism adaptation therapy in spatial neglect: The importance of connectional anatomy.

The meta-analysis conducted by Székely et al. described the lack of beneficial effect of prism adaptation in neglect patients. The authors concluded that the results did "not support the routine use of prism adaptation as a therapy for spatial neglect". However, a possible nuance to this conclusion could be that the response (or lack thereof) of neglect patients to prism adaptation may actually depend on the connectional anatomy of their lesion. We develop this idea in our commentary, in order to offer a more balanced perspective on the implications of the findings obtained by Székely et al.

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.

Discriminative value of different combinations of tests to detect unilateral neglect in patients with right hemisphere damage.

BACKGROUND AND PURPOSE: This study was undertaken to assess the most sensitive combination of tests to detect peripersonal unilateral neglect (UN) after stroke. METHODS: The present study is a secondary analysis of a previously reported multicentric study of 203 individuals with right hemisphere damage (RHD), mainly subacute stroke, 11 weeks postonset on average, and 307 healthy controls. A battery of seven tests, providing 19 age- and education-adjusted z-scores, were given: the bells test, line bisection, figure copying, clock drawing, overlapping figures test, and reading and writing. Statistical analyses used a logistic regression and a receiver operating characteristic (ROC) curve after adjustment on demographic variables. RESULTS: A combination of four z-scores based on the following three tests provided good discrimination of patients with RHD from matched healthy controls: the starting point and the difference between the number of omissions on left and right sides from the bells test, rightward deviation in bisection of long lines (20 cm), and left-sided omissions in a reading task. The area under the ROC curve was 0.865 (95% confidence interval = 0.83-0.901), with sensitivity = 0.68, specificity = 0.95, accuracy = 0.85, positive predictive value = 0.90, and negative predictive value = 0.82. CONCLUSIONS: The most sensitive and parsimonious combination of tests to detect UN after stroke relies on four scores from three simple tests (bells test, line bisection, and reading). Future study is warranted to assess its ability to account for the functional difficulties of UN in daily life in the patient's actual environment.