Acute right opercular stroke-associated polyopic heautoscopy and hallucinations caused by disconnection to the inferior parietal lobule through the superior longitudinal fasciculus III: A single case study.

Illusory neuropsychiatric symptoms such as hallucinations or the feeling of a presence (FOP) can occur in diffuse brain lesion or dysfunction, in psychiatric diseases as well as in healthy individuals. Their occurrence due to focal brain lesions is rare, most probably due to underreporting, which limits progress in understanding their underlying mechanisms and anatomical determinants. In this single case study, an 86-year-old patient experienced, in the context of an acute right central opercular ischemic stroke, visual hallucinatory symptoms (including palinopsia), differently lateralized auditory hallucinations and FOP. This unusual clinical constellation could be precisely documented and illustrated while still present, allowing a realistic and immersive visual experience validated by the patient. The acute stroke appeared to be their most plausible cause (after exclusion of other etiologies). Furthermore, accurate analysis of tractographic data suggested that disruption in the posterior bundle of the superior longitudinal fasciculus connecting the stroke lesion to the inferior parietal lobule was the anatomical substrate explaining the FOP and, indirectly, also hallucinations through whiter matter involvement, in coherence with existing literature. We could finally elaborate on symptoms taxonomy and phenomenology (e.g., polyopic heautoscopy, hallucinatory FOP, etc), and on patient's remarkable distancing from them (with some therapeutic implications supported by plausibly engaged mechanisms). This case not only authentically enriched the description of such rare combination of heterogenous illusory symptoms through this novel visualization-based reporting approach, but disclosed an unrevealed anatomo-clinical link relating all of them to the acute stroke lesion through an association fiber, thereby contributing to the understanding of these intriguing symptoms and their determinants.

Assessment and treatment of visuospatial neglect using active learning with Gaussian processes regression.

Visuospatial neglect is a disorder characterised by impaired awareness for visual stimuli located in regions of space and frames of reference. It is often associated with stroke. Patients can struggle with all aspects of daily living and community participation. Assessment methods are limited and show several shortcomings, considering they are mainly performed on paper and do not implement the complexity of daily life. Similarly, treatment options are sparse and often show only small improvements. We present an artificial intelligence solution designed to accurately assess a patient's visuospatial neglect in a three-dimensional setting. We implement an active learning method based on Gaussian process regression to reduce the effort it takes a patient to undergo an assessment. Furthermore, we describe how this model can be utilised in patient oriented treatment and how this opens the way to gamification, tele-rehabilitation and personalised healthcare, providing a promising avenue for improving patient engagement and rehabilitation outcomes. To validate our assessment module, we conducted clinical trials involving patients in a real-world setting. We compared the results obtained using our AI-based assessment with the widely used conventional visuospatial neglect tests currently employed in clinical practice. The validation process serves to establish the accuracy and reliability of our model, confirming its potential as a valuable tool for diagnosing and monitoring visuospatial neglect. Our VR application proves to be more sensitive, while intra-rater reliability remains high.

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.

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.

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.

[Clinical examination of spatial neglect and other disorders of spatial cognition]. / Klinische Untersuchung des unilateralen Neglects und weiterer Störungen der Raumkognition.

Neglect occurring after stroke, neoplasms or degenerative processes can lead to considerable disability in everyday life as can other disorders of spatial orientation. Therefore, a dedicated examination and early diagnostic classification are obligatory. Behavioral tests are helpful in this respect, enabling the clinician to obtain an initial overview of the existing deficits even at the patient's bedside. The clinical (bedside) examination of spatial neglect as well as the corresponding differential diagnostic procedure for the clarification of (possibly additionally or exclusively existing) hemianopia and extinction, as well as the examination of disorders of visuospatial perception, visuoconstructive disorders, topographic disorders, Bálint's syndrome, simultanagnosia, and optic ataxia are presented. The presentation is based on the newly revised (year 2023) guidelines of the Association of the Scientific Medical Societies in Germany (AWMF) on this subject area.

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.

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.

An immersive virtual reality system for ecological assessment of peripersonal and extrapersonal unilateral spatial neglect.

BACKGROUND: Unilateral spatial neglect (USN) is a debilitating neuropsychological syndrome that often follows brain injury, in particular a stroke affecting the right hemisphere. In current clinical practice, the assessment of neglect is based on old-fashioned paper-and-pencil and behavioral tasks, and sometimes relies on the examiner's subjective judgment. Therefore, there is a need for more exhaustive, objective and ecological assessments of USN. METHODS: In this paper, we present two tasks in immersive virtual reality to assess peripersonal and extrapersonal USN. The tasks are designed with several levels of difficulty to increase sensitivity of the assessment. We then validate the feasibility of both assessments in a group of healthy adult participants. RESULTS: We report data from a study with a group of neurologically unimpaired participants (N = 39). The results yield positive feedback on comfort, usability and design of the tasks. We propose new objective scores based on participant's performance captured by head gaze and hand position information, including, for instance, time of exploration, moving time towards left/right and time-to-reach, which could be used for the evaluation of the attentional spatial bias with neurological patients. Together with the number of omissions, the new proposed parameters can result in lateralized index ratios as a measure of asymmetry in space exploration. CONCLUSIONS: We presented two innovative assessments for USN based on immersive virtual reality, evaluating the far and the near space, using ecological tasks in multimodal, realistic environments. The proposed protocols and objective scores can help distinguish neurological patients with and without USN.

Association of delirium and spatial neglect in patients with right-hemisphere stroke.

BACKGROUND: Delirium, an acute and fluctuating decline in cognitive functioning, increases mortality and length of hospital stays (LOS) and adversely affects functional outcomes. Previous studies suggested that the incidence of delirium may be increased in right-hemisphere strokes. Similarly, spatial neglect, a disabling deficit in unilateral spatial processing, is more common and more severe following a right-sided stroke. Spatial neglect has been established as a risk factor for delirium. OBJECTIVE: It was hypothesized that functionally relevant spatial neglect and delirium are associated in patients with right-hemisphere stroke during acute inpatient rehabilitation. Data were examined from consecutive unilateral stroke patients evaluated with the 3-minute diagnostic interview for confusion assessment method (3D-CAM) and the Catherine Bergego Scale (CBS) via the Kessler Foundation Neglect Assessment Process (KF-NAP). DESIGN: A retrospective, cohort study. SETTING: Data collected in an acute inpatient rehabilitation facility. PARTICIPANTS: Six hundred twenty six patients with stroke were included. MAIN OUTCOME MEASURES: The measures were the relative risk of patients with right-hemisphere stroke having delirium when also positive for spatial neglect compared to patients with right-hemisphere stroke without spatial neglect, the incidence of 3D-CAM positive results by stroke hemisphere, and the effect of spatial neglect and delirium on functional outcomes for patients with right-brain stroke patients. RESULTS: There was a significantly higher risk of delirium in patients with right-hemisphere stroke with spatial neglect compared to patients with right-hemisphere stroke without spatial neglect. The rates of 3D-CAM positive results were not statistically different for left- compared to right-hemisphere strokes. Both delirium and spatial neglect had significant adverse effects on right-hemisphere stroke patients' functional independence. CONCLUSIONS: The results demonstrate an association between spatial neglect and delirium in patients with right hemisphere stroke in the acute inpatient rehabilitation setting. Because of the negative effect of these impairments on functional outcomes after stroke, prevention, early detection, and targeted treatments should be prioritized for these patients.

Clinical assessment of unilateral spatial neglect dissociations and heterogeneities: A narrative synthesis.

OBJECTIVE: Unilateral spatial neglect (USN) is a neuropsychological syndrome whose symptoms differ considerably between patients. Several heterogeneities and dissociations have been described between processing stages, spatial regions, reference frames, or sensory modalities. However, in clinical practice, current routine tests rarely assess the different USN subtypes. There is a real lack of practice guidance for clinicians to help them choosing the right USN assessment tools for specific USN aspects. METHOD: The present article is a narrative synthesis based on a systematic literature search of (a) the dissociations and heterogeneities that can appear in USN and of (b) the different clinical tools available for their assessment. RESULTS: Several tools have been developed to better assess USN heterogeneities. This review highlights their potential relevance and advocates for their widespread use in a clinical practice context. However, it also raised the issue of the lack of standardized clinical tools for the evaluation of some USN aspects. CONCLUSION: While USN heterogeneities and dissociations are difficult to assess in current clinical practice, there is a real need to improve their assessment. This will allow clinicians to establish the individual USN profile of each patient not only in terms of severity but also of impaired aspects in order to provide them the rehabilitation program that suits the best their needs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Spatial neglect in the digital age: Influence of presentation format on patients' test behavior.

OBJECTIVE: Computerized neglect tests could significantly deepen our disorder-specific knowledge by effortlessly providing additional behavioral markers that are hardly or not extractable from existing paper-and-pencil versions. This study investigated how testing format (paper versus digital), and screen size (small, medium, large) affect the Center of cancelation (CoC) in right-hemispheric stroke patients in the Letters and the Bells cancelation task. Our second objective was to determine whether a machine learning approach could reliably classify patients with and without neglect based on their search speed, search distance, and search strategy. METHOD: We compared the CoC measure of right hemisphere stroke patients with neglect in two cancelation tasks across different formats and display sizes. In addition, we evaluated whether three additional parameters of search behavior that became available through digitization are neglect-specific behavioral markers. RESULTS: Patients' CoC was not affected by test format or screen size. Additional search parameters demonstrated lower search speed, increased search distance, and a more strategic search for neglect patients than for control patients without neglect. CONCLUSION: The CoC seems robust to both test digitization and display size adaptations. Machine learning classification based on the additional variables derived from computerized tests succeeded in distinguishing stroke patients with spatial neglect from those without. The investigated additional variables have the potential to aid in neglect diagnosis, in particular when the CoC cannot be validly assessed (e.g., when the test is not performed to completion).

Visual neglect: does it exist in children with unilateral brain lesion? A systematic review.

Visual Neglect (VN) is a common neuropsychological disorder in adults with unilateral brain lesion (UBL), characterized by the failure to attend and to report sensory events occurring in one side of space, contralateral to an area of brain damage. Less is known about VN expression in children following brain injury. The aim of this systematic review is to evaluate the presence of VN in UBL children and to identify the best neuropsychological assessment's tool for this population. A comprehensive search of 4 databases (Pubmed, Cochrane Database, SCOPUS, DARE) was undertaken from May 2020 to January 2021. Inclusion criteria were (i) subjects less than 18 years with cerebral lesions and with MRI, (ii) specific neuropsychological assessments for VN, (iii) studies published in English since 2000. A total of 309 articles were found in the initial search but only 10 observational studies met the full inclusion criteria. In these studies, 1051 subjects were evaluated for VN, of them 749 were controls and 302 had brain lesions. The two most common types of neuropsychological tools used in children with unilateral brain damage to assess the presence of VN were target cancellation tests and drawing tests.This review confirms the possibility that children with UBL can develop VN, even if it is not very clear which brain structure's characteristics can increase this risk. Children with right lesion showed visuo-spatial attention deficits focalized on the contralateral side, compatible with diagnosis of VN, while children with left lesion showed more generalized attention difficulties. The overall level of evidence correlating the presence of VN and different types of UBL in children was low and neuropsychological assessment of VN for children are sparse. Some important limitations of this review must be reported: the limited number of studies included, the administration of various types of tests to evaluate VN, the lack of information regarding the cognitive level of children in most of the studies. Further research is needed to understand patterns of VN based on brain structure and time since lesion.Systematic Review Registration: ID on PROSPERO: CRD42021281993.

To treat or not to treat? High-potency benzodiazepine use in a case of comorbid hallucinogen persisting perception disorder and alcohol use disorder.

Hallucinogen persisting perception disorder (HPPD) is characterized by visual disturbances that resemble psychedelic intoxication and linger after use has ceased. The most common substances precipitating HPPD, lysergic acid diethylamide (LSD) and psilocybin, are posited to do so via damage to serotonergic neurons involved in vision. Mr. N is a 37-year-old with a history of alcohol, cannabis, LSD, cocaine, and nicotine use disorders who described visual distortions that resolved when he drank heavily or received benzodiazepines for withdrawal. He did not appear psychotic. Over 20 years after his last LSD use, he continued to experience illusions of halos around objects, moving walls, and figures appearing cartoonish. He understood that his perceptual disturbances were not reality based. During hospitalization for suicidal ideation, laboratory tests, head computed tomography (CT), and electroencephalogram (EEG) studies offered no explanation for his visual disturbances other than HPPD. The visual distortions remitted with scheduled clonazepam treatment, although chemical dependency treatment programs were hesitant to accept him while on a benzodiazepine. This case emphasizes the importance of diagnostic clarification when patients present with perceptual disturbances that do not fit typical psychotic presentations. Our discussion will distinguish misperceptions from hallucinations and review the pathophysiology of HPPD. Last, we will discuss management strategies for patients with co-occurring HPPD and substance use disorders. It is necessary to discern the correct cause of visual disturbances in order to provide proper treatment. The risks and benefits of long-term benzodiazepine use must be weighed when deciding whether to prescribe them for patients with comorbid HPPD and alcohol use disorder. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The attention atlas virtual reality platform maps three-dimensional (3D) attention in unilateral spatial neglect patients: a protocol.

BACKGROUND: Deficits in visuospatial attention, known as neglect, are common following brain injury, but underdiagnosed and poorly treated, resulting in long-term cognitive disability. In clinical settings, neglect is often assessed using simple pen-and-paper tests. While convenient, these cannot characterise the full spectrum of neglect. This protocol reports a research programme that compares traditional neglect assessments with a novel virtual reality attention assessment platform: The Attention Atlas (AA). METHODS/DESIGN: The AA was codesigned by researchers and clinicians to meet the clinical need for improved neglect assessment. The AA uses a visual search paradigm to map the attended space in three dimensions and seeks to identify the optimal parameters that best distinguish neglect from non-neglect, and the spectrum of neglect, by providing near-time feedback to clinicians on system-level behavioural performance. A series of experiments will address procedural, scientific, patient, and clinical feasibility domains. RESULTS: Analyses focuses on descriptive measures of reaction time, accuracy data for target localisation, and histogram-based raycast attentional mapping analysis; which measures the individual's orientation in space, and inter- and intra-individual variation of visuospatial attention. We will compare neglect and control data using parametric between-subjects analyses. We present example individual-level results produced in near-time during visual search. CONCLUSIONS: The development and validation of the AA is part of a new generation of translational neuroscience that exploits the latest advances in technology and brain science, including technology repurposed from the consumer gaming market. This approach to rehabilitation has the potential for highly accurate, highly engaging, personalised care.

Gaze-contingent display technology can help to reduce the ipsilesional attention bias in hemispatial neglect following stroke.

BACKGROUND: Hemispatial neglect results from unilateral brain damage and represents a disabling unawareness for objects in the hemispace opposite the brain lesion (contralesional). The patients' attentional bias for ipsilesional hemispace represents a hallmark of neglect, which results from an imbalanced attentional priority map in the brain. The aim of this study was to investigate whether gaze-contingent display (GCD) technology, reducing the visual salience of objects in ipsilesional hemispace, is able to rebalance this map and increase awareness and exploration of objects in the neglected contralesional hemispace. METHODS: Using remote eye-tracking, we recorded gaze positions in 19 patients with left hemispatial neglect following right-hemisphere stroke and 22 healthy control subjects, while they were watching static naturalistic scenes. There were two task conditions, free viewing (FV) or goal-directed visual search (VS), and four modification conditions including the unmodified original picture, a purely static modification and two differently strong modifications with an additional gaze-contingent mask (GC-LOW, GC-HIGH), that continuously reduced color saturation and contrast of objects in the right hemispace. RESULTS: The patients' median gaze position (Center of Fixation) in the original pictures was markedly deviated to the right in both tasks (FV: 6.8° ± 0.8; VS: 5.5° ± 0.7), reflecting the neglect-typical ipsilesional attention bias. GC modification significantly reduced this bias in FV (GC-HIGH: d = - 3.2 ± 0.4°; p < 0.001). Furthermore, in FV and VS, GC modification increased the likelihood to start visual exploration in the (neglected) left hemifield by about 20%. This alleviation of the ipsilesional fixation bias was not associated with an improvement in detecting left-side targets, in contrast, the GC mask even decreased and slowed the detection of right-side targets. Subjectively, patients found the intervention pleasant and most of the patients did not notice any modification. CONCLUSIONS: GCD technology can be used to positively influence visual exploration patterns in patients with hemispatial neglect. Despite an alleviation of the neglect-related ipsilesional fixation bias, a concomitant functional benefit (improved detection of contralesional targets) was not achieved. Future studies may investigate individualized GCD-based modifications as augmented reality applications during the activities of daily living.

A Proposal for a New Index to Quantify the Ratio of Near and Far Spatial Neglect Using Immersive Virtual Reality Technology: A Technical Report.

Unilateral spatial neglect (USN) is defined as impaired attention to sensory stimuli on one side, which can exist for near and far spaces combined or independently. Thus, quantifying both near- and far-space neglect is crucial. This study aims to propose an index to quantify the near/far spatial neglect ratio to describe the USN symptoms' characteristics in each patient using immersive virtual reality (VR) technology. An object-detecting task was performed for five USN patients in a three-dimensional VR space. The examiner recorded the positional data of the objects that were recognized by the USN patient using coordinate data. The near/far ratio (NFRatio) was calculated using the proposed equation to quantify the difference in neglect severity in near and far spaces of each patient. Among the patients, four tended to have greater far-space neglect, and one tended to have greater near-space neglect. Moreover, the near/far spatial neglect ratio was shown to vary according to height. This is the first study to propose immersive VR to quantify the near and far spatial neglect. However, further study is needed to assess its reliability and validity and describe its clinical usability. Clinical Relevance- In clinical practice USN symptoms cause neglected symptoms in 3D space so the proposed system will be of high clinical significance if 3D assessment is realized.

Quantification of Unilateral Spatial Neglect Symptoms Based on Identification of Exploratory Ability.

Unilateral spatial neglect (USN) is the failure to report, respond, or orient to novel or meaningful stimuli presented on the side opposite a brain lesion. In our previous study, we reported that the ability of patients with USN to perform when the neck was fixed (called cognitive ability) was different from that when the neck was not fixed (called exploratory ability). However, the exploratory ability index has not been clarified, and cognitive and exploratory abilities have not been quantified. Thus, in this study, we identified neck movement as an exploratory ability index for patients with USN. Furthermore, we proposed equations to quantify cognitive and exploratory abilities and suggested that these equations can be used to understand patients' neglect symptoms in more detail. These findings revealed that the two evaluations of cognitive and exploratory abilities are crucial in USN evaluation and are key to individualizing intervention for each patient.

Detection of Stroke-Induced Visual Neglect and Target Response Prediction Using Augmented Reality and Electroencephalography.

We aim to build a system incorporating electroencephalography (EEG) and augmented reality (AR) that is capable of identifying the presence of visual spatial neglect (SN) and mapping the estimated neglected visual field. An EEG-based brain-computer interface (BCI) was used to identify those spatiospectral features that best detect participants with SN among stroke survivors using their EEG responses to ipsilesional and contralesional visual stimuli. Frontal-central delta and alpha, frontal-parietal theta, Fp1 beta, and left frontal gamma were found to be important features for neglect detection. Additionally, temporal analysis of the responses shows that the proposed model is accurate in detecting potentially neglected targets. These targets were predicted using common spatial patterns as the feature extraction algorithm and regularized discriminant analysis combined with kernel density estimation for classification. With our preliminary results, our system shows promise for reliably detecting the presence of SN and predicting visual target responses in stroke patients with SN.