Unilateral Spatial Neglect Symptoms Research Articles

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.

Reaction time analysis in patients with mild left unilateral spatial neglect employing the modified Posner task: vertical and horizontal dimensions.

Unilateral spatial neglect (USN) is a common neurological syndrome that develops after a right hemisphere lesion. By examining the performance of the modified Posner task added to the vertical dimensions of the left and right visual fields, we studied whether the lower left area had different neglect symptoms than the other locations. 41 patients with right hemisphere damage were classified into those with mild USN (USN+ ; n = 20) and without USN (USN- ; n = 21). Twenty older participants made up the healthy control (HC; n = 20) group. All participants recorded deficits in the paper-and-pencil tests established for neglect and reaction times in the modified Posner task. In the paper-and-pencil tests, there was no difference in deficit between the upper and lower left visual fields in any of the groups. According to the modified Posner task, the USN+ group exhibited delays in reaction time in the lower left visual field rather than the upper left visual field. Importantly, reaction times were delayed, and USN symptoms persisted, particularly for the lower left quadrant. Our findings imply that the modified Posner task can accurately uncover neglect symptoms in the case of mild USN.

Effect of acupuncture on unilateral spatial neglect after stroke: A systematic review and meta-analysis of randomized controlled trials

ObjectiveTo systematically evaluate the effects of acupuncture in patients with unilateral spatial neglect (USN) after stroke. Data sourcesRelevant English- and Chinese- language studies published until 12th February 2022, were retrieved from China National Knowledge Infrastructure (CNKI), Wanfang, China Scientific Journals Database (VIP), SinoMed, PubMed, Cochrane Library, Embase, Web of Science and OVID. Review methodsRandomized controlled trials (RCTs) assessing the effects of acupuncture in patients with USN after stroke were included. Two researchers independently identified eligible studies and extracted the data. The methodological quality of the studies was evaluated using the Cochrane Handbook for Systematic Reviews of Interventions v5.1.0. ResultsTwelve studies (731 participants) were included. The meta-analysis found that compared with the control group, acupuncture increased MMSE, BI, MBI, and FMA scores and reduced the USN scores (all P < 0.05). These results indicated that acupuncture improved cognitive function, activities of daily living (ADLs), and motor function and relieved the degree of USN in patients with USN after stroke. ConclusionAcupuncture could promote the rehabilitation of cognitive function, ADLs, and motor function and relieve the symptoms of USN in patients with USN after stroke. It may be a good complementary treatment to rehabilitation therapy for USN.

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

ABSTRACT 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.

Immediate effects of head-mounted display adaptation in cases of unilateral spatial neglect: study of straight-ahead pointing.

[Purpose] This study aimed to clarify the effect of an adaptation of a deviation of the visual field in three axes on spatial cognition in patients with unilateral spatial neglect and distorted spatial perception in three dimensions. [Participants and Methods] Fifteen patients with cerebrovascular disease and symptoms of unilateral spatial neglect were included. Forty-eight pointing movements with a camera attached to a head-mounted display changed in three axes were compared with the control condition in which the camera was deflected only in the horizontal plane as with the prism adaptation. The main outcome measures were subjective straight-ahead pointing, line bisection, line cancellation, and star cancellation. [Results] The head-mounted display adaptive therapy was performed under conditions that varied in all three axes. The results indicated that it was possible to deflect the subjective straight-ahead pointing position to the lower left direction. [Conclusion] In contrast to the prism adaptation, which deflects the visual field in a single axis in the horizontal plane, the tri-axial adaptation corrected the median cognition in the left–right direction as well as the cognition of the body center, including the vertical direction.

Efficacy of Repetitive Transcranial Magnetic Stimulation Combined With Visual Scanning Treatment on Cognitive-Behavioral Symptoms of Unilateral Spatial Neglect in Patients With Traumatic Brain Injury: Study Protocol for a Randomized Controlled Trial.

Left hemispatial neglect (LHSN) is a frequent and disabling condition affecting patients who suffered from traumatic brain injury (TBI). LHSN is a neuropsychological syndrome characterized clinically by difficulties in attending, responding, and consciously representing the right side of space. Despite its frequency, scientific evidence on effective treatments for this condition in TBI patients is still low. According to existing literature, we hypothesize that in TBI, LHSN is caused by an imbalance in inter-hemispheric activity due to hyperactivity of the left hemisphere, as observed in LHSN after right strokes. Thus, by inhibiting this left hyperactivity, repetitive Transcranial Magnetic Stimulation (rTMS) would have a rebalancing effect, reducing LHSN symptoms in TBI patients. We plan to test this hypothesis within a single-blind, randomized SHAM controlled trial in which TBI patients will receive inhibitory i-rTMS followed by cognitive treatment for 15 days. Neurophysiological and clinical measures will be collected before, afterward, and in the follow-up. This study will give the first empirical evidence about the efficacy of a novel approach to treating LHSN in TBI patients.Clinical Trial Registration: https://www.clinicaltrials.gov/ct2/show/NCT04573413?cond=Neglect%2C+Hemispatial&cntry=IT&city=Bologna&draw=2&rank=2, identifier: NCT04573413.

Virtual Reality Tools for Assessing Unilateral Spatial Neglect: A Novel Opportunity for Data Collection.

Unilateral spatial neglect (USN) is a syndrome characterized by inattention to or inaction in one side of space and affects between 23-46% of acute stroke survivors. The diagnosis and characterization of these symptoms in individual patients can be challenging and often requires skilled clinical staff. Virtual reality (VR) presents an opportunity to develop novel assessment tools for patients with USN. We aimed to design and build a VR tool to detect and characterize subtle USN symptoms, and to test the tool on subjects treated with inhibitory repetitive transcranial magnetic stimulation (TMS) of cortical regions associated with USN. We created three experimental conditions by applying TMS to two distinct regions of cortex associated with visuospatial processing- the superior temporal gyrus (STG) and the supramarginal gyrus (SMG) - and applied sham TMS as a control. We then placed subjects in a virtual reality environment in which they were asked to identify the flowers with lateral asymmetries of flowers distributed across bushes in both hemispaces, with dynamic difficulty adjustment based on each subject's performance. We found significant differences in average head yaw between subjects stimulated at the STG and those stimulated at the SMG and marginally significant effects in the average visual axis. VR technology is becoming more accessible, affordable, and robust, presenting an exciting opportunity to create useful and novel game-like tools. In conjunction with TMS, these tools could be used to study specific, isolated, artificial neurological deficits in healthy subjects, informing the creation of VR-based diagnostic tools for patients with deficits due to acquired brain injury. This study is the first to our knowledge in which artificially generated USN symptoms have been evaluated with a VR task.

Ecological Virtual Reality Evaluation of Neglect Symptoms (EVENS): Effects of Virtual Scene Complexity in the Assessment of Poststroke Unilateral Spatial Neglect

Background. Unilateral spatial neglect (USN) is a highly prevalent and disabling poststroke impairment. USN is traditionally assessed with paper-and-pencil tests that lack ecological validity, generalization to real-life situations and are easily compensated for in chronic stages. Virtual reality (VR) can, however, counteract these limitations. Objective. We aimed to examine the feasibility of a novel assessment of USN symptoms in a functional shopping activity, the Ecological VR-based Evaluation of Neglect Symptoms (EVENS). Methods. EVENS is immersive and consists of simple and complex 3-dimensional scenes depicting grocery shopping shelves, where joystick-based object detection and navigation tasks are performed while seated. Effects of virtual scene complexity on navigational and detection abilities in patients with (USN+, n = 12) and without (USN−, n = 15) USN following a right hemisphere stroke and in age-matched healthy controls (HC, n = 9) were determined. Results. Longer detection times, larger mediolateral deviations from ideal paths and longer navigation times were found in USN+ versus USN− and HC groups, particularly in the complex scene. EVENS detected lateralized and nonlateralized USN-related deficits, performance alterations that were dependent or independent of USN severity, and performance alterations in 3 USN− subjects versus HC. Conclusion. EVENS’ environmental changing complexity, along with the functional tasks of far space detection and navigation can potentially be clinically relevant and warrant further empirical investigation. Findings are discussed in terms of attentional models, lateralized versus nonlateralized deficits in USN, and tasks-specific mechanisms.

Patients' characteristics and outcomes depending on complete or incomplete unilateral spatial neglect.

Unilateral spatial neglect (USN) is known to depress the activities of daily living. The purpose of this study was to clarify that categorizing the type of USN using line cancelation and line bisection tests is important when evaluating patients with acute intracerebral hemorrhage (ICH). In this study, patients with ICH were prospectively evaluated for the presence of USN using line cancelation and line bisection tests. They were classified into an incomplete USN group (iUSN=abnormal results in either test) or a complete USN group (cUSN=abnormal findings in both tests). We compared the initial severity of ICH and the outcomes of USN in the two groups. We were able to assess 16 patients, among whom 10 showed USN. Seven were then categorized as having iUSN and three as having cUSN. The median hematoma volume was larger in the cUSN group than in the iUSN group. The USN symptoms of patients in the iUSN group disappeared during the chronic phase, whereas the symptoms of patients in the cUSN group continued. The type of USN was associated with the initial severity of ICH and the persistence of USN.

Effects of acupuncture combined with rehabilitation training on unilateral spatial neglect

Objective To explore the effect of acupuncture combined with rehabilitation training on unilateral spatial neglect (USN). Methods One hundred stroke patients with USN were randomly divided into a treatment group (n=50) and a control group (n=50). Both groups were treated with routine rehabilitation training for 4 weeks, while the treatment group was additionally treated with acupuncture. Before and after the treatment, the degree of USN was evaluated in both groups along with the Fugl-Meyer assessment, the modified Barthel index and the incidence of shoulder pain. Results No significant differences were found between the 2 groups in any of the measurements before the treatment. After the treatment the incidence of shoulder pain in the treatment group was significantly lower than that in the control group. All the other measurements were significantly higher in the treatment group than in the control group. Conclusion Acupuncture combined with rehabilitation training can significantly improve the symptoms of unilateral spatial neglect, improve motor function in a hemiplegic limb and improve performance in the activities of daily living. Key words: Acupuncture; Stroke; Unilateral spatial neglect; Rehabilitation

Disturbed resting functional inter-hemispherical connectivity of the ventral attentional network in alpha band is associated with unilateral spatial neglect.

Unilateral spatial neglect (USN) is one of the most common symptoms of right hemisphere damage; its classical symptom is that patients fail to respond to information on their left side. It has been postulated that disturbance of 2 separate attentional networks relates to the occurrence of USN. However, little is known about the underlying mechanism and neuronal substrates. In this study, we measured spontaneous neural activity by means of magnetoencephalography in 13 patients with brain damage and 5 control subjects. To study the relationship between functional connectivity at rest and severity of USN symptoms, we determined the imaginary coherence values relating to the inter-hemispherical ventral and dorsal attentional networks, as well as the clinical severity of USN using neuropsychological tests and behavioral rating scales. The present results showed that inter-hemispherical connectivity in the ventral attentional network, especially between the left and right angular gyri, detected in the alpha band is associated with the severity of USN symptoms. This may suggest that connectivity of inter-hemispherical homologous regions of the ventral attentional network in the alpha band could be one of the biomarkers of attentional network imbalance occurring in patients with USN.

Brain Activity Stimulated by Prism Adaptation Tasks Utilized for the Treatment of Unilateral Spatial Neglect: A Study with fNIRS.

We investigated the neurological basis for efficacy of prism adaptation therapy, which is used for the treatment of poststroke unilateral spatial neglect (USN). Study subjects were 6 USN-positive (+), 6 USN-negative patients, and 6 healthy volunteer control subjects. USN was identified by the Behavioural Inattention Test (BIT). During the tasks, brain activity was assessed with fNIRS via changes in oxyHb concentration per unit length. There was no significant difference in the number of errors in the task between the 3 groups. However, in the USN(+) group there was a significantly greater reduction in oxyHb levels in the right parietal association cortex during the prism adaptation task than in the other 2 groups (P < 0.05). There was an immediate improvement in USN symptoms as well as a significant increase in oxyHb levels during the prism adaptation in the channels covering the right frontal and parietal lobes in 2 patients in the USN(+) group (P < 0.05). This result suggested that decreased activity in the right parietal association cortex, which is related to spatial perception, during the prism adaptation task and task-induced reorganization of the right frontal and parietal areas were involved in improvement in USN symptoms.

Effects of prism directionality and active movement adaptation on the symptoms of unilateral spatial neglect

Yoneda C, Saitoh E, Suzuki M, Yamada M. Effects of prism directionality and active movement adaptation on the symptoms of unilateral spatial neglect. Jpn J Compr Rehabil Sci 2011; 2: 1�4. Objective: Prism adaptation therapy is one of the treatment methods for unilateral spatial neglect (USN). In this study, we examined the infl uence of prism deviations toward the right and toward the left. We also studied the additional effects of hand movements as performance adaptation to prisms. Methods: Patients with left USN caused by stroke were split into 2 groups on the basis of whether or not they performed adaptation movements. In all the patients, prisms deviating the visual fi eld 10° to the right and to the left were used, and the adaptation task consisted of right index fi nger movements to reach 3 targets on a desk, 50 times each. During the movements, hand trajectories were visible. In the group in which adaptation movements were not performed, the participants wore the prisms for 20 minutes. A line bisection test using a 50-cm tape was used to evaluate the USN before and after treatment. Results: The use of left-deviating prisms resulted in worsening of the USN in the group in which adaptation movements were performed (p=0.01). In this group, the point of bisection showed a tendency to move toward the left (p=0.29) when right-deviating prisms were used. Conclusions: The results indicated that adaptation treatment using right-deviating prisms might be

Effects of prismatic adaptation on spatial gradients in unilateral neglect: A comparison of visual and auditory target detection with central attentional load

Prismatic adaptation is increasingly recognised as an effective procedure for rehabilitating symptoms of unilateral spatial neglect – producing relatively long-lasting improvements on a variety of spatial attention tasks. The mechanisms by which the aftereffects of adaptation change neglect patients’ performance on these tasks remain controversial. It is not clear, for example, whether adaptation directly influences the pathological ipsilesional attention bias that underlies neglect, or whether it simply changes exploratory motor behaviour. Here we used visual and auditory versions of a target detection task with a secondary task at fixation. Under these conditions, patients with neglect demonstrated a spatial gradient in their ability to orient to the brief, peripheral visual or auditory targets. Following prism adaptation, we found that overall performance on both the auditory and visual task improved, however, most patients in our sample did not show changes in their visual or auditory spatial gradient of attention, despite adequate aftereffects of adaptation and significant improvement in neglect on visual cancellation. Although there were individual cases that suggested prism-induced changes in visual target detection, and even reversal of the visual spatial gradient, such cases were not evident for the auditory modality. The findings indicate that spatial gradients in stimulus-driven attention may be less responsive to the effects of prism adaptation than neglect symptoms in voluntary orienting and exploratory behaviour. Individual factors such as lesion site and symptom severity may also determine the expression of prism effects on spatial neglect.

A single blinded randomised controlled pilot trial of prism adaptation for improving self-care in stroke patients with neglect

Prism adaptation has been shown to alleviate the symptoms of unilateral spatial neglect following stroke in single case and small group studies. The purposes of this single blinded pilot randomised controlled trial were to determine the feasibility of delivering prism adaptation treatment in a clinically valid sample and to assess its impact on self-care. Thirty seven right hemisphere stroke patients with unilateral spatial neglect were randomised into either prism adaptation (using 10 dioptre, 6 degree prisms) or sham treatment (using plain glasses) groups. Treatment was delivered each weekday for two weeks. Pointing accuracy, without vision of the finger, was recorded each day before treatment. Outcome was measured, by blinded assessors, four days and eight weeks after the end of treatment using the Catherine Bergego Scale (CBS) and the conventional neuropsychological tests from the Behavioural Inattention Test (BIT). Thirty four patients received treatment: 16 with prisms, 18 sham. Mean compliance was 99% and 97%, respectively. Over the treatment days only the prism treated group showed increased leftward bias in open loop pointing to targets on a touch screen. However, despite the group level changes in pointing behaviour no overall effect of the treatment on self-care or BIT were found.

Association between auditory and visual symptoms of unilateral spatial neglect

Unilateral spatial neglect due to right brain damage (RBD) can occur in several different sensory modalities in the same patient. Previous studies of the association between auditory and visual neglect have yielded conflicting outcomes. Most such studies have compared performance on relatively simple clinical measures of visual neglect, such as target cancellation, with that on more sophisticated measures of auditory perception. This is problematic because such tasks are typically not matched for the cognitive processes they exercise. We overcame this limitation by using equivalent visual and auditory versions of extinction and temporal-order judgment (TOJ) tasks. RBD patients demonstrated lateralized deficits on both visual and auditory tasks when compared with same-aged, healthy controls. Critically, a significant association between the severity of visual and auditory deficits was apparent on the TOJ task but not the extinction task, suggesting that even when task demands are matched across modalities, dissociations between visual and auditory neglect can be apparent. Across the auditory tasks, patients showed more pronounced deficits for verbal stimuli than for non-verbal stimuli. These findings have implications for recent models proposed to explain the role of spatial attention in multimodal perception.

Visuomotor Adaptation to Optical Prisms: A New Cure for Spatial Neglect?

In this issue, McIntosh and colleagues show that visual and haptic deficits in spatial neglect can be improved following a brief period of visuomotor adaptation to rightward displacing optical prisms. Their paper is the latest in a series of recent studies that have demonstrated the utility of prismatic adaptation in reducing the clinical symptoms of unilateral spatial neglect (Pisella et al., 2002; Rode et al., 1999; Rossetti et al., 1998; Rossetti et al., 1999). The technique has great promise as a rehabilitative tool, and may provide unique insights into the underlying mechanisms of spatial perception and action in normality and pathology. In this article I provide an introduction to the neuropsychological syndrome of spatial neglect, highlighting the significant rehabilitative challenges it poses for clinicians. I then outline the prism adaptation procedure, and consider the possible reasons for its beneficial effects in patients with spatial neglect. I conclude with some open questions and suggestions for future research.