The Character-line Bisection Task: a new test for hemispatial neglect

A failure to report or respond to stimuli presented in a portion of space is termed hemispatial neglect. Line bisection and line cancellation are two of the tests used most commonly to assess for neglect. Perhaps, because neglect can be induced by a variety of deficits, neither of these tests used alone is as sensitive as both used together. Hence, the primary purpose of this study was to assess the sensitivity, reliability and validity of a new test called the Character-line Bisection Task (CLBT) that combines features of both the bisection and cancellation tests. Since local attention and language are primarily mediated by and activate the left hemisphere, our second goal was to learn if the CLBT and especially the letter version induce a greater rightward bias than the solid-line bisection task. Eighty patients with acute right hemisphere stroke and 81 controls performed the CLBT that consists of two subtests, the Letter-line and Star-line Bisection tasks. All subjects also completed four conventional tests for neglect (Standard solid-line bisection, line cancellation, Star Cancellation, and figure copying). In the bisection tasks both patients and controls bisected to the right with the CLBT than with the solid-line bisection task, suggesting the CLBT induces asymmetrical hemispheric activation. This enhanced rightward deviation with the CLBT was the same for the Letter-line and Star-line Bisection tasks. In regard to sensitivity, we defined the presence of neglect syndrome based on a total score derived from performance of controls on all six tests. This total score detected 55 (68.8%) patients with neglect. Within this group, the Letter-line and Star-line tasks diagnosed neglect in 50 and 48 patients, respectively, resulting in the highest sensitivities (90.9, 87.3%) of the six tests. Thus, the CLBTs demonstrated higher sensitivities than the other commonly used neglect tests and these new tests can be useful for the detection and quantification of unilateral neglect.     

脑卒中急性期左右大脑半球病变所致偏侧空间忽视的比较

目的比较脑卒中急性期左右大脑半球病变所致偏侧空间忽视(hemispati-neglect,HSN)的异同.方法对42例脑卒中急性期患者进行视空间功能检查,对左右大脑半球病变所致HSN的发生率及其严重程度进行显著性检验,并描述其临床表现.结果脑卒中急性期HSN的发生率为26.2%(11/42),其中右侧大脑半球病变HSN的发生率为47.0%(8/17),左侧大脑半球病变HSN的发生率为12.0%(3/25),两侧大脑半球病变所致HSN的发生率比较有显著性差异(x2=4.75,P＜0.05),而严重程度无显著性差异(μc=1.23,P＞0.05).导致HSN的左右大脑半球病变的病变部位相似.结论脑卒中后双侧大脑半球损伤均可引起HSN,以右侧更多见,提示双侧大脑半球内均存在分析对侧空间刺激的结构,而对空间注意的优势半球可能主要在右侧.     

Adding transcutaneous electrical nerve stimulation to visual scanning training does not enhance treatment effect on hemispatial neglect: a randomized,controlled, double-blind study

Background: Left-sided transcutaneous electrical nerve stimulation (TENS) increases right hemispheric activity, which may improve the rehabilitative outcome of hemispatial neglect.

Objective: To examine the behavioral effect of electrical stimulation of the nerve afferents of the left hand during early neuropsychological rehabilitation of post-stroke patients with hemispatial neglect.

Methods: This randomized, controlled, double-blind study included 29 patients (enrolled in the experimental or control group) with left hemispatial neglect after right hemispheric stroke. For 3 weeks, patients received 15 therapeutic sessions involving TENS (active or sham) with a mesh glove applied on the entire left hand during the first 30 minutes of a 45-minute conventional visual scanning training (VST). Signs of hemispatial neglect were assessed using a psychometric test before and after treatment.

Results: Univariate analysis of covariance revealed that differences between the control and experimental groups were not significant after treatment (F(1, 22)?=?0.294, P?=?0.593) when adjusted for pre-treatment scores and time since stroke onset. This suggested that electrical stimulation failed to mitigate the severity of hemispatial neglect symptoms.

Conclusion: Our study did not provide evidence of the effectiveness of TENS when added to VST during early rehabilitation for patients with post-stroke hemispatial neglect. Other techniques (applied alone or together) should be sought to improve recovery in this population.     

Manual responses and saccades in chronic and recovered hemispatial neglect: a study using visual search

Hemispatial neglect affects both the ability to respond to targets on the contralesional side of space and to programme saccades to such targets. In the current study, we looked in detail at saccade programming and manual reaction times (RTs) in a range of visual search tasks, in which task difficulty was systematically increased by changing the nature of the distractors. In condition 1, the target was presented with no distractors. In the other conditions, displays contained three distractors that were changed across conditions to manipulate similarity to the target and so task difficulty.We tested two neglect patients, one chronic, one recovered along with two RCVA control patients and 12 age-matched controls. Both neglect patients studied could successfully execute saccades into the neglected field when the target was presented alone. However, a dissociation emerged between the two patients when the target was presented with distractor items. Patient ERs first saccade to target performance in the three search conditions revealed clear effects of distractor type. In contrast for the recovered patient AF, the left/right difference was present for all search displays and appeared to be constant regardless of distractor type. This differential pattern of behaviour may reflect the different underlying neural causes of the neglect in these patients. In the current study, the measurement of saccades allowed the task to be fractionated, and thus, reveal the action of multiple mechanisms controlling saccades in search.     

Effects of visible and invisible cueing on line bisection and Landmark performance in hemispatial neglect.

A total of 12 patients with hemispatial neglect (and two control groups) were tested to examine the effects of lateralized cues on line bisection and Landmark judgements. The experiment was designed to investigate whether bisection and landmark biases induced by cueing are simply a result of a direct perceptual lengthening of the cued part of the line caused by the fact that the cue is visible, thus creating a composite 'line plus cue' or whether cueing indeed induces an attentional bias. Secondly, earlier work by Harvey et al. [Harvey M, Milner AD, Roberts RC. An investigation of hemispatial neglect using the landmark task, Brain and Cognition 1995; 27: 59-78] has shown that in neglect patients cues work by inducing orientational biases rather than via the alteration of subjective length perception. An attempt was made to replicate this finding and extend it to cues that are not physically present. The bisection data clearly showed that cues bias attention rather than work via a direct lengthening of the line: both visible and invisible cues biased bisection performance equally well. The Landmark data, however, revealed much less clear-cut results and we failed to repeat the earlier observation by Harvey et al. that cues induce orientational biases. Even when the neglect patients were categorised into premotor and perceptual categories a clear effect failed to emerge. It is hypothesised that the earlier reported effect may be linked to neglect severity rather than to perceptual type neglect.     

Hemispatial neglect: its effects on visual perception and visually guided grasping

Hemispatial neglect is a neurological disorder characterized by a failure to represent information appearing in the hemispace contralateral to a brain lesion. In addition to the perceptual consequences of hemispatial neglect, several authors have reported that hemispatial neglect impairs visually guided movements. Others have reported that the extent of the impairment depends on the type of visually guided task. Finally, in some cases, neglect has been shown to impair visual perception without affecting visuomotor control in relation to the very same stimuli. While neglect patients may be able to successfully pick up an object they have difficulty perceiving in its entirety, it does not mean that they are picking up the object in the same way that a neurologically intact individual would. In the current study, patients with hemispatial neglect were presented with irregularly shaped objects, directly in front of them, that lacked clear symmetry and required an analysis of their entire contour in order to calculate stable grasp points. In a perceptual discrimination task, the neglect patients had difficulty distinguishing one object from another on the basis of their shape. In a grasping task, the neglect patients showed more variance in the position of their grasp on the target objects than their control subjects, with an overall shift to the relative right side of the presented objects. The perceptual and visuomotor deficits seen in patients with hemispatial neglect deficits may be the result of an inability to form good structural representations of the entire object for use in visual perception and visuomotor control.     

The modular architecture of the neglect syndrome: Implications for action control in visual neglect

In our recent review of action control deficits in hemispatial neglect we concluded that many patients with the disorder have deficits in visuomotor control [Coulthard, E., Parton, A., & Husain, M. (2006). Action control in visual neglect. Neuropsychologia, 44(13), 2717-2733]. This conclusion has been questioned and it has been argued instead that there are no action deficits in neglect [Himmelbach, M., Karnath, H.-O., & Perenin, M.-T. (2007). Action control is not affected by spatial neglect: A comment on Coulthard et al. Neuropsychologia, 45(8), 1979-1981]. We proposed that rather than being specific to the neglect syndrome, action control deficits are more likely to relate to lesion location. Although many of these impairments may contribute to the manifestation of neglect, they may also occur in brain-damaged patients without the condition. In this article, we explore this framework further, discussing how neglect behaviour may emerge from damage to a set of visuomotor or cognitive modules, or their connections. Central to our view is the idea that the critical combination of deficits leading to neglect varies considerably between cases, and that visuomotor or cognitive modules disrupted in the syndrome may not, in fact, be specific to neglect.     

The prediction of functional dependency by lateralized and non‐lateralized neglect in a large prospective stroke sample

Background and purpose: Lateralized and non‐lateralized impairments in visual attention have been identified as important components in patients with visuospatial neglect. This study investigated the course of these two phenomena across time in relation to neurological symptoms and functional outcome in a large consecutive and prospective stroke sample. Methods: A total of 375 consecutive stroke patients were divided into three groups (lateralized, non‐lateralized or no visual inattention) acutely and 3 months post‐stroke using the star cancellation test. Neurological impairments, localization of brain damage, asymmetry in clinical symptoms and functional outcome were assessed. Possible group differences were analysed, and stepwise logistic regressions were performed to examine the relative importance of predictors of functional dependency. Results: Participants with acute lateralized inattention differed (P ≤ 0.05) from the other two groups by more often exhibiting severe neurological symptoms, functional dependency and persisting visual inattention. The regression analyses selected acute lateralized inattention as an important and independent predictor of functional dependency following right hemisphere damage, but not following left hemisphere damage. Conclusions: The results emphasize the prognostic value of lateralized inattention and the importance of separating lateralized and non‐lateralized symptoms of visual inattention at the commencement of rehabilitation.     

Dissociation in the recovery from neglect dyslexia and visuospatial unilateral neglect: a case report

The recovery of the ability to read of a patient affected by persistent visuospatial neglect suggests the functional independence of the two phenomena. Neglect dyslexia seems to be an example of a dissociation between an implicit and explicit knowledge of the characteristics of the stimulus.

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Sommario Il recupero della capacità di lettura in un paziente con persistente neglect visuo-spaziale suggerisce l'indipendenza funzionale dei due fenomeni. La neglect dyslexia sembra costituire un esempio di dissociazione tra conoscenza implicita ed esplicita delle caratteristiche dello stimolo.

     

A comparison of the effects of directive visuomotor intervention versus nondirective supportive intervention in kindergarten and elementary school children

To compare the efficacy of a directive visual motor intervention (DVMI) versus a nondirective supportive intervention (NDSI) on psychological-adjustment, self-esteem, and visuomotor-integration (VMI) skills in mainstream elementary school and kindergarten children. A total of 168 poor VMI children of low socioeconomic status attending regular kindergarten or first grade were randomly allocated to receive 12 weeks of DVMI, NDSI, or no treatment. Psychological adjustment, self-esteem, and VMI skills were evaluated before and after the intervention period. In the kindergarten subset, NDSI significantly improved VMI skills compared to DVMI and no treatment. In the first-graders, NDSI and DVMI yielded a similar, significant, improvement in VMI compared to no treatment. There were no significant differences among the NDSI, DVMI, and control groups in improvement in psychological-adjustment or self-esteem. This study, conducted in a socioeconomically disadvantaged population, suggests that kindergarten children with poor VMI might benefit from the positive and meaningful relationships inherent in NDSI.     

Dynamic assessment of visual neglect: The Mobility Assessment Course as a diagnostic tool

Introduction: Visual neglect is a frequent disorder following stroke and is often diagnosed by neuropsychological assessment. However, paper-and-pencil tasks have low predictive value as they lack sensitivity to capture neglect in complex, dynamic situations, such as activities of daily living. Aims of the current study were to assess the feasibility of the Mobility Assessment Course (MAC), a visual search multitask, to assess neglect, and its relation with existing neglect tasks. Method: Stroke patients admitted for inpatient rehabilitation and healthy controls were tested with the MAC in different corridors. Participants had to move through a corridor, finding and reporting 24 targets attached to the walls. In addition, the shape cancellation, line bisection, and Catherine Bergego Scale (CBS) were used in order to compare the MAC with existing diagnostic tools for neglect. Results: Administering the MAC was feasible, as 112 of 113 patients completed the MAC with a median duration of 4.09 min. Depending on the corridor where the assessment took place, in 88.5–93.3% of assessments all targets were visible. The number of omissions (total and contralesional) and the asymmetry score (contralesional–ipsilesional omissions) on the MAC as well as collisions and corrections, were higher for patients with neglect than for those without neglect. Depending on the neglect task used, 4.0–18.6% of patients without neglect on neuropsychological tasks or the CBS showed neglect on the MAC. Vice versa, 17.2–29.3% of patients who showed neglect at neuropsychological assessment or the CBS did not do so on the MAC. Finally, a moderate to strong positive relation was seen between neglect at neuropsychological assessment, the CBS, and the MAC. Conclusions: The MAC is an ecological task in which both quantitative and qualitative data on neglect can be collected. In order to assess the presence of neglect and neglect severity in a dynamic way, the MAC could be administered in conjunction with neuropsychological assessment.     

The effects of computer-based cognitive rehabilitation in patients with visuospatial neglect following stroke: a systematic review

Objectives: To identify studies concerning the effects of computer based cognitive rehabilitation (CBCR) on visuospatial neglect (VN) after stroke to summarize the current state of knowledge in this research field and make recommendations for future research.

Methods: Four electronic databases were systematically searched. Authors of relevant studies were contacted to detect unpublished data or articles not found by searching databases. Data was extracted from included studies using predefined coding schemes and characteristics and results of individual studies were summarized qualitatively.

Selection criteria: Studies were included if at least 50% of the included patients had a stroke, if the studies explored the effects of CBCR as a primary intervention for rehabilitation of VN and if they included neuropsychological outcome measures for the presence of VN.

Results: Seven studies were included. Six of the seven studies suggested positive effects of CBCR on VN after stroke. However, the study that did not find these effects was also the study with the strongest methodological quality. All included studies consisted of small samples, varied greatly in design and had various methodological limitations.

Conclusion: Because the existing literature is very sparse and studies have various methodological limitations, it is currently not possible to either support or reject the effects of CBCR on VN after stroke. Future studies should aim to compare CBCR with active and passive control conditions and include larger samples in randomized and blinded designs.     

Judging the angles formed by visible and imaginary clock hands: a study of hemispatial effects in healthy volunteers

Healthy, right-handed volunteers (six male, six female) either saw or imagined the hands of a clock set a particular time. In both conditions, they then judged whether the angle between the clock hands was greater than or less than 90 degrees. Subjects pressed one of two response keys to indicate their decision, and hand of response (left/right) was counterbalanced within and between subjects. The subjects had significantly longer reaction times and made significantly more errors when the imaginary angles formed by the clock hands were located in left hemispace (e.g. 8:30) than right hemispace (e.g. 4:30). With visible hands, there was no reaction time difference between visual hemifields, although significantly more errors were made when the angle formed by the hands fell within the left visual field. In the perceptual task (visible hands), reaction times and error rates increased monotonically as the distance between the hands approximated more closely to 90 degrees. This psychophysical relationship was not found in the representational task (imaginary hands). Rather, there was a significant positive correlation between reaction times/error rates and the magnitude of the number indicative of the position of the minute hand. The latter finding is consistent with the hypothesis that the lateral asymmetry in the representational task (reaction times and error rates are higher in left hemispace) is due to the time taken to mentally rotate the imaginary minute hand in a clockwise direction. No such operation is required in the perceptual condition where the hands are clearly visible.     

Noradrenergic stimulation and motor performance: Differential effects of reboxetine on movement kinematics and visuomotor abilities in healthy human subjects

Evidence from studies in both animals and humans suggests that pharmacological stimulation of the noradrenergic system may modulate cortical excitability. However, the influence of such a modulation on the motor system remains unclear. We here explored the effects of noradrenergic stimulation on different motor tasks with increasing complexity and sensorimotor demands. Healthy human subjects received either reboxetine - a selective noradrenaline reuptake inhibitor - or placebo in a double-blind within-subject design. The analysis of movement kinematics revealed differential effects of RBX on subjects’ motor performance. While isolated stereotypic finger movements and simple reach-to-grasp movements did not change under RBX stimulation (compared to placebo), subjects showed a significant gain in movement speed in visuomotor tasks requiring online-control of precision movements. The results suggest that stimulating the noradrenergic system via RBX does not influence motor performance in general, but rather supports neural circuits involved in visuomotor control of movements.     

The effects of working memory resource depletion and training on sensorimotor adaptation

We have recently demonstrated that visuospatial working memory performance predicts the rate of motor skill learning, particularly during the early phase of visuomotor adaptation. Here, we follow up these correlational findings with direct manipulations of working memory resources to determine the impact on visuomotor adaptation, a form of motor learning. We conducted two separate experiments. In the first one, we used a resource depletion strategy to investigate whether the rate of early visuomotor adaptation would be negatively affected by fatigue of spatial working memory resources. In the second study, we employed a dual n-back task training paradigm that has been shown to result in transfer effects [1] over five weeks to determine whether training-related improvements would boost the rate of early visuomotor adaptation. The depletion of spatial working memory resources negatively affected the rate of early visuomotor adaptation. However, enhancing working memory capacity via training did not lead to improved rates of visuomotor adaptation, suggesting that working memory capacity may not be the factor limiting maximal rate of visuomotor adaptation in young adults. These findings are discussed from a resource limitation/capacity framework with respect to current views of motor learning.     

视觉反馈结合MOTOmed智能运动训练系统对脑卒中患者平衡以及步行能力的疗效观察

目的 观察视觉反馈结合MOTOmed智能运动训练系统治疗对脑卒中患者平衡以及步行能力的影响。方法 将脑卒中30例患者随机分为观察组和对照组各15例,2组均进行常规康复治疗以及MOTOmed智能运动训练系统训练,观察组在进行MOTOmed智能运动训练系统训练时引导并督促患者将仪器显示器上显示的两侧对称性尽量都保持在50%,直到训练结束; 对照组在进行MOTOmed智能运动训练系统训练时遮蔽显示器上的对称性显示。结果 治疗3周后2组Berg平衡量表(BBS)评分、简式Fugl-Meyer下肢运动功能评定量表(FMA)评分以及起立步行实验(TUGT)评分均较治疗前明显提高(P<0.05),且观察组3项评分均高于对照组(P<0.05)。MOTOmed智能运动训练系统中的患侧对称性所占比、训练距离以及训练强度也较对照组有了明显的进步(P<0.05)。结论 视觉反馈结合MOTOmed智能运动训练系统通过患者自身的参与以及自我调整可以更好地提高患者的平衡及步行能力。     

The effects of prism adaptation on daily life activities in patients with visuospatial neglect: a systematic review

Studies that have investigated prism adaptation (PA) effects on symptoms of visuospatial neglect have primarily used neuropsychological tests as outcome measures. An important question that remains to be answered is whether PA effects translate into improvements in patients’ daily life activities. In the present review, we examined systematically the evidence for the effect of PA treatment on daily life activities in patients with neglect. Two authors independently assessed the methodological quality of 25 intervention and 1 follow-up studies using validated scales. PA effects were evaluated for reading/writing, activities of daily living (ADL) direct tests, ADL questionnaires, and navigation tests. Studies were evaluated as being of excellent (n?=?1), good (n?=?12), fair (n?=?10), or poor (n?=?3) quality. Among the 26 articles, a total of 32 measurements showed significant PA effects (one measurement from a study of excellent quality, 17 from studies of good quality, 10 from studies of fair quality, four from studies of poor quality), whereas non-significant effects were found in 15 measurements (two from a study of excellent quality, three from studies of good quality, eight from studies of fair quality, two from studies of poor quality). There is some evidence suggesting that PA can improve daily functioning, particularly as measured by reading/writing and ADL direct tests. The impact of several variables on PA effects should be investigated further including sample heterogeneity and time since injury.     

The effects of practicing target-shooting sport on the severity of inattentive,hyperactive, and impulsive symptoms in children: a non-randomised controlled open-label study in Denmark

Abstract

Purpose: Target-shooting sport requires mental effort and concentration. Training may reduce inattentiveness and distractibility. There is little knowledge if children with symptoms of attention-deficit/hyperactivity disorder (ADHD) benefit from practicing target-shooting sport.

Materials and methods: Our study aims to investigate this in a non-randomised controlled open-label study of 128 children, 10–14 years of age, with ADHD-symptoms. The intervention-group (n?=?64) practiced target-shooting in local shooting associations once a week for 6 months. The control group (n?=?64) received treatment as usual. Primary outcome: teacher-rated ADHD-RS-IV-total score. Secondary outcomes: (a) parent-rated ADHD-RS-IV-total score; (b) teacher- and parent-rated Strengths-and-Difficulties-Questionnaire (SDQ); (c) self-rated quality of life (KIDSCREEN-27-total score); and (d) four objective measurements of ADHD-symptoms using the QbTest^?. The data were collected at baseline and after 6 months.

Results: When estimating the marginal effect of the intervention on our primary outcome, the teacher-rated ADHD-RS-IV, we found no significant effect (mean change between groups (contrast)=2.23; p?=?0.193). However, we did find significant beneficial effects on four of the eight secondary outcomes, including the parent-rated ADHD-RS-IV-total score (contrast = 4.76; p?=?0.024), the parent-rated SDQ-total score (contrast = 2.09; p?=?0.027), and on the QbTest^? measurements of the Reaction Time Variation (RTVar) (contrast = 36.96; p?=?0.013), and of Omission Errors (contrast = 7.57; p?=?0.019).

Conclusions: Despite the negative result on the primary outcome, the robust findings on these secondary outcomes in this open-label study indicate proof of concept that practicing target-shooting sport may have some beneficial effects on the severity of ADHD-symptoms in children. No adverse events were reported. Randomised trials of this non-pharmacological intervention are needed.     

The Brentano Illusion Test (BRIT): An implicit task of perceptual processing for the assessment of visual field defects in neglect patients

ABSTRACT

In brain damaged patients with unilateral spatial neglect (USN), the differential diagnosis between the presence and absence of a unilateral visual half-field deficit (VHFD) is hampered by the similarity of their phenomenology. The absence of stimuli detection in the contralateral visual field, indeed, can be due to the co-occurrence of USN and VHFD or the sole presence of the USN. The disentangling of the two conditions is required to devise more specific rehabilitation programmes. Daini et al. [2002. Exploring the syndrome of spatial unilateral neglect through an illusion of length. Experimental Brain Research, 144(2), 224–237.] reported a difference in performance for the two conditions when the tasks required the bisection of Brentano illusory stimuli. Only when USN and VHFD co-occurred, the leftward illusory effect was disrupted. Based on previous findings, in this cross-sectional study, we developed the Brentano Illusion Test (BRIT), a clinical tool that helps the identification of VHFD in USN patients. The BRIT is a simple behavioural test of line bisection aimed at verifying the presence or absence of implicit processing in USN and thus helping the diagnosis of VHFD in USN patients; it also provides normative data for the line bisection task and the length effect.