Attention capture by salient object groupings in the neglected visual field.

The integration of fragmentary parts into coherent whole objects has been proposed either to rely on the availability of attentional resources or to arise automatically, that is, from preattentive processing (prior to the engagement of selective attention). In the present study, these two alternative accounts were tested in a group of neglect patients with right-hemisphere parietal brain damage and associated deficits of selective attention in the left (visual) hemispace. The reported experiment employed a search task that required detection of targets in the left and/or right hemifields, which were embedded in configurations that consisted of variants of Kanizsa figures. The results showed that a salient, grouped Kanizsa triangle presented within the unattended, left hemifield can substantially improve contralesional target detection, though the very same triangle configuration does not facilitate target detection in the impaired hemifield when presented together with an ipsilesional, but non-salient (i.e., structurally non-integrated, isolated) target. That is, attention is captured by the grouped object in the impaired hemispace only when it is not engaged in the processing of an (isolated) object in the attended hemispace. This demonstrates that both part-to-whole-object integration and search guidance by salient, integrated objects crucially require attentional resources.

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

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

On the Illumination Influence for Object Learning on Robot Companions.

Most collaborative tasks require interaction with everyday objects (e.g., utensils while cooking). Thus, robots must perceive everyday objects in an effective and efficient way. This highlights the necessity of understanding environmental factors and their impact on visual perception, such as illumination changes throughout the day on robotic systems in the real world. In object recognition, two of these factors are changes due to illumination of the scene and differences in the sensors capturing it. In this paper, we will present data augmentations for object recognition that enhance a deep learning architecture. We will show how simple linear and non-linear illumination models and feature concatenation can be used to improve deep learning-based approaches. The aim of this work is to allow for more realistic Human-Robot Interaction scenarios with a small amount of training data in combination with incremental interactive object learning. This will benefit the interaction with the robot to maximize object learning for long-term and location-independent learning in unshaped environments. With our model-based analysis, we showed that changes in illumination affect recognition approaches that use Deep Convolutional Neural Network to encode features for object recognition. Using data augmentation, we were able to show that such a system can be modified toward a more robust recognition without retraining the network. Additionally, we have shown that using simple brightness change models can help to improve the recognition across all training set sizes.

Attention as the 'glue' for object integration in parietal extinction.

Patients with unilateral, parietal brain damage frequently show visual extinction, which manifests in a failure to identify contralesional stimuli when presented simultaneously with other, ipsilesional stimuli (but full awareness for single stimulus presentations). Extinction reflects an impairment of spatial selective attention, leaving basic preattentive processing unaffected. For instance, access to bilaterally grouped objects is usually spared in extinction, suggesting that grouping occurs at a stage preceding (in the patients: abnormally biased) spatial-attentional selection. Here, we reinvestigated this notion by comparing (largely between participants, but also within a single-case participant) conditions with objects that varied in their dominant direction of grouping: from the attended to the non-attended hemifield (data from Conci et al., 2009) versus from the non-attended to the attended hemifield (new data). We observe complete absence of extinction when shape completion extended from the attended hemifield. By contrast, extinction was not diminished when object groupings propagate from the unattended hemifield. Moreover, we found the individual severity of the attentional impairment (assessed by a standard "inattention" test) to be directly related to the degree of completion in the unattended hemifield. This pattern indicates that grouping can overcome visual extinction only when object integration departs from the attended visual field, implying, contrary to many previous accounts, that attention is crucial for grouping to be initiated.

Effects of repetitive galvanic vestibular stimulation on spatial neglect and verticality perception-a randomised sham-controlled trial.

Recent evidence shows that bipolar galvanic vestibular stimulation (GVS) with the cathode on the left (CL) or right (CR) mastoid ameliorates spatial neglect, extinction and verticality perception transiently and partly permanently. However, no randomised controlled trial evaluated the long-term effects of repetitive GVS in comparison to sham-GVS on exploration and verticality perception. To compare the effects of CL-GVS, CR-GVS and Sham-GVS on spatial exploration and verticality perception in right-hemispheric stroke patients with left neglect we conducted a randomised controlled trial with minimisation. Twenty-four patients completed 10-12 training sessions on a daily basis, 5 days/week. The CL-and CR-GVS group received 20 min of stimulation at 1.5 mA, the Sham-GVS group only 30 s of CL-GVS. Simultaneously, all patients performed a standard therapy of smooth pursuit eye movement training (SPT) followed by visual scanning training (VST). Outcome measures (Neglect test, visuo-tactile search task, subjective visual and tactile vertical) were assessed before and immediately after the intervention and at 2- and 4-week follow-ups. Our results show that neither our standard therapy nor the combination of standard therapy and GVS improved neglect symptoms significantly. The reasons for our non-significant results are discussed.

Object integration requires attention: Visual search for Kanizsa figures in parietal extinction.

The contribution of selective attention to object integration is a topic of debate: integration of parts into coherent wholes, such as in Kanizsa figures, is thought to arise either from pre-attentive, automatic coding processes or from higher-order processes involving selective attention. Previous studies have attempted to examine the role of selective attention in object integration either by employing visual search paradigms or by studying patients with unilateral deficits in selective attention. Here, we combined these two approaches to investigate object integration in visual search in a group of five patients with left-sided parietal extinction. Our search paradigm was designed to assess the effect of left- and right-grouped nontargets on detecting a Kanizsa target square. The results revealed comparable reaction time (RT) performance in patients and controls when they were presented with displays consisting of a single to-be-grouped item that had to be classified as target vs. nontarget. However, when display size increased to two items, patients showed an extinction-specific pattern of enhanced RT costs for nontargets that induced a partial shape grouping on the right, i.e., in the attended hemifield (relative to the ungrouped baseline). Together, these findings demonstrate a competitive advantage for right-grouped objects, which in turn indicates that in parietal extinction, attentional competition between objects particularly limits integration processes in the contralesional, i.e., left hemifield. These findings imply a crucial contribution of selective attentional resources to visual object integration.

Neurofeedback in three patients in the state of unresponsive wakefulness.

Some severely brain injured patients remain unresponsive, only showing reflex movements without any response to command. This syndrome has been named unresponsive wakefulness syndrome (UWS). The objective of the present study was to determine whether UWS patients are able to alter their brain activity using neurofeedback (NFB) technique. A small sample of three patients received a daily session of NFB for 3 weeks. We applied the ratio of theta and beta amplitudes as a feedback variable. Using an automatic threshold function, patients heard their favourite music whenever their theta/beta ratio dropped below the threshold. Changes in awareness were assessed weekly with the JFK Coma Recovery Scale-Revised for each treatment week, as well as 3 weeks before and after NFB. Two patients showed a decrease in their theta/beta ratio and theta-amplitudes during this period. The third patient showed no systematic changes in his EEG activity. The results of our study provide the first evidence that NFB can be used in patients in a state of unresponsive wakefulness.

Subliminal galvanic-vestibular stimulation recalibrates the distorted visual and tactile subjective vertical in right-sided stroke.

Stroke of the right cerebral hemisphere often causes deficits in the judgement of the subjective visual vertical (SVV) and subjective tactile vertical (STV) which are related to central vestibular functioning. Clinically, deficits in the SVV/STV are linked to balance problems and poor functional outcome. Galvanic Vestibular Stimulation (GVS) is a non-invasive, save stimulation technique that induces polarity-specific changes in the cortical vestibular systems. Subliminal GVS induces imperceptible vestibular stimulation without unpleasant side effects. Here, we applied bipolar subliminal GVS over the mastoids (mean intensity: 0.7 mA, 20 min duration per session) to investigate its online-influence on constant errors, difference thresholds and range values in the SVV and STV. 24 patients with subacute, single, unilateral right hemisphere stroke were studied and assigned to two patient groups (impaired vs. normal in the SVV and STV) on the basis of cut-off scores from healthy controls. Both groups performed these tasks under three experimental conditions on three different days: a) sham GVS where electric current was applied only for 30s and then turned off, b) left-cathodal GVS and c) right-cathodal GVS, for a period of 20 min per session. Left-cathodal GVS, but not right-cathodal GVS significantly reduced all parameters in the SVV. Concerning STV GVS also reduced constant error and range numerically, though not significantly. These effects occurred selectively in the impaired patient group. In conclusion, we found that GVS rapidly influences poststroke verticality deficits in the visual and tactile modality, thus highlighting the importance of the vestibular system in the multimodal elaboration of the subjective vertical.

Stimulus-dependent modulation of visual neglect in a touch-screen cancellation task.

OBJECTIVE: Patients with left-sided neglect frequently show omissions and repetitive behavior on cancellation tests. Using a touch-screen-based cancellation task, we tested how visual feedback and distracters influence the number of omissions and perseverations. METHOD: Eighteen patients with left-sided visual neglect and 18 healthy controls performed four different cancellation tasks on an iPad touch screen: no feedback (the display did not change during the task), visual feedback (touched targets changed their color from black to green), visual feedback with distracters (20 distracters were evenly embedded in the display; detected targets changed their color from black to green), vanishing targets (touched targets disappeared from the screen). RESULTS: Except for the condition with vanishing targets, neglect patients had significantly more omissions and perseverations than healthy controls in the remaining three subtests. Both conditions providing feedback by changing the target color showed the highest number of omissions. Erasure of targets nearly diminished omissions completely. The highest rate of perseverations was observed in the no-feedback condition. The implementation of distracters led to a moderate number of perseverations. Visual feedback without distracters and vanishing targets abolished perseverations nearly completely. CONCLUSIONS: Visual feedback and the presence of distracters aggravated hemispatial neglect. This finding is compatible with impaired disengagement from the ipsilesional side as an important factor of visual neglect. Improvement of cancellation behavior with vanishing targets could have therapeutic implications.

Extra-powerful on the visuo-perceptual space, but variable on the number space: Different effects of optokinetic stimulation in neglect patients.

We studied the effects of optokinetic stimulation (OKS; leftward, rightward, control) on the visuo-perceptual and number space, in the same sample, during line bisection and mental number interval bisection tasks. To this end, we tested six patients with right-hemisphere damage and neglect, six patients with right-hemisphere damage but without neglect, and six neurologically healthy participants. In patients with neglect, we found a strong effect of leftward OKS on line bisection, but not on mental number interval bisection. We suggest that OKS influences the number space only under specific conditions.

Subliminal galvanic-vestibular stimulation influences ego- and object-centred components of visual neglect.

Neglect patients show contralesional deficits in egocentric and object-centred visuospatial tasks. The extent to which these different phenomena are modulated by sensory stimulation remains to be clarified. Subliminal galvanic vestibular stimulation (GVS) induces imperceptible, polarity-specific changes in the cortical vestibular systems without the unpleasant side effects (nystagmus, vertigo) induced by caloric vestibular stimulation. While previous studies showed vestibular stimulation effects on egocentric spatial neglect phenomena, such effects were rarely demonstrated in object-centred neglect. Here, we applied bipolar subsensory GVS over the mastoids (mean intensity: 0.7mA) to investigate its influence on egocentric (digit cancellation, text copying), object-centred (copy of symmetrical figures), or both (line bisection) components of visual neglect in 24 patients with unilateral right hemisphere stroke. Patients were assigned to two patient groups (impaired vs. normal in the respective task) on the basis of cut-off scores derived from the literature or from normal controls. Both groups performed all tasks under three experimental conditions carried out on three separate days: (a) sham/baseline GVS where no electric current was applied, (b) left cathodal/right anodal (CL/AR) GVS and (c) left anodal/right cathodal (AL/CR) GVS, for a period of 20min per session. CL/AR GVS significantly improved line bisection and text copying whereas AL/CR GVS significantly ameliorated figure copying and digit cancellation. These GVS effects were selectively observed in the impaired- but not in the unimpaired patient group. In conclusion, subliminal GVS modulates ego- and object-centred components of visual neglect rapidly. Implications for neurorehabilitation are discussed.

Verticality perception during and after galvanic vestibular stimulation.

The human brain constructs verticality perception by integrating vestibular, somatosensory, and visual information. Here we investigated whether galvanic vestibular stimulation (GVS) has an effect on verticality perception both during and after application, by assessing the subjective verticals (visual, haptic and postural) in healthy subjects at those times. During stimulation the subjective visual vertical and the subjective haptic vertical shifted towards the anode, whereas this shift was reversed towards the cathode in all modalities once stimulation was turned off. Overall, the effects were strongest for the haptic modality. Additional investigation of the time course of GVS-induced changes in the haptic vertical revealed that anodal shifts persisted for the entire 20-min stimulation interval in the majority of subjects. Aftereffects exhibited different types of decay, with a preponderance for an exponential decay. The existence of such reverse effects after stimulation could have implications for GVS-based therapy.

Smooth Pursuit "Bedside" Training Reduces Disability and Unawareness During the Activities of Daily Living in Neglect: A Randomized Controlled Trial.

UNLABELLED: Background Neglect is associated with disability, unawareness, poor long-term outcome, and dependence from caregivers. No randomized trial has evaluated the effects of smooth pursuit eye movement training (SPT) and visual scanning training (VST) at the bedside on these variables. Objective To compare the effects of SPT and VST in postacute stroke at 1 month with left neglect. METHODS: We carried out an assessor-blinded, randomized controlled trial. The 24 participants were randomly allocated to either SPT or VST (n = 12 each). They received 20 treatment sessions lasting 30 minutes each at the bedside over 4 weeks. Outcome measures included the Functional Neglect Index (FNI) based on 4 tasks: find objects on a tray, stick bisection, picture search, and gaze orientation. In addition, the Unawareness and Behavioral Neglect Index (UBNI) with 6 items about unawareness and 4 about neglect in activities of daily living, the Help index (required assistance in 10 functional activities), the Barthel Index, and the rehabilitation phase were rated by treatment-blinded assessors. Outcome measures were obtained before and immediately after the end of the interventions and at a 2-week follow-up. Results Significantly greater improvements were obtained after SPT versus VST treatment in the FNI and UBNI, and there were continued improvements selectively in the SPT group 2 weeks later. Conclusions SPT accelerates recovery from functional neglect and reduces unawareness significantly. Bedside neglect treatment using SPT is effective and feasible early after stroke.

Smooth pursuit eye movement training promotes recovery from auditory and visual neglect: a randomized controlled study.

BACKGROUND: No treatment for auditory neglect and no randomized controlled trial evaluating smooth pursuit eye movement therapy (SPT) for multimodal neglect are available. OBJECTIVE: To compare the effects of SPT and visual scanning therapy (VST) on auditory and visual neglect in chronic stroke patients with neglect. METHODS: A randomized, prospective trial was conducted. Fifty patients with left auditory and visual neglect were randomly assigned. Twenty-four patients completed SPT therapy and 21 patients VST. Five patients (4 VST, 1 SPT) were lost. Each group received 1-hour sessions of neglect therapy for 5 consecutive days totaling 5 hours. Outcome measures in visual neglect (digit cancellation, visuoperceptual- and motor line bisection, paragraph reading) and auditory neglect (auditory midline) were assessed twice before therapy, thereafter, and at 2-week follow-up. The SPT group practiced smooth pursuit eye movements while tracking stimuli moving leftward. The VST group systematically scanned the same but static stimuli. Both groups were divided into subgroups, and effects were separately investigated for mild and severe neglect. RESULTS: Both groups did not differ before therapy in clinical/demographic variables or neglect severity (auditory/visual). After treatment, the SPT group showed significant and lasting improvements in all visual measures and normal performance in the auditory midline. Neither visual nor auditory neglect impairments changed significantly after VST. Moreover, the treatment effect sizes (Cohen's d) were considerably higher for visual and auditory neglect after SPT versus VST, both for mild and severe neglect. CONCLUSIONS: Repetitive contralesional, smooth pursuit training induces superior, multimodal therapeutic effects in mild and severe neglect.

Galvanic vestibular stimulation improves arm position sense in spatial neglect: a sham-stimulation-controlled study.

BACKGROUND: Disturbed arm position sense (APS) is a frequent and debilitating condition in patients with hemiparesis after stroke. Patients with neglect, in particular, show a significantly impaired contralesional APS. Currently, there is no treatment available for this disorder. Galvanic vestibular stimulation (GVS) may ameliorate neglect and extinction by activating the thalamocortical network. OBJECTIVE: The present study aimed to investigate the immediate effects and aftereffects (AEs; 20 minutes) of subsensory, bipolar GVS (M = 0.6 mA current intensity) on APS in stroke patients with versus without spatial neglect and matched healthy controls. METHODS: A novel optoelectronic arm position device was developed, enabling the precise measurement of the horizontal APS of both arms. In all, 10 healthy controls, 7 patients with left-sided hemiparesis and left-spatial neglect, and 15 patients with left hemiparesis but without neglect were tested. Horizontal APS was measured separately for both forearms under 4 experimental conditions (baseline without GVS, left-cathodal/right-anodal GVS, right-cathodal/left-anodal GVS, sham GVS). The immediate effects during GVS and the AEs 20 minutes after termination of GVS were examined. RESULTS: Patients with neglect showed an impaired contralateral APS in contrast to patients without neglect and healthy controls. Left-cathodal/right-anodal GVS improved left APS significantly, which further improved into the normal range 20 minutes poststimulation. GVS had no effect in patients without neglect but right-cathodal/left-anodal GVS worsened left APS in healthy participants significantly. CONCLUSIONS: GVS can significantly improve the impaired APS in neglect. Multisession GVS can be tested to induce enduring therapeutic effects.

Line bisection error predicts the presence and severity of neglect dyslexia in paragraph reading.

Cancellation tasks and line bisection tasks are commonly used to diagnose spatial neglect after right hemisphere lesions. In such tasks, neglect patients often show leftsided omissions of targets in cancellation tests as well as a pathological rightward deviation in horizontal line bisection. However, double dissociations have also been reported and the relation between performance in both tasks is not clear. Another impairment frequently associated with the neglect syndrome are omissions or misread initial letters of single words, a phenomenon termed neglect dyslexia (ND). Omissions of whole words on the contralesional side of the page are generally considered as egocentric or space-based errors, whereas misreadings of the left part of a word in ND can be viewed as a type of stimulus-centered or word-based, perceptual error. As words, sentences and horizontal lines have a similar spatial layout in the sense that they all are horizontally aligned, long stimuli with a canonical left-right orientation (with a defined beginning on the left and an end on the right side), we hypothesized a significant association between the horizontal line bisection error (LBE) in neglect and the extent (number) of neglected or substituted letters within single words in ND (neglect dyslexia extension, NDE). To this purpose, we computed Center-of-Cancellation (CoC) scores in a cancellation task as well as Center-of-Reading (CoR) scores in an experimental paragraph reading test. We found that the CoR was a better indicator for egocentric word omissions than the CoC in a group of 17 patients with left visuospatial neglect. Furthermore, the LBE predicted the severity of ND, indicated by highly significant correlations between the LBE and the extent of the neglected letter string within single words (NDE; r=0.73, p<0.001) as well as between the LBE and the frequency of ND errors (r=0.61; p=0.009). In contrast, we found no significant correlation between the CoC and the severity of ND. These results indicate two different pathological mechanisms being responsible for contralesional spatial neglect and ND. In conclusion, the LBE is a more sensitive predictor of the presence and severity of the reading disorder in spatial neglect than conventional cancellation tasks.

Error types and error positions in neglect dyslexia: comparative analyses in neglect patients and healthy controls.

Unilateral spatial neglect frequently involves a lateralised reading disorder, neglect dyslexia (ND). Reading of single words in ND is characterised by left-sided omissions and substitutions of letters. However, it is unclear whether the distribution of error types and positions within a word shows a unique pattern of ND when directly compared to healthy controls. This question has been difficult to answer so far, given the usually low number of reading errors in healthy controls. Therefore, the present study compared single word reading of 18 patients with left-sided neglect, due to right-hemisphere stroke, and 11 age-matched healthy controls, and adjusted individual task difficulty (by varying stimulus presentation times in participants) in order to reach approximately equal error rates between neglect patients and controls. Results showed that, while both omission and substitution errors were frequently produced in neglect patients and controls, only omissions appeared neglect-specific when task difficulty was adapted between groups. Analyses of individual letter positions within words revealed that the spatial distribution of reading errors in the neglect dyslexic patients followed an almost linear increase from the end to the beginning of the word (right-to-left-gradient). Both, the gradient in error positions and the predominance of omission errors presented a neglect-specific pattern. Consistent with current models of visual word processing, these findings suggest that ND reflects sublexical, visuospatial attentional mechanisms in letter string encoding.

How does phasic alerting improve performance in patients with unilateral neglect? A systematic analysis of attentional processing capacity and spatial weighting mechanisms.

In visual hemi-neglect, non-spatial deficits such as reduced intrinsic alertness can significantly modulate the degree of left visual field inattention. However, to date, the precise mechanisms mediating this effect are hardly understood. In the present study, we assessed the influence of increased alertness on both general attentional capacity (perceptual processing speed) and spatial attentional selection processes (spatial distribution of attentional weighting). For this purpose, a whole-report paradigm based on Bundesen's 'theory of visual attention' (TVA) was combined with a non-spatial, visual alerting cue. Three different cue-target stimulus onset asynchronies (SOAs; of 80, 200, and 650 ms), allowed us to observe the time course of the alerting-cue effects. A group of six patients with visual hemi-neglect was examined and their performance compared with six healthy control subjects matched for age, gender, and education. In neglect patients, the alerting cue evoked a phasic increase of perceptual processing speed. However, this effect was mainly found in the ipsilateral, i.e. in the "preserved" hemifield. Importantly, however, patients displayed a fast-evolving and short-lasting, phasic modulation of spatial attentional weighting, with a re-distribution of attentional weights from the pathological rightward bias to a normal, more balanced distribution of visual attention. In control participants, the cueing effects on perceptual processing speed and spatial weighting were generally less pronounced than in neglect patients. Replicating results of a prior study, cueing induced a stable, slightly leftward, distribution of attentional weights, whilst in the no-cue condition, a temporary rightward shift of attentional weights was found. This pattern of effects suggests a close interaction between alertness and spatial-attentional weighting in the syndrome of visual hemi-neglect. It supports the hypothesis that the manifestation of spatial neglect involves at least in part intrinsic alertness deficits. It also provides clues to a more detailed account of the mechanisms responsible for alleviating neglect in patients following manipulations of the alertness level, both in the short (cueing) and in the long term (alertness training).

Minor adverse effects of galvanic vestibular stimulation in persons with stroke and healthy individuals.

OBJECTIVE: Galvanic vestibular stimulation (GVS) induces polarity-specific activations in the vestibular nerves and upstream in the vestibular and parietotemporal cortices as well as sub-cortical regions. This makes it an attractive technique for cognitive neuromodulation. However, systematic studies regarding adverse effects of GVS are unavailable. Thus, this study assessed adverse effects during and after sub-sensory GVS (mean: 0.6 mA) and GVS with 1.5 mA. METHODS: Two hundred and fifty-five GVS sessions delivered to 55 persons with stroke and 30 healthy individuals were analysed using a 34-item-questionnaire including potential symptoms and rating scales for adverse effects. RESULTS: The most frequent symptoms during and after GVS were slight itching (mean: 10.2%) and tingling (mean: 10.7%) underneath the electrodes. Healthy individuals and persons with stroke did not differ in their incidence and rated intensity of adverse effects, nor did persons with or without unilateral spatial neglect. Adverse effects were found more frequently with GVS with 1.5 mA as with sub-sensory GVS. Participants were unable to differentiate real from sham conditions during sub-sensory GVS. Importantly, neither seizures nor vertigo or nausea were observed. CONCLUSION: Sub-sensory GVS and GVS with 1.5 mA induce very few and mild adverse effects in healthy and persons with stroke and are safe when safety guidelines are followed.

Galvanic vestibular stimulation reduces the pathological rightward line bisection error in neglect-a sham stimulation-controlled study.

Patients with right hemisphere lesions often show left spatial neglect and the typical rightward deviation in horizontal line bisection. Previous studies have shown that sensory stimulation modulates line bisection. A less well-known but promising sensory stimulation method is galvanic vestibular stimulation (GVS). This non-invasive technique leads to activation of the vestibular cortices and adjacent cortical areas in the temporo-parietal cortex via polarization effects of the vestibular nerves. This is accomplished by application of weak direct currents, delivered by two electrodes attached to the mastoids. Despite the relative benefits of GVS its effects on line bisection have not yet been studied in neglect patients. Thus, the present study investigated the impact of GVS on performance in a modified line bisection task in right-brain damaged patients with versus without leftsided visual neglect. In neglect patients, but not in control patients, left-cathodal and right-cathodal GVS significantly reduced the rightward line bisection error as compared to Baseline (without GVS) and sham stimulation. A larger decrease of the rightward line bisection error was observed during right-cathodal GVS. Sham stimulation showed no specific effects on line bisection. The beneficial effects of GVS might be due to activation of preserved structures of the lesioned right posterior parietal cortex which is known to be involved in line bisection.