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.

On the Illumination Influence for Object Learning on Robot Companions.

Most collaborative tasks require interaction with everyday objects (e.g., utensils while cooking).

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.

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.

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.

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.

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.

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 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.

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).

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.

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.

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.

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.

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.

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.

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.

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).

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.

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).

Effects of head rotation on space- and word-based reading errors in spatial neglect.

Patients with right hemisphere lesions often omit or misread words on the left side of a text or the beginning letters of single words which is termed neglect dyslexia (ND). Two types of reading errors are typically observed in ND: omissions and word-based reading errors. The prior are considered as space-based omission errors on the contralesional side of the page, while the latter can be viewed as a kind of stimulus- or word-based reading errors where leftsided parts of a single perceptual entity (the word) are neglected.

Improvement of visual search after audiovisual exploration training in hemianopic patients.

Objective: A variety of rehabilitation strategies have been tried in patients with chronic hemianopia and quadrantanopia. The authors compared 2 approaches of blind field exploration in those with recent onset of disease.

Methods: A total of 20 patients with visual field defects were studied between 3 and 24 weeks primarily after stroke.

Preattentive surface and contour grouping in Kanizsa figures: evidence from parietal extinction.

Visual extinction commonly occurs after unilateral, parietal brain damage and manifests in a failure to identify contralesional stimuli when presented simultaneously with other, ipsilesional stimuli - but full awareness for single stimulus presentations. However, extinction can be substantially reduced when preattentive grouping operations link fragmentary items across hemifields into a coherent object. For instance, one study demonstrated preserved access to bilateral stimulus segments when these could be grouped to form a Kanizsa square [Mattingley, J.

Scanning your body is different from performing body movements: a double dissociation between body representational neglect and apraxia.

Body representational neglect (BRN) and apraxia can be found after left hemisphere (LH) lesions. Additionally, both disorders recruit knowledge about certain body parts, their position in space, and their spatial relationship to each other. Hence, the present study examined whether BRN and apraxia can be functionally dissociated at the behavioral and neural level.

Inhibitory and facilitatory location priming in patients with left-sided visual hemi-neglect.

In visual search for pop-out targets, reaction times are facilitated when the target on the current trial appears at a previous target location, and inhibited when it appears at a previous distractor location, relative to when it appears at a previously empty (neutral) location (Maljkovic and Nakayama, Perception and Psychophysics 58:977-991, 1996). However, while normal subjects are able to positively/negatively tag selected target/rejected distractor locations to guide search on the next trial, patients with visual hemi-neglect may have a (uni- or bilateral) deficit in these functions that may contribute to their disturbed visual scanning behavior. To examine this, using a pop-out search task, the present study assessed cross-trial facilitatory and inhibitory priming in 14 patients with left-sided visual hemi-neglect and in 14 age-, education-, and IQ-matched control subjects.