Visuospatial asymmetry and non-spatial attention in subacute stroke patients with and without neglect

Virtual reality tasks with eye tracking for mild spatial neglect assessment: a pilot study with acute stroke patients

Objective

Increasing evidence shows that traditional neuropsychological tests are insensitive for detecting mild unilateral spatial neglect (USN), lack ecological validity, and are unable to clarify USN in all different spatial domains. Here we present a new, fully immersive virtual reality (VR) task battery with integrated eye tracking for mild visual USN and extinction assessment in the acute state of stroke to overthrow these limitations.

Methods

We included 11 right-sided stroke patients and 10 healthy controls aged 18-75 years. Three VR tasks named the Extinction, the Storage and the Shoot the target tasks were developed to assess USN. Furthermore, neuropsychological assessment examining various parts of cognitive functioning was conducted to measure general abilities. We compared VR and neuropsychological task performance in stroke patients - those with (USN+, n = 5) and without USN (USN-, n = 6) - to healthy controls (n = 10) and tentatively reported the usability of VR system in the acute state of stroke.

Results

Patients had mostly mild neurological and USN symptoms. Nonetheless, we found several differences between the USN+ and healthy control groups in VR task performance. Compared to controls, USN+ patients showed visual extinction and asymmetry in gaze behavior and detection times in distinct spatial locations. Extinction was most evident in the extrapersonal space and delayed detection times on the extreme left and on the left upper parts. Also, USN+ patients needed more time to complete TMT A compared with USN- patients and TMT B compared with controls. VR system usability and acceptance were rated high; no relevant adverse effects occurred.

Conclusion

New VR technology with eye tracking enables ecologically valid and objective assessment methods with various exact measures for mild USN and thus could potentially improve future clinical assessments.

Immersive virtual reality gameplay detects visuospatial atypicality, including unilateral spatial neglect, following brain injury: a pilot study

BACKGROUND

In neurorehabilitation, problems with visuospatial attention, including unilateral spatial neglect, are prevalent and routinely assessed by pen-and-paper tests, which are limited in accuracy and sensitivity. Immersive virtual reality (VR), which motivates a much wider (more intuitive) spatial behaviour, promises new futures for identifying visuospatial atypicality in multiple measures, which reflects cognitive and motor diversity across individuals with brain injuries.

METHODS

In this pilot study, we had 9 clinician controls (mean age 43 years; 4 males) and 13 neurorehabilitation inpatients (mean age 59 years; 9 males) recruited a mean of 41 days post-injury play a VR visual search game. Primary injuries included 7 stroke, 4 traumatic brain injury, 2 other acquired brain injury. Three patients were identified as having left sided neglect prior to taking part in the VR. Response accuracy, reaction time, and headset and controller raycast orientation quantified gameplay. Normative modelling identified the typical gameplay bounds, and visuospatial atypicality was defined as gameplay beyond these bounds.

RESULTS

The study found VR to be feasible, with only minor instances of motion sickness, positive user experiences, and satisfactory system usability. Crucially, the analytical method, which emphasized identifying 'visuospatial atypicality,' proved effective. Visuospatial atypicality was more commonly observed in patients compared to controls and was prevalent in both groups of patients-those with and without neglect.

CONCLUSION

Our research indicates that normative modelling of VR gameplay is a promising tool for identifying visuospatial atypicality after acute brain injury. This approach holds potential for a detailed examination of neglect.

Using non-invasive transcranial direct current stimulation for neglect and associated attentional deficits following stroke

Neglect is a disabling neuropsychological syndrome that is frequently observed following right-hemispheric stroke. Affected individuals often present with multiple attentional deficits, ranging from reduced orienting towards contralesional space to a generalized impairment in maintaining attention over time. Although a degree of spontaneous recovery occurs in most patients, in some individuals this condition can be treatment-resistant with prominent ongoing non-spatial deficits. Further, there is a large inter-individual variability in response to different therapeutic approaches. Given its potential to alter neuronal excitability and affect neuroplasticity, non-invasive brain stimulation is a promising tool that could potentially be utilized to facilitate recovery. However, there are many outstanding questions regarding its implementation in this heterogeneous patient group. Here we provide a critical overview of the available evidence on the use of non-invasive electrical brain stimulation, focussing on transcranial direct current stimulation (tDCS), to improve neglect and associated attentional deficits after right-hemispheric stroke. At present, there is insufficient robust evidence supporting the clinical use of tDCS to alleviate symptoms of neglect. Future research would benefit from careful study design, enhanced precision of electrical montages, multi-modal approaches exploring predictors of response, tailored dose-control applications and increased efforts to evaluate standalone tDCS versus its incorporation into combination therapy.

Relationships of attention and arousal are responsible for action in sports

Study aim: The most important psychological mechanisms that are responsible for sports activity are arousal and attention. Study aim the relationships between the level of arousal and the level of attention, an attempt has been made to explain the mechanisms responsible for sportsman activity.

Material and method: The study was conducted in a group of sportsman-students (68 individuals) using the Vienna Test System: FLIM, a test of flicker/fusion frequency, which is a measurement procedure allowing to determine the functional readiness of the central nervous system in terms of arousal and COG (Cognitron), which is a test measuring the level of attention.

Results: The following in statistical analysis of the data were observed: inversely proportional relationships of image fusion frequency (FLIM1) during the recording of the level of arousal with: the correct acceptance of stimuli (COG1, r = –0.287), the correct rejection of stimuli (COG2, r = –0.320), the time of correctly accepted stimuli (COG3, r = –0.299), and with the time of correctly rejected stimuli (COG4, r = –0.317) in the attentional activity.

Conclusion: Fusion frequency indicates the level of fatigue and is inversely proportional to the correctly accepted stimuli in attentional activity, the correctly rejected stimuli in attentional activities, and the duration of the attentional actions.

Unilateral Stroke: Computer-based Assessment Uncovers Non-Lateralized and Contralesional Visuoattentive Deficits

OBJECTIVE

Patients with unilateral stroke commonly show hemispatial neglect or milder contralesional visuoattentive deficits, but spatially non-lateralized visuoattentive deficits have also been reported. The aim of the present study was to compare spatially lateralized (i.e., contralesional) and non-lateralized (i.e., general) visuoattentive deficits in left and right hemisphere stroke patients.

METHOD

Participants included 40 patients with chronic unilateral stroke in either the left hemisphere (LH group, n = 20) or the right hemisphere (RH group, n = 20) and 20 healthy controls. To assess the contralesional deficits, we used a traditional paper-and-pencil cancellation task (the Bells Test) and a Lateralized Targets Computer Task. To assess the non-lateralized deficits, we developed a novel large-screen (173 × 277 cm) computer method, the Ball Rain task, with moving visual stimuli and fast-paced requirements for selective attention.

RESULTS

There were no contralesional visuoattentive deficits according to the cancellation task. However, in the Lateralized Targets Computer Task, RH patients missed significantly more left-sided than right-sided targets in bilateral trials. This omission distribution differed significantly from those of the controls and LH patients. In the assessment of non-lateralized attention, RH and LH patients missed significantly more Ball Rain targets than controls in both the left and right hemifields.

CONCLUSIONS

Computer-based assessment sensitively reveals various aspects of visuoattentive deficits in unilateral stroke. Patients with either right or left hemisphere stroke demonstrate non-lateralized visual inattention. In right hemisphere stroke, these symptoms can be accompanied by subtle contralesional visuoattentive deficits that have remained unnoticed in cancellation task.

Interaction between spatial neglect and attention deficit in patients with right hemisphere damage

Unilateral spatial neglect (USN) was originally regarded as a parietal syndrome, but it has become evident that USN is a disturbance in the widespread attention network. Here, we focused on an interaction between spatial neglect and non-spatial aspect of attention deficit, and aimed to establish a novel evaluation approach based on the characteristics of the spatial distribution of reaction times. We tested 174 patients with right hemisphere damage and divided them based on their prescreening scores on the Behavioral Inattention Test (BIT): (1) USN++ (n = 79: BIT<131), (2) USN+ (n = 47: BIT≥131 with history of USN), and (3) RHD (n = 48: without neglect symptom). The patients were asked to conduct a touch panel-based pointing task toward 2D-arranged (seven columns × five rows) circular targets on a PC monitor, and the reaction time to each object was recorded. To evaluate aspects of attention deficit and neglect symptoms, we calculated the total average of the reaction time for all objects (RT_mean) and the ratios of the right and left space (L/R_ratio), respectively. The results revealed that RT_mean and L/R_ratio can be regarded as independent evaluation parameters for attention deficit and neglect symptoms, respectively. Voxel-based lesion-symptom mapping based on RT_mean and L/R_ratio values revealed relevant lesions with attention-related brain areas (middle temporal gyrus, angular gyrus, and inferior frontal gyrus), and neglect-related brain areas (superior temporal gyrus and superior longitudinal fascicules). A cluster analysis with Gaussian mixture model detected six different states of USN with an interaction between neglect symptoms and attention deficit. Interestingly, the recovery process after USN can be properly explained by the transition pattern from one cluster to another. Our results suggest that a novel evaluation approach to distinguish between neglect symptoms and attention deficit, namely the characterization of the interaction between RT_mean and L/R_ratio, provides useful information for understanding pathological features of USN.

Dual-Task in Large Perceptual Space Reveals Subclinical Hemispatial Neglect

OBJECTIVE

Both clinically observable and subclinical hemispatial neglect are related to functional disability. The aim of the present study was to examine whether increasing task complexity improves sensitivity in assessment and whether it enables the identification of subclinical neglect.

METHOD

We developed and compared two computerized dual-tasks, a simpler and a more complex one, and presented them on a large, 173 × 277 cm screen. Participants in the study included 40 patients with unilateral stroke in either the left hemisphere (LH patient group, n = 20) or the right hemisphere (RH patient group, n = 20) and 20 healthy controls. In addition to the large-screen tasks, all participants underwent a comprehensive neuropsychological assessment. The Bells Test was used as a traditional paper-and-pencil cancellation test to assess neglect.

RESULTS

RH patients made significantly more left hemifield omission errors than controls in both large-screen tasks. LH patients' omissions did not differ significantly from those of the controls in either large-screen task. No significant group differences were observed in the Bells Test. All groups' reaction times were significantly slower in the more complex large-screen task compared to the simpler one. The more complex large-screen task also produced significantly slower reactions to stimuli in the left than in the right hemifield in all groups.

CONCLUSIONS

The present results suggest that dual-tasks presented on a large screen sensitively reveal subclinical neglect in stroke. New, sensitive, and ecologically valid methods are needed to evaluate subclinical neglect.

Predictors of Arm Nonuse in Chronic Stroke: A Preliminary Investigation

Background. Nonuse (NU) after stroke is characterized by failure to use the contralesional arm despite adequate capacity. It has been suggested that NU is a consequence of the greater effort and/or attention required to use the affected limb, but such accounts have not been directly tested, and we have poor understanding of the predictors of NU. Objective. We aimed to provide preliminary evidence regarding demographic, neuropsychological (ie, apraxia, attention/arousal, neglect), and psychological (ie, self-efficacy) factors that may influence NU in chronic stroke. Methods. Twenty chronic stroke survivors with mild to moderate sensory-motor impairment characterized by the Upper-Extremity Fugl-Meyer (UEFM) were assessed for NU with a modified version of the Actual Amount of Use Test (AAUT), which measures the disparity between amount of use in spontaneous versus forced conditions. Participants were also assessed with measures of limb apraxia, spatial neglect, attention/arousal, and self-efficacy. Using stepwise multiple regression, we determined which variables predicted AAUT NU scores. Results. Scores on the UEFM as well as attention/arousal predicted the degree of NU (P < .05). Attention/arousal predicted NU above and beyond UEFM (P < .05). Conclusions. The results are consistent with the importance of attention and engagement necessary to fully incorporate the paretic limb into daily activities. Larger-scale studies that include additional behavioral (eg, sensation, proprioception, spasticity, pain, mental health, motivation) and neuroanatomical measures (eg, lesion volume and white matter connectivity) will be important for future investigations.

Visual processing features in patients with visual spatial neglect recovering from right-hemispheric stroke

OBJECTIVE

Visual spatial neglect (VSN) is a disorder of spatial-temporal attention, often as a result of traumatic brain injury, including stroke. Accumulating evidence suggests that the recovery from VSN follows a very predictable pattern. In this study, we aimed to determine the specific electrophysiology readout that might have predictive value for recovery from VSN in the typical early events, including the recovery rate of visual processing, within the first four weeks of recovery.

METHODS

This was a prospective study of 18 right ischemic stroke patients with VSN who performed a visual cue-target task within 3 days after stroke. The patients were divided into two groups according to their outcome. We compared behavioral data, the amplitudes and latencies of ERP components（P1, N1, and P300） between patients with persistent-VSN (P-VSN) and those with rapid recovery-VSN (R-VSN).

RESULTS

The amplitudes and latencies of the P1 and N1 components were not significantly influenced by the validity of the cue-based expectancy (all p > 0.05). However, a longer mean P300 latency evoked an effective cue (p < 0.001), and there was a significant difference between the P-VSN and R-VSN groups when using the left target (left hemisphere, p = 0.014; right hemisphere, p = 0.027). The recovery rate found in our study (18.75% at four weeks after stroke) was lower than that of previously reported studies.

CONCLUSIONS

Our findings support the use of the event-related potential as a tool for investigating rapid recovery from VSN after stroke and suggest that other factors, such as an asymmetrical omission toward the contralateral side or impairment in the temporal processing capacity, might also be potential biomarkers of recovery.

Are there correlations between attention, physical endurance and anthropometric parameters of athletes?

Study aim: The aim of the study was to investigate the relationship between attention and physical endurance (running) and anthropometric parameters of athletes.

Material and methods: The study examined 61 students aged 19 to 25 years, divided into two groups: athletes (33 participants) and non-athletes (28 participants). We employed anthropometric measurements and the Vienna System Test, including tools to measure focused attention, such as LVT (visual orientation performance test) and DAUF (test for examination of sustained attention) and the Cooper test to measure endurance.

Results: Analysis of the results demonstrated a relationship between attention and physical endurance with median time from LVT (r = –0.552). A relationship was also found between the Cooper test results and the mean time to incorrect answer (r = –0.900).

Conclusions: The analysis demonstrated a relationship between attention, physical endurance and anthropometric parameters of athletes.

The ipsilesional attention bias in right-hemisphere stroke patients as revealed by a realistic visual search task: Neuroanatomical correlates and functional relevance

OBJECTIVE

Right-hemisphere stroke may cause an ipsilesional attention bias and left hemispatial neglect. Computerized time-limited tasks are more sensitive than conventional paper-pencil tests in detecting these spatial attention deficits. However, their frequency in the acute stage of stroke, the neuroanatomical basis and functional relevance for patients' everyday life are unclear.

METHOD

A realistic visual search task is introduced, in which eye movements are recorded while the patient searches for paperclips among different everyday objects on a computer display. The "desk task" performance of 34 acute right-hemisphere stroke patients was compared to established paper-pencil tests for neglect and the Posner reaction time task, and finally correlated to structural brain lesions.

RESULTS

Most of the patients, even those without clinical neglect signs and with normal paper-pencil test performance, exhibited a clear ipsilesional attention bias in the desk task. This bias was highly correlated to the left-right asymmetry in the Posner task and to neglect-related functional impairment scores. Lesion-symptom mapping revealed task-specific differences: deficits in the desk task were associated with lesions of the superior temporal gyrus, contralesional unawareness in the Posner task with ventral frontal cortex lesions and paper-pencil cancellation bias with damage to the inferior parietal lobe. Neglect behavior was further associated with distinct frontoparietal white matter tract disconnections (inferior longitudinal fasciculus, superior longitudinal fasciculus, arcuate).

CONCLUSIONS

Results from the novel desk task indicate a functional relevance of spatial attention deficits in right-hemisphere stroke patients, even if they are "subclinical." This should be considered especially in patients without obvious clinical neglect signs. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Simulated driving: The added value of dynamic testing in the assessment of visuo-spatial neglect after stroke

BACKGROUND

Visuo-spatial neglect (VSN) is generally assessed with neuropsychological paper-and-pencil tasks, which are often not sensitive enough to detect mild and/or well-compensated VSN. It is of utmost importance to develop dynamic tasks, resembling the dynamics of daily living.

OBJECTIVE

A simulated driving task was used to assess (1) differences in performance (i.e., position on the road and magnitude of sway) between patients with left- and right-sided VSN, recovered VSN, without VSN, and healthy participants; (2) the relation between average position and VSN severity; and (3) its diagnostic accuracy in relation to traditional tasks.

METHODS

Stroke inpatients were tested with a cancellation task, the Catherine Bergego Scale and the simulated driving task.

RESULTS

Patients with left-sided VSN and recovered VSN deviated more regarding position on the road compared to patients without VSN. The deviation was larger in patients with more severe VSN. Regarding diagnostic accuracy, 29% of recovered VSN patients and 6% of patients without VSN did show abnormal performance on the simulated driving task. The sensitivity was 52% for left-sided VSN. Right-sided VSN was not well detected, probably due to the asymmetric layout.

CONCLUSIONS

Based on these results, the simulated driving task should not be the only task to assess VSN, especially in its current form. Given the heterogenic nature of VSN, the assessment should always consist of several tasks varying in nature and complexity and include a dynamic task to detect mild and/or recovered VSN. A symmetric design should be used when designing novel tasks to assess right-sided VSN.

Occurrence and Recovery of Different Neglect-Related Symptoms in Right Hemisphere Infarct Patients during a 1-Year Follow-Up

OBJECTIVES

To examine the occurrence of and recovery from visual neglect-related symptoms with the focus on neglect laterality, ipsilateral orienting bias, and slowed processing speed in right hemisphere (RH) infarct patients during a 1-year follow-up. Furthermore, to propose guidelines for assessing processing speed alongside the Behavioural Inattention Test (BIT).

METHODS

We studied three RH patient groups: neglect (N+), mild left inattention (MLI+), and non-neglect (N-) patients, and healthy controls. The BIT with some additional analyses was conducted at the acute phase and at 6 and 12 months.

RESULTS

The N+ group's BIT score increased and originally lateralized omissions became more evenly distributed during the follow-up. The N+ and MLI+ groups' starting points were more rightward located than the healthy group's at the acute phase and at 6, and partly at 12 months. Patient groups were slower than the controls in performing cancellation tests at the acute phase. The N+ and MLI+ groups remained slower than the controls throughout the follow-up.

CONCLUSIONS

During the first year after RH infarct, originally left-sided manifestation of neglect shifted toward milder non-lateralized attentional deficit. Ipsilateral orienting bias and slowed processing speed appeared to be rather persistent neglect-related symptoms both in neglect patients and patients with initially milder inattention. We propose some effortless, tentative ways of examining processing speed and ipsilateral orienting bias alongside the BIT to better recognize these neglect-related symptoms, and highlight the need to assess and treat patients with initially milder inattention, who have been under-recognized and under-treated in clinical work. (JINS, 2018, 24, 617-628).

EEG-based neglect assessment: A feasibility study

BACKGROUND

Spatial neglect (SN) is a neuropsychological syndrome that impairs automatic attention orienting to stimuli in the contralesional visual space of stroke patients. SN is commonly assessed using paper and pencil tests. Recently, computerized tests have been proposed to provide a dynamic assessment of SN. However, both paper- and computer-based methods have limitations.

NEW METHOD

Electroencephalography (EEG) shows promise for overcoming the limitations of current assessment methods. The aim of this work is to introduce an objective passive BCI system that records EEG signals in response to visual stimuli appearing in random locations on a screen with a dynamically changing background. Our preliminary experimental studies focused on validating the system using healthy participants with intact brains rather than employing it initially in more complex environments with patients having cortical lesions. Therefore, we designed a version of the test in which we simulated SN by hiding target stimuli appearing on the left side of the screen so that the subject's attention is shifted to the right side.

RESULTS

Results showed that there are statistically significant differences between EEG responses due to right and left side stimuli reflecting different processing and attention levels towards both sides of the screen. The system achieved average accuracy, sensitivity and specificity of 74.24%, 75.17% and 71.36% respectively.

COMPARISON WITH EXISTING METHODS

The proposed test can examine both presence and severity of SN, unlike traditional paper and pencil tests and computer-based methods.

CONCLUSIONS

The proposed test is a promising objective SN evaluation method.

The Mobility Assessment Course for the Diagnosis of Spatial Neglect: Taking a Step Forward?

Spatial neglect after stroke can be a challenging syndrome to diagnose under standard neuropsychological assessment. There is now sufficient evidence that those affected might demonstrate neglect behavior in everyday settings despite showing no signs of neglect during common neglect tasks. This discrepancy is attributed to the simplified and unrealistic nature of common pen and paper based tasks that do not match the demanding, novel, and complex environment of everyday life. As such, increasing task demands under more ecologically valid scenarios has become an important method of increasing test sensitivity. The main aim of the current study was to evaluate the diagnostic utility of the Mobility Assessment Course (MAC), an ecological task, for the assessment of neglect. If neglect becomes more apparent under more challenging task demands the MAC could prove to be more diagnostically accurate at detecting neglect than conventional methods, particularly as the time from initial brain damage increases. Data collected by Guide Dogs of SA/NT were retrospectively analyzed. The Receiver Operating Characteristic (ROC) curve, a measure of sensitivity and specificity, was used to investigate the diagnostic utility of the MAC and a series of paper and pencil tests in 67 right hemisphere stroke survivors. While the MAC proved to be a more sensitive neglect test (74.2%) when compared to the Star Cancellation (43.3%) and Line Bisection (35.7%) tests, this was at the expense of relatively low specificity. As a result, the ROC curve analysis showed no statistically discernable differences between tasks (p > 0.12), or between subacute and chronic groups for individual tasks (p > 0.45). It is concluded that, while the MAC is an ecologically valid alternative for assessing neglect, regarding its diagnostic accuracy, there is currently not enough evidence to suggest that it is a big step forward in comparison to the accuracy of conventional tests.

Association between daily activities, process skills, and motor skills in community-dwelling patients after left hemiparetic stroke

[Purpose] The purpose of this study was to evaluate the relationships between daily activities, information processing, and motor skills in individuals with hemineglect after having a left hemiparetic stroke. [Subjects and Methods] The instrumental activities of daily living of 35 patients (22 male and 13 female; age: 57.1 ± 16.9 years) with hemineglect after having a left hemiparetic stroke were assessed by using three clinical measurement tools, including activity card sorting, assessment of motor and process skills, and the modified Barthel Index. [Results] The results of the regression analysis indicated that the patients' processing skills in instrumental activities of daily living after having a left hemiparetic stroke were reduced. Participation in leisure and social activities was also affected as assessed by using the modified Barthel Index. [Conclusion] This study supports the clinical need for rehabilitation intervention after a left hemiparetic stroke to improve patients' processing skills and independence in performing activities of daily living.

"Getting the Left Right": The Experience of Hemispatial Neglect After Stroke

We used a phenomenological approach to gain insight into the experiences of self, other, and world in patients with hemispatial neglect within the first month following stroke. Comprehensive descriptions of circumstances were conjoined with open-ended interviews of 12 participants. The neglect experience was captured in the overarching theme, "getting the left right," which encompasses the two subthemes of (a) surreal awareness of the left and (b) emergence of a different world. Patients had unclear perceptions of their own body and surroundings, their attention was brittle, and they encountered bewildering reactions from other people. They simultaneously pursued the ineffable neglected space and searched for coherence. The vulnerability, loss, and conflicting perceptions that patients with neglect face should be acknowledged and alleviation sought. Facilitating methods should provide additional opportunities for patients to communicate their experiences. We underscore the importance of readjusting the current approaches of neglect and emphasizing meaningfulness in professional guidance.

Effects of contralesional robot-assisted hand training in patients with unilateral spatial neglect following stroke: a case series study

Background

A reduction of hemispatial neglect due to stroke has been associated with activation of the contralesional hand in the contralesional hemispace. Robot-assisted upper limb training was found to effectively improve paretic arm function in stroke patients. To date no proof of concept of robot-assisted hemispatial neglect therapy has been reported in literature. This study aimed to determine whether robot-assisted left (contralesional) hand activation alone could lead to an improvement in hemispatial neglect following stroke.

Methods

Three stroke patients with right brain injury underwent a 2-week training program of robotic left hand activation with the Gloreha® hand rehabilitation glove, which provides repetitive, passive mobilization of the fingers. Outcomes were assessed using the Line Crossing test, the Bells test, the Sentence Reading test, the Saccadic Training, the Sustained Attention to Response Task, and the Purdue Pegboard test.

Results

Changes were observed after treatment as follows. Line Crossing test: all patients showed improved performance (6.7%, 89.5% and 80% increase in lines crossed) with two patients reaching normal performance levels. Bells test: one patient improved performance (50% increase), while one patient showed no change and one patient declined (−10.3% change); no patient reached normal performance levels. Sentence Reading test: all patients showed improved performance (800%, 57.1% and 42.9% increase in number of sentences read) with no patient reaching normal performance level. Saccadic Training: all patients showed improved performance (−62.8%, −15.5% and −9.7% change of the left hemifield reaction time). Sustained Attention to Response Task: all patients showed improved performance (−20.5%, −5.8% and −10% change of the reaction time) with two patients reducing incorrect responses (−42.9% and −73.3%) and one patient increasing them (9.1%). Purdue Pegboard test: all patients showed improved performance (100%, 27.3% and 75% change in the left + right + both hands sub-item score).

Conclusions

Some caution is warranted when interpreting our results, as the responses to the intervention were variable and might have been due to a placebo effect or fluctuating clinical conditions. However, robot-assisted hemispatial neglect therapy might be useful in stroke patients. Larger-scale investigations are needed to confirm our preliminary findings.

Electronic supplementary material

The online version of this article (doi:10.1186/1743-0003-11-160) contains supplementary material, which is available to authorized users.

Virtual reality-based navigation task to reveal obstacle avoidance performance in individuals with visuospatial neglect

Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30 (°) contralesionally/ipsilesionally. Our results indicate that in the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. We conclusion the observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alter obstacle avoidance abilities.

Novel insights in the rehabilitation of neglect

Visuospatial neglect due to right hemisphere damage, usually a stroke, is a major cause of disability, impairing the ability to perform a whole range of everyday life activities. Conventional and long-established methods for the rehabilitation of neglect like visual scanning training, optokinetic stimulation, or limb activation training have produced positive results, with varying degrees of generalization to (un)trained tasks, lasting from several minutes up to various months after training. Nevertheless, some promising novel approaches to the remediation of left visuospatial neglect have emerged in the last decade. These new therapy methods can be broadly classified into four categories. First, non-invasive brain stimulation techniques by means of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS), after a period of mainly diagnostic utilization, are increasingly applied as neurorehabilitative tools. Second, two classes of drugs, dopaminergic and noradrenergic, have been investigated for their potential effectiveness in rehabilitating neglect. Third, prism adaptation treatment has been shown to improve several neglect symptoms consistently, sometimes during longer periods of time. Finally, virtual reality technologies hold new opportunities for the development of effective training techniques for neglect. They provide realistic, rich, and highly controllable training environments. In this paper the degree of effectiveness and the evidence gathered to support the therapeutic claims of these new approaches is reviewed and discussed. The conclusion is that for all these approaches there still is insufficient unbiased evidence to support their effectiveness. Further neglect rehabilitation research should focus on the maintenance of therapy results over time, on a more functional evaluation of treatment effects, on the design and execution of true replication studies and on the exploration of optimal combinations of treatments.

Visual Scanning Training for Neglect after Stroke with and without a Computerized Lane Tracking Dual Task

Neglect patients typically fail to explore the contralesional half-space. During visual scanning training, these patients learn to consciously pay attention to contralesional target stimuli. It has been suggested that combining scanning training with methods addressing non-spatial attention might enhance training results. In the present study, a dual task training component was added to a visual scanning training (i.e., Training di Scanning Visuospaziale - TSVS; Pizzamiglio et al., 1990). Twenty-nine subacute right hemisphere stroke patients were semi-randomly assigned to an experimental (N = 14) or a control group (N = 15). Patients received 30 training sessions during 6 weeks. TSVS consisted of four standardized tasks (digit detection, reading/copying, copying drawings, and figure description). Moreover, a driving simulator task was integrated in the training procedure. Control patients practiced a single lane tracking task for 2 days a week during 6 weeks. The experimental group was administered the same training schedule, but in weeks 4-6 of the training, the TSVS digit detection task was combined with lane tracking on the same projection screen, so as to create a dual task (computerized visual reaction time task designed for training). Various neglect tests and driving simulator tasks were administered before and after training. No significant group and interaction effects were found that might reflect additional positive effects of dual task training. Significant improvements after training were observed in both groups taken together on most assessment tasks. Ameliorations were generally not correlated to post-onset time, but spontaneous recovery, test-retest variability, and learning effects could not be ruled out completely, since these were not controlled for. Future research might focus on increasing the amount of dual task training, the implementation of progressive difficulty levels in driving simulator tasks, and further exploration of relationships between dual task training and daily functioning.

Neglect and extinction depend greatly on task demands: a review

This review illustrates how, after unilateral brain damage, the presence and severity of spatial awareness deficits for the contralesional hemispace depend greatly on the quantity of attentional resources available for performance. After a brief description of neglect and extinction, different frameworks accounting for spatial and non-spatial attentional processes will be outlined. The central part of the review describes how the performance of brain-damaged patients is negatively affected by increased task demands, which can result in the emergence of severe awareness deficits for contralesional space even in patients who perform normally on paper-and-pencil tests. Throughout the review neglect is described as a spatial syndrome that can be exacerbated in the presence and severity by both spatial and non-spatial tasks. The take-home message is that the presence and degree of contralesional neglect and extinction can be dramatically overlooked based on standard clinical (paper-and-pencil) testing, where patients can easily compensate for their deficits. Only tasks where compensation is made impossible represent an appropriate approach to detect these disabling contralesional deficits of awareness when they become subtle in post-acute stroke phases.

To what extent can multimorbidity be viewed as a determinant of postural control in stroke patients?

OBJECTIVE

To investigate the determinants of postural imbalance after stroke in geriatric patients admitted for low-intensity rehabilitation in skilled nursing facilities (SNFs), particularly the role of multimorbidity.

DESIGN

Cross-sectional study design.

SETTING

Fifteen SNFs.

PARTICIPANTS

All patients who were admitted for rehabilitation after stroke in one of the participating SNFs (N=378) were eligible.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Berg Balance Scale (BBS) was selected as a measure of standing balance and the Functional Ambulation Categories (FAC) as a measure of walking balance.

RESULTS

Multimorbidity was present in 34% of the patients. The patients with multimorbidity differed from the patients without multimorbidity with respect to age, proprioception, and vibration sense, but not for any of the cognitive tests, muscle strength, or sitting balance. Patients with multimorbidity had, on average, lower scores on both outcome measures. In linear regression analyses, both the BBS and FAC were best explained by multimorbidity, muscle strength, and the interaction between muscle strength and static sitting balance (overall explained variance 66% and 67%, respectively), while proprioception added only to the variance of the FAC.

CONCLUSIONS

Multimorbidity was independently related to postural imbalance after stroke in patients admitted for rehabilitation in SNFs. Muscle strength and the interaction of muscle strength with static sitting balance were important determinants of both standing and walking balance, indicating these factors as essential targets for rehabilitation.

Current tests and trends in single-case neuropsychology

In this issue of Cortex, Crawford, Garthwaite and Ryan publish bayesian statistical tests that will enable researchers to take account of covariates when comparing single patients to control samples. In this article, we provide some context for this development, from an audit of the Cortex archives. We suggest that single-case research is alive and well, and more rigorous than ever, and that current practice has been shaped considerably by Crawford and colleagues' statistical refinements over the past 12 years. However, there is scope for further tightening and standardisation of statistical methods and reporting standards. The advantages offered by the new bayesian tests should promote the even wider use of appropriate statistical methods, with benefits for the validity of individual studies, and for cross-comparability in the single-case literature.

The need for a revised version of the Benton judgment of line orientation test

The Judgment of Line Orientation Test (JLOT) is considered a valid task for the assessment of visuospatial perception, and, for this reason, it is also considered to be a sensitive tool able to discriminate between right-hemisphere-damaged (RHD) patients and left-hemisphere-damaged (LHD) patients. In contrast with this view, we report evidence that the greater impairment in JLOT usually shown by RHD patients is unrelated to the supposed JLOT effectiveness in measuring visuospatial judgment ability and to the putative dominant role of the right hemisphere in visuospatial processing. JLOT is characterized by a left-right structural asymmetry (i.e., left-side lines are easier to judge) that seriously undermines the test validity: This asymmetry interacts with ipsilesional attentional biases of brain-damaged patients and affects their performance. Results obtained with a JLOT version composed of both the original items and their mirror-reversed versions clearly indicate that the cognitive functions tested by the JLOT are distributed across the two hemispheres: LHD and RHD patients did not differ from each other or from their matched controls when their performances were compared on this balanced JLOT version. Impaired performances of either RHD or LHD patients were found only when performances in original and mirror-reversed items were considered separately. This suggests that the original JLOT cannot assess visuospatial perception independently from attentional biases. The test can be a powerful clinical tool, as long as both original and mirror-reversed items are used, and the standard scoring method is replaced by the evaluation of the individual lines of stimulus pairs.

A simple measure of neglect severity

Cancellation tasks are popular clinical and scientific tools for identifying spatial neglect, with neglect patients tending to miss targets on the contralesional side of the test. However, methods for analysis are not well established. Indeed, these tests are often used as a binary classifier to simply identify the presence or absence of spatial neglect, even though it is clear that there is a spectrum of disability on these tasks. We suggest that the Center of Cancellation (CoC) provides an intuitive, continuous and robust measure of neglect severity. First employed by Binder and colleagues [Archives of Neurology, 49, 1187-1194 (1992)], its use has not been replicated since. Our aim was to ease deployment of this measure through validation, development of software and focused exposition. To validate this index, we evaluated a group of 110 individuals with right-hemisphere injury. For two different cancellation tasks (the Bells Test and the Letter Cancellation Task) we predicted spatial neglect (as defined by independent measures) using the new CoC index. Examining each individual's performance on a single cancellation task, we were able to correctly determine with better than 98% accuracy whether three tests with binary classifiers would define them as having spatial neglect. Specifically, an acute CoC score greater than 0.081 on the Bells Test or 0.083 on the Letter Cancellation Task turned out to indicate neglect behavior after a right-hemisphere brain lesion. Finally, we provide free software allowing other groups not only to rapidly analyze new but also previously existing (paper-and-pencil based) datasets using this measure.

Geriatric rehabilitation of stroke patients in nursing homes: a study protocol

BACKGROUND

Geriatric patients are typically underrepresented in studies on the functional outcome of rehabilitation after stroke. Moreover, most geriatric stroke patients do probably not participate in intensive rehabilitation programs as offered by rehabilitation centers. As a result, very few studies have described the successfulness of geriatric stroke rehabilitation in nursing home patients, although it appears that the majority of these patients are being discharged back to the community, rather than being transferred to residential care. Nevertheless, factors associated with the successfulness of stroke rehabilitation in nursing homes or skilled nursing facilities are largely unknown. The primary goal of this study is, therefore, to assess the factors that uniquely contribute to the successfulness of rehabilitation in geriatric stroke patients that undergo rehabilitation in nursing homes. A secondary goal is to investigate whether these factors are similar to those associated with the outcome of stroke rehabilitation in the literature.

METHODS/DESIGN

This study is part of the Geriatric Rehabilitation in AMPutation and Stroke (GRAMPS) study in the Netherlands. It is a longitudinal, observational, multicenter study in 15 nursing homes in the Southern part of the Netherlands that aims to include at least 200 patients. All participating nursing homes are selected based on the existence of a specialized rehabilitation unit and the provision of dedicated multidisciplinary care. Patient characteristics, disease characteristics, functional status, cognition, behavior, and caregiver information, are collected within two weeks after admission to the nursing home. The first follow-up is at discharge from the nursing home or one year after inclusion, and focuses on functional status and behavior. Successful rehabilitation is defined as discharge from the nursing home to an independent living situation within one year after admission. The second follow-up is three months after discharge in patients who rehabilitated successfully, and assesses functional status, behavior, and quality of life. All instruments used in this study have shown to be valid and reliable in rehabilitation research or are recommended by the Netherlands Heart Foundation guidelines for stroke rehabilitation.Data will be analyzed using SPSS 16.0. Besides descriptive analyses, both univariate and multivariate analyses will be performed with the purpose of identifying associated factors as well as their unique contribution to determining successful rehabilitation.

DISCUSSION

This study will provide more information about geriatric stroke rehabilitation in Dutch nursing homes. To our knowledge, this is the first large study that focuses on the determinants of success of geriatric stroke rehabilitation in nursing home patients.