Adaptation to poststroke visual field loss: A systematic review

Validation of the brain injury associated visual impairment - impact questionnaire (BIVI-IQ)

PURPOSE

The Brain Injury associated Visual Impairment - Impact Questionnaire (BIVI-IQ) was developed to assess the impact of post-stroke visual impairment. The development of the questionnaire used robust methods involving stroke survivors and clinicians. The aim of this study was to assess the validity of the BIVI-IQ in a stroke population.

METHODS

Stroke survivors with visual impairment were recruited from stroke units, outpatient clinics and non-healthcare settings. Participants were asked to complete questionnaire sets on three separate occasions; the BIVI-IQ at each visit with additional questionnaires at baseline and visit 2. Vision assessment and anchor questions from participants and clinicians were collected. The analysis included assessment of missing data, acceptability, Rasch model analysis, test-retest reliability, construct validity (NEI VFQ-25, EQ-5D-5L) and responsiveness to change.

RESULTS

316 stroke survivors completed at least one questionnaire of the 326 recruited. Mean age was 67 years and 64% were male. Adequate fit statistics to the Rasch model were reached (χ2 = 73.12, p = 0.02) with two items removed and thresholds of two adjusted, indicating validity and unidimensionality. Excellent test-retest reliability was demonstrated (ICC = 0.905) with a 3-month interval. Construct validity was demonstrated with a strong significant correlation to the NEI VFQ-25 (r = 0.837, p < 0.01). The BIVI-IQ also demonstrated responsiveness to change with significant differences identified between groups based on participant and clinician anchor questions (X2 = 23.29, p < 0.001; X2 = 24.56, p < 0.001).

CONCLUSION

The BIVI-IQ has been shown to be valid and practical for 'everyday' use by clinicians and researchers to monitor vision-related quality of life in stroke survivors with visual impairment.

The attention atlas virtual reality platform maps three-dimensional (3D) attention in unilateral spatial neglect patients: a protocol

BACKGROUND

Deficits in visuospatial attention, known as neglect, are common following brain injury, but underdiagnosed and poorly treated, resulting in long-term cognitive disability. In clinical settings, neglect is often assessed using simple pen-and-paper tests. While convenient, these cannot characterise the full spectrum of neglect. This protocol reports a research programme that compares traditional neglect assessments with a novel virtual reality attention assessment platform: The Attention Atlas (AA).

METHODS/DESIGN

The AA was codesigned by researchers and clinicians to meet the clinical need for improved neglect assessment. The AA uses a visual search paradigm to map the attended space in three dimensions and seeks to identify the optimal parameters that best distinguish neglect from non-neglect, and the spectrum of neglect, by providing near-time feedback to clinicians on system-level behavioural performance. A series of experiments will address procedural, scientific, patient, and clinical feasibility domains.

RESULTS

Analyses focuses on descriptive measures of reaction time, accuracy data for target localisation, and histogram-based raycast attentional mapping analysis; which measures the individual's orientation in space, and inter- and intra-individual variation of visuospatial attention. We will compare neglect and control data using parametric between-subjects analyses. We present example individual-level results produced in near-time during visual search.

CONCLUSIONS

The development and validation of the AA is part of a new generation of translational neuroscience that exploits the latest advances in technology and brain science, including technology repurposed from the consumer gaming market. This approach to rehabilitation has the potential for highly accurate, highly engaging, personalised care.

How to test blindsight without light-scatter artefacts?

Light-scatter artefacts are a methodological problem in testing residual visual capacities (RVCs), for instance blindsight, in patients with homonymous visual field defects (HVFDs). The term light-scatter artefact describes the phenomenon that light from targets directed towards the HVFD can stray into the sighted visual field. This might enable an observer to respond correctly to information directed at her blind field despite the fact that she is unable to process that information in the blind field itself. In this manuscript, we present a review of the relevance of light-scatter in visual neuroscience, discuss factors that influence the impact of light-scatter and evaluate means to test for light-scatter artefacts. Furthermore, we present findings from an empirical study that was aimed at developing tests for RVCs that are free of light-scatter artefacts. Previous studies on light scatter only used small sample sizes and equipment that is no longer in use. Hence, their results cannot be generalized to future experiments making it necessary to run laborious light-scatter tests for every new study on RVCs. To avoid this, we hereby start a pool of stimuli and paradigms which demonstrably do not elicit light-scatter artefacts. To this end, we investigated 21 healthy young participants in three frequently used RVC-paradigms: (1) temporal 2AFC task, (2) movement direction discrimination, and (3) redundant target paradigm. For each paradigm, we applied the blind-spot method. But first, we had to establish that our testing paradigm was sufficiently sensitive to detect light-scatter artefacts. For this, we used conditions that are known to produce strong light scatter and a paradigm that is very sensitive to such effects. Specifically, we presented white targets on a black background in a dark room. The stimuli were presented to observers' blind spot. To check for light-scatter artefacts, we used a target-detection task in a temporal 2AFC format. We obtained clear light-scatter artefacts. Participants produced reliably above-chance detection performance under these conditions. The other two luminance conditions, measured in an illuminated room, did not produce light-scatter artefacts. Accuracy in the temporal 2AFC task was at chance level for white targets on a grey background at the blind-spot position. Additionally, black targets on a grey background avoided light-scatter artefacts in all three RVC-paradigms. In future, researchers can apply these stimulus and illumination conditions when using one of the three above paradigms in their studies. Using these conditions, they will be able to avoid light-scatter artefacts without having to perform their own blind-spot tests.

Audio-visual stimulation for visual compensatory functions in stroke survivors with visual field defect: a systematic review

Background

Hemianopia is a complete or partial blindness in the visual fields of both eyes, commonly caused by cerebral infarction. It has been hypothesized that systematic audio-visual (AV) stimulation of the blind hemifield can improve accuracy and search times, probably due to the stimulation of bimodal representations in the superior colliculus (SC), an important multisensory structure involved in both the initiation and execution of saccades.

Methods

A narrative synthesis of the findings is presented to highlight how AV rehabilitation impacts on patients with hemianopia including visual oculomotor function, functional ability in activities of daily living, hemianopic dyslexia, visual scanning and searching tasks, maintaining of functional ability post training and the effect on brain multisensory integration by using neuroimaging.

Results

Sixteen studies were included (fourteen articles (188 participants) and two literature reviews). Results were grouped into AV training of hemianopia in adults and in children and then further grouped according to the AV task type: tasks measuring the training effects by comparing visual stimulation training to audio-visual training, localization abilities in homonymous hemianopia (HH) and AV integration in patients with HH.

Conclusion

Systematic AV training may improve the processing of visual information by recruiting subcortical pathways, and because most of the patients with visual cortex damage have an intact SC, it might be useful to use the bimodal AV training to activate retinotectal functions. Nevertheless, the underlying mechanisms supporting the reported positive effects are not currently understood. Systematic functional and/or structural imaging studies may help in understanding the underlying mechanism and inform the design of optimal training paradigms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-022-05926-y.

Adaptation to post-stroke homonymous hemianopia - a prospective longitudinal cohort study to identify predictive factors of the adaptation process

PURPOSE

To determine any factors that predict how an individual will adapt to post-stroke hemianopic visual field loss, with close monitoring of the adaptation process from an early stage.

MATERIALS AND METHODS

The Hemianopia Adaptation Study (HAST) is a prospective observational longitudinal cohort clinical study. Adult stroke survivors (n = 144) with new onset homonymous hemianopia were monitored using standardised mobility assessment course (MAC) as the primary outcome measure of adaptation.

RESULTS

Several baseline variables were found to be good predictors of adaptation. Three variables were associated with adaptation status at 12-weeks post-stroke: inferior % visual field, % total MAC omissions, and MAC completion time (seconds). Baseline measurements of these variables can predict the adaptation at 12 weeks with moderate to high accuracy (area under ROC curve, 0.82, 95% CI 0.74-0.90). A cut-off score of ≤25% target omissions is suggested to predict which individuals are likely to adapt by 12-weeks post-stroke following gold standard care.

CONCLUSIONS

Adaptation to hemianopia is a personal journey with several factors being important for prediction of its presence, including MAC outcomes and extent of inferior visual field loss. A clinical recommendation is made for inclusion of the MAC as part of a functional assessment for hemianopia.Implications for rehabilitationThe mobility assessment course (MAC) should be considered as an assessment of mobility/scanning in the rehabilitation of patients with homonymous hemianopia.A cut-off score of ≤25% omissions on MAC could be employed to determine those likely to adapt to hemianopia long-term.Targeted support and therapy for patients with significant visual loss in the inferior visual field area should be considered.

Biomechanical adaptation to post-stroke visual field loss: a systematic review

BACKGROUND

Homonymous visual field defects represent the most frequent type of visual field loss after stroke, affecting nearly 30% of individuals with unilateral post-chiasmal brain damage. This review aimed to gather the available evidence on the biomechanical changes to visual field loss following stroke.

METHODS

A systematic review was conducted inclusive of randomised controlled trials, cohort studies, before-after studies and case-controlled studies. Studies including adult and paediatric participants that investigated eye, head, or body movements in post-stroke visual field loss during visual exploration tasks were included. Search terms included a range of MESH terms as well as alternative terms relating to stroke, visual field loss, hemianopia, visual functions and scanning behaviour. Articles were selected by two authors independently. Data were extracted by one author and verified by a second. All included articles were assessed for risk of bias using checklists appropriate to the study design.

RESULTS

Thirty-six articles (1123 participants) were included in the overall review (Kappa 0.863) and categorised into simulated or true visual field loss (typically hemianopia). Seven studies identified the biomechanical alterations to simulated hemianopia compared to normal performance. Twenty-nine studies detailed eye, head and body movement parameters in true hemianopia. Hemianopic participants and healthy adults with simulated hemianopia differed significantly from controls in various fixation and saccade parameters as indicated by increased number and duration of fixations, number and duration of saccades and scan path length with shorter mean saccadic amplitude. Under simulated hemianopia, participants were consistently biased towards the sighted visual field while gaze behaviour in true hemianopia was biased in the direction of the blind hemifield.

CONCLUSIONS

There is considerable evidence on the altered eye movements that occur in true hemianopia and in healthy adults with simulated hemianopia. Successful performance in naturalistic tasks of visual exploration appears to be related to compensatory mechanisms of visual exploratory behaviour, namely, an increase in the amplitude and peak velocity of saccades, widening horizontally the distribution of eye movements, and a shift of the overall distribution of saccades into the blind field. This review highlights the lack of studies reporting head and other body movement parameters in hemianopia. Further studies with robust methodology and large sample sizes involving participants with post-stroke visual field loss are needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020194403.

Rehabilitation of cortically induced visual field loss

PURPOSE OF REVIEW

Homonymous visual field defects are a common sequela of stroke, and are assumed to be permanent within a few weeks of the event. Because consensus about the efficacy of rehabilitation is lacking, visual therapy is rarely prescribed. Here, we review current rehabilitation options and strategies in the translational pipeline that could change these perspectives.

RECENT FINDINGS

The mainstays of available therapy for homonymous visual defects are compensation training and substitution, which allow patients to better use their spared vision. However, early clinical studies suggest that vision can partially recover following intensive training inside the blind field. Research into the relative efficacy of different restorative approaches continues, providing insights into neurophysiologic substrates of recovery and its limitations. This, in turn, has led to new work examining the possible benefits of earlier intervention, advanced training procedures, noninvasive brain stimulation, and pharmacological adjuvants, all of which remain to be vetted through properly powered, randomized, clinical trials.

SUMMARY

Research has uncovered substantial visual plasticity after occipital strokes, suggesting that rehabilitative strategies for this condition should be more aggressive. For maximal benefit, poststroke vision-restorative interventions should begin early, and in parallel with strategies that optimize everyday use of an expanding field of view.

"Invisible" visual impairments. A qualitative study of stroke survivors` experience of vision symptoms, health services and impact of visual impairments

BACKGROUND

Visual impairments (VIs) have a negative impact on life and affect up to 60% of stroke survivors. Despite this, VIs are often overlooked. This paper explores how persons with VIs experience vision care within stroke health services and how VIs impact everyday life the first 3 months post stroke.

METHODS

Individual semi-structured interviews were conducted with 10 stroke survivors 3 months post stroke, and analyzed using qualitative content analysis.

RESULTS

The main theme, "Invisible" visual impairments, represents how participants experience VIs as an unknown and difficult symptom of stroke and that the lack of attention and appropriate visual care leads to uncertainty about the future. VIs were highlighted as a main factor hindering the participants living life as before. The lack of acknowledgement, information, and systematic vision rehabilitation leads to feelings of being unsupported in the process of coping with VIs.

CONCLUSION

VIs are unknown symptoms pre stroke and sequelas after stroke that significantly affect everyday life. VIs and vision rehabilitation needs more attention through all phases of stroke health services. We request a greater awareness of VIs as a presenting symptom of stroke, and that visual symptoms should be included in stroke awareness campaigns. Further, we suggest increased competence and standardized evidence-based clinical pathways for VIs to advance all stroke health services including rehabilitation in order to improve outcomes and adaptation to future life for stroke survivors with VIs.

Visual processing speed in hemianopia patients secondary to acquired brain injury: a new assessment methodology

Background

There is a clinical need to identify diagnostic parameters that objectively quantify and monitor the effective visual ability of patients with homonymous visual field defects (HVFDs). Visual processing speed (VPS) is an objective measure of visual ability. It is the reaction time (RT) needed to correctly search and/or reach for a visual stimulus. VPS depends on six main brain processing systems: auditory-cognitive, attentional, working memory, visuocognitive, visuomotor, and executive. We designed a new assessment methodology capable of activating these six systems and measuring RTs to determine the VPS of patients with HVFDs.

Methods

New software was designed for assessing subject visual stimulus search and reach times (S-RT and R-RT respectively), measured in seconds. Thirty-two different everyday visual stimuli were divided in four complexity groups that were presented along 8 radial visual field positions at three different eccentricities (10^o, 20^o, and 30^o). Thus, for each HVFD and control subject, 96 S- and R-RT measures related to VPS were registered. Three additional variables were measured to gather objective data on the validity of the test: eye-hand coordination mistakes (ehcM), eye-hand coordination accuracy (ehcA), and degrees of head movement (dHM, measured by a head-tracker system). HVFD patients and healthy controls (30 each) matched by age and gender were included. Each subject was assessed in a single visit. VPS measurements for HFVD patients and control subjects were compared for the complete test, for each stimulus complexity group, and for each eccentricity.

Results

VPS was significantly slower (p < 0.0001) in the HVFD group for the complete test, each stimulus complexity group, and each eccentricity. For the complete test, the VPS of the HVFD patients was 73.0% slower than controls. They also had 335.6% more ehcMs, 41.3% worse ehcA, and 189.0% more dHMs than the controls.

Conclusions

Measurement of VPS by this new assessment methodology could be an effective tool for objectively quantifying the visual ability of HVFD patients. Future research should evaluate the effectiveness of this novel method for measuring the impact that any specific neurovisual rehabilitation program has for these patients.

Slowed Information Processing Speed at Four Years Poststroke: Evidence and Predictors from a Population-Based Follow-up Study

BACKGROUND AND PURPOSE

Slowed Information Processing Speed (IPS) is a commonly reported cognitive deficit following stroke, affecting up to 50% to 70 % of stroke survivors. IPS has a major influence on poststroke cognitive dysfunction, affecting quality of life and increasing dependence on others. Few studies have examined predictors of slow IPS after stroke, and there is a paucity of data in terms of long-term prevalence. This study examined baseline predictors associated with long-term slow IPS in a population-based stroke incidence cohort, 4 years after stroke onset.

METHODS

Adults with stroke (n = 133, m = 71.1 ± 13.5 years) completed the Symbol Digit Modalities Test (SDMT) at 4 years poststroke. Baseline predictors were obtained within 2 weeks of the acute event. Multivariate regression linear and logistic models were used to identify baseline predictors (reported as OR with 95%CI) and prevalence of impaired IPS at 4-years.

RESULTS

51% of people with stroke had low scores on the SDMT as indicated by a score of -1.0 SD to -2.5 SD (ranging from low to very low respectively). There were significant associations between slow IPS at 4-years after controlling for age and education level and the following baseline factors: older age (>75 years) (OR 3.03, 95% CI .9-9.3,P = .05), previous stroke (OR 2.74, 95% CI 1.0-7.4,P = .05), high cholesterol (OR 2.72, 95% CI 1.3-5.4,p = .01), hypertension (OR 1.82, 95% CI 0.9-3.6,p = .05), and presence of coronary artery disease (OR 3.35, 95% CI 1.6-9.6,P = .01), or arrhythmia (OR 4.40, 95% CI 1.5-12.4,P = .01).

CONCLUSIONS

Even after 4-years poststroke, slowed IPS is highly prevalent, with comorbid vascular risk factors significantly contributing to persistent impaired IPS. Early identification of adults who are at higher risk of deficits in IPS is vital to targeting the timely delivery of cognitive rehabilitation interventions, improving overall outcomes.

Digital Therapeutics: Emerging New Therapy for Neurologic Deficits after Stroke

Digital therapeutics is an evidence-based intervention using high-quality software, with the sole purpose of treatment. As many healthcare systems are encountering high demands of quality outcomes, the need for digital therapeutics is gradually increasing in the clinical field. We conducted review of the implications of digital therapeutics in the treatment of neurological deficits for stroke patients. The implications of digital therapeutics have been discussed in four domains: cognition, speech and aphasia, motor, and vision. It was evident that different forms of digital therapeutics such as online platforms, virtual reality trainings, and iPad applications have been investigated in many trials to test its feasibility in clinical use. Although digital therapeutics may deliver high-quality solutions to healthcare services, the medicalization of digital therapeutics is accompanied with many limitations. Clinically validated digital therapeutics should be developed to prove its efficacy in stroke rehabilitation.

The Impact of Visual Field Loss on Driving Skills: A Systematic Narrative Review

Purpose

To review the evidence on the impact of visual field loss on skills required for driving.

Methods

A literature search was undertaken using a systematic approach. Papers within scope were identified by two independent reviewers, and papers were grouped into similar themes for discussion.

Key findings

Evidence suggests that both binocular and monocular visual field defects have a negative impact on driving skills. Both central and peripheral cause difficulties, but the degree of impact is dependent on the defect severity and compensation ability. Many factors that affect compensation to visual field loss and the effects of visual field loss on driving skills are discussed, including cognitive status, age and duration of visual field loss. In summary, in central visual field loss compensation, strategies include reduction of overall driving speed; whereas, in peripheral field loss, increased scanning is reported to aid adaptation.

Conclusions

For driving, there is evidence that complete and/or binocular visual field loss poses more of a difficulty than partial and/or monocular loss, and central defects cause more problems than peripheral defects. A lack of evidence exists concerning the impact of superior versus inferior defects. The level of peripheral vision loss that is incompatible with safe driving remains unknown, as compensation abilities vary widely between individuals. This review highlights a lack of evidence in relation to the impact of visual field loss on driving skills. Further research is required to strengthen the evidence to allow clinicians to better support people with visual field loss with driving advice.

Adaptation to poststroke visual field loss: A systematic review

AIM

To provide a systematic overview of the factors that influence how a person adapts to visual field loss following stroke.

METHOD

A systematic review was undertaken (data search period 1861-2016) inclusive of systematic reviews, randomized controlled trials, controlled trials, cohort studies, observational studies, and case controlled studies. Studies including adult subjects with hemifield visual field loss, which occured as a direct consequence of stroke, were included. Search terms included a range of MESH terms as well as alternative terms relating to stroke, visual field loss, visual functions, visual perception, and adaptation. Articles were selected by two authors independently, and data were extracted by one author, being verified by the second. All included articles were assessed for risk of bias and quality using checklists appropriate to the study design.

RESULTS

Forty-seven articles (2,900 participants) were included in the overall review, categorized into two sections. Section one included seventeen studies where the reviewers were able to identify a factor they considered as likely to be important for the process of adaptation to poststroke visual field loss. Section two included thirty studies detailing interventions for visual field loss that the reviewers deemed likely to have an influence on the adaptation process. There were no studies identified which specifically investigated and summarized the factors that influence how a person adapts to visual field loss following stroke.

CONCLUSION

There is a substantial amount of evidence that patients can be supported to compensate and adapt to visual field loss following stroke using a range of strategies and methods. However, this systematic review highlights the fact that many unanswered questions in the area of adaptation to visual field loss remain. Further research is required on strategies and methods to improve adaptation to aid clinicians in supporting these patients along their rehabilitation journey.