Aging and the rehabilitation of homonymous hemianopia: The efficacy of compensatory eye-movement training techniques and a five-year follow up

Non-invasive brain stimulation for treating visual defects: a systematic review and meta-analysis

OBJECTIVE

We evaluated the efficacy of applying repetitive transorbital alternating current stimulation (rTACS) to patients suffering from visual defects, especially homonymous hemianopia.

BACKGROUND

Stroke or optic neuropathy would result in vision loss or Visual field defect (VFD) and homonymous hemianopia. Recently, one of the commonly used procedures to relieve VFD is non-invasive brain stimulation (NIBS).

METHODS

A comprehensive search covering publications in PubMed, Embase, Cochrane, and Scopus, spanning until September 2023 was performed. Relevant Randomized controlled trials (RCTs) were selected, and their data were extracted and analyzed. Pooled mean difference (MD) was calculated for change in the high-resolution perimetry detection accuracy (HRP DA) and fixation accuracy (HRP FA), static automated perimetry foveal threshold (SAP FT), and visual acuity (VA) of near vision outcomes.

RESULTS

We pooled in our analysis 4 RCTs. Compared to the sham group, rTACS patients had a significantly higher HRP DA (SMD = 0.35; 95% CI [0.003,0.694] P = 0.048). However, the analysis did not favor any of the compared groups in HRP FA, SAP FT, VA of near vision, and mean threshold (SMD = 0.14; 95% CI [-0.21,0.48] P = 0.43], (SMD = 0.17; 95% CI [-0.11,0.45] P = 0.23), (SMD = 0.32; 95%CI [-0.24,0.88] P = 0.26), and (SMD = 0.31; 95% CI [-0.04,0.65] P = 0.08) respectively.

CONCLUSIONS

Current evidence suggests that rTACS exhibits a promising approach in homonymous hemianopia patients, where it significantly increased HRP DA. Despite the results' failure to attain statistical significance in some outcomes, it underscores the necessity for larger RCTs with longer follow-up periods.

Telerehabilitation for visual field defects with a multisensory training: a feasibility study

BACKGROUND

Acquired homonymous visual field defects (HVFDs) result in significant disability, reducing quality of life. Spontaneous recovery occurs within the first months, then the likelihood of vision recovery decreases, making rehabilitation necessary. HVFDs rehabilitation is typically lengthy and intensive, done on an outpatient basis, hardly compatible with the return to everyday life. Telerehabilitation represents an option for continuing the therapy in the chronic phase of the disease, offering long-term support after hospital discharge. It also allows individuals with HVFDs to exercise independently, intensively, and actively at home, in a familiar environment, under remote supervision. However, the efficacy of telerehabilitation for chronic HVFDs in adults still requires empirical support.

METHODS

This single-arm clinical trial assesses the efficacy of a home-based, remote-supervised, compensatory audio-visual training (AVT) in 26 adults with chronic HVFDs following a brain lesion. Immediate and long-term (up to 6 months) effects on visual field scanning, reading, activities of daily living and mood were assessed. Predictors of treatment-induced gains were also investigated considering behavioral, neuro-ophthalmological (visual field perimetry and visual evoked potentials) and neuroradiological variables (structural imaging of grey- and white-matter damages). Finally, the efficacy of the home-based AVT was compared to that of its in-person version (16 new participants with chronic HVFDs).

RESULTS

Home-based AVT improves accuracy and speed of visual search, reading, mood, and disability in the activities of daily living, with improvements persisting up to 6 months after the end of the training (baseline vs. post-training assessments, all ps < 0.04). Post-treatment gains correlate with the severity of visual search deficit and the efficiency of multisensory integration (rs = -0.7/-0.5, all ps < 0.04). Neuro-ophthalmological and neuroradiological (structural connectivity) parameters are unaffected by the AVT, in line with its compensatory nature, although being associated to its efficacy (all ps < 0.03). Finally, the telerehabilitation version of the AVT produces effects comparable to the in-person AVT.

CONCLUSION

Multisensory training delivered in telerehabilitation is feasible and effective for ameliorating oculomotor compensation of visual field loss, improving mood and reducing functional disabilities in adults with chronic HVFDs. Trial registration This study was retrospectively registered at clinicaltrials.gov (NCT06341777; 26/03/2024).

Enhancing multisensory rehabilitation of visual field defects with transcranial direct current stimulation: A randomized clinical trial

BACKGROUND AND PURPOSE

Visual rehabilitation is necessary for improving the quality of life of patients with acquired homonymous visual field defects (HVFDs). By modulating brain excitability and plasticity, transcranial direct current stimulation (tDCS) may accelerate and increase the effects of compensatory trainings, which are usually long and intensive. In the present proof-of-principle, double-blind, randomized, sham-controlled study, we assess whether anodal tDCS applied over ipsilesional occipital or parietal cortices can increase the effects of a compensatory audiovisual training for HVFDs.

METHODS

Eighteen participants with chronic HVFDs were randomized to receive anodal or sham tDCS over the ipsilesional parietal or occipital cortex during a 2-week (10 days, 2 h/day) audiovisual treatment aimed at improving oculomotor visual field exploration. Improvements were assessed by administering visual detection with eye movements and visual search tests, and a questionnaire for activities of daily living (ADLs) before the treatment, at its end, and at 1-month and 4-month follow-ups; lesion analyses were performed to look for predictors of treatment effects.

RESULTS

Anodal ipsilesional tDCS, regardless of the target area (occipital vs. parietal), speeds up and increases daily improvements during the training. Whereas long-lasting (up to 4 months) post-treatment improvements in visual search and ADLs were observed in all groups, a greater and stable increase of visual detections in the blind hemifield was brought about only by the adjuvant use of occipital tDCS.

CONCLUSIONS

Compensatory audiovisual rehabilitation of HFVDs is effective and benefits from the adjuvant application of occipital and parietal tDCS, which speeds up and increases training-induced improvement.

REGISTRY NUMBER

NCT06116760.

Revealing the Causes of Dyslexia through a Differential Diagnosis, a Short-Term Effective Treatment and an Appropriate Conceptual Framework

Various different impairments and their interactions can cause reading problems referred to as "dyslexia". Since reading requires the interaction of many abilities, the impairment of each of these abilities can result in dyslexia. Therefore, the diagnosis must differentiate various kinds of dyslexia. The diagnosis of a certain kind of dyslexia cannot be delimited to the investigation and description of symptoms but must also include the investigation of the causes of each kind of dyslexia. For this purpose, a scientifically unequivocal concept of causation and appropriate methods are needed to distinguish them from co-existing impairments that have no causal influence on reading performance. The results of applying these methods cannot be adequately accounted for by a non-scientific, intuitive understanding of necessary and sufficient conditions and causation. The methods suitable for revealing the causes of dyslexia are described in detail, and the results of applying these methods in experiments, in which 356 children with developmental dyslexia participated, are reviewed. Since the concepts of "necessary" and "sufficient" conditions and "causation" proposed in the philosophy of science are not suitable for describing causes of dyslexia and their interaction, they are replaced by a more detailed, experimentally based conceptual framework that provides an accurate description of the conditions required for correct reading and the causes of dyslexia.

Reading Difficulties in Individuals with Homonymous Visual Field Defects: A Systematic Review of Reported Interventions

Reading difficulties are amongst the most commonly reported problems in individuals with homonymous visual field defects (HVFDs). To be able to provide guidance for healthcare professionals considering offering reading training, researchers in this field and interested individuals with HVFDs, this systematic review aims to (1) provide an overview of the contextual and intervention characteristics of all published HVFD interventions and (2) generate insights into the different reading outcome measures that these studies adopted. A search on PsycINFO, MEDLINE and Web of Science was conducted up to February 2, 2023. All intervention studies for HVFD in which reading was measured were included. Data was collected about the intervention type, session duration, number of sessions, the intensity, duration, circumstance of the interventions, country in which the intervention was studied and reading measures. Sixty records are included, describing 70 interventions in total of which 21 are specifically reading interventions. Overall, adjusted saccadic behaviour interventions occur most in the literature. A wide range within all intervention characteristics was observed. Forty-nine records reported task-performance reading measures, and 33 records reported self-reported reading measures. The majority of task-performance measures are based on self-developed paragraph reading tasks with a time-based outcome measure (e.g. words per minute). Future research could benefit from making use of validated reading tests, approaching the measurement of reading mixed-methods and providing participants the possibility to supply outcomes relevant to them.

The effects of occipital and parietal tDCS on chronic visual field defects after brain injury

Introduction

Homonymous visual field defects (HVFDs) following acquired brain lesions affect independent living by hampering several activities of everyday life. Available treatments are intensive and week- or month-long. Transcranial Direct current stimulation (tDCS), a plasticity-modulating non-invasive brain stimulation technique, could be combined with behavioral trainings to boost their efficacy or reduce treatment duration. Some promising attempts have been made pairing occipital tDCS with visual restitution training, however less is knows about which area/network should be best stimulated in association with compensatory approaches, aimed at improving exploratory abilities, such as multisensory trainings.

Methods

In a proof-of-principle, sham-controlled, single-blind study, 15 participants with chronic HVFDs underwent four one-shot sessions of active or sham anodal tDCS applied over the ipsilesional occipital cortex, the ipsilesional or contralesional posterior parietal cortex. tDCS was delivered during a compensatory multisensory (audiovisual) training. Before and immediately after each tDCS session, participants carried out a visual detection task, and two visual search tasks (EF and Triangles search tests). Accuracy (ACC) and response times (RTs) were analyzed with generalized mixed models. We investigated differences in baseline performance, clinical-demographic and lesion factors between tDCS responders and non-responders, based on post-tDCS behavioral improvements. Lastly, we conducted exploratory analyses to compare left and right brain-damaged participants.

Results

RTs improved after active ipsilesional occipital and parietal tDCS in the visual search tasks, while no changes in ACC were detected. Responders to ipsilesional occipital tDCS (Triangle task) had shorter disease duration and smaller lesions of the parietal cortex and the superior longitudinal fasciculus. On the other end, on the EF test, those participants with larger damage of the temporo-parietal cortex or the fronto-occipital white matter tracts showed a larger benefit from contralesional parietal tDCS. Overall, the visual search RTs improvements were larger in participants with right-sided hemispheric lesions.

Conclusion

The present result shows the facilitatory effects of occipital and parietal tDCS combined with compensatory multisensory training on visual field exploration in HVFDs, suggesting a potential for the development of new neuromodulation treatments to improve visual scanning behavior in brain-injured patients.

The effects of rehabilitative interventions on reading disorders caused by homonymous visual field defects: a meta-analysis focusing on improvement in reading speed

INTRODUCTION

Reading disorders caused by homonymous visual field defects (HVFDs) have a significant impact on a patient's quality of life. However, no review has been conducted to evaluate the available evidence on the effects of rehabilitative interventions on reading disorders caused by HVFDs. Thus, the aim of this study was to systematically evaluate the effects of rehabilitative interventions on reading disorders caused by HVFDs.

METHODS

We searched the MEDLINE/PubMed, Cochrane Library, ClinicalTrials.gov, CINAHL, and ScienceDirect databases for relevant articles. Relevant search terms were used to identify reports of randomized controlled trials or randomized crossover trials published between January 1990 and December 2021. Only studies that included reading-speed-related outcomes were analyzed. Risk of bias was assessed using the PEDro scale. Meta-analysis was conducted using a random-effects model, and standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed using the Ι2 statistic.

RESULTS

Nine studies were included in the meta-analysis. The results showed that rehabilitative interventions significantly improved reading disorders caused by HVFDs (SMD = 0.30; 95% CI 0.08-0.51; P < 0.01; Ι2 = 0.0%). Subgroup analysis showed that reading training significantly improved reading disorders (SMD = 0.35; 95% CI 0.05-0.66; P = 0.02; Ι2 = 0.0%).

CONCLUSION

Reading disorders caused by HVFDs can be improved through rehabilitation. In addition, reading training for the improvement of eye movement and fixation to compensate for foveal and parafoveal visual field defects may improve reading speed.

The aging mind: A complex challenge for research and practice

Cognitive decline as part of mental ageing is typically assessed with standardized tests; below-average performance in such tests is used as an indicator for pathological cognitive aging. In addition, morphological and functional changes in the brain are used as parameters for age-related pathological decline in cognitive abilities. However, there is no simple link between the trajectories of changes in cognition and morphological or functional changes in the brain. Furthermore, below-average test performance does not necessarily mean a significant impairment in everyday activities. It therefore appears crucial to record individual everyday tasks and their cognitive (and other) requirements in functional terms. This would also allow reliable assessment of the ecological validity of existing and insufficient cognitive skills. Understanding and dealing with the phenomena and consequences of mental aging does of course not only depend on cognition. Motivation and emotions as well personal meaning of life and life satisfaction play an equally important role. This means, however, that cognition represents only one, albeit important, aspect of mental aging. Furthermore, creating and development of proper assessment tools for functional cognition is important. In this contribution we would like to discuss some aspects that we consider relevant for a holistic view of the aging mind and promote a strengthening of a multidisciplinary approach with close cooperation between all basic and applied sciences involved in aging research, a quick translation of the research results into practice, and a close cooperation between all disciplines and professions who advise and support older people.