Audio-visual Stimulation for Visual Compensatory Functions in Stroke Survivors With Visual Field Defect; a Systematic Review

Abstract

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 in visual exploration, 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. The review aimed to assess evidence for the effectiveness of AV stimulation as a rehabilitation strategy for stroke survivors with hemianopia in adult- and childhood.Methods: This review is registered with PROSPERO. A narrative synthesis of the findings is presented to highlight how AV rehabilitation impacts on hemianopia patients 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 HH, and AV integration in patients with HH.Conclusion: The review findings support the concept that compensatory audio-visual training can be useful as rehabilitation method for stroke survivors with hemianopia. 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.Systematic review registration: This review is registered with PROSPERO by the correspondence author (CRD42020197348).

Research hotspots and frontiers about role of visual perception in stroke: A bibliometric study

“…In addition, the Cochrane database systematic review indicated that compensatory scanning training may be more beneficial for VFD (23). However, the evidence for the effect of interventions for VFD is mostly of very low quality, and the effects are uncertain (23)(24)(25). Therefore, further studies with high-quality methodology and large sample sizes involving stroke patients with VFD are needed.…”