Visual field restorative rehabilitation after brain injury.

Barbara Maria Matteo,Cesare Giuseppe Cerri,Cecilia Perin,Barbara Viganò

doi:10.1167/16.9.11

Abstract

About 20%-30% of patients undergoing neurological rehabilitation report visual field defects, one of the most frequent of which is homonymous hemianopsia (loss of the same half of the visual field in both eyes). There is still no consensus as to whether homonymous hemianopsia is best treated in a restorative or compensatory manner. The aim of this review is to describe the effects of restorative rehabilitation, whose long-term efficacy is still being debated. We analyzed 56 articles describing the use of various techniques used to promote visual field recovery but concentrating on two approaches: "border training," which involves exercising vision at the edge of the damaged visual field, and "blindsight training," which is based on exercising unconscious perceptual functions in the mild of the blind hemifield where the scotoma is deep. Both techniques have been supported by functional imaging studies showing evidence of cortical rearrangement (plasticity) after rehabilitation. Although no formal meta-analysis was possible, the results of a semiquantitative evaluation suggested that the improvement in visual skills obtained is related to the type of training used: Border rehabilitation seems to improve the detection of visual stimuli, whereas blindsight rehabilitation seems to improve their processing. Finally, the addition of transcranial direct current stimulation seems to enhance the effects of visual field rehabilitation.

Highlights

Visual field defectsOne of the most frequent symptoms of neurological damage is a lesion affecting the retrochiasmal visual pathways that leads to the loss of the left or right half of the visual field of both eyes depending on whether the lesion is on the right or left side of the brain
The most frequent cause is stroke: It is estimated that 20–57% of stroke survivors are affected by homonymous hemianopsia (HH) (Rowe et al, 2009), but this percentage increases to 70% in the case of a stroke involving the district supplied by the posterior cerebral artery (Pambakian, Currie, & Kennard, 2005)
Each endpoint of each study was associated with the type of instrument used to detect and measure it and subsequently evaluated on the basis of the significance of the results: Those that showed no positive variation in comparison with pretraining were classified as ‘‘unchanged or worsened’’, those leading to an improvement that was not significant or was only described qualitatively were classified as ‘‘improved’’, and those leading to a statistically significant improvement were classified as ‘‘significantly improved.’’ ‘‘Improved’’ was used for the studies without a statistical analysis of the results, when the results were analyzed in a descriptive qualitative manner, and when the author(s) explicitly declared that there was no improvement but the presented data showed an increase in comparison with baseline

Summary

Introduction

One of the most frequent symptoms of neurological damage is a lesion affecting the retrochiasmal visual pathways that leads to the loss of the left or right half of the visual field of both eyes depending on whether the lesion is on the right or left side of the brain. The lesion affects the visual fibers posterior to the lateral geniculate nucleus (LGN) and may involve the occipital lobe (about 40% of cases), the parietal lobe (30%), the temporal lobe (25%), or the pathway between the optic tract and the LGN (5%; Grunda, Marsalek, & Sykorova, 2013). The most frequent cause is stroke: It is estimated that 20–57% of stroke survivors are affected by HH (Rowe et al, 2009), but this percentage increases to 70% in the case of a stroke involving the district supplied by the posterior cerebral artery (Pambakian, Currie, & Kennard, 2005).

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