Visual rehabilitation: visual scanning, multisensory stimulation and vision restoration trainings

Abstract

Neuropsychological training methods of visual rehabilitation for homonymous vision loss caused by postchiasmatic damage fall into two fundamental paradigms: “compensation” and “restoration”. Existing methods can be classified into three groups: Visual Scanning Training (VST), Audio-Visual Scanning Training (AViST) and Vision Restoration Training (VRT). VST and AViST aim at compensating vision loss by training eye scanning movements, whereas VRT aims at improving lost vision by activating residual visual functions by training light detection and discrimination of visual stimuli. This review discusses the rationale underlying these paradigms and summarizes the available evidence with respect to treatment efficacy. The issues raised in our review should help guide clinical care and stimulate new ideas for future research uncovering the underlying neural correlates of the different treatment paradigms. We propose that both local “within-system” interactions (i.e., relying on plasticity within peri-lesional spared tissue) and changes in more global “between-system” networks (i.e., recruiting alternative visual pathways) contribute to both vision restoration and compensatory rehabilitation, which ultimately have implications for the rehabilitation of cognitive functions.

Reversing Hemianopia by Multisensory Training Under Anesthesia

“…The multisensory rehabilitation paradigm has also been shown to restore some visual responsiveness in human hemianopic populations (Bolognini et al, 2005;Dundon et al, 2015a; see also Purpura et al, 2017). However, some differences in the results have also been noted.…”

“…It is commonly believed that the success of this rehabilitative paradigm is a retraining of the visuomotor targeting behavior itself (see, review in Dundon et al, 2015a). In this case, the key factor would be the orienting action (initially elicited by the auditory stimulus) in the presence of the visual stimulus.…”

Auditory enhancement of illusory contour perception

“…There are instances where altered late-life experience, for example following brain injury, can lead to visual impairments (Dundon, Bertini, Làdavas, Sabel, & Gall, 2015). Neglect or hemianopic patients, generally fail to report, respond, or orient to visual stimuli presented contralaterally to the lesioned hemisphere (Halligan, Fink, Marshall, & Vallar, 2003), due to either a visual field deficit in hemianopia or to a visuospatial attentional deficit in neglect.…”

“…Neglect or hemianopic patients, generally fail to report, respond, or orient to visual stimuli presented contralaterally to the lesioned hemisphere (Halligan, Fink, Marshall, & Vallar, 2003), due to either a visual field deficit in hemianopia or to a visuospatial attentional deficit in neglect. Similarly, homonymous visual field defects (HVFD) are among the most serious deficits after cerebral artery stroke and traumatic brain injury (TBI) in adults that result in either complete or partial loss of visual perception in one half of the visual field, and lead to numerous impairments in everyday functions (Dundon et al, 2015). In such patients, multisensory training improves not only their ocular functions, but also decreases their self-perceived disability in daily life activities such as bumping into objects, finding objects, and crossing the street (Bolognini, Rasi, Coccia, Ladavas, & Làdavas, 2005; Passamonti, Bertini, & Làdavas, 2009).…”

An effect of multisensory training on visual processing (Commentary on Grasso et al. (2016))

“…The present author group previously combined these ideas in a spectacular series of experiments in which they rehabilitated patients suffering large unilateral lesions of visual cortex, lesions which rendered them functionally blind to visual stimuli in contralateral space (hemianopia) (see review in Dundon et al ., ). Amazingly, non‐invasive multisensory training (involving repeated exposures of spatiotemporally concordant visual‐auditory cues) can restore some basic visual processing capabilities within the previously blind hemifield.…”