Functional and structural brain modifications induced by oculomotor training in patients with age-related macular degeneration

Abstract

Patients with age-related macular degeneration (AMD) are reliant on their peripheral visual field. Oculomotor training can help them to find the best area on intact peripheral retina and to efficiently stabilize eccentric fixation. In this study, nine patients with AMD were trained over a period of 6 months using oculomotor training protocols to improve fixation stability. They were followed over an additional period of 6 months, where they completed an auditory memory training as a sham training. In this cross-over design five patients started with the sham training and four with the oculomotor training. Seven healthy age-matched subjects, who did not take part in any training procedure, served as controls. During the 6 months of training the AMD subjects and the control group took part in three functional and structural magnetic resonance imaging (MRI) sessions to assess training-related changes in the brain function and structure. The sham-training phase was accompanied by two more fMRI measurements, resulting in five MRI sessions at intervals of 3 months for all participants. Despite substantial variability in the training effects, on average, AMD patients benefited from the training measurements as indexed by significant improvements in their fixation stability, visual acuity, and reading speed. The patients showed a significant positive correlation between brain activation changes and improvements in fixation stability in the visual cortex during training. These correlations were less pronounced on the long-term after training had ceased. We also found a significant increase in gray and white matter in the posterior cerebellum after training in the patient group. Our results show that functional and structural brain changes can be associated, at least on the short-term, with benefits of oculomotor and/or reading training in patients with central scotomata resulting from AMD.

Perceptual learning leads to long lasting visual improvement in patients with central vision loss

“…Previous studies (Chung, 2011;Rosengarth et al, 2013;Plank et al, 2014) aimed at improving a specific visual ability (e.g., texture discrimination, fixation stability) by directly training it. In these studies, authors used perceptual tasks (guided saccades, texture discrimination) known for their high specificity of learning, so generalization of learning to other visual abilities, triggered by changes in neural plasticity, was unlikely to happen.…”

“…Few recent studies used PL with age-related macular degeneration (AMD) patients in order to improve their visual abilities (Chung, 2011;Rosengarth, Keck, Brandl-Rühle, Frolo, Hufendiek, Greenlee, & Plank, 2013;Plank, Rosengarth, Schmalhofer, Goldhacker, Brandl-Rühle, & Greenlee, 2014). For example, Rosengarth et al (2013) trained a group of eight AMD patients with an oculomotor training and found improvements in reading speed and fixation stability between pretests and mid-tests, but not between pre-tests and post-tests.…”

“…For example, Rosengarth et al (2013) trained a group of eight AMD patients with an oculomotor training and found improvements in reading speed and fixation stability between pretests and mid-tests, but not between pre-tests and post-tests. Moreover, no significant changes in BOLD signals were observed between pre and post training tests in early visual areas (V1, V2 and V3) or in associative areas (LOC, fusiform gyrus, ITG).…”

The application of online transcranial random noise stimulation and perceptual learning in the improvement of visual functions in mild myopia

“…So far, PL has been shown to be effective in improving, among other dysfunctions, visual abilities in amblyopia (Campana, Camilleri, Pavan, Veronese, & Lo Giudice, 2014;Hussain, Webb, Astle, & McGraw, 2012;Levi & Li, 2009;Li, Young, Hoenig, & Levi, 2005;Polat, 2009;Polat, Ma-Naim, Belkin, & Sagi, 2004;Zhou, et al, 2006), mild refractive defects like myopia (Camilleri, Pavan, Ghin, Battaglini, et al, 2014;Tan & Fong, 2008) and presbyopia (Polat, et al, 2012), and central or peripheral vision loss and cortical blindness (Chung, 2011;Das, Tadin, & Huxlin, 2014;Huxlin, et al, 2009;Kasten, et al, 1998;Plank, et al, 2014;Rosengarth, et al, 2013;Sabel, Kenkel, & Kasten, 2005). In myopia, visual input is limited by an optical de-focus, despite normal neuronal connectivity and image processing.…”

Visual perception and visual cognition in healthy and pathological ageing

“…The results indicate decreased activation in parietal lobe in healthy elderly persons compared to young persons and decreased activation in frontal eye fields in aMCI patients compared to healthy elderly persons during the execution of anti-saccades. The study by Rosengarth et al (2013) examined the effects of oculomotor training on the fMRI response in patients with AMD. During a 6-month eccentric-fixation training period the AMD subjects and the control group took part in three functional and structural magnetic resonance imaging sessions.…”