Recovery of visual functions after early acquired occipital damage

Abstract

Plasticity of visual systems after early brain damage has been extensively studied in animal models but poorly documented in children after visual pathway lesions. This report describes the visual recovery of a male child who had a bilateral occipital lobe infarction at the age of 2 years 6 months, 10 days after colon resection for Hirschsprung disease. In the acute phase he had severe visual impairment without visual response. Some weeks later he could perceive movement. Since then, progressive recovery of his visual acuity and oculomotor abilities has been accompanied by a progressive reduction of the visual field defect. At 6 years 8 months, visual recognition acuity was 10/10 in both eyes and neuro‐ophthalmological examination was normal, except for persistence of the visual field defect in the upper hemifield and a selective impairment of higher visual functions (recognition of object presented in a hard‐to‐decode way [e.g. overlapping figures], or use of complex visuospatial skills). The functional recovery observed in this patient confirms the adaptive plasticity of developing visual systems after early brain lesions. It suggests that in humans, as in animal models, processes related to cerebral plasticity may take place years after a brain lesion has been sustained.

Functional outcomes following lesions in visual cortex: Implications for plasticity of high-level vision

“…Taken together, the parellel findings between behavior and the neural basis of object recognition suggest that visual inputs from the early visual cortex at a young age may be necessary to trigger not just the activation but also the fine-tuned development of high-level visual functions in object-selective cortex (although note that the RH was spared at all stages and this may be the basis of the normal recognition). The differential trajectories of functional recovery in low- and high-level vision in both Bova et al (2008) and Hu et al (2013) echo the quality of the input argument mentioned previously. That is, the development of category-selective regions might depend on visual inputs at an early age, and early-onset disorders of low-level vision may impede experience-dependent maturation.…”

“…A dissociation between recovery of early and later parts of cortex might be possible: pattern recognition may continue to be adversely affected even though some lower-level visual abilities may be functional or even recovered over time. This pattern of dissociation is found in some cases of object agnosia (gradually recovered low-level vision: Bova et al, 2008 and Hu et al, 2013; normal or near-normal low-level vision: Fazzi et al, 2009 and Schiavetto et al, 1997) and prosopagnosia (gradually recovered low-level vision: MJH in Michelon and Biederman, 2003; Xu and Biederman, 2014; functional low-level vision: GA in Barton et al, 2003; Hadjikhani and De Gelder, 2002). It is the case, however, that there are a number of cases that have moderate to severe impairment in basic visual abilities and persistent category-level impairments (e.g., object agnosia: Lê et al, 2002; prosopagnosia: KBN and KT in Barton et al, 2003; Farah et al, 2000; Sergent and Villemure, 1989; Young and Ellis, 1989).…”

“…A differential pattern of functional recovery may be associated with the status of low-level vision. For example, Bova et al (2008) documented recovery of their patient’s visual functions from the age of 2.6 years to 6.8 years. Motion perception was fully recovered first at 2.9 years, followed by gradual recovery of visual acuity and visual field from age 2.6 to 5 years, and then complete recovery of basic visual–perceptual abilities at age 6.8 years.…”

“…A different pattern, this time of some recovery of low-level visual skills, is reported in a case of object agnosia with relatively preserved face and word recognition (Bova et al, 2008). This patient suffered a bilateral V1 lesion at the age of 2 years 6 months (hemorrhagic infarcts and blood perfusion deficit were seen on imgaging in both occipital lobes).…”

“…That is, the development of category-selective regions might depend on visual inputs at an early age, and early-onset disorders of low-level vision may impede experience-dependent maturation. Even the gradual recovery of low-level vision (within about 6 years) appears to be insufficient and category-selective behavior and neural responses remain abnormal (Bova et al, 2008; Hu et al, 2013). …”