Visual impairment in infancy: impact on neurodevelopmental and neurobiological processes

Abstract

IntroductionThis review draws together current understanding of the impact of visual impairment (VI) on early neurodevelopmental and neurobiological processes. The impact is recognized as being substantial. Two major problems make it difficult to draw conclusions from much of the literature on this subject. The first is the heterogeneity of samples of children with VI in terms of additional impairments that introduce multiple confounding variables: in Western societies the prevalence of additional impairments is 60 to 70%. 1-3 Secondly, subgrouping according to the degree or severity of VI is inconsistent and can be suboptimal for developmental studies of infancy. Our group has reconsidered these questions of taxonomy and applied new ones to our recent research cohorts.Below we describe our research/service teams and clinic population, define the new taxonomies, and discuss the influences of VI on, and interactions between the visual, psychological, psychosocial, neurological, and genetic domains. Within the diagnostic category with the fewest confounding variables we identify a subgroup with an unfavourable outcome: those with a developmental setback. We debate how this subgroup might inform our understanding, not only of the impact of VI on neurodevelopmental processes but also of the mechanisms underlying the genesis of regressive disorders in those with VI and in the sighted. These issues are discussed in the context of research of our own and other groups and of current theory. Potential avenues for future investigation are put forward in each section.

Reversible autism among congenitally blind children? A controlled follow‐up study

“…If this is true, then the likelihood of autism among congenitally blind children would be increased by other factors that also limit such experience. Such factors might be as diverse as neurological dysfunction on the one hand, or adverse rearing conditions on the other (e.g., Keeler, 1958;Mukaddes et al, 2007;Sonksen & Dale, 2002).…”

Social identity, autism and visual impairment (VI) in the early years

“…The risks that have been identified so far include any visual disorder, male gender, multiple brain lesions, the nought to two year age period and profound visual impairment (lack of 'form' vision). Some preliminary evidence also suggests that profound visual impairment under 10-16 months, even if 'form' vision emerges later, and adversity in the psychosocial and familial environment may also be risk factors (see reviews by Sonksen and Dale, 2002;Dale, 2005).…”

Development of a national monitoring protocol (developmental guide) for children with visual impairment 0–36 months

“…Our recent research has demonstrated that children with dpotentially simpleT congenital disorders of the peripheral visual system (dpotentially simpleT CDPVS) are the most appropriate subgroup for establishing developmental norms [5,7]. We have also shown that development is likely to proceed at different rates in infants who have dformT vision compared with those without.…”

“…Through a series of research studies spanning 25 years, our team has demonstrated that impaired vision can impose far-reaching and complex constraints on early development including motor, cognitive, language and social development [3][4][5]. Constraints on any target skill are often cumulative, acting directly upon it and also on one or more of the skills that underpin its acquisition [4].…”

“…It will build and expand on our current guide [13], providing more finely graded steps of key developmental stages especially in the areas of object relationships and reasoning, communication and social development [5,7], language and meaning, play and learning, movement and mobility and self help skills. The protocol will be specifically designed to be used jointly by parents and their key worker, with the scope to record achievements and any concerns.…”