Psychophysiological indices of reading skills in adults with a history of early psychosocial deprivation
Most of children left without parental care in Russian Federation reside in institutional settings that are characterized by suboptimal levels of stimulation and early care. Existing body of research shows that early institutionalization is associated with a cascade of negative effects on children's development in a variety of developmental domains, including detectable alterations in brain structure and functioning (e.g. Nelson, Fox, & Zeanah, 2014). However, to the best of our knowledge, there are currently no published studies that examine the long-term effects of early institutionalization on the neural indices of literacy development and reading.
Our study tested the hypothesis that individuals who grew up in institutional care settings demonstrate altered trajectrories of spoken and written language development, in particular in the domain of literacy, which includes both writing and reading skills. This hypothesis is rooted in a) the observations of delayed language development and lower academic achievement of children raised in institutional settings, compared to their peers raised in biological families, and b) the complexity of reading as a multidimensional set of skills that relies on the complex interplay between linguistic, visual, phonological, motor, and cultural factors (e.g., Massaro et al., 1994, Dehaene, Cohen, Morais, & Kolinsky, 2015).
For example, recent evidence suggests that reading ability is correlated with efficiency of early visual processing, including repetition suppression and exemplar discrimination in the left occipital-temporal region known as the visual word form area — VWFA (Cohen et al., 2002; Ludersdorfer et al., 2013). This activity can be linked to letter-specific processing also revealed in the N1 (or N170) event-related potential (ERP; Pegado et al., 2014), and has been hypothesized to be sensitive to reading exposure and the development of fine print tuning.
Our study investigated orthographic processing in adults with a history of institutionalization and individually-matched controls (accounting for age, gender and SES) by analyzing a set of event-related potentials elicited during the lexical decision task that contained several experimental conditions, including legal orthographic strings (words), symbol strings (false font), legal pseudowords, and illegal non-words, aimed at eliciting specific neural responses (i.e., the N1 component).
The sublexical orthographic properties of words include general attributes of the writing system such as sequential dependencies and letter position frequencies. We focused on the ERPs that indexed sublexical orthographic effect through the difference in the amplitude of the N1 response to to pseudowords (orthographically legal) and non-words (containing illegal bigrams). In addition, we examined coding of orthographic information at the whole-word level that is based on the ability to represent the unique array of letters that defines a printed word (Araújo et al., 2015).
At the time of the writing of this abstract, our data collection was still in progress. We will present the preliminary findings regarding group differences in print tuning and orthographic processing between adults with and without history of early institutionalization.