Understanding the Predictive Factors and the Neurocognitive Basis of Developmental Language Disorder

Overview

For most children, language acquisition might appear like an effortless phenomenon, mostly arising from informal daily interaction with their surrounding people. Despite an adequate learning environment however, some children encounter major difficulties in learning their native tongue and develop a Developmental Language Disorder (DLD). Although the existence of a multi-factorial etiology has seemed to reach an agreement, presumably combining genetic and environmental factors to some kind of neural disruption, the underlying mechanisms leading to DLD are, to date, poorly understood. Many studies have attempted to identify risk factors and early predictors associated with the future development of a language impairment. However, despite the constant efforts to identify early markers able to differentiate between transient and persistent language difficulties, early detection of children who will be developing a DLD remains highly difficult, partially due to the lack of direct and ecological measures of early language and communication development. In addition research on the causal neural correlates of DLD is in its infancy, and often compromised by small sample sizes or analyses methods that lack anatomical specificity to determine the neural correlates of language impairment. Hence, In order to improve early detection and, therefore, language intervention, this longitudinal research project aims at investigating the early predictive factors as well as the neurocognitive basis of DLD by means of an integrative, multi-dimensional, and multi-methodological approach. To substantially gain insight, this research ideally integrates risk factors at multiple different levels, including the cognitive, neurobiological, parental and environmental level. From a methodological perspective, we will combine direct and indirect behavioral methods with neuroimaging methods in order to propose an early predictive model of language development.

The present research project can be divided into four main data collection steps. The first step concerns families' recruitment through a principle of population-based screening. Parents and/or caregivers of children aged from 0 to 18 months will be asked to complete a screening questionnaire that aims to evaluate families' general risk profile associated with the development of DLD. A subsample of at-risk and control families will be selected based on the screening phase for longitudinal follow-up. The second step consists of the investigation of the neural correlates of DLD by using a natural-sleep MRI protocol in infants of 6 to 12 months old. The third step concerns the evaluation of predictive factors leading to DLD using indirect measures based on digital assessment of language development, parental and environmental characteristics (i.e., parents will have to fill in online questionnaires every 6 months during a 3-year timeframe). This step will also be dedicated to the development of an application that aims at evaluating early development of language and communication (i.e., LANCOM app). Finally, the fourth step comprises additional in-depth investigation of DLD's predictive factors, by means of direct measures, including individual cognitive and behavioral assessment, as well as an automated analysis of the child's language environment using the Language ENvironment Analysis digital language processor recording device (LENA®). Data collection for this last step will take place once a year over the whole project's timeframe.