Language Perception in Infants at Risk for ASD：a Functional Near Infrared Spectroscopy Study

Background:

Researchers have gained interest in the early development of behaviour and brain functions in Autism Spectrum Disorder (ASD) over the past decade. In order to investigate such an early developmental issue, they started to study infants who have older sibling with ASD (HR) and thus have a high risk to develop ASD. The majority of individuals with ASD have difficulties in language processing, especially when they have to extract implicit social cues. There is increasing consensus that language impairments in ASD are linked to disturbances of brain functions. However, such functional alterations related with language dysfunction in infants at risk of ASD have not yet been fully characterized.

Objectives:

In this study, we aimed to explore whether the brain response in HR infants differs from low risk (LR) controls by using functional near infrared spectroscopy (fNIRS). The developmental trajectory of brain functions related to language processing in HR infants was also observed through the comparison of different age groups.

Methods:

We recruited 5- and 10- month-old infants to participate in this language study. Infants were coming from two different groups including the HR group and LR group with no family history with ASD. All subjects underwent a 16-minute experiment with three sessions of fNIRS measurements. The first session was 5-min resting state, and the latter two sessions were 5.5-minutes speech tasks using forward and backward Dutch sentences respectively. Infants were held in the parent’s arms or sat on the lap of the parent in a silent room with dim lighting. A NIRScout (NIRX, Germany/USA) device was used to measure the hemodynamic changes in bilateral neural activity of the brain. The probe holders were placed over the bilateral frontal, temporal and inferior parietal areas. To investigate possible patterns of brain response in HR infants in the process of language perception, changes in the hemodynamic response were recorded and compared between HR and LR infants in the language-related regions.

Results:

Our preliminary results suggested that 5-month-old infants with HR show less neural responses to speech stimuli in the left temporal areas than the LR group. During the non-speech task, there were no significant differences in the left temporal areas between these two groups. For 10-month-old infants, the changes in the oxygenated hemoglobin (Hb) showed a different pattern between speech and non-speech tasks in LR group but not in HR infants.

Conclusions:

Our initial results show a different neural response in the language brain regions in infants at high risk for ASD at 5 and 10 months. This suggests that language development may already be impaired in the first year of life in (some of the) infants in the HR group. A complete analysis on 40 participants in each group will be presented at the conference.