fNIRS Shines a Light on Early Atypical Brain Responses in Autism

• In Event: 3-088 - Infant Predictors of Social and Behavioral Impairments in Childhood and Adolescence

Integrative Statement

Autism Spectrum Disorder (ASD) is a common, highly heritable, developmental disorder, and later-born siblings of diagnosed children are at higher familial likelihood for developing ASD than the general population. Given the importance of social perception in our day to day interactions it is noteworthy that converging evidence has implicated atypical brain responses to visual and auditory social stimuli in children and adults diagnosed with ASD (Čeponienė et al., 2003; Gervais et al., 2004; Pelphrey & Carter, 2008; Eyler et al., 2012; Zhu et al., 2014). Although the emergence of behavioural symptoms of ASD in toddlerhood is well characterised, far less is known about development during the first months of life of infants at familial risk.

In a prospective longitudinal study of infants at increased familial likelihood of ASD followed to 36 months (Lloyd-Fox et al., 2018), we measured functional near infrared spectroscopy (fNIRS) brain responses to social videos of people (i.e. peek-a-boo) compared to non-social images (vehicles) and human vocalisations compared to non-vocal sounds. We hypothesized that within social brain regions the HR–ASD infants would show reduced selective responses to the social stimuli compared with the non-social stimuli relative to the low risk (LR) infants. At 4 to 6 months, infants who went on to develop ASD at 3 years (N = 5) evidenced reduced activation to visual social stimuli relative to low risk infants (N = 16) across inferior frontal (IFG) and posterior temporal (pSTS-TPJ) regions of the cortex. Furthermore, these infants also showed reduced activation to vocal sounds within left lateralised temporal (aMTG-STG/pSTS-TPJ) regions compared with low risk infants and high-risk infants who did not develop ASD (N = 15) – see Figure 1.

Building on this work we have since investigated how these findings may relate to later social interaction and communication difficulties characteristic of ASD. We find correlations between the degree of social selective activation at 4 to 6 months of age and parent reported ASD symptomology (Social Responsiveness Scale), repetitive behaviours (Autism Diagnostic Inventory and Observation Scales) and social and communication difficulties (ADI) at 36 months (r = 0.374 to 0.513; p < 0.03; N = 35).

Furthermore, we have now extended the high-risk ASD cohort with an additional N = 31, and preliminary channel by channel t-tests continue to show reduced socially selective activation in the high-risk group (N = 51) relative to the low-risk cohorts previously described (i.e. Lloyd-Fox et al., 2018). Using putative fNIRS biomarkers selected during the first study (see Figure 2) we are currently identifying which individual infants show “high-risk haemodynamic predictors” indicative of atypical function. These will be followed through to diagnosis of ASD at 36 months. It is critical that we study ASD early in development to (1) measure the mechanisms underpinning risk versus resilience in early infancy prior to the onset of atypical behaviours, and (2) establish intervention strategies and support for families from an earlier age (Green et al., 2017; Jones et al., 2017).

Group Authors

the BASIS team

Authors

• Sarah Lloyd-Fox, Birkbeck, University of London
  Presenting Author

• Anna Blasi, University of London
  Non-Presenting Author

• Laura Pirazzoli, University of London
  Non-Presenting Author

• Greg Pasco, King's College London
  Non-Presenting Author

• Teodora Gliga, University of East Anglia, Norwich
  Non-Presenting Author

• Emily Jones, University of London
  Non-Presenting Author

• Declan Murphy, King's College London
  Non-Presenting Author

• Clare E Elwell, University College London
  Non-Presenting Author

• Tony Charman, King's College London
  Non-Presenting Author

• Mark Johnson, University of London
  Non-Presenting Author