669 - Impact of Preterm Birth on Cerebral Functional Response to Face and Social Perception (The BabyFace Study)

Publication Number: 2652.669

Eri Nanizawa, Aichi Medical University, Nagakute, Aichi, Japan; Celina Brunsch, Monash University, Melbourne, Victoria, Australia; Srikar Vallabhapurapu, Monash University, Melbourne, Victoria, Australia; david W. Walker, Hudson Institue for medical Research, Melbourne, Victoria, Australia; Robin Laycock, RMIT University, Melbourne, Victoria, Australia; Flora Wong, Monash Children's Hospital, Clayton, Victoria, Australia

Background: Preterm birth is associated with socio-cognitive dysfunction, which is not routinely monitored in early follow-up. Face perception plays an important role in early socio-cognitive development, and may be altered in infants born preterm.

Objective: Using functional near-infrared spectroscopy (fNIRS), we aimed to assess the cerebral haemodynamic response to face and social perception in preterm and term infants using social visual stimuli.

Design/Methods: Preterm (born at 24-30 weeks' gestation, n=25) and term infants (n=24) were studied at the post-term age of 6 months. The infants viewed social videos of female adults performing games with movements (e.g. peek-a-boo) and non-social videos of moving toys/objects, in alternating 16-s experimental trials. The experimental trials were interspersed with static pictures of vehicles for 9-12s as baseline. The cerebral functional response was measured bilaterally using multichannel fNIRS (18 channels over both hemispheres, BRITE, Artinis, Netherlands) over the inferior-frontal (IF), temporo-parietal (TP), and lateral occipital (LO) regions, as changes in oxy- and deoxyhaemoglobin concentration (ΔHbO2 and ΔHbR, µM). Averaged ∆HbO2 in 3 time windows after stimulus onset (3-8s, 9-14s, 15-23s) were compared using two-way RM ANOVA between the social and non-social dynamic conditions, and between the term and preterm groups.

Results: Comparing infant groups, the ΔHbO2 was higher in term than preterm infants for both social and non-social stimuli in the left TP region (Main effect p< 0.001, post-hoc p=0.01 for social and p=0.006 for non-social), and for the social stimulus in the right TP region (p=0.04). Comparing the conditions, preterm infants showed higher ∆HbO2 for social than non-social stimuli in right IF (p=0.04), while term infants showed no differential response between the social and non-social stimuli.

Conclusion(s): Preterm infants show lower activation in bilateral TP for both social and non-social dynamic stimuli, suggesting altered/immature neural processing of face and object movements compared to the term brain. Reduced motion processing may underlie neurodevelopmental delay in preterm children. Unexpectedly, preterm, but not term, infants showed higher response to social than non-social stimuli, suggesting the importance of social stimuli in activating the preterm brain. These findings, which will be followed up beyond 6 months of age, may inform early developmental interventions for preterm infants.

Figure 1: Functional responses to social and non-social dynamic stimuli.
Examples of ΔHbO2 (solid lines) and ΔHbR (dashed lines) following social (A&B) and non-social (C&D) stimuli, averaged in term (A&C) and preterm (B&D) infants, are shown for the left hemisphere. The coloured lines represent the 3 brain region of interests (pink - IF, orange - TP, blue- LO). Note the marked difference between term and preterm infants in the TP region (orange line). The colour-shaded areas indicate the 3 time windows post-stimulus onset for data analyses (pink 3-8 sec, yellow 9-14 sec, green 15-23 sec).

Figure 2: Peak ΔHbO2 in the 3 brain region of interests in term and preterm infants.
Circles (closed, term infants; open, preterm infants; blue, social; red, non-social) show individual values and bars represent mean±SD.
Panels A&B: Term ∆HbO2 > preterm ∆HbO2 in bilateral TP regions (Left: Pgroup <0.001, p<0.01 for both social and non-social stimul; Right:p < 0.05 for social stimulus), indicated as orange triangles on the babyheads
Panels C&D: Social ∆HbO2 > non-social ∆HbO2 in preterm infants in the right IF region (p < 0.05), indcated as pink triangle on the babyhead.
Pgroup = main effects between infant groups. *p < 0.05 = post-hoc between term vs preterm infants. #p < 0.05 post-hoc between social vs non-social stimuli.