Visual scanning preferences in low birth weight preterm infants

Introduction: Few studies have used eye tracking as a screening tool for autism spectrum disorder (ASD) in preterm infants. Objectives: To evaluate fixation time on social and non-social figures and percentage of preterm babies who gazed at the images. Methods: This was a cross-sectional study of 31 preterm infants born weighing ≤ 2,000 g in which eye gaze was evaluated at 6 months of corrected age. Six boards with social and non-social figures were projected on a computer screen, successively, evaluating time and percentage of preterm babies who gazed at each board. The Modified Checklist for Autism in Toddlers (M-CHAT) was answered at 18 months of corrected age. Results: Preterm infants showed longer visual fixation time on social figures compared with non-social images, regardless of the position of the social figure on the board. Similar percentages of preterm infants gazed either at social or non-social figures, at social figures with a direct or an indirect look, and at the eyes or mouth of the social figures. No preterm infant screened positive on the M-CHAT. Conclusion: At 6 months of corrected age, preterm infants show the ability to gaze in an eye-tracking test, with preference for social figures, suggesting that this tool could be useful as another screening instrument for ASD.


Introduction
With the improvement of survival rates of smaller and more immature preterm infants, the presence of injuries poses a major challenge for public health services. 1 Between 15 and 45% of preterm infants present perceptual, cognitive and motor skill impairments. 2 Although detection can be difficult in the early years, the manifestation of problems in social communication, emotional attachment and joint attention -all signs compatible with autism spectrum disorder (ASD) -is frequent in preterm infants. 3 Whether or not a diagnosis of ASD is established, the prompt identification of development delays permits early intervention and condition improvement. 4 The American Academy of Pediatrics (AAP) recommends ASD screening at 18 Nevertheless, visual scanning studies of preterm infants are still limited, and contributions are relevant to establish their typical eye-gaze pattern, aiming for the identification of early impairments. In this sense, the objective of this study was to assess whether preterm infants show the ability to gaze at social and non-social figures at 6 months of corrected age, determining the percentage of preterm babies who gazed at the images and the time lapse of eye gaze.

Clinical data
Socioeconomic data, details of the clinical evolution during the hospitalization period in the neonatal intensive care unit, and perinatal clinical data were collected from the charts, as follows: mother's age at were also collected, as well as information about siblings with an ASD diagnosis.
Screening for ASD signs was performed at 18 months of corrected age, using the M-CHAT. 9

Sample demographic and clinical characteristics
The study sample comprised 31 preterm infants with birth weight ≤ 2,000 g, of which 12 (38.7%) were male.
Mother's age at birth was 28.2±6.0 years and 73.9%

Eye-tracking test
Visual scanning was performed in 31 preterm infants. infants who gazed at the boards is presented in Figure 2.

Duration time of visualization of the two figures
in each board is presented in Table 1. Preterm babies  In our study, the preterm infants evaluated at 6 months of corrected age showed adequate and similar percentages of gaze at social and non-social figures.
Although data for term children are well known, 6  Even though this is a preliminary study, the fact that visual screening of preterm infants at 6 months of corrected age is possible, and that they have a visual preference pattern similar to that of typical fullterm children, provides important indications that eye tracking is a useful instrument for use in the preterm population and may aid in the evaluation of social skills impairments.
As study limitations, it is important to mention the small convenience sample used and the lack of a control group, which prevents definitive conclusions. Also, term infants were not included in this study, as it was In conclusion, according to our results, at 6 months of corrected age, children born prematurely have visual fixation ability in eye-tracking tests and show a preference for social figures to the detriment of nonsocial ones. This findings suggest that it is possible to use eye tracking in this population, at this age, to evaluate visual preferences, which in turn can be important to identify early signs of ASD.

Disclosure
No conflicts of interest declared concerning the publication of this article.