Screen use during infancy may hamper development of high-order cognitive skills: JAMA

"We showed that infant screen use was linked with altered cortical EEG (electroencephalography) activity before the age of 2 years; the identified EEG markers moderated the association between infant screen time and executive functions," the researchers wrote. "There is an urgent requirement for further efforts to distinguish the direct association of infant screen use compared to family factors predisposing early screen use to executive function impairments."

There is increasing research evidence on the association between infant screen use and adverse cognitive outcomes tied to executive and attention functions. Currently, there is no information on the timing, nature and persistence of screen time exposure on neural functions. Electroencephalography allows an explanation of the neural correlates associated with cognitive impairments.

Against the above background, Evelyn C. Law from the National University of Singapore in Singapore and colleagues aimed to assess the associations between infant screen time, EEG markers, and cognitive outcomes at school age through mediation analysis with structural equation modelling in a prospective maternal-child dyad cohort study.

EEG was performed at age 18 months in a subset of children who fulfilled neurodevelopmental visits at ages 12 months and nine years. The study included participants from GUSTO, a population-based study. Enrollment was done for pregnant mothers in their first trimester from 2009 to 2010.

The involvement of neural correlates in the paths from infant screen time to the latent construct of executive and attention functioning was investigated using mediation analyses. The data was reported at ages 12 months, 18 months, and nine years.

Power spectral density was collected from EEG at the age of 18 months. Child executive and attention functions were measured with objective laboratory-based tasks and teacher-reported questionnaires at the age of nine years.

The study revealed the following findings:

• In the sample of 437 children, the mean age at follow-up was 8.84 years, and 51.9% were male.
• The mean daily screen time at age 12 months was 2.01 hours. Screen time at 12 months contributed to multiple 9-year executives and attention functioning measures.
• In a subset of 157 children who had EEG performed at age 18, EEG relative theta power and theta/beta ratio at the parietal and frontocentral regions revealed a graded correlation with the 12-month screen.
• In the structural equation model considering household income, parietal and frontocentral theta/beta ratios partially mediated the association between infant screen time and executive functioning, forming an indirect path contributing to 39.4% of the association.

The team noted that infant screen use was linked with altered cortical EEG activity before age two years when real-life attention problems could not be reliably confirmed. Furthermore, the association between infant screen time and executive function was mediated by EEG markers.

"Given the widespread use of screens by infants, our results have public health implications on a population level," the researchers conclude. "There is an urgent need for efforts to differentiate the direct association of infant screen use versus family factors that predispose early screen use to executive function impairments."

Reference:

Law EC, Han MX, Lai Z, et al. Associations Between Infant Screen Use, Electroencephalography Markers, and Cognitive Outcomes. JAMA Pediatr. Published online January 30, 2023. doi:10.1001/jamapediatrics.2022.5674