Infants exposed to excessive screen time show differences in brain function after eight years of age

Abstract: Greater exposure to screen time during childhood was associated with poor self-regulation and brain immaturity at age eight.

Source: Agency for Science, Technology and Research

More and more children are now exposed to mobile digital devices at an early age as a form of entertainment and distraction.

A longitudinal cohort study in Singapore confirmed that excessive screen time during infancy is associated with adverse outcomes in cognitive function, which are still evident after eight years of age.

The research team reviewed data from 506 children who were enrolled from birth in the Growing Up in Singapore to Healthy Outcomes (GUSTO) cohort study.

When children were 12 months old, parents were asked to report the average amount of screen time on weekdays and weekends each week. The children were then classified into four groups based on the time spent in front of the screen per day – less than one hour, one to two hours, two to four hours and more than four hours. At 18 months of age, brain activity was also collected using electroencephalography (EEG), a highly sensitive tool that monitors changes in brain activity.

In addition to undergoing an EEG, each child participated in a variety of cognitive tests that measured his or her attention span and executive functions (sometimes called self-regulatory skills) at age nine.

The team first examined the relationship between screen time and brain EEG activity. EEG readings revealed that infants exposed to longer screen time had stronger “low-frequency” waves, a condition associated with a lack of cognitive alertness.

To find out if the screen time and changes observed in brain activity had any negative consequences during later childhood, the research team analyzed all the data at three time points for the same children – at the ages of 12 months, 18 months and nine years. As screen time increased, more altered brain activity and more cognitive deficits were measured.

Children with executive function deficits often have difficulty controlling impulses or emotions, maintaining attention, following multi-step instructions, and persevering with a difficult task.

A child’s brain grows rapidly from the moment of birth to early childhood. However, the part of the brain that controls executive functioning, or the prefrontal cortex, takes longer to develop.

Executive functions include the ability to maintain attention, process information, and regulate emotional states, all of which are essential for learning and school success. The advantage of this slower growth in the prefrontal cortex is that the permeation and shaping of executive function skills can occur during the school years through higher education.

However, the same area of ​​the brain responsible for executive functioning skills is also highly sensitive to environmental influences over long periods of time.

This study points to excessive screen time as one of the environmental influences that can interfere with the development of executive functions. Previous research shows that infants have trouble processing information on a two-dimensional screen.

While viewing the screen, the infant is bombarded with a series of rapid movements, constant flashing lights, and scene changes that require sufficient cognitive resources to comprehend and process. The brain becomes “overloaded” and cannot leave itself adequate resources to mature cognitive skills such as executive functions.

Researchers are also concerned that families who allow very young children hours of screen time often face additional challenges. These include stressors such as food or housing insecurity and parental mood problems. More work is needed to understand the reasons behind excessive screen time in young children.

Further efforts are needed to distinguish the direct association of infant screen use versus family factors that predispose early screen use to executive function impairment.

The study was a collaborative effort involving researchers from the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), A*STAR’s Singapore Institute of Clinical Sciences (SICS), National Institute of Education, KK Women’s and Children’s Hospital , McGill University and Harvard Medical School. It was published in JAMA Pediatrics on January 31, 2023.

Lead author Dr Evelyn Law from NUS Medicine and SICS’s Translational Neuroscience Programme, said: “The study adds compelling evidence to existing studies that our children’s screen time needs to be closely monitored, particularly during early brain development.” dr. Law is also a consultant in the Department of Developmental and Behavioral Paediatrics at Khoo Teck Puat – National University Children’s Medical Institute, National University Hospital.

Professor Chong Yap Seng, NUS Dean of Medicine and Chief Clinical Officer, SICS, added: “These findings from the GUSTO study should not be taken lightly as they have implications for the potential development of future generations and human capital.

“With these results, we are one step closer to a better understanding of how environmental influences can affect the health and development of children. This would enable us to make more informed decisions in improving the health and potential of every Singaporean, giving every child the best start in life.”

Professor Michael Meaney, Program Director of the Translational Neuroscience Program at SICS, said: “In a country like Singapore, where parents work long hours and children are exposed to frequent screen time, it is important to study and understand the impact of screen time on children’s development. brains.”

About this technology and brain development research news

Author: Sharmaine Loh
Source: Agency for Science, Technology and Research
Contact: Sharmaine Loh – Agency for Science, Technology and Research
Picture: The image is in the public domain

Original research: Open access.
“Associations between infant screen use, electroencephalographic markers, and cognitive outcomes” Evelyn Law et al. JAMA Pediatrics

---

Abstract

Associations between infant screen use, electroencephalographic markers, and cognitive outcomes

Importance

There is increasing research evidence linking infant screen use and negative cognitive outcomes related to attention and executive functions. The nature, timing, and persistence of exposure to screen time on neural function are currently unknown. Electroencephalography (EEG) allows elucidation of neural correlates associated with cognitive impairment.

Goal

To examine associations between infant screen time, EEG markers, and school-age cognitive outcomes using mediation analysis with structural equation modeling.

Design, setting and participants

This prospective cohort study of mother-child dyads included participants from the Growing Up in Singapore Toward Healthy Outcomes (GUSTO) population-based study. Pregnant women were included in the first trimester from June 2009 to December 2010. A subgroup of children who completed neurodevelopmental visits at 12 months and 9 years of age had an EEG performed at 18 months of age. Data were reported from 3 time points at ages 12 months, 18 months, and 9 years. Mediation analyzes were used to investigate how neural correlates were involved in the pathways from infant screen time to the latent construct of attention and executive functioning. Data for this study were collected from November 2010 to March 2020 and analyzed between October 2021 and May 2022.

Exposures

Parents reported screen time at 12 months of age.

Main outcomes and measures

Power spectral density from EEG was collected at 18 months of age. Children’s attention and executive functions were measured by teacher-administered questionnaires and objective laboratory tasks at age 9 years.

the results

In this sample of 437 children, the mean (SD) age at follow-up was 8.84 (0.07) years, and 227 children (51.9%) were male. The mean (SD) amount of daily screen time at 12 months of age was 2.01 (1.86) hours. Screen time at age 12 months contributed to multiple measures of attention and executive functioning over 9 years (η²0.03-0.16; Cohen d, 0.35-0.87). A subgroup of 157 children underwent EEG at the age of 18 months; EEG relative theta power and theta/beta ratio in frontocentral and parietal regions showed a graded correlation with 12-month screen use (r= 0.35-0.37). In a structural equation model accounting for household income, frontocentral and parietal theta/beta ratios partially mediated the association between infant screen time and school-age executive functioning (exposure mediator β, 0.41; 95% CI, 0.22 to 0.59; mediator outcome β, -0.38; 95% CI, -0.64 to -0.11), forming an indirect path accounting for 39.4% of the association.

Conclusions and relevance

In this study, infant screen use was associated with altered cortical EEG activity before age 2 years; the identified EEG markers mediated the association between the time spent in front of the child’s screen and executive functions. Further efforts are urgently needed to distinguish direct associations of infant screen use versus familial factors that predispose early screen use to executive function impairment.