SINGAPORE: When children in the study were 12 months old, parents were asked to report the average amount of screen time consumed on weekdays and weekends each week.

The children were then classified into four groups based on screen time per day - less than one hour, one to two hours, two to four hours, and more than four hours.

When the children were 18 months old, researchers measured brain activity using electroencephalography (EEG), a tool which tracks changes in brain activity.

Each child also participated in various cognitive ability tests that measured his or her attention span and executive functioning - sometimes referred to as self-regulation skills - at the age of nine years, the National University of Singapore and Singapore Institute for Clinical Sciences said in a statement on Monday.

The team first examined the association between screen time and EEG brain activity.

The EEG readings revealed that infants who were exposed to longer screen time had greater “low-frequency” waves, a state that correlated with lack of cognitive alertness.

To find out whether screen time and the changes observed in the brain activity have any adverse outcomes during later childhood, the research team analysed the data across three points for the same children - at 12 months, 18 months and nine years.

It said: “As the duration of screen time increased, the greater the altered brain activity and more cognitive deficits were measured.”

 - ANN