Electrical signals from the brain could help identify potential issues in the organ’s development, a new study reports. Researchers hope that their study will enable better tracking of infants’ neurodevelopment in the first months of life and reveal individual maps of brain maturation early on.

Scientists from the University of Fribourg in Switzerland and the University of Surrey investigated electrical activity from the brains of sleeping infants longitudinally, at age three and six months. They examined three electrical signals with distinct frequencies: slow wave activity (0.75–4.25 Hz), theta (4.5-7.5 Hz) power and sigma (9.75–14.75 Hz) power, which are key markers of sleep depth and brain development.

Dr Salome Kurth, Research Group Leader at University of Fribourg said:

“At birth, the human brain size has reached only 27 percent of its adult size. Development happens rapidly in the first months of life, which is therefore a critical period for brain maturation. Sleep plays a central role in neuronal development, however very little is known about the electrical signals the brain generates whilst an infant rests and the impact they have on their neurological maturation process.

“Using EEG (electroencephalography) is non-invasive and can provide us with an opportunity to map brain activity, track how it matures, and assess its influence on later behavioural outcomes.”

To learn more, high-density EEG recordings (during which a net with 124 sensors was placed on the scalp) were taken of 11 healthy infants during their regular sleep time. Behavioural development, focusing on gross motor skills and personal/social ability, of the infants was also assessed.

The research team found that between three and six months, electrical signal intensity changed across all frequencies. This likely reflects increases in the number of synaptic connections between neurons and increases in the wiring insulation through myelin, a fatty substance that wraps around nerve fibres and serves to increase the speed of electrical communication between neurons. These changes make visible how rapidly and where exactly the infant brain reorganizes, with shifting patterns of sleep-related brain activity reflecting the underlying maturation of neural networks.

Scientists note that continued monitoring of sleep brain activity could highlight issues with neuronal network growth early on with potential for early diagnosis and intervention for a number of neuropsychiatric conditions such as ADHD.

The research team also found an association between the individual change in electrical signals during this period and behavioural development. It was identified that greater power increases over frontal regions of the brain correlated with more advanced skills at six months across behavioural domains. In particular, higher frontal theta power was linked to better gross motor skills whereas higher frontal sigma power was associated with better personal social skills.

Dr Valeria Jaramillo, a Wellcome Early Career Fellow at the University of Surrey, said:

“Many neurodevelopmental disorders are not diagnosed until school age, highlighting the need to find a new way to identify such conditions early before symptoms emerge. Tracking sleep brain activity using EEG is a promising technique to spot when the brain has not matured as expected and to identify early indicators of developmental delays.”

This study was published in the journal: npj biological timing and sleep