MR Images Assess Infant Brain Growth

Assessing the size, asymmetry, and rate of growth of different regions of the brain could be key in detecting and treating the earliest signs of neurodevelopmental disorders, such as autism or perinatal brain injury, in infants, according to a study published online in JAMA Neurology. The study was conducted by researchers at the University of California, San Diego School of Medicine and the University of Hawaii.

For the first time, researchers used MRI scans of the newborn’s brain to calculate the volume of multiple brain regions and to map out regional growth trajectories during his or her first 90 days of life. The study followed the brain growth of full-term and premature babies with no neurological or major health issues.

On average, researchers found the newborn brain grows 1% each day immediately following birth but slows to 0.4% per day by three months. In general for both sexes, the cerebellum, which is involved in motor control, grew at the highest rate, more than doubling volume in 90 days. The hippocampus grew at the slowest rate, increasing in volume by only 47% in 90 days, suggesting that the development of episodic memory is not as important at this stage of life.

“We found that being born a week premature, for example, resulted in a brain 4% to 5% smaller than expected for a full-term baby. The brains of premature babies actually grow faster than those of term-born babies, but that’s because they’re effectively younger—and younger means faster growth,” says Dominic Holland, PhD, first author of the study and a researcher in the department of neurosciences at UC San Diego School of Medicine. “At 90 days postdelivery, however, premature brains were still 2% smaller. The brain’s rapid growth rates near birth suggest that inducing early labor, if not clinically warranted, may have a negative effect on the infant’s neurodevelopment.”

The study also found that many asymmetries in the brain are already established in the early postnatal period, including the right hippocampus being larger than the left, which historically has been suggested to occur in the early adolescent years. Cerebral asymmetry is associated with functions such as dexterity and language abilities.

The next step will be to continue making advances in the application of different MRI modalities to examine the newborn brain. Future research will investigate how brain structure sizes at birth and subsequent growth rates are altered due to alcohol and drug consumption during pregnancy.

For more than two centuries, clinicians have tracked brain growth by measuring the outside of the infant’s head with a measuring tape. The results are plotted on a percentile chart to determine whether normal growth patterns exist. While the measurement is helpful for observing growth, it does not reveal whether the individual structures within the brain are developing normally.

Source: University of California, San Diego