Preterm infants exposed to stressors in NICU display reduced brain size

October 4, 2011, Wiley

New research shows that exposure to stressors in the Neonatal Intensive Care Unit (NICU) is associated with alterations in the brain structure and function of very preterm infants. According to the study now available in Annals of Neurology, a journal published by Wiley-Blackwell on behalf of the American Neurological Association and Child Neurology Society, infants who experienced early exposure to stress displayed decreased brain size, functional connectivity, and abnormal motor behavior.

Infants born prior to the 37th week of pregnancy are considered preterm, which occurs in 9.6% of all births worldwide, according to the Bulletin of the (WHO). A report by The National Institute of Child Health and Human Development confirms that preterm birth occurs in 12% of all pregnancies in the U.S. In addition to increased , prior studies have shown that up to 10% of very (22-32 weeks gestation) have cerebral palsy, nearly 40% display mild motor deficiency, and up to 60% experience cognitive impairments, social difficulties and emotional issues.

Babies who are premature are commonly admitted to the NICU for specialized medical attention, allowing time for immature organs to further develop. While interventional studies have demonstrated that exposure to stressors in the NICU may be harmful and reducing stress in premature infants improved outcomes, it is unknown how stressors in neonatal units impacts infant brain development. The present study, led by Drs. Terrie Inder and Gillian Smith, both Washington University researchers at St. Louis Children's Hospital in Missouri, is the first to report on the effects of stress among hospitalized preterm infants and its impact on brain development.

For their observational study, the research team recruited 44 preterm infants within 24 hours of birth from November 2008 to December 2009. Study participants were less than 30 weeks gestation, or very preterm, and stress was measured by using the Neonatal Infant Stressor Scale (NISS)—a scale consisting of 36 interventions that contribute to infant stress, ranging from diaper change to intubation. Magnetic resonance imaging (MRI) and neurobehavioral examinations were used to evaluate cerebral structure and function.

Results show that the average daily exposure to stressors was greatest in the first 14 days following birth. The greater number of stressors that an infant was exposed to was associated with decreased frontal and parietal brain width. Researchers also reported altered brain microstructure and within the temporal lobes in infants with early stress exposure. Abnormal movement pattern and reflex scores were lower among preterm infants exposed to higher stress in the first two weeks of life.

"Our findings suggest that stress exposure reduces the in early preterm infants and long-term consequences are unknown," said Dr. Inder. "However, prior research has found that brain volume at (term) birth is a predictor of neurodevelopmental outcomes later in childhood." The authors suggest that further research of stress exposure on the preterm brain, independent of illness severity, is needed to improve outcomes for premature infants.

Explore further: Study examines trends in withholding treatment for infants in neonatal intensive care units

More information: "NICU Stress Associated with Brain Development in Preterm Infants," Gillian C. Smith, Jordan Gutovich, Christopher Smyser, Roberta Pineda, Carol Newnham, Tiong H. Tjoeng, Claudine Vavasseur, Michael Wallendorf, Jeffrey Neil and Terrie Inder. Annals of Neurology; Published Online: October 4, 2011 (DOI:10.1002/ana.22545).

Related Stories

Study examines trends in withholding treatment for infants in neonatal intensive care units

July 4, 2011
Withdrawal of life-sustaining support and withholding lifesaving measures (such as CPR) appear to be the primary modes of infant deaths in a neonatal intensive care unit, according to a report in the July issue of Archives ...

Recommended for you

Epilepsy linked to brain volume and thickness differences

January 22, 2018
Epilepsy is associated with thickness and volume differences in the grey matter of several brain regions, according to new research led by UCL and the Keck School of Medicine of USC.

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.