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The neonatal ICU environment gets more attention, with preemies' neurosensory development first in mind.
By WES ALLISON, Times Staff Writer
© St. Petersburg Times, published January 16, 2002
Taylor Wacker was born three months early and weighed a tad over 2 pounds. She should have been in the womb until mid-February, so she'll spend the next month as she has the last two, busily growing in the neonatal intensive care unit at All Children's Hospital in St. Petersburg.
Her bed helps her stay in a fetal position when she's sleeping, her incubator keeps her warm. The unit's overhead lights are dim, providing a restful ambiance.
The ventilators and monitors hum more quietly than they did several years ago. A quilt draped over Taylor's incubator cover further muffles the sound and softens the light.
The unit, or NICU, is not nearly as homey as her mother's womb. But it's about the best modern science can offer.
Increasingly, experts in neonatal care and fetal and childhood development are learning that the environment of neonatal units can significantly affect how premature infants develop hearing, sight and communications skills.
For most of the history of neonatology, which emerged as a specialty in the 1960s, doctors were consumed with keeping these fragile babies alive. Now they're addressing other issues, said Dr. Roberto Sosa, director of neonatal services at All Children's and a 26-year veteran of the field.
"As things get better, we're trying to refine things, and now we're worrying about the environment," Sosa said.
As part of this evolution, 340 national and international experts spent the past three days at a conference in Clearwater discussing the leading research. The University of South Florida has hosted the meeting, "The Physical and Developmental Environment of the High-Risk Infant," for eight years.
Topics included feeding, new equipment, and helping parents better care for a premature baby. But some of the most intriguing work focuses on the concept of "sensory interference," based on evidence that human fetuses, like other animals, develop senses in a sequence: touch, then a sense of motion, followed by smell and taste, hearing and vision.
Dr. Stanley N. Graven, the conference co-chairman and director of the Lawton and Rhea Chiles Center for Healthy Mothers and Babies at USF in Tampa, said forcing one sense into service out of order may disrupt the development of the others.
For full-term babies, this isn't a problem. But for those born months early, it most surely is.
"Neurosensory developmental issues do affect how they learn, see, hear and feel, and the origins are in the NICU," Graven said.
On Tuesday, he and Dr. Jennifer Lister, assistant professor of communication sciences and disorders at USF, presented preliminary data from an ongoing study of Pinellas County students that show students who were born prematurely exhibit subtle deficiencies in hearing.
About half the 34 preemies in the group have been examined. While their ears are normal and pick up the same sounds as their full-term classmates, sophisticated tests show they process the sounds differently.
"If you test them for word understanding in a quiet setting, the preemies and the term babies are the same," Graven said. "If you add the background noise of a classroom, the former preemies have to struggle."
It's not clear why, but Graven and Lister suggest two suspects: The lights and noise of the NICU.
Studies show a newborn puppy that has its eyes surgically opened prematurely is unable to recognize its mother's bark; for some reason, light interferes. The same is true for infant birds and primates.
Four years ago, the National Institutes of Health enrolled 2,000 premature infants to test whether lights in NICUs hurt their eyes. Half wore patches, to mimic the darkness of the womb, until they were discharged. The others did not.
Tests showed no eye damage in either group. But in a couple years, when the children are old enough, Graven hopes to test their hearing as well.
Most NICUs, including those at All Children's, St. Joseph's Hospital in Tampa and Morton Plant Hospital in Clearwater, have cut background noise in recent years, but the effect of the remaining noise is largely unknown.
Full-term babies generally are protected from noise by the womb, but Mom's voice clearly reaches the uterus. The fetus learns its pattern and tone, providing an early foundation for language. At birth the infant can pick out her voice, something Taylor's mom, Tracie Wacker, quickly noticed.
"If I sing songs I sang when she was in the womb, she will open her eyes," Wacker said as she held her daughter, who now weighs about 3 pounds, 9 ounces.
But too much background noise in the NICU, even it seems quiet, can drown out mother's voice, affecting how baby learns to processes language.
"We thought mother talking to baby in the NICU was nice, but it really didn't matter, soon you'd get home," Graven said. "But it does matter."
Researchers still are struggling to determine the effect of pain on premature babies, who undergo many tests and needle-sticks. Dr. Fran Porter Lang, associate dean of arts and sciences at Washington University in St. Louis, said evidence is mounting that recurrent pain can cause neurological changes, and babies remember it.
Simply applying a topical anesthetic to an infant's heel before drawing blood can help greatly, especially if the baby is repeatedly tested, she said.
"The assumption that babies cannot remember early pain and, therefore, it's unimportant, is wrong," she said.
Much of what's been discovered in recent years may seem intuitive: Make the NICU as womblike as possible. But scientists say they need proof to spark changes at the nation's NICUs, which treat about 250,000 children each year.
Manufacturers also need data to build better incubators and other machines, and architects need research for standards for NICU construction and remodeling.
Sosa, of All Children's, said finding what's best for premature babies is difficult, and often depends simply on watching to see what works.
At his hospital, the staff once noticed that babies under the care of a particular nurse seemed to do generally better than others. They eventually realized she was speaking and moving much more slowly than her colleagues.
That kept her babies from being over-stimulated.
"When you talk to the baby, or look at the baby, they follow you," Sosa said. "The younger the gestation, the less amount of stimulus they should have."