December 17, 2009 — 根據一篇新研究，一種測量新生兒神經和行為問題的量表，可預測孩童期的發育遲緩。
根據比較生產前曝露於藥物之嬰兒與對照組嬰兒之結果的研究，這個量表－Neonatal Intensive Care Unit Network Neurobehavioral Scale(NNNS)－在預測孩童到學齡前發育問題上，優於妊娠年齡與社會經濟狀態(socioeconomic status[SES])。
Neonatal Scale Predicts Developmental Delays in Early Childhood
By Pauline Anderson
Medscape Medical News
December 17, 2009 — A scale that measures neurologic and behavioral problems in newborns predicts developmental delays later in childhood, according to a new study.
The scale — the Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS) — is better at predicting developmental problems in children up to preschool age than gestational age and socioeconomic status (SES), according to the study that compared outcomes of infants exposed prenatally to drugs with their unexposed counterparts.
The NNNS, which includes measures of such things as the ability to follow animate and inanimate auditory and visual stimuli, hypertonic responses, lethargy, and levels of arousal and stress, takes about 20 minutes to complete and can be administered by any trained medical personnel.
Picking up developmental problems early is important because research shows that children benefit most when they get help at a young age.
Although it is too soon to call for universal NNNS screening, it is something to look at in the future, said the study’s lead author, Barry Lester, PhD, director of the Brown Center for the Study of Children at Risk, Brown University, Providence, Rhode Island.
"Universal screening is only worth doing if, number 1, we know it works in other populations and, number 2, we’ve done the treatment studies to show we can effectively intervene and prevent the bad outcome," Dr. Lester told Medscape Psychiatry.
The study was published online December 7 in Pediatrics.
Drug Exposure
The study included subjects from the Maternal Lifestyle Study, a multisite, longitudinal study of infants exposed prenatally to drugs and born prematurely. This current analysis included 658 infants who were exposed to cocaine before birth. These children were compared to a group of 730 infants who were not exposed to cocaine who were matched for gestational age, sex, race, and ethnicity.
In addition to determining whether the infants had been exposed to cocaine, opiates, tobacco, alcohol, and/or marijuana and the level of such exposure, researchers gathered information on the infants' birth weight, length, head circumference, and intracranial ultrasound reading at 44 weeks.
The NNNS was administered at the 1-month clinic visit to 90% of the original infants (1248 of 1388). On the basis of the NNNS scores, the infants were grouped into 5 risk categories or "profiles," with those in profile 5 having the worst scores.
Compared with other infants, the 72 infants in profile 5 (5.8% of the total sample) had poor attention and were highly aroused, excitable, hypertonic, and highly stressed. These infants tended to have been exposed to alcohol and drugs prenatally and to have been born prematurely or had a low birth weight. More than 50% of them weighted less than 2500 g.
During the next 3 years, the researchers administered infant developmental tests, including the Bayley Mental Developmental Index and the Psychomotor Developmental Index. At the 3-year visit, the mothers completed the Child Behavioral Checklist (CBCL). At 4 years, researchers evaluated school readiness, and at 4.5 years, they measured IQ using the Wechsler Preschool and Primary Scale of Intelligence.
The study found that about 40% of infants in the profile 5 group had clinically significant behavior and school readiness problems and about 35% had a low IQ. In addition, a worrisome 42% had deviant total behavior scores on the CBCL.
About 22% of the infants fell into the profile 4 group, the next worst category. These infants had extremes in tone, the most nonoptimal reflexes, poor quality of movement, and a high number of stress signs.
When researchers combined profiles 4 and 5, they found additional developmental red flags. "If you add in profile 4, you do pick up a few more kids on different outcomes, but whether we use profile 5 alone or combine it with profile 4 will depend on how this plays out in different populations," said Dr. Lester.
Including only infants who had drug exposures and were born prematurely was a limitation of the current study. Dr. Lester and his colleagues are conducting other studies using the NNNS in different populations of infants in the United States and other countries.
Better Predictor
After controlling for gestational age and SES — 2 variables that also predict poor developmental outcomes — the NNNS still effectively predicted an abnormal ultrasound reading at 1 month in profile 5 infants (odds ratio [OR], 2.37; compared with other profiles), chronic neuralgic abnormalities (OR, 2.35), externalizing behavior problems (OR, 2.05), internalizing behavior problems (OR, 2.72), and total behavioral problems (OR, 2.37).
"We make the point that even if things like birth weight and SES predict as well as the NNNS, which they don’t, you can’t do anything about them," said Dr. Lester.
"You’re not going to change a baby’s birth weight and you’re not going to change a baby’s level of poverty, but the baby’s behavior is something you can work with and make a difference."
Picking up developmental problems and initiating preventive measures early on could optimize long-term benefits. "If we confirm that these profile 5 kids are headed for trouble at 4 years of age, perhaps we can develop an intervention based on that profile and see if the intervention can reduce or prevent the problems from occurring," said Dr. Lester.
Incorrectly Labeled
Like any scale, the NNNS is not perfect; it’s inevitable that some infants will be incorrectly labeled as destined to have developmental problems. Many children appear worrisome as infants but go on to develop normally.
Mislabeling an infant could create a self-fulfilling prophecy, with parents unintentionally treating their infant differently, noted Dr. Lester. "They may treat the baby as if it’s fragile, they may not provide the appropriate stimulation, or they may be very anxious. So you might be creating the very problem you’re trying to prevent."
However, he added, that the NNNS is noninvasive and early intervention is benign. He also thinks that parents should eventually have access to their infant’s NNNS results and decide for themselves what to do with that information. He likened it to the breast cancer genes BRCA-1 and BRCA-2. "If you have a gene that makes you more likely to have breast cancer, you should be entitled to that information and decide what you want to do with it."
Impressive and Important
In commenting on this research, Joan Luby, MD, professor of psychiatry, Washington University School of Medicine in St. Louis, Missouri, and chair of the Infant Preschool Committee, American Academy of Child and Adolescent Psychiatry, Washington, DC, called the findings "impressive and important."
The results should go a long way toward filling the "black hole" that exists around the question of which newborns will run Into difficulty later on, said Dr. Luby. "More research needs to be done, but this provides a key piece of the puzzle."
It might be possible, added Dr. Luby, to develop interventions that focus on enhancing cognition and attention in very young children with low NNNS scores or helping them with spatial skills. "Not that these interventions are currently available to my knowledge, but it’s certainly very, very plausible that they could be developed."
The authors have disclosed no relevant financial relationships.
