Impact of Premature Birth on Development
Years ago, premature birth almost always meant death for the baby. Today, however, we have the technology to nurture these infants’ development, and many of them survive to lead normal, healthy lives. Although, very premature infants (that is, those born before about the fifth month) are still not likely to survive, many born at five months and older will thrive. Some preterm babies, however, do have many obstacles to overcome. There are a variety of medical problems that affect some of them, they may have impaired mental or physical conditions, and they may be looked upon by others in their environment as slow, or they might be treated differently because they were premature. All of these factors, plus a few more that will be discussed, affect the development of preterm infants into their adolescent years, and sometimes beyond.
Many preterm babies are born with medical problems because they simply were not ready to come into the world yet. They will not have very developed primitive reflexes, and they may look a little strange, with translucent skin, misshapen ears, and fine hair covering their entire bodies. One of the biggest problems for premature infants is a condition called Respiratory Distress Syndrome (RDS), in which the lungs do not produce enough surfactant, which is the substance that keeps the airsacs in the lungs from collapsing. If not treated in time, the infant’s brain will become oxygen deprived, which would lead to death. It can cause some brain damage. Another condition that often affects premature babies is Patent Ductus Arteriosus (PDA). This happens when the ductus arteriosus, which connects the pulmonary artery to the aorta, doesn’t close, leading to the infant’s blood not being properly oxgenated. This can also lead to brain damage if not caught in time. Premature infants also may just stop breathing, which is called apnea. This is why they must be closely monitored, for without close supervision, they could die.
Another medical condition common to premature infants which affects the brain is Intraventricular Hermorrage, where the blood vessels in the brain bleed. This affects most premature babies, but it is not very severe in most cases, and is easily treated. In more severe cases, it can be associated with cerebral palsy or mental retardation.
Premature infants generally show a lower IQ than full term babies, but only by about 10 points. This still puts them in the same IQ range as their full term peers. They are more likely to need special education classes later in life, though, and more likely to have to repeat a grade in school. This is most likely because some premature infants have been shown to have some cognitive impairment when compared to full term infants of the same age. Their memories are not as good, and their information processing speed is significantly lower.
There have been many studies performed that compare the cognitive performance of preterm infants with full term infants. One study in particular, performed by Susan A. Rose and Judith F. Feldman, tested the memory and the processing speed of preterm children versus full term children at the age of eleven. They used the Colorado Specific Abilities Test, which is a comparison of eight paper and pencil tasks the child must perform. This test showed the degree of these four abilities: memory, perceptual speed, spatial ability, and verbal ability. They also used the Cognitive Abilities Test (CAT) which is a detailed exam of memory and speed. This test shows us exactly what aspects of speed and memory it is that pre and full term children differ in, and how much this difference actually affects them. It is comprised of a set of basic cognitive tasks used to study the individual elements of cognitive processing.
The results they came upon are detailed, but they are not very surprising. In the general memory section and learning (recall), full term children performed slightly better than preterms. The researchers proposed an interesting theory as to why preterms have poor memory. They said that it might be directly related to the presence, and in particular, the severity of Respiratory Distress Syndrome (RDS), because the hypoxic-ishemic episodes that come with it damage the brain.
In the section of the test, the Sternberg Memory Search, which tested the children’s ability to recall pictures, the preterms made errors significantly more often than the full term children did over the 24 trials. The premature children took a significantly longer amount of time to complete all the tasks. When they were simple tasks, such as when there was only one choice, the premature children were very fast in choosing the answer, but when the amount of choices increased, so did the amount of time it took them to answer it.
The premature children also performed poorly on the Tachistoscopic Threshold test, which showed the minimum amount of time required to determine whether two stimuli are the same or not, as compared to the full term group. On average, the preterms needed exposure to the stimulus one and a half times longer than the full terms did. This shows that most premature children are slower on the intake of information and on acting on the information they just obtained. This slower action does not have anything to do with a lack of motor skills, it is completely cognitive in nature. The researchers found in the last test that there is virtually no difference between motor speed in pre and full term children.
Another study performed testing the differences between pre and full term infants was done by Jacob, Roach, Benedict, and Blackledge. They used the McCarthy Scale Index to measure differences in cognitive, perceptual, and personal-social development of premature preschoolers. The general cognitive index, perceptual-performance, quantitative, memory, and motor scales test all favor the full term preschoolers. There was no difference between the two groups in the measure of self-direction, playfulness, impulsivity, task persistence, and speech articulation (Perceptual and Motor Skills, v.58 p 559). The researchers had the parents’ report on personal-social development, and there was no significant difference between the two groups.
There was a large difference between pre and full term groups on the visual-perceptual tests, particularly having to do with drawing ability on the Draw-a-Design test. Kaufman and Kaufman propose that this is because premature children have less visual-motor coordination than full term children. The theory that premature children have impaired visual-motor coordination is consistent with the high amount of cases of cerbral palsy and associated motor impairments that are found among premature children. This all suggests that premature children will have more problems with arithmetic than reading when they get to school age (Perceptual and Motor Skills, v.58 p 560).
A study was done in Israel by Rachel Levy-Shift and Gili Einat that measured the emotional and behavioral development of prematurely born children. They found that premature children had higher levels of anxiety, depression, and aggression than full term children, and that they had a lower self-concept. Premature children were found to have more disturbances at home and at school. One cause of this may be the mother-child relationship, and how stable it is. When the mother and child had a better relationship, the child showed fewer behavioral disturbances than when the mother/child relationship was bad (Journal of Clinical Child Psychology, v.23 p 328-9). Typically, the more negative the environment, the less well-adjusted the premature child was. Another factor in their emotional development is the income of the family. In higher SES environments, the children were typically more well-adjusted. Birth weight is also a factor in this. The smaller the birth weight, the less emotionally adjusted and more behaviorally disturbed the child will be.
Levy-Shift and Gili Einat concluded that the reason why premature babies have these problems is that they are generally less intelligent than full terms. They had more trouble learning, which could lead to negative emotional reactions. They say that premature children sometimes have impaired neurological processes that underlie cognitive dysfunction which is detrimental to behavioral and emotional functioning (Journal of Clinical Child Psychology, v.23 p 329). Premature children are less responsive, less alert, and less active when they are babies, which can lead to a bad start to the mother-child relationship.