Effects of Prematurity on Development: Outcome Studies
Effects of Prematurity on Development - part 1
By Michelle Bell
Half a century ago prematurely born children were described by medical practitioners as suffering from “restlessness, fatigability and nervousness which resulted in diminished concentration and immature relational behaviour” (Benton, 1940). More recently, a general type of investigation examining this population generally labeled the ‘outcome approach’, contends that a considerable number of premature children score highly on various behavioural checklists, primarily on symptoms denoting hyperactivity, low attention span and poor social functioning (Hack, Breslau, Aram, Weissmen, Klein & Borawski-Clark, 1992; Breslau, Brown, DelDotto, Kumar, Ezhuthachan, Andreski & Hufnagle, 1996).
Dominated by the medical model, the outcome approach takes percentages of premature children who score high on various behavioural checklists and categorises them according to birt hweight. The majority of outcome studies have focussed upon the intellectual functioning of premature children as a possible factor contributing to compromised psychosocial development (Sykes, Hoy, Bill, Mc Clure, Halliday & Reid, 1997). Findings applying Intelligence Quotient measures indicate that 9 premature children score approximately a half, to one standard deviation below their peers (Wolke, 1991).
Although important, measures of intelligence, particularly when they fall within the normal range, offer only a limited understanding into the social and emotional development achieved by premature children. For example, Szatmari, Saigal, Rosenbaum and Campbell (1993) compared extremely low birthweight children (ELBW, ‹1000g) with full-term controls on impairments in adaptive functioning at age eight. Results suggested significantly increased rates of symptoms reflecting Attention Deficit Hyperactivity Disorder (ADHD), which the authors interpreted as being associated with the lower IQ of their premature group. However, premature children with or without small intellectual impairments, were also found to have internalising problems reflecting depression and anxiety along with impairments in social functioning when compared to their full-term counterparts.
Along a similar vein, Breslau, Brown, DelDotto, Kumar, Ezhuthachan, Andreski and Hufnagle (1996) extended previous findings of premature children aged 6-7 and included those up to 2500g (low birth weight) and also suggested that ADHD applies to this group. Supporting Szatmari et al. (1996) contention, the associa tion between low birth weight children and attentional problems varied by level of IQ. That is, premature children with IQ’s > 100 were no more likely to be diagnosed with ADHD than their full-term counterparts. Again however, the premature group as a whole were significantly more withdrawn and presented with more symptoms of anxiety and depression. Unfortunately, the authors offer no interpretation regarding these findings and assume these difficulties are related to birthweight rather than possible proble ms in psychological functioning. Similar findings were reported by Breslau, Klein and Allen (1988) on very low birth weight children (‹1500 g) aged 9, 10 who were rated as manifesting more emotional distress, and significantly lower social adjustment than controls. However, the associations between the social and emotional difficulties peculiar to the premature group were not related to their intellectual functioning or to birthweight.
Another suggested pathway to compromised development documented in outcome studies is thought to be the generally lower socioeconomic status (SES) of the parents of premature children. Social disadvantage together with biological risk is thought to increase the risk of adverse developmental outcomes. For example, Ross, Lipper, and Auld, (1990) found that premature children in upper SES families had significantly greater social competence and less behavioural problems than premature children in lower SES groups. Although, for each social class category, premature children were rated less optimally on aspects of interpersonal functioning than a normative sample. These findings concur with others such as McCormick, Gortmaker and Sobol (1990) who conclude that the socially disadvantaged, very low birth weight child is at greatest risk for the development of behavioural disorders.
However, agreement with the hypothesis that SES influences the outcome of premature children’s psychosocial functioning has not been unanimous, where some authors support this contention (e.g., Smith, Somner, & Von Tezchener, 1982; Hunt, Cooper Tooley, 1988; McCormick, Gortmaker & Sobol, 1990; Ross, Lipper, & Auld, 1990) and others do not (e.g., Escalona, 1984; Sykes, Hoy, Bill, McClure, Halliday & McC. Reid. 1997; Hack, Flannery, Schluchter, Carter, Borawski, & Klein, 2002). Given the mixed evidence, SES will be treated as a possible confounding variable in the current study.
Overall, the above mentioned studies contend that premature children of all birth weights often suffer with symptoms reflecting hyperactivity and low attention 11 span. These studies imply that variables such as, small intellectual deficits and low birthweight predispose premature children specifically to ADHD. However, all the above mentioned studies also report that premature children with or without minor intellectual impairment also suffer with difficulties in interpersonal functioning and internalising problems denoting anxiety and depression. Further clarification is therefore needed on why these children present with such difficulties. It may still be possible that prematurity confers a general vulnerability to compromised psychosocial functioning, apparent in later problematic relational behaviours.
In addressing this issue, Schothorst and van Engeland (1996) conducted a longitudinal evaluation of the social functioning and behavioural problems in premature children free of intellectual impairment. The follow-up extended from early school age to early adolescence and children were subdivided according to gestational age rather than birth weight. Pertinent to the current investigation are the findings that premature children with relatively low neonatal risks (i.e. those born ›32 weeks) appear to function as well as their full-term counterparts. Conversely however, premature children who were born very premature (i.e. ‹32 weeks) and those who were small for gestational age, and spent a greater time in hospital, seemed to be at an increased risk of developing social problems and internalizing difficulties. In addition, the social problems of premature children appeared to persist with age, and attentional problems were found to be related to the impaired social abilities of these very premature children. This suggests therefore, that the social difficulties of premature children may play some part in the causation of attention problems in premature school age children.
It is interesting to note that the behavioural outcome of children who were hospitalised in early infancy for reasons other than prematurity have also been found 12 to have compromised psychological functioning. For example, Beavers (1974, cited in Minde, 2000) examined a group of children aged 7-14 who had undergone pervasive medical procedures that required prolonged hospital care in early infancy and compared them with a control group on their psychological functioning. Although the hospitalized group did not differ from the control group in terms of their intellectual functioning or socioeconomic status, they were found to have poorer social functioning and greater anxiety. Similar findings are reported by Shapiro (1978, cited in Minde, 2000), Douglas (1975) and Quinton and Rutter (1976) who found that adolescent children who had undergone various hospital procedures in early infancy demonstrated poorer psychosocial development. Considering these and other similar research findings (e.g. Eiser, 1990; Pless & Nolan, 1991; Minde, 2000), the current study proposes that prolonged hospital care could effect later psychosocial development. As Minde (2000) suggests, children who have experienced prolonged hospital care in early infancy, have about twice the risk of developing an “emotional handicap” such that psychosocial functioning is compromised (pp, 8).
Surprisingly, apart from SES, variables such as length of hospital stay and the care taking environment are not included in outcome studies as potential factors which may influence premature children’s development. That is, all of the outcome studies reviewed thus far assume a mechanistic orientation toward the processes of child development, that is they interpret development as a linear chain of cause and effects (Sameroff & Chandler, 1975) rather than assuming multi-causality. Thus, outcome studies proceed on the assumption that it is possible to specify particular characteristics of the child (i.e. birth weight) or family (i.e. SES) that will permit long term predictions regarding the course of psychosocial development. Process studies however, embrace multi-causality and the dynamics of family systems in their 13 investigation of the effects of prematurity, a condition that this thesis argues cannot be understood meaningfully in terms of individual psychology alone. Accordingly, process studies move beyond a focus on only the child or on only the mother, and attempt to consider the two in combination.