In one study, found a variety of neuropsychological differences in a group of six-year-old LBW children when compared to age-matched children of normal birth weight (i.e., the groups differed on measures of language, visuospatial, fine-motor, and attention skills). Further, these investigators found evidence of gradient effects in this cohort with greater reductions in performance being obtained at progressively lower birth weights. Taylor and collaborators also found evidence of cognitive deficits, academic dysfunction, and greater behavioral problems in a group of middle school aged children born very low birth weight (i.e., <1500 grams). These researchers indicated that, within the extremely low birth weight group, disparities grew more pronounced on measures of global cognitive abilities, basic reading skills, academic performance, and parent-reported measures of behavior and attention as children increased in age. Finally, in a follow-up study to their 1996 paper, found that previously LBW children continued exhibiting decreases in academic skills at the age of 17.
In addition, other perinatal neurologic injuries and environmental factors such as low socioeconomic status (SES) and maternal infections may exacerbate these problems. For example, demonstrated that LBW children sustaining an interventricular hemorrhage (IVH) were more likely to exhibit a psychiatric diagnosis (especially attention deficit hyperactivity disorder) at six years of age compared to LBW children who had not sustained a concurrent IVH. showed that LBW children growing up under disadvantaged circumstances had a higher rate of attention problems when compared to LBW children growing up in circumstances with more resources.
Taken together, the above studies indicate LBW children are at a significant risk for long-term cognitive and behavioral difficulties and suggest that at least some of these deficits may be influenced by environmental factors and/or exacerbated by other perinatal insults such as an IVH. However, other investigations have suggested that children born LBW demonstrate considerable plasticity and recovery of cognitive skills following birth, and some studies have suggested that children born late preterm (e.g., between 34 and 36 weeks gestation) who are otherwise healthy do not exhibit any significant decrements in cognitive skills when evaluated years later.
Few, if any, studies have examined how LBW children respond to future neurologic injuries that occur years after birth. addressed a similar question by examining the influence of environmental stress on the rate of psychiatric diagnosis in a group of children with various handicaps. Interestingly, she found no greater adverse effect of environmental stress within the handicapped group suggesting that children with neurological dysfunction did not have greater vulnerability to environmental stress. However, this study was concerned only with increases in the rate of psychiatric diagnosis and was primarily intended to examine relatively low-level, but chronic environmental stress as opposed to a secondary injury. Other investigations have examined the relationship between LBW and complex injuries occurring secondary to premature birth. These investigations indicate that LBW children who also demonstrate brain anomalies are at a significantly higher risk for developmental or motor delays, but most of these investigations are concerned with injuries occurring soon after birth. An important question is whether LBW status contributes to long-term alterations in brain development that lead to different (i.e., more attenuated) patterns of recovery following a future neurologic insult.
Research with other populations has examined the influence of cumulative risk on long-term cognitive outcomes. Research with children who have sustained traumatic brain injuries (TBIs) suggests that these children remain at risk for significantly worse outcomes following a second injury even if one or both of the traumas was relatively minor. Further, evidence suggests that repetitive, even mild, head traumas in young adulthood may result in very long-term increases in mild cognitive impairment and earlier onset of Alzheimer's type dementia. Thus, it seems plausible that even in the context of apparently intact functioning, LBW children may be at increased risk for an attenuated recovery following future neurologic insults. This small study reports a prospective case-series of children who were part of a larger investigation on the long-term cognitive impact of traumatic brain injury (TBI) but who were also born with birth weights below 2500 grams. We hypothesized that LBW children may exhibit a different pattern of recovery following a mild, moderate, or severe TBI when compared to a group of normal birth weight children who had sustained a TBI of similar severity.