SUMMARY

Dogmatic statements on the use of head circumference in evaluating institutionalized children cannot be developed by analysis of the data presented above. In lieu of doctrine, I offer the guidelines on which I rely when counseling prospective adoptive families on the meaning of head circumference measurements in the referral document.

• Cognitive abilities are determined primarily by genetic factors. A child's innate intelligence is unlikely to be improved by enhancement strategies under normal circumstances. Early brain insults can decrease cognitive potential, but enriched environments can mitigate their effects.
• While valuable as one of the few object measures of brain health in a referral document, head circumference should not be interpreted in isolation if at all possible. Probable gestational age of the child, the presence of additional risk factors and the growth pattern of the head over time strengthen the predictive value of head circumference.
• For a given head circumference, genetic, biologic and environmental risk factors as well as the presence of a specific medical diagnosis will worsen the prognosis for any given head circumference (e.g., retardation in the family, congenital rubella, syphilis or prenatal alcohol exposure, prematurity, early childhood institutionalization, cerebral palsy or severe developmental delay).
• A consistently small head circumference (> 2 SD below the mean) markedly increases the risk for mental retardation. The smaller the head, the more profound the deficit.
• Early brain insults are associated with short- and long-term deficits. The longer the insult, the more profound the deficit.
• The environment in which a child is raised after such an insult has profound effects on short- and long-term outcome. Adoptive and single-placement foster families have consistently been shown to have a powerful positive effect on the outcome of at-risk children.
• Relying on head circumference alone rather than proportionality for prognosis is probably more reliable.
• Big heads probably are better, though in rare circumstances can be a sign of a disorder with neurologic sequlae.

While data to support the following statements are limited, I offer the following for consideration:

Average risk group: Full- or near-term infants with head sizes anywhere in the normal range at birth and at the time of referral (± 2 SD) without genetic, environmental or biologic risk factors aside from early institutionalization.

Parents who are considering adopting these children should be counseled that no child arrives unscathed from an institution, but that these children have as good a chance as any institutionalized child for a healthy brain.

Higher risk group: Children who are within the normal range at birth but who become microcephalic over time (greater than 2 standard deviations below the mean).

Parents should be counseled that function within the normal range is possible and may even be probable, but that these children are at risk for long-term neurologic dysfunction, including lower IQ scores and hyperactivity with accompanying learning disabilities. Of these children, those with a head circumference at the time of referral close to the lower limits of normal probably have a level of risk close to the average risk group. Those who have profound head growth failure and additional risk factors, the most common being prolonged institutionalization (>= 2 years), probably have a prognosis closer to the highest risk group

Highest risk group: Children with consistently small head circumferences (greater than 2 standard deviations below the mean).

Parents considering these children should be counseled that their outcome will be positively affected by the environment of an adoptive home, but they still have a high probability of long-term neurologic problems, including significant mental deficits, learning disabilities, hyperactivity and a variety of behavioral problems. The smaller the head, the higher the likelihood of retardation and the greater the deficit. The addition of any risk factor increases the probability of long-term neurologic dysfunction. In children with profound microcephaly (>= 3 SD below the mean) coupled with additional risk factors, the possibility of life-long supervisory or custodial care should be discussed.

Does This Data Apply to International Adoptees? | References