Transient Tone Abnormalities in “High Risk” Infants and Cognitive Outcome at Five Years.

Objective: To identify transient tone abnormalities and determine its prevalence in “high risk” infants and their cognitive outcome at 5 years. Design: Prospective cohort observational study. Setting: High risk infants discharged from a level II neonatal unit in a 12 month period, and followed upto 5 years. Methods: High risk infants and normal controls were assessed for abnormalities of tone using the method described by Amiel-Tison at 3, 6, 9, 12 months. An IQ by Stanford–Binet method and a preschool inventory by Ayres, Bobath was done at 5 years. Those infants who had normal tone at 6 and 12 months were called normal high risk (HR) group and those who had abnormalities at 6 months, which disappeared at 12 months, were called the transient tone abnormalities (TTA) group. Results: Out of 190 high risk infants, 113 were normal HR and 67 (35.2%) were labeled as TTA. Ten infants with cerebral palsy had abnormal tone throughout the first year. Controls had normal tone throughout the follow-up period. Although there was no difference in the IQ of the TTA group (98.5 + 12.4) and the normal HR (99.1+13.1) group, it was significantly less (P=0.04) than that of controls (106.1 + 9.1). Preschool inventory in TTA children showed poor language development (P=0.014). Conclusion: Many of the tone abnormalities detected at 6 months resolve by 12 months, hence a hasty diagnosis of cerebral palsy should not be made. High risk infants with transient tone abnormalities have a normal cognitive outcome at 5 years, except for poor language skills.

Biology versus environment in low birth weight children.

OBJECTIVE: To explore the contribution of biologic risk factors versus socio-demographic and environmental risk factors in cognitive development of children with birth weight less than 2000 g, at the age of 12 years. DESIGN: Prospective cohort study. SETTING: Infants discharged from a NICU of a referral hospital, with birth weight less than 2000 g between 1987-89 and followed up in the High Risk Clinic. METHODS: The children were assessed at the age of 12 years, with the Weschler's Intelligence Scale for IQ and by Wide Range Achievement Test for mathematics skills. Mother's education, father's education, socio-economic status, family structure, spaciousness of the house, the locality in which the child lived and the type of school the child attended, were all recorded. A stimulation score was determined at 6 and 12 months and 3 years. Family environment score was used at 12 years. RESULTS: The cohort consisted of 180 children, with 90 controls. The mean IQ of the study group was 89.5 +- 16.9, which was significantly lower than that of controls (97.2 +- 14.1) (P < 0.05). The mathematical skills of the study group were significantly poorer (P < 0.05) than that of controls. A multiple linear regression analysis was done using IQ as the dependent variable and all risk factors at birth, stimulation scores and socio-environmental factors as independent variables. Mothers education was the most important factor contributing to the total IQ, a variance of 25.2 % of the total variance 44.2 PERCENT. Fathers education emerged as an important factor for mathematics skills. School was the next important factor for IQ as well as academics. Controlling for all other background factors, birth weight was the only biologic factor of significance, and this had a very small contribution. CONCLUSION: Parental education and the type of school attended by the child were the most important factors influencing cognitive development. The only biologic factor of importance was birth weight, but this too had a very small contribution.

Pune low birth weight study--cognitive abilities and educational performance at twelve years.

OBJECTIVE: To assess the intelligence, visuo-motor perception, motor competence and school performance of children with birth weight less than 2000 grams, at the age of 12 years. DESIGN: Prospective cohort study. SETTING: Infants discharged from a Neonatal Special Care Unit of a referral hospital with birth weight less than 2000 g between 1987-89 and followed up in the High Risk Clinic. METHODS: The children were assessed by the Weschler's Intelligence Scale, Bender Gestalt test for visuo-motor perception, Wide Range Achievement Test for specific learning disability, Draw-a-Person screening test for emotional problems and Movement Assessment Battery for motor competence. Academic achievement was also scrutinised. RESULTS: One hundred and eighty children weighing less than 2000 grams at birth and ninety control children were assessed. The mean IQ of the study group was normal (89.5 +/- 16.9), though significantly lower than that of controls (97.2 +/- 14.1; p<0.05). Pre term SGA children had the lowest mean IQ (85.4 +/- 17.7). In the 78 VLBW children, there were 12 (15.4%) mentally retarded children as compared to only 3 (3.3%) amongst controls (p<0.001). There were only 3 (3.8%) 'bright' children among the VLBW group, as compared to 20 (22.2%) in the control group (p<0.001). Visuo-motor perception and motor competence of the study group was poor, and they had writing and mathematics learning disability, especially the preterm SGA and VLBW group. Academic achievement was poor and the incidence of borderline intelligence was 24.4%, which has increased from 13.4% at 6 years. CONCLUSIONS: The intelligence and academic performance of the children weighing less than 2000 grams is significantly lower than that of controls, though within normal limits. They also have poor visuo-motor perception, motor incompetence, reading and mathematics learning disability. The preterm SGA and VLBW children had the poorest cognitive abilities.