The effect of psychosocial stimulation on cognition and behaviour at 6 years in a cohort of term, low-birthweight Jamaican children


Professor Susan P Walker at Epidemiology Research Unit, Tropical Medicine Research Institute, The University of the West Indies, Mona, Kingston 7, Jamaica. E-mail:


Aim  The aim of this study was to determine whether psychosocial stimulation up to the age of 2 years benefits cognition and behaviour at age 6 years in low-birthweight, term-born (LBW-T) children (gestational age ≥37wk, birthweight <2500g), and to compare LBW-T and normal-birthweight (NBW) children.

Method  LBW-T Jamaican infants were randomized at birth to a control group or an intervention group. Children in the intervention group received psychosocial stimulation for 2 years. LBW-T infants were also compared with NBW infants born in the same hospital. IQ, cognitive function, and behaviour were measured at age 6 years in 109 LBW-T infants. The LBW-T group were divided into the intervention group (55 out of 70 enrolled, 32 females, 23 males; mean birthweight 2190g, SD 200g; and the control group (54 out of 70 enrolled, 33 females, 21 males; birthweight 2240g, SD 180g]. These were compared with 73 out of 94 enrolled NBW infants (38 females 35 males; birthweight 3130g, SD 330g).

Results  Among the LBW-T children performance IQ scores were higher in the intervention group than in the control group (regression coefficient [B] 4.06, 95% confidence interval [CI] 0.01–7.98) as were visual–spatial memory scores (B 1.12, 95% CI 0.45–1.87). Children in the intervention group also exhibited fewer behavioural difficulties (B −2.21, 95% CI −4.13 to −0.10) than children in the control group. Compared with NBW children, LBW-T children in the control group had poorer selective attention (B=−3.35, 95% CI −5.59 to −1.26) and visual–spatial memory (B=−0.76, 95% CI −1.54 to 0.00), but there were no differences in IQ, language, or behaviour.

Interpretation  Stimulation had sustained benefits in LBW-T infants. Finding few differences between LBW-T and NBW school-aged children concurs with results from other developing countries.