NEONATAL SOCIETY ABSTRACTS
Evidence of early reaching and object permanence in term neonates
Presented at the Neonatal Society 2009 Autumn Meeting (programme).
Al-whaibi R, Graziadio S, Eyre J
Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE1 4LP UK
Background: Previously there has not been clear evidence for object permanence until about 6 months of age. However, to our surprise we found evidence consistent with object permanence being present in term neonates, during a large study of the development of early reaching behaviour.
Aim: To determine at what age there is evidence for early reaching for a small toy placed laterally. Ethical approval from the Joint Ethical Committee of Newcastle University and Newcastle and North Tyneside Health Authority and informed and written consent from the parents were obtained.
Subjects: 17 healthy term neonates aged 4 to 28 days; 10 female; normal delivery, Apgar scores 9-10.
Methods: Each session started with baseline recording for 2 minutes prior to 20 presentations of the following sequence - “TOY ON” - a toy was placed within reaching distance on either the left or right side for 21s; -“TOY OFF”- the toy was then removed and after a variable delay (2-12s) a further 21s of hand position data was collected. The side of toy presentation was randomised between subjects. The positions of both hands were recorded using a Polhemus 3 D motion tracking system and a video recording was made. The total distance moved by each hand and the position of each hand relative to the toy or the homologous position of the toy on the other side (virtual toy position) were measured.
Statistical Analysis: A General Linear Model - Univariate Analysis was used. Fixed factors: condition (baseline, TOY ON,TOY OFF); hand (hand on the toy side, hand opposite to the toy side); Random factor: subjects.
Results: During baseline there were no significant differences between the two hands. In TOY ON and TOY OFF the hand on the toy side moved a greater distance and was positioned closer to the toy than during baseline (TOY ON: p<0.001 for both; TOY OFF: total distance p<0.05, position p<0.01). In addition, for TOY ON and TOY OFF the hand on the toy side moved a greater distance than the hand opposite to the toy side (TOY ON, p<0.001; TOY OFF, p<0.05) and was positioned closer to the toy than the hand opposite to the toy side was relative to virtual toy position (TOY ON, p<0.001; TOY OFF p<0.01).
Conclusion: 1. In TOY ON, the significant difference between the two hands for both distance moved and position in space provides evidence of early reaching behaviour in neonates, which was also supported by the video recordings. 2. The significant difference between baseline and TOY OFF for position in space of the hand on the toy side and the significant differences between the two hands in TOY OFF provide evidence of object permanence.