The manual habituation and discrimination of shapes in preterm human infants from 33 to 34+6 post-conceptional age.
BACKGROUND
Grasping at birth is well-known as a reflex in response to a stimulation of the palm of the hand. Recent studies revealed that this grasping was not only a pure reflex because human newborns are able to detect and to remember differences in shape features. The manual perception of shapes has not been investigated in preterm human infants. The aim of the present study was to investigate manual perception by preterm infants.


RESULTS
We used a habituation/reaction to novelty procedure in twenty-four human preterm infants from 33 to 34+6 post-conceptional age. After habituation to an object (prism or cylinder) in one hand (left or right) in a habituation phase, babies were given either the same object or the other (novel) object in the same hand in a test phase. We observed that after successive presentations of the same object, a decrease of the holding time is observed for each preterm infant. Moreover, a significant increase of the holding time is obtained with the presentation of the novel object. Finally, the comparison between the current performance of preterm infants and those of full-term newborns showed that preterm babies only had a faster tactile habituation to a shape.


CONCLUSIONS
For the first time, the results reveal that preterm infants from 33 to 34+6 GW can detect the specific features that differentiate prism and cylinder shapes by touch, and remember them. The results suggest that there is no qualitative, but only quantitative, difference between the perceptual abilities of preterm babies and those of full-term babies in perceiving shape manually.
Lejeune
Fleur
F
Laboratoire Psychologie et NeuroCognition (UMR CNRS), CNRS and Université Pierre Mendès France, Grenoble, France.
Audeoud
Frédérique
F
Marcus
Leïla
L
Streri
Arlette
A
Debillon
Thierry
T
Gentaz
Edouard
E
D000704:Analysis of Variance; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D013997:Time Factors