title: The effect of postnatal age on the early tactile manual abilities of preterm infants.
abstract: BACKGROUND
  Although preterm infants possess early tactile manual abilities, the influence of the postnatal experience has not yet been systematically examined.
  
  
  OBJECTIVE
  To investigate whether early tactile manual habituation, discrimination and recognition (following interference) of shape in preterm infants are modified by postnatal age.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Forty preterm infants were assessed from the post-conceptional age (PCA) of 34 weeks. Two groups were made up according to postnatal age (PNA): low PNA (PNA≤10 days of life) and high PNA (PNA≥12 days of life).
  
  
  METHODS
  An object (prism or cylinder) was presented repeatedly in the left hand, and holding times of the object were recorded during each trial.
  
  
  RESULTS
  Holding time was shorter for all preterm infants following successive presentation of the same object irrespective of postnatal age range. In the discrimination phase, the mean holding time for the novel object was longer than holding times in the last two habituation trials, in both PNA groups. Finally, the mean holding time of the familiar object presented in the recognition phase was shorter than the holding time of the novel object presented previously, but only in the low PNA group.
  
  
  CONCLUSIONS
  Tactile manual habituation and discrimination of shape information is present in preterm infants at a post-conceptional age of 34 weeks, independently of postnatal age. However, tactile manual recognition of familiar shapes following interference is affected by length of postnatal experience. The significance of this last result is discussed in detail.
authors.affiliation: Child Clinical Neuropsychology Unit, University of Geneva, Switzerland. Electronic address: Fleur.Lejeune@unige.ch.
authors.forename: Fleur
authors.initials: F
authors.lastname: Lejeune
authors.affiliation: Intensive and Regular Neonatal Care Unit, CHRU Grenoble, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Berne-Audéoud
authors.affiliation: Intensive and Regular Neonatal Care Unit, CHRU Grenoble, France.
authors.forename: Leïla
authors.initials: L
authors.lastname: Marcus
authors.affiliation: Intensive and Regular Neonatal Care Unit, CHRU Grenoble, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Debillon
authors.affiliation: Psychology and NeuroCognition Laboratory, University of Grenoble, CNRS, Grenoble, France; Sensorimotor, Affective and Social Development Unit, University of Geneva, Switzerland.
authors.forename: Edouard
authors.initials: E
authors.lastname: Gentaz
mesh_terms: D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000523:psychology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D046709:Pattern Recognition, Physiological; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*
keywords: Haptic memory; Manual perception; Postnatal age; Preterm infants; Shape