Fleur Lejeune1, Frédérique Berne-Audéoud2, Leïla Marcus2, Thierry Debillon2, Edouard Gentaz3. 1. Child Clinical Neuropsychology Unit, University of Geneva, Switzerland. Electronic address: Fleur.Lejeune@unige.ch. 2. Intensive and Regular Neonatal Care Unit, CHRU Grenoble, France. 3. Psychology and NeuroCognition Laboratory, University of Grenoble, CNRS, Grenoble, France; Sensorimotor, Affective and Social Development Unit, University of Geneva, Switzerland.
Abstract
BACKGROUND: Although preterm infants possess early tactile manual abilities, the influence of the postnatal experience has not yet been systematically examined. AIMS: To investigate whether early tactile manual habituation, discrimination and recognition (following interference) of shape in preterm infants are modified by postnatal age. STUDY DESIGN: Prospective study. SUBJECTS: 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). OUTCOME MEASURES: 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.
BACKGROUND: Although preterm infants possess early tactile manual abilities, the influence of the postnatal experience has not yet been systematically examined. AIMS: To investigate whether early tactile manual habituation, discrimination and recognition (following interference) of shape in preterm infants are modified by postnatal age. STUDY DESIGN: Prospective study. SUBJECTS: 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). OUTCOME MEASURES: 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.