The Performance of Infants Born Preterm and Full-term in the Mobile Paradigm: Learning and Memory

Abstract

Background and Purpose. By 3 to 4 months of age, infants born full-term and without known disease display associative learning and memory abilities in the mobile paradigm, where an infant's leg is tethered to a mobile such that leg kicks result in proportional mobile movement. The first purpose of this study was to examine the learning and memory abilities of a group of infants born full-term compared with those of a comparison group. Little is known about the learning and memory abilities in infants born preterm, a group at known risk for future impairments in learning and movement. The second purpose of this study was to determine if and when an age-adjusted group of infants born prematurely display associative learning and memory abilities over a 6-week period. Subjects. Ten infants born full-term (38 -42 weeks gestational age [GA]) and 10 infants born preterm (Ͻ33 weeks GA and Ͻ2,500 g) who were tethered and had control over the mobile movement were independently compared with a comparison group of 10 infants born full-term who were tethered and viewed a moving mobile but did not have control over the mobile movement. Infants in all 3 groups were seen at 3 to 4 months of age and were excluded from participation for any known visual or orthopedic diagnoses. Methods. Infants were tested using the mobile conjugate reinforcement paradigm, where one leg is tethered to an overhead mobile such that kicking with that leg results in proportional mobile movement. The kicking rates of the full-term group and the preterm group were compared with their own initial (baseline) kicking rates and with those of the comparison group. Results. After exposure to the conjugate relationship between kicking and mobile movement, the full-term group kicked more frequently compared with their own baseline levels and compared with the comparison group, fulfilling both criteria for learning and memory. In contrast, the preterm group did not increase their kicking rate according to both criteria. Discussion and Conclusion. These results suggest that infants born prematurely differ in their performance in the mobile paradigm as compared with age-matched infants born full-term. The mobile paradigm may provide clinicians with an important early assessment of infants' associative learning and memory abilities. Follow-up studies are needed, however, to further validate this paradigm as a clinical assessment tool. [Heathcock JC, Bhat AN, Lobo MA, Galloway JC. The performance of infants born preterm and full-term in the mobile paradigm: learning and memory. Phys Ther. 2004;84:808 -821.]

Independent development of the Reach and the Grasp in spontaneous self-touching by human infants in the first 6 months

“…It is important to note that the present study was primarily directed toward describing self-touching hand movements and secondarily at assessing the idea that during development there is some independence in the display of reaching and grasping movements as has been suggested in studies largely directed toward visually guided reaching (Von Hofsten and Lindhagen, 1979 ; Trevarathen, 1982 ; von Hofsten, 1984 ; Savelsbergh and van der Kamp, 1994 ; Wimmers et al, 1998a , b ). Thus, although it is obvious that the spontaneous activity that we have observed is likely the result of interactions between nervous system development, morphological development of the body, the posture of the infants during testing, and the life history of the experimental subjects (Savelsbergh and van der Kamp, 1994 ; Thelen and Spencer, 1998 ; Heathcock et al, 2004 ; Lobo et al, 2014 ; Soska and Adolph, 2014 ), there was no intent in the present study to distinguish between these contributing factors. Rather, it was our view that any differences in the developmental profile of reaching and grasping might contribute to a growing body of evidence that the Reach and the Grasp are mediated by different sensorimotor channels (for a review of other infant work directed toward this question see Karl and Whishaw, 2014 ).…”

Quantifying Learning in Young Infants: Tracking Leg Actions During a Discovery-learning Task

“…In previous infant mobile paradigms, frequency of leg movement [4][5][6] , specific hip and knee angles 7,8 , or kicking a panel 9 have been reinforced with mobile movement. Performance each day was defined as an increase in these leg actions during the acquisition or extinction condition as compared to the baseline condition [4][5][6][7][8][9] .…”

“…Learning across days was defined as an increase in these leg actions during the baseline or acquisition condition of Days 2 or 3 and the baseline condition of Day 1 5,6 . These previous mobile paradigms demonstrate that infants increase the frequency of leg actions that are reinforced with mobile activation, however, they do not provide information on the movement options infants have available to them when learning the task.…”

Social and non‐social visual attention patterns and associative learning in infants at risk for autism

“…Within these tasks, infants also display predictable patterns of attention shifting (Mast, Fagen, & Rovee-Collier, 1980), motor coordination (Heathcock et al, 2005), and affect variation (Alessandri, Sullivan, & Lewis, 1990). These tasks have been used to identify early impairments across a range of other populations such as infants with preterm birth (Rose, Feldman, & Jankowski, 2001;Heathcock et al, 2005;Heathcock et al, 2004), Down syndrome (Ohr & Fagen, 1993), and prenatal cocaine exposure (Alessandri et al, 1993). Although AU sibs have not been tested within learning tasks, preliminary evidence of abnormality in aspects of their visual attention may affect their performance (Bryson et al, 2007;Rose et al, 2001).…”