Arm posture of spontaneous touches in the first weeks of life

• In Event: Poster Session 13
  In Poster Session: PS 13 Topic - Perceptual, Sensory, Motor

Abstract

Early spontaneous self-touch activity could be foundational to growing body-knowledge in infancy. This activity begins prenatally in an aqueous environment where arm movements are less challenged by gravity, but are constricted by the limited physical space, especially in the last months of gestation. In contrast, at birth, gravity hampers arm movements, but the open physical space can afford a larger range of movements. This study aims to examine whether arm postures adopted by infants following birth remain tightly flexed against the body as in the late stage of gestation and if they change in the subsequent months. Prior studies have examined the spontaneous arm movements of newborns, but none have investigated the range of arm postures they adopt while spontaneously touching their body or their surrounding, and none have tracked how these arm postures evolved in the first months of life.

Five infants were followed weekly from 3-weeks-old until they gained head control, between 9-to-13 weeks old. Infants were observed in the supine position for five conditions lasting 5 minutes each: baseline, toys-in-view where colorful toys were positioned on the side of the infants preferred head turn, sounding toys where the toys were placed on the side of the infants non-preferred head turn, caregiver speaking where a parent out of view, spoke or read to the infant, and mobile entailing a high contrast black and white mobile hanging over the infant and gently shaken through the trial. All touches to the body and supporting surface were coded for location and duration. Subsequently, the arm postures at touch onsets were coded following 3 dimensions: angle of arm at elbow (acute or obtuse), orientation of arm relatively to body (towards head, feet, left, right, or vertical), and forearm support (resting on a supporting surface or not).

Preliminary analyses on four infants across three conditions revealed that infants were equally likely to hold their arms in an acute or obtuse posture during a touch. The forearms were also just as likely to be supported or unsupported. There was a main effect of orientation, where the arms were more often oriented towards the head (p = 0.004). Additionally, a condition by orientation interaction showed that infants oriented their arms towards the head more in the mother speaking condition as compared to the baseline and toys-in-view conditions (p = 0.014). There were no developmental trends for the orientation or supporting surface, but an “n” shaped developmental trend emerged for the arm angle. Infants had a peak of acute angle postures at 6-weeks-old.

These preliminary findings demonstrate that from 3 weeks old, infants do not maintain the same postures of late stage fetal development. They produce flexed and extended arm postures alike. Furthermore, infants quickly adjust to the new challenges of gravity and engage in a variety of supported and unsupported postures. All data have been collected and complete analyses will include all infants across the five conditions and link posture to specific areas of touch on the body and supporting surface.

Authors

• Abigail DiMercurio, University of Tennessee - Knoxville
  Presenting Author

• Daniela Corbetta, University of Tennessee - Knoxville
  Non-Presenting Author