Posture, muscular tone and visual attention in 5 month-old infants

✍ Scribed by Carole Lefèvre

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 126 KB
• Volume: 11
• Category: Article
• ISSN: 1522-7227
• DOI: 10.1002/icd.262

✦ Synopsis

Abstract

The present paper aims at studying the relationships between posture, muscle tone and visual attention in 5 month‐old infants. To this end, a specially designed seating arrangement made it possible to vary posture while keeping constant the spatial relationship between eyes and stimuli. Five month‐olds were placed in the reclining position (30°) or in a more erect position (60°). The more erect the posture, the more difficult it should be for the infant to maintain a straight body axis. Muscle tone was evaluated, and infants distinguished in terms of whether they were hypertonic or hypotonic. It was hypothesised that in a more erect position hypotonic children, who experience more difficulties in maintaining posture, should organise their visual exploration in ways different from those considered to be hypertonic. To test it, pairs of three‐dimensional stimuli were presented in the distal visual field for one group (N=48) and in the proximal visual field in another group (N=32) for 2 min in each posture.

The dynamical organisation of attention was evaluated through the number and duration of fixations on each target, the number of shifts from one target to the other (alternations) and the number of repetitions (back to the previous target). Results showed that visual behaviour was significantly affected by the distance at which stimuli were presented. Infants spent more time in visual exploration when the object was within reach than when it was out of reach. Although posture was shown to play a role in the organisation of visual exploration, no link with muscle tone was found, a surprising result which is discussed. Copyright © 2002 John Wiley & Sons, Ltd.