Neuromuscular control of posture in the infant and child: is vision dominant?

Area of Science:

• Developmental neuroscience
• Motor control
• Human physiology

Background:

• Postural control is crucial for daily activities.
• Understanding the development of neuromuscular responses is key to identifying potential motor deficits.
• The role of vision versus proprioception in early balance development requires further investigation.

Purpose of the Study:

• To investigate the impact of vision and maturation on neuromuscular responses for balance control in children.
• To determine the developmental trajectory of postural responses from infancy to pre-adolescence.
• To examine the interplay between visual and proprioceptive input in modulating muscle responses during balance perturbations.

Main Methods:

• Utilized a balance platform to deliver unexpected anterior or posterior translations.
• Recorded surface electromyograms (EMG) from leg, trunk, and neck muscles.
• Assessed neuromuscular responses in five age groups ranging from 3.5 months to 10 years, with and without visual input.

Main Results:

• Neuromuscular responses for balance control were present across all tested age groups, irrespective of vision.
• A significant reduction in neck flexor response latency was observed in 2- to 3-year-olds when vision was removed.
• A cephalo-caudal gradient of postural response development was evident, with neck, trunk, and leg responses emerging sequentially.
• Immature and varied response patterns in the youngest infants (3-5 months) suggest limited functional postural control before experience.

Conclusions:

• Vision is not a prerequisite for activating neuromuscular balance responses in children.
• A developmental shift occurs, potentially moving from visual dominance to proprioceptive reliance for faster postural adjustments in early childhood.
• Postural control develops in a head-to-toe sequence, with functional stabilization emerging after experience in managing the center of mass.