Variation and Variability: Key Words in Human Motor Development

Abstract

This article reviews developmental processes in the human brain and basic principles underlying typical and atypical motor development. The Neuronal Group Selection Theory is used as theoretical frame of reference. Evidence is accumulating that abundance in cerebral connectivity is the neural basis of human behavioral variability (ie, the ability to select, from a large repertoire of behavioral solutions, the one most appropriate for a specific situation). Indeed, typical human motor development is characterized by variation and the development of adaptive variability. Atypical motor development is characterized by a limited variation (a limited repertoire of motor strategies) and a limited ability to vary motor behavior according to the specifics of the situation (ie, limited variability). Limitations in variation are related to structural anomalies in which disturbances of cortical connectivity may play a prominent role, whereas limitations in variability are present in virtually all children with atypical motor development. The possible applications of variation and variability in diagnostics in children with or at risk for a developmental motor disorder are discussed.

Use and functioning of the affected limb in children with unilateral congenital below-elbow deficiency during infancy and preschool age: A longitudinal observational multiple case study

“…Typical motor development is characterized by variation and the development of adaptive variability [5]. Variation denotes the presence of a repertoire of strategies for a certain function.…”

“…This ability develops through active trial and error activity and its associated multimodal sensory feedback. Reduced variation is associated with an early lesion of the brain; limited variability is considered to reflect minor or major brain dysfunction interfering with sensorimotor processing [5]. Children with UCBED have an altered repertoire of upper extremity movements which -given the anatomical restriction -may, or may not, have an appropriate size.…”

Feasibility of Orientation and Mobility Services for Young Children with Vision Impairment using Teleintervention

“…The way that the human nervous system develops varies with age and early childhood is a critical time period for motor development (Bushnell & Boudreau, 1993;Ferrell, 2011;Hadders-Algra, 1995). Midway through the fi rst year, children should begin to move toward landmarks in their environment prompted by their interest and social interactions with others, rather than only referencing their own bodies.…”

Anticipatory control and spatial cognition in locomotion and navigation through typical development and in cerebral palsy

“…4 Head-trunk blockage is a rough but efficacious strategy aimed at reducing the number of degrees of freedom, responding to the fundamental principle of motor control. 1,5 However, this strategy has only limited flexibility and is probably energy-demanding. To move the reference frame upward from the pelvis to the head, the development of a richer repertoire of postural-motor synergies, coupling the kinematics of lower segments to head orientation is required.…”