The underlying assumptions about the nature and reasons for movement difficulties a child may have strongly informs the intervention approach adopted by a therapist.
Children with movement difficulties who have been evaluated for sensory integrative deficits are often said to have poor bilateral motor coordination, and this is hypothesized to be an important underlying reason for their motor control deficits (Ayres 1972, Magalhaes 1989).
Ayres (1972) defines bilateral motor coordination as the ability to use both sides of the body in an integrated and skillful manner. Ayres further asserts that the process of integration of vestibular and proprioceptive sensations and the efficiency of inter-hemispheral connections are the bases for good bilateral integration of both sides of the body.
Ayres' understanding of development is based on the idea that central nervous system (CNS) has a hierarchical organization such that sensory input must be organized by the lower brain for processing in higher levels of the brain to occur. Once organized, the sensory information can be processed by the CNS to produce adaptive behavior. Ayres does not provide any evidence to support this idea.
This assumption about the nature of sensory processing is not supported by modern theories of perceptual control that emphasize the role of active selection and gating of sensory input based on circumstances as well as task and environmental demands. It does not take into account the active gathering of sensory information for predicting and anticipating upcoming events. And finally it does not allow for the complex ways in which the movement brain integrates multiple sources of sensory information within different brain networks for planning actions. (Corbetta 2018 , von Hofsten 2018, Adolph 2019)
Ayers' theory of the development of bilateral integration
The proponents of the sensory integration deficit approach to understanding movement difficulties in children propose that development of bilateral motor coordination begins early in life and is the basis for further motor development (Berk & DeGangi, 1983; Kauffman, 1983).
“Although there are differences among individuals, the acquisition of control over the use of the extremities follows a developmental sequence that usually starts with control over bilateral, symmetrical movements (e.g., pat-a-cake), then moves to homolateral or unilateral movements (e.g., unilateral reaching), and finally proceeds to reciprocal movements of the extremities and skilled bilateral function (e.g., crawling.)” Magalhaes et al 1989. Maturation of the nervous system is thought to underlie this developmental sequence.
The theoretical basis for this proposed developmental sequence is not provided.
An alternative view of development
The difficulty with the Ayers account of perceptual motor development is that it skips over the complex interactions between the head, trunk and limbs seen in infants from before birth (Yamanda et al 2016). These include bilateral and reciprocal kicking, reaching to the midline seen at 3 months, followed by using the two hands to explore toys that are presented in the midline.
Although infants and toddlers engage in hand activities that require symmetrical reach and grasp, in most instances t two handed activities the hands play a different roles.
Infants who have learned to sit independently combine keeping the head and trunk steady with coordinated actions of the hands to explore and manipulate objects in ever more complex ways.
From an early age infants start to understand the structure of two handed tasks and are ability to generalize from one situation to another similar situation allows them to learn a new task with at least a rudimentary plan in place.
This coordination of the postural control and movements of the hands to achieve goals involves use of visual information for planning the movements, and rely on the ability to anticipate and predict changing circumstance.
The use of jumping jacks to test bilateral motor coordination
A child's ability to perform a series of jumping jacks smoothly is often used as a measure of bilateral motor coordination. These are rhythmic, repeated jumps while moving the upper and lower limbs laterally in a symmetrical manner.
The ability to perform a series of jumping jacks is not well established before the age of 7-8 years (Magalhaes 1989). In fact, even the simpler task of doing repeated stride jumps has been shown to be too difficult for 6-year-old children (Hughes et al 1981).
If a child of 8 or more years has difficulty performing jumping jacks then it may be reasonable to assume that the child may have a motor coordination problem. But remember that motor co-ordination always involves all areas of the brain working in an integrated manner, and poor performance cannot be ascribed to one or two putative processes such as integration of vestibular and proprioceptive sensations and the efficiency of interhemispheral connections as Ayres claims.
The Bilateral Coordination subtest of BOT-2
The Bilateral Coordination subtest of BOT-2 contains eight test-items. First and fifth item assess coordination of upper limb alone and remaining six items assess sequential and simultaneous coordination of upper limbs with lower limbs.
The BOT 2 manual claims that the Bilateral Coordination subtest measures the motor skills involved in playing sports and many recreational games. The tasks require body control, and sequential and simultaneous coordination of the upper and lower limbs. However this assertion is not supported by research that looked at the ecological validity of the BOT 2. “Gross motor subtests of 'Bilateral Coordination' and 'Balance' showed no relationship to bike riding or performance in sports.
“The results of this study suggest that the closer the proximity in the nature of the motor skills assessed in the German BOT-2 to daily motor tasks, the stronger the relationship between the clinical test and parental report of everyday performance of their child. The body functions tested in the German BOT-2, and hypothesized to underpin certain skills, were not automatically relevant for specific activities undertaken by German children.” Vincon et al 201
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