The primacy of motor development for infant development: NDC evolutionary bodywork
Primacy of motor development for child development
Motor, sensory, cognitive, and social communication development are not independent phenomena occurring in sequential order or in discrete neuroanatomic locations, but are complex functions which dynamically co-evolve within the global neuronal workspace of the complex adaptive systems of the developing foetus and infant.9, 51, 52
NDC draws on the hypotheses concerning the primacy of either in-utero, intra-partum, or very early life motor lesions in infant development. Researchers propose that a structural (genetic or injury) or functional (monoaminergic) motor lesion, if sustained in the brainstem systems or cortical subplate in the critically neuroplastic window in-utero, intra-partum, or in very early life, may impair prospective, affect-driven movement. Cascades of imbalance between local and global connectivity emerge, resulting in atypical neurological, psychological, and behavioural development.
Chronic SNS-HPS hyperarousal and disrupted parent-infant biobehavioral synchrony are key physiological and behavioural mechanisms which either predispose to very early functional motor lesions, or perpetuate the effects of very early subtle anatomic or injury-acquired motor lesions.
The importance of postural variability for motor development
Infants require complex and unpredictable postural variability from birth in order to optimise postural control strategies; they also require rich and active movement experiences in order to learn to perceive visual and tactile stimuli.19, 60-62 Reduced movement complexity and variability, that is, reduced movement repertoire, associated with decreased affect-driven prospective movement, impairs sensory feedback and parent response, limiting capacity to process sensory information.63
In the phase of secondary variability of general movements, these infants have further difficulty selecting an appropriately adapted strategy from of their repertoire, due to limited variability.58, 60, 62, 63 Schafer et al propose that motor stereotypy is a downstream manifestation of low motor complexity.64 The reduced exploratory motor drive evident in many neurodivergent children is hypothesized to begin with these deficits in primary and secondary variability of movement, which cascade to motor coordination difficulties and impaired complex motor sequencing.65
Social communication depends upon early motor competency
The social communication developmental pathway depends throughout early life on motor competency and capacity for motor synchrony with another, including mutual gaze, joint attention and shared positive affect, attention disengagement, gesture, touch, and language learning.66 For example, from birth multiple sequential motor and sensory-motor patterns lead to joint attention. By three months of age, social gaze is the primary modality of coordinated interactions.
Eye contact, joint attention, and touch synchrony are driven by the motor-emotional system for the enjoyment of shared experience.22, 59 Early motor and coordination deficits result in atypical control of eye movements, delays in development of gestures such as pointing, and associated impairment of joint attention.69 In neurotypical infants, touch synchrony, the coordination of affectionate touch with episodes of shared gaze, increases significantly from 3-9 months with the development of fine-motor skills.
In this time, episodes of shared gaze decrease to about a third of the time, while shared attention to objects increases dramatically. This emphasises the dynamic relationship between downstream development in the motor domain, which allows infants to crawl, grasp, and manipulate objects, and development of social competencies. ‘Sticky’ attention to objects is one of the earliest biomarkers of ASD, evident from 7-14 months. Difficulty disengaging attention interferes with social orienting and impairs social communication skills.
Speech comprehension relies on multi-sensory integration, predominantly auditory, enhanced by concomitant visual information; speech capacity relies on motor competence.70-72
The relationship between motor development in infancy and later cognition correlates neurally with the involvement of extensive cortico-subcortical networks and structures such as the dorsolateral prefrontal cortex and the neocerebellum in both motor and cognitive functions.73
Sensory processing development depends upon early environmental stimulation
Up to 87% of individuals with ASD, for example, demonstrate atypical sensory processing, usually categorised as hyper-sensitive, hypo-sensitive, or sensory-seeking behaviors. From six months of age, signs of sensory processing abnormality are predictive of social communication deficits and repetitive behaviors in childhood, and ASD diagnosis.74
Synchronous multisensory experiences, including proprioceptive, haptic, visual, and auditory, enhance neural connectivity and sensory-motor processing.75 NDC hypothesizes that relative societal impoverishment of environmental stimulation, both social and non-social, chronic SNS-HPA hyperarousal, and disrupted parent-infant biobehavioral synchrony, might result in trajectories of compensatory sensory hyper- or hypo-sensitivity and sensory seeking behaviors in genetically susceptible infants.
In the same way that short-sightedness is a neuronal consequence of prolonged exposure to interior environments with suboptimal opportunities for long-distance focus, NDC proposes that the three variations of sensory processing difficulty are compensations within the global neuronal workspace for suboptimal motor and sensory-motor enrichment in very early life. Compensatory trajectories vary according to the environmental experience, predispositions, and feedback loops activated within that individual infant.
