The developmental cascades framework

NDC translates the developmental cascades framework into the NDC steps for optimising sensory motor development. The developmental cascades model proposes that disparate domains in infant development are interconnected and reciprocally influential. This approach requires consideration of the whole child, even if we have particular concerns about one particular domain of infant behaviour.

Developmental cascades framework also provides an explanatory model of developmental divergence and also psychopathology. Accumulating interactions between child and environment shape adapative psychological functioning. The imagery of a spiral, like a snail’s shell, has been used by some to represent the continuous, bidirectional, and interconnected nature of development across different levels (e.g., neural structures, cognitive processes, environmental inputs, and exhibited behaviors).

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 divergences or 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 divergent or 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

Synchronous multisensory experiences, including proprioceptive, haptic, visual, and auditory, enhance neural connectivity and sensory-motor processing are necessary for neurotypical development.75

NDC hypothesizes that relative sociocultural impoverishment of environmental stimulation, both social and non-social, chronic SNS-HPA hyperarousal, and disrupted parent-infant biobehavioral synchrony in very early life 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, in some infants. Compensatory trajectories vary according to the environmental experience, predispositions, and feedback loops activated within that individual infant.

NDC and motor development

NDC aims to optimise developmental outcomes by advocating adult-mediated motor and sensory-motor environmental enrichment post-birth, both socially and non-socially, if early motor deficits are to be prevented or early disruption of feedback loops stabilised.

NDC aims to optimise infant sensory motor feedback by promoting

• Patterns of rich postural variability, so that the general movements of the infant’s limbs and trunk occur against the adult’s changing bodily configurations (rather than in the context of long periods on an immobile cot or mattress)

• Patterns of rich multi-centric social interactions, that is, physically interactive play and enjoyment with older children and adults.98

The NDC sensory domain is unique amongst infant-care programs in de-problematising sensory stimulation, and offers parents multiple practical strategies for environmental enrichment, referred to in NDC as rich and changing sensory motor nourishment.

NDC supports parental responsiveness to infant cues, so that the infant is able to control her own doses of sensory motor input.

• Her sympathetic nervous system will dial up if she is receiving suboptimal sensory motor stimulation, and a responsive adult attempts to better enrich her environmental experiences.

• Her sympathetic nervous system may dial up if she wishes to change to environmental stimulation she is experiencing. A responsive adult will experiment with responses to see what dials her down.

Physical contact with the infant is encouraged where this is sensibly possible, which helps address the infant’s biological need for complex and continuing postural variation. NDC supports the primary carer to leave the low sensory environment of the Western interior daily for social contact, activities, and tasks, including frequent walks, as carers focusses on creating a rich, full and meaningful life, in large part outside the home, and to have the infant sleep day or night in the vicinity of the carer.

References

Schneider JL, West KL. A matter of time: developmental cascades for developmental science. Infant behavior and development. 2025;80:102078.

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