Opportunities for Early Intervention Based on Theory, Basic Neuroscience, and Clinical Science

Theoretical Foundation

Finding an agreed-upon name for a unified theory to explain the emergence of, and change in, motor skills over time is more difficult today than it was a decade ago. In 2000, I would have selected easily the term “dynamic systems theory,” although even then “theories” (plural) would have been more appropriate, given the diversity of disciplines from which the core principles emerged.^1,2 Today, terms used more frequently that embrace similar underlying concepts and expand to include the growing body of neuromotor data include “developmental systems approach,”^3–5 “probabilistic epigenesis,”⁶ and “neuroconstructivism.”^7–9 To avoid the confusion of adding another term to the mix, I suggest that the material that follows may cluster under the more inclusive of these options: developmental systems.

One of the most important conclusions scientists examining and developing these approaches, including dynamic systems, support is that the extant body of data moves us beyond relevance in continuing to accept or debate a nature-nurture dichotomy with regard to the causes underlying emergence of and changes in patterns of behavior over time. This conclusion holds, whether we examine change early in life or later, at all levels, from subcellular entities to human organisms and populations. Replacing this is focus on processes—the ways in which many components in a system interact, sometimes including those with no obvious relevance, causing change among each other and in behavior. Smith eloquently laid out such an approach during a speech delivered at the International Conference on Infant Studies in 1998 and subsequently in publication.¹⁰ Spencer and colleagues updated this argument recently in a target article in Child Development Perspectives.³ Their point is that attributing behaviors, even those as persistent across intact humans as the emergence of walking, to an a priori genetic code for primacy is neither defensible empirically nor helpful in terms of facilitating the emergence or recovery of this functional skill. Genes, to quote Spencer et al, “do not create anything…. Genes participate in the production of proteins and in the regulation of other genes. The building of brains, bodies, and flexibility involves a cascading developmental process in which genes and their products interact within their local environment to create the substrates for further development.”^11(p104) Nor does this argument accept that humans or their brains are blank slates, on which organization and behavior are created exclusively by a process of learning or exploration of the world around them. However, development is a process of self-organization, among multiple factors, within the organism and without, driven by interactions and experiences. For description alone, one might ignore processes that drive change; to have an impact on change in a system, we must understand the history, context, and interactions that constructed the current state in order to facilitate subsequent adaptations.

That behavior is dynamic and adaptive may be illustrated by a series of studies that addressed historical observations of an inverted U in the development of stepping in infants, part of the traditional sequence of motor milestones in infancy. Maturationist and some neurophysiological approaches proposed that neonatal stepping is a reflex, the essence of which resides in a central pattern generator (CPG), that is innately prescribed, located in the spinal cord, and, ultimately, is the core component for, later in life, walking.^12,13 Sensory stimuli, provided by holding newborns upright and moving them forward over a firm surface, activate the neural program and cause stepping. By 2 to 3 months of age, this behavior disappears, to reappear between 8 and 11 months of age when infants cruise and walk. The argument was that as the nervous system matures, higher levels of the central nervous system inhibit the free-running action of the CPG, then restructure in subsequent months to drive the onset of walking.^14,15

Thelen and Ulrich^16,17 illustrated the dynamic and plastic nature of infant stepping by showing that intralimb and interlimb temporal and kinematic characteristics of newborn steps persisted in other postures, such as supine kicking, and that stepping displayed its own trajectory of interlimb coordination patterns when the context was shifted and infants were supported upright on a motorized treadmill. Even when stepping was supposed to be inhibited by higher brain centers, the behavior was easily elicited when infants were supported in water,¹⁸ and given practice, stepping never disappeared at all.^19,20 Furthermore, the behaviors infants generate when supported on a treadmill are not stereotypic. Several researchers^17,21–23 have shown that when babies step on a treadmill, their leg movements are highly variable, yet adaptive. Early in life, the treadmill elicits a variety of interlimb couplings (alternating, single, parallel, and double steps), and infants produce lots of nonstepping leg movements, then settle into alternation over time, without directed practice.^17,22 They used multiple foot postures to contact the support surface at the end of swing, including heel-strike, which was not deemed available based on maturationists' arguments, until several months after walking onset.^12,24 When the treadmill belt was split down the middle and one side moved twice as fast as the other, infants adapted spontaneously by modulating the “fast” leg to a slower frequency and increasing the frequency on the “slow” leg to maintain a steady interlimb coordination.^17,25

Yet, underlying these overt alternating kinematic patterns on the treadmill were muscle activations that only began to show signs of consistency or rhythmicity late in the first year. While the many muscles and joints in the legs and pelvis converged to produce the net effect of patterned behaviors, the underlying neuromotor system vascillated among many of the possible combinations of muscle activity to respond to this context (unpublished research).²⁶ Just as toddlers explore their many options for which muscles to use, including the timing of their onset and duration, to control upright locomotion before they settle into a stable activation pattern,^27,28 infants demonstrate similarly on a treadmill the dynamic and adaptive responses possible to produce this kinematic pattern of globally rhythmic leg flexions and extensions.

The implication of these data is not that organized populations of neurons in the spinal cord and brain do not play critical roles in the emergence of stepping and walking, but rather that the essence of walking does not reside in any of these neural modules. Stepping behaviors, like other patterns of movement, are dynamic, fluid, and adaptive; their essence is in the convergence of many innate and external factors, including the context and goal of the performer. Furthermore, populations of neurons in the spinal cord are themselves dynamic, affected by the process of perceiving and acting, of changes in the periphery and centrally, like other populations of neurons throughout the nervous system.

Research also has shown that humans, including infants and young children, have multiple, redundant pathways for achieving the same functional goal. Variability in individual behaviors was a hallmark of the earliest descriptions of motor patterns observed by developmentalists such as McGraw,^29,30 Gesell,³¹ and Shirley.³² Collapsing their many observations into normative age means and categories seems to have obscured the fact that infants who are typically and atypically developing skip common milestones, revert to earlier patterns after more complex ones emerge, and produce their own unique patterns under varied environmental contexts and their own performance goals. To be clear, these early scientists themselves correlated their developmental sequences and progressions with underlying neural maturation. Yet, as McGraw³⁰ concluded in later writings, attempts to uncover unique neural substrates that drove these maturational outcomes had largely failed.

For a vivid illustration of the flaws in attributing motor outcomes to single causes, such as neural substrates, we can draw from populations such as children and others with Down syndrome (DS), in which multiple factors play a more visible role. One lovely example is in the solution such infants tend to discover for shifting posture from prone to seated. Like infants with typical development, they begin the transition by pushing their chests off the surface with their arms, but there the similarity ends. Infants with typical development swing their legs together around to one side and forward; infants with DS slide their legs first in opposite directions into abduction (doing a split) and then forward.³³ Given the extreme laxity in their hip joints, this pattern is the path of least resistance for accomplishing their goal. Not directed by a prescribed neural plan for their actions, infants with DS, like their peers without DS, are opportunistic, discovering through exploration and practice actions that accomplish their goal, given their current state of subsystem characteristics and the context. Infants with DS can shift to producing more typical patterns for this transition if extrinsic constraints are imposed, such as placing therapeutic bands around the legs, making parallel leg movements the path of least resistance.

Similarly, children who are healthy with relatively shallow hip joints may discover that scooting on their bottoms provides better overall stability, yet allows a more upright trunk during locomotion than creeping on their hands and knees. Both patterns may occur less frequently in the population at large than the mean pattern, but they reflect similar processes in their emergence. That is, each new behavior builds on the foundation of previous experiences and solutions discovered, the functional repertoire, and subsystem strengths to allow discovery of subsequent patterns of movement that accomplish the ever-changing and expanding goals of curious and active young humans.

That history matters at all levels of interacting subsystems, and the outcome of these interactions may appear close to or well downstream of their initial convergence, has been emphasized in developmental work recently and referred to as “cascading effects.” Karmiloff-Smith⁸ described a sequence of behaviors that illustrate this effect in which motor and cognitive factors intertwine in ways that might not be obvious without close longitudinal examination. Early in development, infants born with Williams syndrome show impaired planning of saccadic eye movements. This impairment leads to decreased ability to follow finger-pointing actions, which results in diminished capacity to use referential pointing in parents' normal efforts to help their babies connect objects to vocabulary words. This diminished capacity fosters atypical trajectories and delay in language acquisition, although, ultimately, fairly functional language skills emerge. In an example more central to the motor domain, Holt and colleagues^34,35 conducted a series of experiments with children with cerebral palsy (CP). Their results led them to argue that the high stiffness seen in these children is due, at least in part, to their early muscle weakness and emerges as a solution to generate sufficient force for locomotion. They created a mechanical model of the actual walking patterns for each leg in children with spastic hemiplegic CP. Data showed that these children generate more force with the less-affected limb than a child with typical development. They use this force to project their center of mass forward, but upward too, with each step. This movement enables them to use the stiffened, affected (and weaker) leg as a stiff vertical spring. When the body drops down onto this foot, a pogo stick–style rebound is created, propelling the system forward. These data and theoretical arguments suggest the next question to be asked is, could very early efforts to improve leg strength reduce secondary levels of high tone and stiffness in this population?

One hallmark of complex systems—open, thermodynamic systems, such as those in humans—is that they seek higher levels of complexity.³⁶ This fact fits both the behaviors we observe in early postnatal life, in which infants continually explore and discover new actions, each a bit more demanding than those that led up to them, and our explanation for them. Empirical studies show that even the youngest babies create adaptive, goal-directed movements and demonstrate systematic learning from their experiences,^37–39 and we know that existing neuromotor strength and control form the scaffolding that supports each subsequent level of construction. As newborns use their available eye muscle strength and control to attend to objects or people moving through their space, they push their systems, bit by bit, to go farther, to see more and longer. These repeated cycles of moving and perceiving the consequences lead, over time, to sufficient control of head and neck muscles to lift the head and eyes upward, leading to new, interesting things to explore. Their efforts have cascading effects, enabling more and longer movements through greater distances, toward objects, people, and sounds that attract them. Bit by bit, the foundation takes shape and expands for discovering new concepts, consistencies, and motor control. A predesign for this sequence is not necessary, or likely, given individual differences within infants who are healthy, as well as infants with atypical neurophysiological and biomechanical constraints. Yet, probabilistically, the similarities in sequential progressions follow, given the similarities in goals, substrates, and contexts they have to work with.

That rigorous practice—repeated cycles of perceiving and acting—affects recovery of neuromotor function via distinct changes within areas of the brain in children and adults is commonly accepted.^40,41 The same processes are less often acknowledged in the very early foundational organization among neurons. In 1987, Edelman⁴² published a detailed account of early brain development based on what was known about neuroembryology, neuroanatomy, and principles of physics acting at molecular and cellular levels. Together, the system's biochemical and physical properties and environment interact prenatally to produce cell proliferation, migration, adhesion, differential growth, and the formation of vast numbers of connections. The impact of the organism's own movements and environment contribute both to the typical organization of areas of cortical specialization and to individual variations in connectivity. Labeling his proposals the theory of neuronal group selection,^42,43 Edelman argued that the primary repertoire of broad patterns of network connections established before birth becomes ever more organized as the interaction with increasing numbers of sensory inputs and history of experiences grows after birth. Stated simply, through repeated cycles of perceiving and acting, synapses among populations of neurons within local areas of the brain, as well as globally, become strengthened to work together synergetically in their contributions to patterns of behavior. This process shapes the behavioral repertoire of the organism, according to what is of adaptive value in its eco-niche.

Whether the vast overpopulation of neurons and connections that emerges prenatally and the cell death that begins early to accompany the emergent synaptic organizations are sculpted or constructed continues to be debated. However, the significant role of the baby's own activity in facilitating these changes is not at issue.^44,45 Karmiloff-Smith and colleagues argued that very small differences in emergent properties of areas in the brain make them somewhat more relevant to processing certain types of input than others. However, it is time and through the repeated processing of information that some become more proficient than others and more actively involved in processing particular inputs. Although plasticity in early brain development is not totally unconstrained, it seems evolution has resulted in increasing flexibility for humans, rather than increasing complexity of built-in, domain-specific constraints.⁸ Rather than activity being able to invoke neural plasticity only in recovery from neural damage, plasticity underlies the process of development in infants who are healthy, as well as in infants with atypical development.^46–51

To summarize principles from this brief discussion of a developmental systems perspective, I offer the following principles:

1. Behavior patterns and changes in patterns emerge via self-organized interactions among many subsystems, intrinsic and extrinsic to the organism, within a context, and the performer's goals.

2. Behavior is dynamic and adaptive, changing in response to repeated cycles of perceiving and acting and to variations in the contextual demands or intrinsic capacities of the system.

3. There are multiple, redundant pathways to achieving the same functional goal.

4. History matters; factors that may not have obvious relevance to a particular outcome may have a profound, cascading impact.

5. Organization and change at the level of the nervous system are significantly affected by repeated cycles of perceiving and acting.

Critical Subsystems: Neural, Bone, Muscle, and Adipose Tissues

Clinical Challenges and Opportunities

Contemporary theoretical approaches and developmental neuroscience demand a greater emphasis on rigorous and early activity intervention for infants and young children with motor disabilities. The call for early intervention is not new, but new technologies have advanced, enabling scientists to demonstrate empirically the link between babies' physical activity and normal developmental processes. The mandate is clear that for infants and young children with diminished capacity to optimize their own developmental outcomes, the focus must be not only on very early but also on aggressive and functionally relevant activity protocols. Functionally relevant protocols emphasize activities of daily living, engaging infants in actively moving their limbs and bodies through space and responding to realistic perturbations as they show the capacity to adapt appropriately. Delaying interventions until motor milestones are missed or waiting until they have appeared and then trying to fix what looks “wrong” is to lose ground, perhaps irreparably in some cases. Although plasticity is more the rule than the exception, we must remind ourselves that time marches on. Each infant, child, adult, and geriatric system builds on a history of accumulated experiences. Our delay may mean lost opportunities for a child that in some cases may never be fully recovered, such as lost bone length or the joint's capacity to reshape on its own without surgical intervention, or it may allow the emergence of a compensatory neuromotor strategy for control and force that increases stiffness and tone and that may never be overcome.

Very early and aggressive interventions have become increasingly common in surgical and pharmaceutical treatments for disabilities. For example, babies born with DS who have a heart defect are likely, today, to receive cardiac surgery within months of birth. Cardiac muscle recovers quickly, and babies improve cardiorespiratory function, becoming more active, alert, and stronger overall. These improvements create a better physiological basis for development of other subsystems as well. In 2003, the National Institutes of Health began funding a major clinical trial to determine empirically the potential benefits and negative consequences of in utero surgery to protect the spinal cord of fetuses with myelomeningocele: the Management of Myelomeningocele Study (MOMS).⁷⁸ The hypothesized outcomes include decreased shunt-dependent hydrocephalus and possibly improvement in leg function, among other things. Yet, activity therapy for these same babies, those with DS and myelomeningocele, and those with many other motor disabilities, tends to lag. Physical activity therapy for babies and very young children tends to be: (1) less aggressive than prescribed for older children and adults, (2) less focused on functional skills (tending toward precursors, control of specific postures, or joint range of motion), and (3) delayed months beyond onset of disability, which would not be the strategy followed for older children and adults. These efforts may help, but they are not likely sufficient to promote optimal development of neuromotor control.

Multiple factors contribute to these disparities. Perhaps the most salient to therapists is the unwillingness, too often, of third-party payers to fund the onset of therapy until milestones are missed and to pay for the amount of time a therapist needs in order to take an aggressive approach with patients. Unfortunately, a second factor supporting the third-party payers' stance is a dearth of empirical results that show, via well-controlled and generalizable samples, the: (1) functional benefits (behavioral as well as in underlying mechanisms), especially over the long term, and (2) the cost:benefit ratio. Although we have strong theoretical and basic science arguments for the functional and long-term cost benefits of aggressive activity interventions for both younger and older adults, the data are not as conclusive for early interventions. Third, the remnants of old theoretical models, such as the maturationist approach, hinder a broader, more comprehensive approach that includes infants and young children in models designed for older people. Waiting for a skill to appear on its own, then fixing aspects that look “wrong”⁷⁹ ignores the enormous weight of developmental science showing that the processes and activities and contexts in which the infant engages lead to both the quality and rate at which patterns emerge. A fourth factor is the challenge of finding ways to motivate infants to engage in the therapies we design. Motivating adults can be challenging, even when they understand the advantages to their focused efforts. Infants' motivations are quite different from ours, and their reticence to repeat actions that are not fun or comfortable can be compelling.

Dynamic systems/developmental systems theory pushes us to think out of the box about ways, from the psychological to the physical and contextual, to engage pediatric populations in self-generated repetitions of activity. “Self-generated” implies that children engage in generating muscle activations in order to adapt to the dynamic context we create for them or to explore or pursue their own goals. This process builds the subsystems necessary for new and more effective functional patterns to emerge. Basic neuroscience identifies real mechanisms, such as neural transmitters, dendritic arborization, synaptic strengths, and brain activation patterns, that are dynamic and change in response to physically active engagement, even in, or perhaps particularly in, very young children. Muscle, bone, and adipose tissue mechanisms also show similarly positive responses. Dynamic systems/developmental systems theory addresses the processes by which these mechanisms change, affecting each other in an integrated manner and converging to allow new patterns of behavior and stronger bodies to emerge. Together, the groundwork is in place to support the goals of those who need to provide and guide intervention, but more needs to be done to expand the empirical database to design protocols for implementing these goals.

Funding may always be the bane of our health care existence when it comes to providing the level of therapy required to optimize outcomes in the short term and long term. Current funding for nonacute phases of long-term problems averages 1 hour biweekly of one-to-one service with a medical professional. We know this is, alone, not sufficient to change anything. Yet, how much therapy we need to fund, how much repetition is needed, remains open to question. A mountain of research evidence has accumulated for adults, allowing some consensus and guidelines that at least 3 to 4 times per week of intense repetition and progressive overload training will increase motor strength and control, although for focused neural control therapy, the amount of time needed to optimize outcomes is much more.^80,81 No one really knows the frequency and intensity of therapy required to enable infants and toddlers to significantly improve their muscle strength and neural control. Adolph and colleagues⁸² reported that toddlers take about 9,000 steps per day and travel the distance of more than 29 football fields when practicing their new walking skill. Yet, improvements in their gait parameters, while showing the typical negatively accelerating learning curve seen in motor learning studies of adults, require between 3 and 6 months for the rate of improvement to asymptote.⁸³ The necessary and sufficient frequency of treatment may be less than 9,000 repetitions per day, but do we approach this in practice?

One option for overcoming the cost of direct services problem and increasing practice repetitions is to devise therapies and develop technologies that can be administered in the home by caregivers and directed by therapists or other professionals. In a series of studies, my colleagues and I designed a portable pediatric treadmill and protocol for caregivers to facilitate the development of trunk and leg control and strength needed to reduce the significant delay in walking onset experienced by infants born with DS. As multiple studies have now shown, infants are not passive when supported on a treadmill; rather, they engage in active exploration of muscle activation patterns, adapt muscle activity to perturbations, and show residual (real-time) and more sustained (over developmental time) learning effects.^21,84,85

In one study, we gave parents of babies in the experimental group a treadmill and prescribed durations of practice and number of days per week.⁸⁶ Caregivers supported their infants upright, on the mini-treadmill, 8 minutes a day, 5 days per week. By their own reports, parents enjoyed both their dedicated “face time” spent in social interaction with their babies and the clear boundaries we prescribed for their efforts, and they expressed optimism that they were contributing in a tangible way to the health and development of their infants. Both experimental and control group infants also received traditional physical therapy sessions biweekly. The mean advance in walking onset was 3 months for the experimental group, which was gratefully embraced by families. Although this lag may not seem large to some people, it seems the design was a step in the right direction. Our intervention provided a maximum of 960 steps per training session, 5 times per week, which did not approach the step frequency Adolph and colleagues⁸² indicated toddlers who are healthy use in their normal “work” of practicing their control of walking.

The next step was to build on these baseline data. We designed the original protocol with no data to guide us on how many days per week or how long practice should persist. We did not know what parents as well as their babies would tolerate without fatigue or frustration. Post hoc, we believed we could be more aggressive. Ulrich and Angulo-Barroso and colleagues^87,88 subsequently replicated this study but tailored the intervention to each child's rate of progress, increasing the treadmill belt speed and adding small weights to the shank to build on the strength and control improvements each child demonstrated along the way. These modifications led to greater behavioral gains, resulting in an average 5-month advancement in walking onset compared with controls. Furthermore, toddlers, after training, showed significantly greater spontaneous activity levels, as monitored by actigraphs.

This secondary impact, greater spontaneous activity levels, was not the initial target outcome, and it may not be the only one. However, it was a relevant subsystem and one particularly meaningful today, given the global recognition of the need to increase activity and reduce adipose tissue levels to improve health. Their results illustrate the need in clinical research to design studies more clearly aligned with developmental systems theory.^87,88 Multiple factors affect and are affected by motor activity and patterns. In recent studies of infants born with myelomeningocele, my laboratory group has shown that throughout the first year after birth, these babies will respond to the treadmill context by producing some steps, although at a reduced rate compared with babies with typical development and with minimal improvement (without training) over the first 6 to 9 months.²³ When supported on the moving belt of the treadmill, even when not stepping, babies with myelomeningocele moved their legs in other ways, more frequently than when simply held upright on a stable surface. The population with myelomeningocele is known to show osteoporosis, reduced rate of bone growth, asymmetrical peripheral sensory and motor neural loss, and reduced frequency of spontaneous leg activity.^23,69,89 To address this set of factors and the facilitation of walking onset, my colleagues and I are designing an early treadmill intervention study that will include assessment of changes in several levels of subsystems that we hypothesize will be affected by this rigorous activity, as well as monitoring external factors that could affect outcomes, such as nutrition, medical history, and so on.

Other encouraging examples of research that shows the impact of intense, activity-based therapy on increased neuromotor function are growing. Mattern-Baxter and colleagues⁹⁰ showed significant improvements in standing and walking skills in children with CP as young as 2.5 years following only 4 weeks of intensive treadmill training (1 hour, 3 times per week). These laboratory-measured improvements were reflected in increased independence and reduced reliance on caregivers for functional mobility. Research documenting the effectiveness of constraint-induced movement therapy (CIMT) for upper-limb function in children with hemiplegic CP has grown substantially in the past few years.^91–93 Huang et al⁹³ concluded that among the most rigorous of these studies, the one significant outcome they had in common was increased frequency of use. In 2009, Coker and colleagues⁹⁴ demonstrated that modified CIMT can be effective, even when the child is under 1 year of age.

More new, creative approaches that can be adapted for home-based, parent-administered use also are within reach. For example, Needham and colleagues^95,96 created “sticky mittens” to improve pre-reaching infants' experiences in reaching for objects as a vehicle to investigate how they develop an understanding of the intentions of others. To build their experiences perceiving and acting with objects, they placed mittens dotted with Velcro* on the hands of 3-month-old infants and provided them with 2 weeks of daily practice interacting with toys that also wore Velcro patches. This intervention led infants who were healthy to explore objects more (visually and manually) and to increased arm activity, especially swipes toward objects, even when not wearing the mittens. This clever, yet simple, idea could be modified for use with infants with disabilities who need assistance building strength and control of their upper limbs. Mobiles hanging above babies' cribs were shown years ago by Rovee-Collier and Gekoski⁹⁷ to elicit significant increases in leg activity in 3-month-old infants who were healthy when their ankles were tied to the mobile with a ribbon. Very recently, movement scientists have begun to study how this simple, yet elegant, perception-action contingency can be harnessed to help babies with DS and those with white matter injury improve neuromotor control.^98,99

A developmental science and activity-driven process approach to facilitating change pushes us to think more critically than ever about the effects, pro and con, of the use of passive devices, such as parapodiums, serial castings, orthoses, and Dennis Brown bars, in intervention therapy. We must take seriously other options, including engaging the child in repeated cycles of activity to stretch ligaments, engage the child in accepting weight on his or her limbs, and aligning joints properly via guided movement through functional ranges of motion. Certainly, the rationales for these static positioning devices are well reasoned, and the empirical data may show generally positive outcomes. However, are these outcomes at the expense of other aspects of development of active neural control of movement, motivation to move (spontaneously), and movement through normal ranges of motion? Decreases in muscle mass and strength and loss of bone density also are outcomes of casting that have been documented in adults, as well as reductions in the cortical motor area responsible for activating muscles surrounding the affected joint.¹⁰⁰ The demands on caregivers' and therapists' time are high, and the physical strength required to assist children as they grow in practicing functional tasks grows with them; overall, the plan for optimizing the child's development must be balanced. However, without well-controlled, aggressive, and multifaceted empirical studies, we fail to provide professionals and caregivers with optimal information from which to make choices and to promote via the health care financial system better support for building strong and, ultimately, cost-effective foundations.

Summary

To date, the idea of very early and aggressive activity-based intervention for babies has, I would argue, suffered from a concern that babies are not able to withstand rigorous efforts to perform repetitions of their own body segments designed specifically to effect change in their subsystems, from neural to ligamentous tissues. A growing body of basic and clinical science results suggest we are missing the boat on opportunities for infants with motor disabilities if we do not develop more empirically based protocols to use very early in life in order to optimize developmental outcomes. Fundamentally, I hope this article encourages more empirical studies that build on theory and basic science to test the impact, at multiple levels, of well-controlled and assertive activity-based intervention programs, the short- and long-term effects, and especially interventions that can be administered by caregivers with professional guidance. Without greater opportunities for early treatment, the costs associated with health care needs in subsequent years will be higher, but the real cost is to those affected with early-onset neuromotor disabilities.