Functioning of peripheral Ia pathways in leg muscles of newly walking toddlers

Early Treadmill Practice in Infants Born With Myelomeningocele: A Pilot Study

PURPOSE

To determine the feasibility of an early treadmill training program for infants with myelomeningocele (MMC) and to measure changes in overt infant motor development and control, including mechanisms underlying the overt changes.

METHODS

Ten infants with MMC were initially enrolled: 8 infants completed 12 consecutive months of training, and 2 completed 6 months of training. Training consisted primarily of home-based, parent-administered treadmill stepping practice 5 days per week, 10 minutes per day starting within 6 months postbirth. We measured motor milestones, treadmill steps, spinal-level reflexes, and body composition.

RESULTS

Infants showed earlier acquisition of gross motor skills than previously reported. The number of alternating steps performed increased, indicating more complex neuromotor control and strength. Integrity of monosynaptic pathways and body composition were improved after controlling for chronological age.

CONCLUSIONS

This study demonstrates the feasibility of using early, home-based treadmill training for infants with MMC starting within 6 months postbirth.

How plastic are human spinal cord motor circuitries?

Human and animal studies have documented that neural circuitries in the spinal cord show adaptive changes caused by altered supraspinal and/or afferent input to the spinal circuitry in relation to learning, immobilization, injury and neurorehabilitation. Reversible adaptations following, e.g. the acquisition or refinement of a motor skill rely heavily on the functional integration between supraspinal and sensory inputs to the spinal cord networks. Accordingly, what is frequently conceived as a change in the spinal circuitry may be a change in either descending or afferent input or in the relative integration of these, i.e. a change in the neuronal weighting. This is evident from findings documenting only task-specific functional changes after periods of altered inputs whereas resting responses remain unaffected. In fact, the proximity of the spinal circuitry to the outer world may demand a more rigid organization compared to the highly flexible cortical circuits. The understanding of all of this is important for the planning and execution of neurorehabilitation.

The developmental dynamics of gait maturation with a focus on spatiotemporal measures

Gait analysis is recognised as a powerful clinical tool for studying relationships between motor control and brain function. By drawing on the literature investigating gait in individuals with neurological disorders, this review provides insight into the neural processes that contribute to and regulate specific spatiotemporal sub-components of gait and how they may mature across early to late childhood. This review also discusses the roles of changing anthropomorphic characteristics, and maturing sensory and higher-order cognitive processes in differentiating the developmental trajectories of the sub-components of gait. Importantly, although studies have shown that cognitive-gait interference is larger in children compared to adults, the contributing neurocognitive mechanisms may vary across age groups who have different types of attentional or cognitive vulnerabilities. These findings have implications for current models of gait maturation by highlighting the need for a dynamic model that focuses on the integration of various factors that contribute to gait though experience and practice. This is essential to elucidating why gait and other motor deficits are often contiguous with cognitive neurodevelopmental disorders.