1. Original Construction of the brain
Starts at the bottom and works upwards. To quote Charles A. Nelson and Floyd E. Bloom from their paper “Child Development and Neuroscience” : “The stepwise sequence of neurodevelopment is genetically predetermined and not alterable by environmental forces. It proceeds from lower to higher brain centres, from the brain stem to the cerebral cortex, in a caudal to rostral direction.”
2. Deconstruction of the brain following injury
Starts at the top and works downwards. Think of a house being demolished. The first to go is the roof, then the exterior materials, then the frame, and finally the foundations. The way alcohol affects the brain is a good example of how this top-to-bottom deconstruction also occurs in the brain. Alcohol temporarily impairs brain function, in a top-to-bottom sequence. The first changes to be noticed are things like slurring words, fine motor skills, and behaviour. As more alcohol is consumed, neurological function progressively deteriorates. Speech is more affected, as is balance and coordination. Eventually skills like walking and talking may be temporarily lost. When traumatic injury occurs, the higher parts of the brain are usually the first affected, and the severity of the trauma determines the extent of the top-to-bottom sequence of deconstruction. In general terms, the more severe the trauma, the more deeper the injury.
The rules that applied to the original construction of the brain still apply to its reconstruction. The National Scientific Council Center on the Developing Child at Harvard University devised the following principles of learning to explain brain growth from birth, but these same principle are equally appropriate to the principles of relearning following traumatic brain injury:
Brain circuits that process basic information are wired earlier than those that process more complex information. Higher level circuits build on lower level circuits, and adaptation at higher levels is more difficult if lower level circuits were not wired properly. Parallel to the construction of brain circuits, increasingly complex skills build on the more basic, foundational capabilities that precede them. Stated in simple terms, circuits build on circuits and skill begets skill.
Neuro-Developmental Therapy Programs uses a Stages of Recovery Milestone Chart to measure the current state of recovery following traumatic brain injury. In effect, this Milestone Chart establishes the “Reconstruction Zone”, which then becomes the focus of the therapy program. This Reconstruction Zone is comprised of the milestones immediately above the highest recovered milestone and any not yet recovered milestones below it.