I disagree with the statement <You only do more if you push yourself to do more, and that applies mentally as well as physically.>

This is true physically but not mentally in an injury situation. Stimulating the brain to a level that does not cause a return of symptoms IS therapeutic. You do not need to push the injured brain to help it improve. The uninjured brain can be pushed but not the injured brain. The uninjured brain has access to a wide bandwidth of processing. Not so with the injured brain, especially the diffuse axonal injured brain.

The important difference that needs to be understood with brain training is simple. The uninjured brain has a great capacity to establish new functional abilities. These can be a wider visual processing ability, better auditory processing, better memory and recall skills. The basic neuronal structure is sound and available to be developed to a higher level of function. Much of this improvement is just from overcoming a trained in laziness.

The injured brain has has a form of laziness that was caused by the injury. The bandwidth for processing has been decreased by the injury. Instead of an 8 lane highway, there may be just 4 lanes available but none of them with an adjacent functioning lane. So, each lane can be used to the limits of that lane. There is a very limited ability to change lanes while in motion.

The uninjured brain can easily change lanes while at a high speed. This is improperly called 'multi-tasking.' In reality, it is the brain switching processes quickly and maintaining a memory bank of data from each task.

The injured brain may be able to switch lanes but it often struggles to memorize and recollect the data needed when it switches back to the original lane of thought. So, in essence, there is no ability to multi-task. Any attempts to multi-task is seen by the brain as over-stimulation with the resulting crash and bio-chemical toxins from that crash being built up.

The simple act of stimulating an individual lane causes blood flow to the brain to increase. This increase of blood flow helps cleanse the brain of toxins and nourish the neighboring brain cells. As one uses a single lane over and over, that lane becomes cleaner with the near-by lanes getting some clean-up.

Then, when one stimulates another lane of thought, the same clean-up and nourish process happens. Rinse and repeat as often as possible and slowly the brain has cleared itself of toxins and nourished itself to accommodate a spontaneous improvement of LOST functions.

Keep in mind that the goal is to restore LOST functions. Those lost functions were injured due to cellular/tissue straining and chemical dysfunction.

The brain does not have physical regrowth. It has natural growth but not beyond the early development years that end by adulthood. There is research still trying to find a way to stimulate growth or regrowth. Even with such regrowth, the training of new neuronal cells takes a long time. The connection of axons and dendrites is a slow and haphazard process.

Muscle regrowth is simple. A muscle cell only has one binary function, contract and relax. There are only 3 kinds of muscle cells. There are 5000 kinds of neurons with a network of 100 to 10,000 axons and dendrites per neuron connecting each one to the others. It is this rebuilding of the axon network that takes sooooo long and that is if the neuron survives the concussion.