Your comment was about blood flow being reduced. My comment was about blood flow being disrupted. It can flow too much or too little due to this disruption. I've never seen anything about 4 weeks of disruption. Anecdotal evidence says it varies widely. Every brain injury is different.

The glymph system is a passive system from what they can tell. It does not control anything. It functions when the sleep cycle allows slow wave sleep.

They know that people with brain injuries have disruptions to their normal sleep process. They know this impacts the brain's ability to recover. They have discovered a need for them to be disciplined to re-establish proper sleep processes. What else would need to be known ?

My point was that they know that getting the full range of sleep stages is important to recovery.