random, Why are you usually up so late ? What are you doing ?

Research suggests that sleeping late is not good, especially for the brain injured. You should try to maintain the same sleep schedule and focus on quality sleep. The need to sleep so long suggests you are not getting good quality sleep with full cycling through the stages of sleep. A sleep specialist may be worth a consult. If you are not experiencing good REM and slow wave sleep, you will not be refreshing your brain.

A FitBit could provide some insights into your sleep.

MRI's rarely pick up the issues that are problematic. The resolution is not fine enough. The SWAN MRI uses special software to process the signal that allows it to show fine bleeding issues.