braindamage,

1st, Where are you so we can recommend clinics?
2nd, Male or female?
3rd, Did you have any anxiety or depression struggles prior to your accident?
4th, What is the Klonopin supposed to treat?

Was the sleep study just a breathing study or did it look at EEG waveforms?

Have you had any therapy for your upper neck? Sleeping postures can cause upper neck inflammation that causes a restriction of blood flow to the brain and mess with quality of sleep leaving your in brain fog.

I call the upper neck issues Subtle Neck Injuries because they have no other symptoms to indicate a neck problem. But, resolving upper neck issues can lead to great improvements. Instability at C-1 to occiput and C-1 to C-2 can lead to inflammation.

A test that might work is simple. Try sleeping in a recliner with your head and shoulders elevated and your head supported in a relaxed straight posture.

NUCCA and Atlas Orthogonal chiropractic or Upper Cervical Physical Therapy may help. Myoworx.com in Guelph, Ontario, Canada does some interesting PT work.

The DTI and SWAN MRI could be helpful in documenting brain struggles but they don't often direct treatment.

A SPECT at an Amen Clinic may be worthwhile. Dr Amen has a huge database for comparison. Check him out on YouTube.

btw, I stopped 14 years of SSRI and take 200 mgs of 5-HTP instead. I do MUCH better with the 5-HTP.