My mom has had declining cognitive function for years, and it got a lot worse last year to the point where she was almost nonverbal.
I put her on a protocol of:
Ultrasound stimulation, 5 minutes 3x per day
Red light therapy, 30 minutes 3x per day
Low dose Methylene blue + magnesium and threonine
Light exercise
Improved ambient lighting conditions removing excess blue light
After 3 months she is starting to initiate and hold conversations again, and already seems to be a lot more 'present' than she was at the start of the year. I was skeptical, but the results have been rather profound, especially given that it's only been a few months.