You can try a root stimulator like cannanutes rhizotonic.
You might want to carefully repot or atleast seperate the pot from the plant to see if its too damp. You could try putting a fan on the floor to blow the pots dry. It really does look like the roots are having trouble getting oxygen or you could possibly be smothering the plant with neem oil. You can't spray too much or it will do the same thing. If you got a bug problem, spray them once every 3 or 4 days.