"chemo brain"

[Mullins, Bill]

My father recently started chemotherapy.  In some of the free literature they gave him, a mental fogginess called "chemo brain" was mentioned (oddly enough, this condition was in a flyer for medicine designed to combat "chemo brain"  . . . )
 
chemo brain is not in the OED, but gets over 20,000 Google hits.

"Support and humor help most women endure breast cancer," by Torri Minton, California | Placerville | Mountain Democrat | 1991-11-01, p. xx col 2.
"I often wanted to record the meetings, but my chemo-brain wouldn't allow me to be that organized." 
"Cancer Specialists Turn to a Long-Ignored Side Effect: Fatigue" By The Associated Press New York Times; Apr 10, 1999;  pg. A16

"There is a mental toll -- "chemo brain," some call it -- in which patients cannot concentrate, are forgetul or are depressed."