Dr. Greg Mewett:

With a terminal illness, things can move very quickly. Let us take cancer for example. Many cancers can progress very quickly and as a result of complications of cancer or the cancer itself indeed, this affects the patient's cognitive ability. In other words, their brains fail along with the rest of their bodies. It can be affected by simple things like a urinary tract infection which does not recover, which can cause the brain to malfunction and not recover.