Comment by robocat
3 days ago
Brain surgery can leave you without the ability to detect something is missing.
https://wikipedia.org/wiki/Anosognosia
Anosognosia is relatively common following different causes of brain injury
The condition does not seem to be directly related to sensory loss but is thought to be caused by damage to higher level neurocognitive processes
Also Meningioma explained: https://en.wikipedia.org/wiki/Meningioma
This was 15 years ago, but he seemed to have all his faculties in order. The major change we saw was for about 3 to 6 months after the surgery he would lose his temper at the slightest thing. He was basically impossible to live with and then all of that just went away and he went back to being very normal.