Well, they're different categories, but my point was brain damage, no matter the cause. Someone with dementia, someone with traumatic brain injury, and someone with chronic substance use all have some degree of damage to their brain and depending on where that damage is, it can and does impact emotions, impulsivity, disinhibition, ability to reason, and understanding of consequences. That was the point. It's not all about vocabulary or frustration.
With regard to word salad, that's a phrase that's been perverted by social media. It is a real thing, but it's been misunderstood and distorted online. Not everyone with dementia has "word salad" and not everyone with "word salad" has dementia. In fact, people who are drunk or high often exhibit "word salad" as do people who are coming out of anesthesia, etc. All it really means is incoherence because their words are strung together in an unusual way.
But word salad and inability to be understood is NOT often what drives behavioral disturbance in dementia. There's an entire field of study around this. There are many different causes, but my point was only that damage to brain structure can cause it.
The reference on TBI is very simplistic to the point of being irrelevant to the discussion about NR or my point about anger. There are many, many forms of TBI and while some may be described as "brain fog" that's generally in the case of concussion or post-concussive syndromes, not the type of TBI I'm referring to. A brain injury, say from lack of oxygen to the brain or mechanical impact like someone being beaten with a hammer or someone falling out of a window absolutely can lead to irreparable damage to the structure of the brain with the same impact on emotions, impulsivity, disinhibition, ability to reason, and understanding of consequences.
As for child tantrums, we don't know enough to know if this was by choice or not. I don't think we can dismiss neurodevelopmental disorders that can and do predispose someone to the same symptoms one would see with dementia and TBI. Was NR born on time? Were there complications with his birth (umbilical cord complications can cause TBI)? Was there an injury in infanthood/childhood? Did he meet all his milestones on time? Was there any type of damage to the brain as a child? Was he diagnosed with some type of disorder in childhood? Was he put on medications in childhood? Add substance to that, and there's no way any mental health professional worth their salt will argue he was making rational choices.
To clarify, I'm not saying he's not responsible for the murders. I'm saying that we know next to nothing about his medical history (that I've seen). We only know symptoms (like tantrums). There's no way we can say his anger was a "choice" yet.
