The second is definitely worse. You’re still pretty much the same person in the first situation. The second one is like Jermaine Taylor. He is a ticking time bomb.
Terry Norris (one of my favorite fighters ever) is immediately who came to mind when I saw this thread. Ken Norton was pretty bad. Some people say Hearns but I honestly don't think he's that bad. I have a number of relatives in Detroit that sound like him. It's kinda a southern/midwest drawl............so it may be a touch of post boxing, but some of that is simply dialect. Evander as well, he was never the most eloquent guy. Tyson still surprisingly sounds fairly articulate, especially in comparison to most of his peers.
Norton was in a really bad auto accident in 1986. He suffered a fractured skull and a broken jaw. I remember him saying that a few years of his memory was gone because of that accident. That may have contributed to his condition later in life...