What type of doctor should I visit if I have cognitive problems?

I've been having this problem for a few years now, the problems has to do with my mental and social well being. I feel like my brain is constantly trapped in a foggy or hazy state. This makes it very difficult for me to maintain a conversation because my mind is very slow that I either can't find the correct words (or any word) to say or can't think of anything at all to say. This make my social life miserable and the fact that I have a small voice doesnt help either. I have had a pretty serious condition in the past with my ear and I'm not sure if that has anything to do with this. I had a serious (left) ear infection 8 years ago when I was 11 years old and had to get 2 surgeries done on it for it to completely stop. I now have permanent hearing loss and tinittus (ringing in ears) in my left ear. I've already been to a few local ear specialists and all of them found nothing abnormal about my damged ear. So about this brain fog hard-to-think-clearly problem im having, which doctor treats this kind of problem?