I suppose you've already cut out alcohol and marijuana and other drugs. If not, do so. Different strains of marijuana is great for some MS symptoms, but there is one study that showed it impacts short-term memory scores for MSers. There are some medications you can take for "cog fog" and it's worth asking your doctor about that. But there are tons of things you can do. Every memory trick or advice for older people to stave off dementia will be helpful for MSers. Develop new habits and hobbies aimed at memory and mental sharpness -- there are tons of advice on these things, everything from crossword puzzles to games. Don't like that or don't have that habit? Doesn't matter, your health is more important so put a happy spin on it, smile and suck it up and learn to enjoy a new habit/hobby. Because our health *is* more important. Myself, I've found I can have cog fog hit when I'm sitting for too long or even if I'm standing and doing something. In that case, "change the environment!" If I'm doing one, I'll change things up and do a different one. Also pay attention to diet and sleep. Sleep can impact many, many things. And I found that I'm sensitive to gluten. Being gluten-free is a pain in the butt because wheat/gluten is now used in everything. I have no problems eating wheat (don't have celiac disease), no upset stomach or gas or anything. But when I *stop* eating gluten, somewhere between 7-10 days later I will experience a "mental sharpness" and clarity so strong it's like someone added 15 IQ points to my brain! It's like I was suffering from the fog of a hangover but someone removed it. I've "tested" that repeatedly. Gluten is in so many things it's easy to fall off the wagon. But each time I stop, about a week later I'll experience that mental clarity thing again.