I'm a bit confused as to why you're wanting to retrain your brain. That's a lot more difficult at older age than coping with slower reflexes.
My suggestion would be to try and minimize any brain re-training, by keeping your left hand on movement duty and finding a mouse that will allow for remapping your skill keys, while keeping the same numerical order, ie. skill key #1 equals side mouse button #1, etc. A couple of the above mentioned do exactly that.
Honestly, a lot of people macro. It's not that you're slower in your old age (although that is true, just not as much of a factor as people think), it's more that technology allows for more automation of multiple tasks by a single key or button, as well as re-mapping an input device, in order to provide an interface that is more intuitive to the user, rather than clumping your way around a standard keyboard, that developers didn't really map as optimally as they could have. (which is a fault of hardware's design, not developer)
Also, keep in mind that many modern keyboards are fully re-programmable. Professional gamers use those, because to be perfectly honest, conventional keyboards were never designed for gaming, so even the pro gamers find that they have "performance problems"... so, it's not just you, or your age.
I understand your concerns, because I, too, am getting older, but I still try to "old school" my gaming and what shows more than anything, when playing against younger players, is my unwillingness to adapt to modern input designs, rather than "old age".
FYI, wanting to read quest text is not a sign of slowing down... it's a sign of wanting to enjoy the bloody game instead of rushing through it. ;)
» Edited on: 2016-04-12 06:18:25