Medical science must really be something in the 24th century. In Trek you really don't see many disabled people. You have Geordi being blind and needing the Visors, and you have Barclay with a stammer, besides them I can't think of any other character with some sort of disability. Were there any others??
I have noticed that, of those diseases that are shown to be incurable, quite a number of them (I can't speak to the proportion) seem to be neurological in origin, which suggests to me that's probably one of the areas that 24th-century medicine still has not fully tamed.
It is mentioned (though we're never shown this) that irreversible nerve damage can result from being stunned with a phaser too many times. At least in my own writing, I have expanded upon this and made "stun-shock" (one of my names for it) an iconic malady of 24th-century warfare much as trench-foot was for the soldiers of WWI and WWII.
We have also seen other incurable neurological disorders in several species, such as Irumodic Syndrome, Bendii Syndrome, and Yarim Fel Syndrome (the last of which involves the central nervous system among other things--I personally place my bets on this being an autoimmune disorder). It is interesting to note that at least in humans, we have
not had mention of Alzheimer's, Parkinson's, or other well-known neurological disorders of our time. This suggests to me that either new problems are being encountered as the human lifespan increases, or that the conditions of space travel and general 24th-century living bring with them a different set of risks than those to which we are exposed. (For instance, could there be effects of warp travel? Unproven, I know, but just a random example.)
Poor Travis.
