Well, matter of perspective ... I don't think he has much to offer anyone here, unless one can relate to this truly ridiculous posting ...
"Yes. Maybe it is something that has a different name like jitter, timing issues, high frequency glare or distortion. When I experience it, it reminds me of a very high buzzing like a mosquito but at an even higher frequency and I can't relax and become involved with the music when I hear it in a system. Some people are just less, or not at all, susceptible to it. I don't know why. I don't know if it can even be measured. Perhaps that is why some people doubt it even exists, or they proclaim that it does not.
I once suffered from temporary tinnitus after going to a rock concert without earplugs. For two days I had this ringing/buzzing in one ear and it drove me crazy. I'll never do that again. For me, the sensation is similar, but it is a higher frequency with digital fatigue overlaying all the music in some systems. It does not seem to be inherent in the digital format, because I have heard three examples of digital replay that does not have it. So I think it is dependent upon implementation, as Al M suggested.
If digital fatigue can't be measured, and it can't be heard by a particular individual, then it will be very difficult to convince him that you hear it. On the other hand, I do hear most or all of the inherent flaws in vinyl, and I am not as bothered by them. I think it is because in very good analog front ends, most of these issues are more or less addressed.
I wonder which is worse: jumping up in one's seat every time he hears a pop or tick from an LP (a rather funny image) or losing interest in the music or even having to leave the room after half an hour because of listening fatigue?"
How anyone can possibly justify comparing tinnitus to digital glare is beyond me, that crap is best left, and more "appreciated" at WBF.