I wonder if it's any relation to other heightened sensitivities, such as to bright light (compared to how other people handle it), lots of competing sounds (large loud halls full of people having independent conversations), and just general hyper-awareness of everything around oneself.
Whether it's accepted or not as "a thing", the book "The Highly Sensitive Person" did mostly describe me. I read the book only recently, so I didn't develop the sensitivities as a result of reading about them :).
It is important to stress that the mechanism described are completely disconnected from so-called psychological aspects "personality traits" and general sensory processing (like falling into the HSP definition). Elaine Aaron's work is remarkable from a scientific standpoint but should also encourage people to pay more attention to the type and amount of external stimuli we expose ourselves to.
The effect of being unable to follow a conversation in a noisy environment however, IS a solid indicator of the processes I describe (you might want to look up "hidden hearing loss" - Kujawa & Libermann have published on this phenomenon).
Whether it's accepted or not as "a thing", the book "The Highly Sensitive Person" did mostly describe me. I read the book only recently, so I didn't develop the sensitivities as a result of reading about them :).