That's why I think the connection has something to do with the Oaths - and why they afflict the skin of the entire body. What is very noteworthy is that RJ answered a question about Shielding thusly: "A Shield is placed not on one point around a channeler, but around them in multiple dimensions..." This seems to indicate that the connection, if manipulated in a certain way, could result in an affect which would afflict the entire body. I.E. If the Binder worked on the connection, the connection would cause the entire body (or in this case, the skin) to have some form of reaction.



Another poster had remarked that the Forsaken believed the Dark One could grant them immortality because they had not aged. We have to assume that they noticed a difference before they Forsook the Light and after they pledged their souls to the Dark One. Maybe the black cables was not only how the Dark One kept tabs on them, but also how It laid claim to their souls? After all, it wasn't until after Rand destroyed Asmodean's cable that Asmodean staggered as if defeated...almost as if he felt his connection to the Dark One, his immortality and the Dark One's ownership of his soul, directly affected. A little later, the Dark One seems unsure as to what happened to him, whereas the Dark One never mused about the whereabouts of Demandred or Moghedien like the Forsaken did. Perhaps It could keep track of the Forsaken via their souls, and didn't lose track of them until they were balefired or lost their connection to them.