I have read a number of times that the sloth bear does not have the hearing normally associated with bears. I have read also that the sloth bears are "intense" animals, much as are badgers, wolverines, etc. and become highly focused in their daily food gathering activities, such as opening bee-hives and termite lodgings. Together, these traits render the sloth bears prime candidates for surprise encounters and especially so in areas of denser forest and undergrowth. People and sloth bears, unknowingly get themselves in the same space and bears the world over are bad news when startled. I have an old Frank Buck movie, filmed in Malaya back in the 1930's. In his narrative, he says similar:
"Sloth bears, come upon in the jungle, are easily startled and the locals fear them more than tigers. Those long claws make quick work of any man." "Walk through any village here and you'll see the mangled faces of the survivors of savage encounters with the sloth bear"