ABSTRACT

The sources of individual susceptibility to noise-induced permanent threshold shift (NIPTS) are many, and as yet, not fully defined. At present, the ability to identify and characterize the many possible factors and their potential interactions is questionable. One variable which is easily studied is the outer ear. Its acoustics have been implicated as a potential factor in susceptibility of NIPTS. The outer ear is an acoustic resonator having frequency and gain characteristics unique to an individual which can be measured and quantified. The purpose of this paper is to trace our understanding of external ear effects in an effort to understand and minimize NIPTS.