The Clinical Detection of Auditory Recruitment

Introduction THE clinical detection of recruitment has aroused considerable interest because of its value in distinguishing nerve deafness from middle-ear deafness, and because it measures hearing ability over a range of intensity well above threshold. A discussion of its diagnostic applications will be found at the end of this paper. Many different recruitment tests have been developed but interest in this subject is so recent that there has been little opportunity to establish their reliability and to find out more about the phenomenon. An earlier article gave a brief description of recruitment, of the established methods of recruitment testing, and of some of the newer tests under development. Recent research has proved the validity of some of these newer tests which have been developed into short, reliable tests, easy to carry out clinically. The purpose of this paper is : (1) to describe the recruitment phenomenon, (2) to explain the principles of recruitment testing, (3) to describe the test methods in use, (4) to describe some controlled experiments on one of the recruitment tests developed by the authors, (5) to point out some pitfalls in recruitment testing, (6) to compare the relative merits of the various test methods, and finally (7) to discuss the clinical uses of recruitment testing.