Principles and Methods for Psychoacoustic Evaluation of Tinnitus.

Tinnitus, the perception of sound in the absence of a physical sound in the environment, is highly heterogeneous. It varies in its etiology, characteristics, and impact on an individual's life. The sound is commonly described as "ringing," "buzzing," "crickets," "hissing," "humming." Tinnitus can be acute or chronic, mild or disabling. It can be perceived unilaterally or, more commonly, bilaterally. The sound and its location differ from person to person and fluctuate in the same individual over a certain period of time. This heterogeneity in characterization has important implications for research and clinical practice. Identifying patterns in how tinnitus sounds and its relationship to hearing may aid in identifying different forms of tinnitus and revealing their underlying mechanisms. However, the subjective nature of characterizing tinnitus makes it difficult to reliably define and measure. This chapter will focus on reviewing the psychoacoustic assessment of tinnitus, its relationship to cognitive and behavioral aspects of tinnitus, and its neuropathophysiology. In particular, it will describe the heterogeneity of tinnitus and tinnitus matching, and how individual variability in measures may be used to guide treatment and as a prognostic factor.