Date of Award

Spring 2007

Document Type


Degree Name

Doctor of Audiology (AuD)


School of Communication

First Advisor

Sheryl Shoemaker


An important aspect of processing auditory stimulus is the ability to localize the source of a sound within the environment. Localization has been defined as the ability to determine the direction of sound (Tonning, 1975; Cranford, Boose, & Moore, 1990; Middlebrooks & Green, 1991; Cranford Andres, Piatz, & Reissig, 1993; Lorenzi Gatehouse, & Lever, 1999; Abel, Giguere, Consoli, & Papsin, 2000). Previous researchers have used a variety of test stimuli, test environments, loudspeaker arrays, and ages and numbers of subjects to measure the ability to localize sounds. Despite the obvious need for individuals to identify the specific location of a sound source, the variety of approaches suggests that there is no standard process for measuring localization abilities. As there is no gold standard for localization assessment, it is difficult to compare previous studies of localization. Therefore, a standardized protocol for measuring localization abilities would attenuate the need to vary testing procedures while determining an individual's ability to identify sound sources as part of a complete audiological assessment.

Forty male and 40 female adults, ages 21 to 60 years with normal hearing sensitivity and normal temporal processing abilities, will be used as subjects in this study. A protocol for localization testing developed by the primary investigator will be used to measure the subjects' localization abilities.

All testing will be completed in an IAC sound treated room, using eight sound field speakers. Each speaker will be arranged symmetrically on the wall, positioned within the horizontal plane with 45 degree intervals between each. The Central Institute for the Deaf Everyday Sentences (Alpiner & Schow, 2000; Healy & Montgomery, 2006) will be used as test stimuli. Five test conditions, one quiet and four noisy listening conditions, will be used to identify elicit localization. Of particular interest is the direction at which a subject can localize a speech stimulus accurately in the presence of background noise.