PROJECT SUMMARY This research will examine the ability of listeners to make multiple rapid judgments about non-speech auditory stimuli. These stimuli will vary simultaneously and/or sequentially on three dimensions: amplitude, frequency and perceived location. Recent work on the ability of hearing-impaired listeners to process rapid, noisy speech (e.g. McCoy et al., 2005) has identified deficits that exist independent of the ability to understand and remember more clearly presented speech. This study will examine the processing of rapid and simultaneous stimulus changes in a design that does not require listeners to make use of any specific language-related mechanisms. The hypothesis to be tested is that the ability to make multiple judgments depends on short-term memory and the availability of processing resources. Specific aims involve 1) examining the role of temporal relationships between stimuli (simultaneous vs sequential), 2) comparing the ability to make multiple judgments within a frequency region with the ability to do so across frequencies and 3) examining the hypothesis that different types of interference occur when listeners try to make several judgments in sequence as opposed to when they must hold the target stimuli in sensory memory to make a comparison with a delayed cue. RELEVANCE Listeners in constantly changing environments often experience more difficulties than when the same noise level is present but the environment is not changing so rapidly. This is a particular problem for those with even mild hearing loss. By improving our understanding of the processes by which a rapidly changing auditory environment is analyzed, we hope to improve our ability to create appropriate therapies and devices to reduce the difficulties hearing-impaired listeners experience.