Understanding Speech in Background Noise

Participants will be seated comfortably throughout the experiment. Stimuli involving speech mixed with background noise at various levels will be played back from a PC and presented diotically over headphones at a level of approximately 65 dBA in each ear. Subjects will be instructed to repeat back each sentence, guessing if unsure. The experimenter will record component words correctly recalled. Sentences will not be repeated, and only exact-word matches will be accepted. A 10-minute practice stage will precede testing, in which subjects will hear example stimuli and sentences not used for testing. Test duration will not exceed two hours. Multiple groups of listeners will be employed, and the basic experimental protocol for each participant will be identical, differing only with regard to differences in the frequency content of the speech and/or the background noise present. Participants will be randomly assigned to groups.