Publication Date


Document Type


First Advisor

Chung, King

Degree Name

B.S. (Bachelor of Science)

Legacy Department

School of Allied Health and Communicative Disorders


The effects of recreational drugs on hearing sensitivity were examined in a previous study and yielded negative results. As speech understanding with background noise is a complex task and recreational drugs affect brain functions, this research project explored if drug abuse had a long-term effect on users’ ability to understand speech in noise. Speech recognition abilities of two former drug users and four non-users were tested when participants listened using 1) the left ear only, 2) the right ear only, and 3) both ears. The signal-to-noise ratio of speech and noise was set at -4 dB. The participants ranged from 23 to 54 years old. Results indicated both users and non-users had similar speech recognition score patterns. The highest scores were obtained using both ears and the lowest scores using the left ear only. Scores also decreased with age and the presence of hearing loss. Future studies need to match the age of the participants and to control the audibility of the signal for people with hearing loss.


Includes bibliographical references.


10 pages




Northern Illinois University

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