Thesis Title

Clinical Feasibility of the MMN as a Correlate of Behavioral Discrimination in Normal Hearing Adults

Date of Graduation

Spring 2008

Degree

Doctor of Audiology

Department

Communication Sciences and Disorders

Committee Chair

Letitia Walker Black

Keywords

mismatch negativity, duration, electrophysiological measures, behavioral discrimination, normal hearing adults

Subject Categories

Communication Sciences and Disorders

Abstract

The purpose of this investigation was to determine the feasibility of using the MMN clinically to objectively evaluate behavioral discrimination. Twenty normal hearing young adults participated. Four different oddball conditions with differing levels of discriminability/difficulty were presented in an oddball paradigm. Standard stimuli were 75 ms, while targets were either 25, 35, 50, or 65 milliseconds in duration. Although MMNs decreased in amplitude and increased in latency as the difference between the target and standard stimuli decreased (discrimination became more difficult), no individual exhibited an MMN in all 4 test conditions. There was no clear relationship between the level of difficulty of the stimulus contrast condition and the presence or absence of MMN responses. For the MMN to be considered a clinically useful correlate of behavioral discrimination, responses should have been minimal/absent for the most difficult contrast, which approximated the behavioral threshold. Further, responses should have been present in all listeners for the other 3 contrasts. The lack of a relationship between contrast difficulty and MMN presence indicates that the MMN is not a clinically useful tool. At this time, it is not recommended for clinical use.

Copyright

© Angela Marie Higdon

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Dissertation/Thesis

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