Date of Award


Degree Type


Degree Name

Master of Science


Communication Sciences and Disorders


Dr. Janis Cardy

Second Advisor

Dr. Marc Joanisse


Audiovisual integration is an important process in human perception. However, it is

unclear whether auditory and visual stimuli are integrated during primary sensory processing, or following independent processing in their respective sensory cortices. This study examined 16 adult participants’ responses to simultaneously presented congruent and incongruent visual letters and auditory letter names using electroencephalography (EEG). Auditorystimuliwerepresentedinanunattendedoddballparadigm,usingthe mismatch negativity (MMN) event-related potential (ERP) component as an indicator of primary auditory processing. Participants also identified whether or not visual letters were vowels using a key press. No difference was found in the MMN across congruent and incongruent triais. However, differences in the P300 ∞mponent were observed. Behavioural data revealed that only deviant task-irrelevant congruent auditory stimuli

facilitated responses, possibly due to an involuntary attention shift toward deviant stimuli. ERP data suggested that audio visual integration of letters occurs following primary sensory processing.



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