Electronic Thesis and Dissertation Repository


Master of Science




Johnsrude, Ingrid


Treatment outcomes for people with schizophrenia are more favourable if treatment starts early in the course of the disorder. Current detection methods lack specificity and do not make use of cognitive markers. We presented individuals experiencing a first episode of psychosis (FEP) and matched control participants with acoustically degraded meaningful and matched nonsense sentences to examine the degree to which people reported words that were not actually presented. Intrusion errors were counted when reported words were unrelated to words in the original sentence. Intelligibility (measured as words reported correctly) did not differ between groups but intrusion errors were more frequent at the lower SNR, for nonsense sentences, and in the FEP group when item variability was controlled. Our approach may hold promise for early identification of a psychotic prodrome.