Event-Related Potentials Distinguish Fluent and Stuttered Speech

Abstract

Background. This study aimed to find the best possible approach to neurotherapy for stuttering. Method. Five right-handed Dysfluent Speakers and five right-handed Fluent Speakers were compared before dysfluent and fluent speech onset with electrical event related potentials. EEG electrodes were at inferior frontal, precentral, and temporoparietal locations on each hemiscalp. Participants processed two words displayed consecutively at center screen, the first or second of which was to be uttered aloud according to the subsequent command digit being 1 or 2. Results. The Fluent Speakers manifested significant left hemisphere contingent negative variations (CNVs) prior to the words and the contingency stimulus. The Dysfluent Speakers presented overall smaller CNVs that were more marked over the right hemisphere than left. This pattern was observed before both their stuttered and fluent words, with the former differing significantly from the fluent speakers hemispheric CNV pattern. Conclusion. These results indicate that dysfluent speech is related to abnormal hemispheric asymmetry. Neurofeedback therapy for persons who stutter could aim at normalizing contingent negativity asymmetry seconds prior to speech.