A multidimensional description of stuttering using a 2 x 2 performance matrix

Date of Completion

January 1999


Health Sciences, Speech Pathology




The goal of this research was to provide a description of stuttering behavior as a multidimensional event. Past research has shown that stuttering varies in response to changes in speech rate (a temporal variable) and changes in articulatory complexity (a spatial variable). However, past descriptions of stuttering have failed to experimentally examine the interaction of these variables in a multidimensional fashion. In the present study, a 2 x 2 skill performance matrix was used to examine the interaction between speech rate and articulatory load (length of utterance) in twenty adult males who stutter. Twenty normally fluent adult male speakers served as experimental controls. Participants were audio and video recorded while producing one spontaneous speech task and speech produced during six controlled speaking tasks. The controlled speaking tasks involved reading lists of words, phrases, and paragraphs at a steady habitual speaking rate and again at variable speaking rates (slow, habitual, and fast). Three 2 x 2 matrix analyses were used to compare words to phrases, words to paragraphs, and phrases to paragraphs. The results clearly differentiated the normally fluent speakers from the stuttering individuals. ANOVA testing and correlation analyses also indicated that increases in articulatory load and speaking rate both led to increases in disfluency in the stuttering individuals. This breakdown in fluent speech production may have been related to the spatio-temporal characteristics of the speaking task. However, the method of calculating disfluency appears to play a critical role in interpreting the results. Breath groups and locus of stuttering appear to be relevant factors when comparing percent disfluency between utterances of various lengths. The implications of these findings with regard to diagnostic protocols and clinical management are discussed. ^