The main and interactive effect of oral reading rate on the frequency of stuttering

Twenty-four adults participated in a 2 (group) by 3 (rate) factorial study designed to determine the main and interactive effects of speech rate during reading on the frequency of stuttering. In this regard, the participants orally read three passages, one at their normal rate, one that was 30% faster than this rate, and one that was 30% slower. Rate was controlled by means of a computer software program, and passage order and reading rate were counterbalanced. The main effect of rate was significant. There was statistically more stuttering in the fast rate condition than in either the normal or slow rate condition. However, the frequency of stuttering in the normal and the slow rate conditions was not significantly different. Analysis of the experimental data of the eight participants who stuttered the most and the eight who stuttered the least, during base-rate oral readings, evidenced the presence of an interaction between group and rate. Those who stuttered the most showed a statistically significant increase in stuttering between the slow, normal, and fast rate conditions. In contrast, there was no significant difference in frequency between any of the three conditions for the group of eight participants who stuttered the least. These findings suggest that the extent to which rate affects fluency is a function of the degree to which stuttering is displayed. This possibility warrants consideration in relation to the use of rate management procedures.