Effects of Timing Training on Stuttering Severity and Motor Timing in Children Who Stutter

Stuttering is caused by the destruction of spatial and temporal control of the movements necessary to produce speech fluency. People who stutter act differently in control of the variability, speed and timing of speech movements at the time of speaking fluently. Physiological evidence suggests that the mechanisms of motor control for speech production and limb movements have the same nervous structures. Accordingly, in the present study, the researchers decided to use a motor timing intervention program assuming that by practicing this task, people who stutter can get the timing or ability to synchronize themselves with each move or the ability to accurately repeat the motor task with the rhythm. In addition, with the help of intrinsic (or emergent) timing processes, they can also transfer this probable improvement of timing stability during the implementation of motor tasks assignments to oral–motor tasks.

A quasi–experimental study with a pre–test post–test design was conducted on 14 children (10 boys and 4 girls) ranged between 4–6 years of age. The participants were recruited conveniently and assigned randomly to two groups of experimental and control. The experimental group underwent an eight–week sequential motor timing training. The Audacity and Stuttering Severity Instrument–Fourth Edition tests were used in order to measure the stuttering severity and motor timing, respectively. The data were analyzed using the covariance analysis.

Analysis of covariance showed that by controlling the effect of pre–test, there was a significant difference between the mean scores of motor timing and the stuttering severity of children in both groups, and the average scores of motor timing (p<0.001) and stuttering severity (p=0.018) in the experimental group were significantly lower than the control group.

Based on the findings of this study, timing training improved mental timing and, as a result, stuttering severity decreased in children who stutter. In these children, speech and non–speech movements control processes had the same nervous structure. Weakness in the speech and non– speech abilities of people who stutter may therefore be due to defect in the timing mechanisms and impact of timing training on the mental timing or in fact same intrinsic (or emergent) timing processes improved the speech and reducing stuttering severity in these children.