Stuttering Research Commentary #1 by HCRI

There is no doubt that stuttering is associated with specific forms of brain activity. In fact, all human behavior is mediated by brain functioning of one type or another. When we learn something new — a fact, a poem, a song or a motor skill — we do so because we have experienced reorganization of brain function.

As research scientists focus on determining the cause of stuttering, it is important to examine how the brain is involved in stuttering. Yet, it is premature to rush to the simple conclusion that the brain is “causing” stuttering.

The brain operates as a complex set of physiological systems that are, in turn, provided with an array of inputs and outputs. The research task is to develop an understanding of the complex context within which the brain functions.

The following research abstract is the first of a series provided as a service by Hollins Communications Research Institute (HCRI).  HCRI is a nonprofit Institute based in Roanoke, Virginia that has been at the forefront of stuttering research and treatment innovation since 1972.

HCRI commentary follows the abstract and is provided Ronald L. Webster, Ph.D., HCRI’s Founder and Director.

ABSTRACT: A positron emission tomography study of short- and long-term treatment effects on functional brain activation in adults who stutter.

J Fluency Disord. 2003 Winter;28(4):357-79; quiz 379-80., e Nil LF, Kroll RM, Lafaille SJ, Houle S., Graduate Department of Speech-Language Pathology, University of Toronto, Ont., Canada M5G 1V7.

Educational Objectives:

1. Use of functional neuroimaging PET in the study of stuttering;
2. Differences in neural activation between stuttering and non-stuttering adults; and
3. Effects of behavioral fluency treatment on cortical and subcortical activations in stuttering speakers.


Previous studies have shown that fluency-inducing techniques, such as choral speech, result in changes in neural activation as measured by functional neuroimaging.

In the present study, positron emission tomography was used to investigate the effects of intensive behavioral treatment, followed by a 1-year maintenance program, on the pattern of cortical and subcortical activation in stuttering adults during silent and oral reading of single words.

The results indicate changes in activation lateralisation, as well as a general reduction in over-activation, especially in the motor cortex, following treatment. The results are discussed in light of previous functional imaging studies with stuttering adults.

HCRI Comment:

This article illustrates clearly that differential brain function is seen in stutterers before and after participation in a therapy derived from one of our earlier therapy systems. The essential point is that post-treatment, brain activity in stutterers was closely similar to the brain activity of fluent speakers.

For more information about HCRI’s work in the field of stuttering and treatment programs, visit .