Primary behaviors[ edit ] Primary stuttering behaviors are the overt, observable signs of speech disfluencies, including repeating sounds, syllables, words or phrases, silent blocks and prolongation of sounds. These differ from the normal dysfluencies found in all speakers in that stuttering dysfluencies may last longer, occur more frequently, and are produced with more effort and strain. Each of these three categories is composed of subgroups of stutters and dysfluencies.
But how much do we understand about the processes that cause stuttering?
I asked Kate about her latest work and how close we are to understanding what causes this condition What had previous research found out about the brain activity of people who stutter? Previous studies have scanned the brains of people who stutter while they speak out loud in the scanner.
Several abnormal patterns of activation are seen under these conditions: The majority of studies done previously have used overt speech production. This may or may not have included stuttered speech in the people who stutter one curious effect of scanning that we observed was a reduction in stuttering when speaking inside the scanner.
Using overt speech production raises some problems for data acquisition but, more importantly, it is not possible to tell if the abnormal patterns of speech production are a cause or a consequence of stuttered speech. How did you study brain activity in this new research?
We used functional MRI to scan the brains of people who stutter and fluent speaking control participants during three conditions: We wanted to know if the same patterns of abnormal brain activity would be seen in people who stutter even when they are not producing speech.
What differences did you find in brain activity between people who stutter and non-stutterers?
We found abnormal patterns of activation in people who stutter in auditory and motor brain areas but these patterns were different to those seen previously and during speech production. In contrast with previous findings, the auditory areas of the brain that responded to listening to other people speaking showed more activity in the people who stutter than the controls; when listening to self-produced speech this region typically had less activity in stutterers than in controls.
Together these findings suggest the reactivity of the auditory system is abnormal in stutterers. When reading, people who stutter showed abnormally reduced activity in a motor circuit that included the left inferior frontal gyrus, putamen and supplementary motor area.
The activity in this motor circuit was reduced even further when listening to speech. This circuit is involved in initiating and sequencing of movement. Even though the people in our study didn't produce any movements related to speech, this circuit is still involved in internal speech and its activity is abnormal in people who stutter.
Our findings can therefore be considered to be characteristic of the stuttering brain rather than simply reflecting differences related to stuttered speech production.
What is the next stage in your research? Next we want to look at the circuitry between the abnormal brain regions in more detail. The integration of auditory information in the motor system seems to be important for highlighting the functional abnormalities that we saw.Brain Imaging Studies.
Brain imaging studies have been done with adult stutterers but not with children who stutter. We don’t know whether the neurological abnormalities found in adult stutterers cause stuttering or were caused by stuttering, i.e., whether growing up stuttering causes a normal child’s brain to develop abnormalities.
Stutterers have abnormal brain development A Canadian study shows that children who stutter have less grey matter in regions of the brain responsible for . brain scan research has found abnormalities in the brains of stutterers and promises new treatments for stuttering using drugs and computerized devices.
differences between stutterers and nonstutterers have been found during silent or rest (Ingham, ). fluent speech, stutterer’s brains look. In a study reported in Brain & Language in , researchers including McAuley and Chang found that stutterers tested worse than controls in rhythm perception, especially for complex rhythms— when the beat is implied rather than clearly marked.
Brain Stimulation May Help Stutterers, Students, and Athletes Written by George Citroner on April 5, Recent research indicates that sending a mild shock to the brain can help with speech problems and performance levels.
Stutterers May Have Brain Differences. Irregularities found in language and speech areas. Please note: This article was published more than one year ago. The facts and conclusions presented may have since changed and may no longer be accurate.
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