They discovered that regional cerebral blood flow is reduced in the Broca's area - the region in the frontal lobe of the brain linked to speech production - in persons who stutter.
More severe stuttering is associated with even greater reductions in blood flow to this region.
In addition, a greater abnormality of cerebral blood flow in the posterior language loop, associated with
processing words that we hear, correlates with more severe stuttering.
This finding suggests that a common pathophysiology throughout the neural "language" loop that connects the frontal and posterior temporal lobe likely contributes to stuttering severity.