Reduced blood flow in brain area causes stuttering: study

 Scientists, including one of Indian origin, have found that reduced blood flow in a brain region linked to speech production causes people to stutter, an advance that could lead to new therapies to treat the condition.

Researchers at Children's Hospital Los Angeles in the US demonstrated evidence of a common underlying lifelong vulnerability in both children and adults who stutter.

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.

Such a study of resting blood flow, or perfusion, has never before been conducted in persons who stutter, said Bradley Peterson, from University of Southern California.
The flow study suggests that disturbances in the speech processing areas of the brain are likely of central importance as a cause of stuttering.

According to Peterson, the research provides scientists with a completely different window into the brain.

The researchers were able to zero in on the Broca's area as well as related brain circuitry specifically linked to speech, using regional cerebral blood flow as a measure of brain activity, since blood flow is typically coupled with neural activity.

"When other portions of the brain circuit related to speech were also affected according to our blood flow measurements, we saw more severe stuttering in both children and adults," said Jay Desai, a clinical neurologist at CHLA.

"Blood flow was inversely correlated to the degree of stuttering - the more severe the stuttering, the less blood flow to this part of the brain," said Desai.
The study was published in the journal Human Brain Mapping.