According to a new study, in adults who have stuttered since childhood the processes of auditory-motor integration are located in a different part of the brain to those who do not stutter.
Dr. Nicole Neef and Dr. Martin Sommer from the University of Goettingen, together with Dr. Bettina Pollok from the University of Duesseldorf, studied the performance of a group of adults who stutter, as well as a control group of adults who do not stutter, in a finger tapping exercise.
They used Transcranial Magnetic Stimulation (TMS) to interfere temporarily with brain activity in the dorsolateral premotor cortex while the participants tapped their fingers in time with the clicks of a metronome.
In the group of non-stutterers, disturbing the left premotor cortex impaired the finger tapping, but disturbing the right premotor cortex had no effect, the researchers said.
In stuttering adults, the pattern was reversed: the accuracy of finger tapping was affected by disturbing the right hemisphere, and unaffected when disturbing the left.
Researchers concluded that a reorganisation in the brains of those who stutter could occur to potentially compensate for subtle white matter disturbances in other parts of the brain.
The study was recently published in Elsevier's Cortex.