Brain develops abnormally over lifespan of people who stutter

A region of the brain thought to control speech production develops abnormally in children who stutter - a pattern that persists into adulthood, according to new University of Alberta research.

In the first study to use MRI imaging to examine brain development in both children and adults who stutter, researchers at the U of A's Institute for Stuttering Treatment and Research (ISTAR) found abnormal development of grey matter in Broca's area, the region of the frontal lobe responsible for speech. It was the only abnormality found in the 30 regions of the brain the research team investigated.

"In every other region of the brain we studied, we saw a typical pattern of brain matter development. These findings implicate Broca's area as a crucial region associated with stuttering," said Deryk Beal, ISTAR executive director and an assistant professor in the Faculty of Rehabilitation Medicine.

Beal's team, which included collaborators from the University of Toronto, studied MRI images of the brains of 116 males between the ages of six and 48 years--both the largest group and widest age range for such a study. Roughly half the participants stuttered; the rest served as a control group.

Brain abnormality persists with age in people who stutter

The research team observed a steady, and expected, decline in the cortical thickness of grey matter in the control group--a decline not observed in people who stutter. This decline in thickness, Beal explained, is actually a good thing because it reflects how the brain gets more efficient as we age, requiring fewer neural resources.

Aphasia is the term used to describe an acquired loss of language that causes problems with any or all of the following: speaking, listening, reading and writing. Some people with aphasia have trouble using words and sentences (expressive aphasia). Some have problems understanding others (receptive aphasia). Others with aphasia struggle with both using words and understanding (global aphasia). Aphasia can cause problems with spoken language (talking and understanding) and written language (reading and writing). Typically, reading and writing are more impaired than talking or understanding. The severity of the aphasia depends on the amount and location of the damage to the brain. Broca’s (expressive or motor) Aphasia

Damage to a discrete part of a the brain in the left frontal lobe (Broca’s area) of the language-dominant hemisphere has been shown to significantly affect use of spontaneous speech and motor speech control. Words may be uttered very slowly and poorly articulated. Speech may be labored and consist primarily of nouns, verbs or important adjectives. Speech takes on a telegraphic character. People suffering from Broca’s aphasia have great difficulty with repetition and a severe impairment in writing. In some patients, however, the understanding of spoken and written language may be relatively well-preserved. The non-fluent variant of primary progressive aphasia (nfvPPA) is a type of expressive aphasia.