Stuttering may result at least in part from anatomical abnormalities in the brain, according to a new study published in today's issue of Neurology. For a long time, scientists presumed that emotional factors caused Persistent Developmental Stuttering (PDS), but a team of researchers, led by Anne Foundas of Tulane University, has discovered interesting patterns that suggest otherwise in the brains of PDS patients.

The scientists took MRI brain scans of 32 people and discovered that the right and left temporal lobe were significantly larger in the 16 test subjects who had PDS. To determine whether men or women--or righties or lefties--were more prone to PDS, the team chose 12 right-handed PDS patients (three women and nine men) and four left-handed men--a combination that approximates the distribution of PDS patients in the general population.

They concluded that the two factors are correlated with several anatomical features: the Pars Triangularis, for example, was considerably larger in left-handed patients than in right-handed ones. And the Pars Triangularis and Pars Opercularis were larger in men than in women. According to the researchers, their study shows that physical anomalies in the speech-language areas of the brain make people more likely to develop a stutter.