Short-term intervention alters neural architecture of stutterers

By MedWire Reporters

A short-term intervention in patients who stutter can help reorganize the intrinsic functional architecture of speech-language processes, a Chinese study shows.

The research, published in Neurology, showed that the midline of the cerebellum appears to be the site responsible for the reorganization as it showed significant changes from pre- to postintervention.

"These results show that the brain can reorganize itself with therapy, and that changes in the cerebellum are a result of the brain compensating for stuttering," lead researcher Chunming Lu (Beijing Normal University, China) said in a press release accompanying the study.

Persistent developmental stuttering (PDS) affects 1% of the adult population and while decades of neuroimaging research have identified various functional and structural abnormalities in these patients, it is not known what neural anomalies are responsible for stuttering and what are compensatory.

In this small study, the researchers provided therapy to 28 patients who stuttered, asking them to repeat two-syllable words and to read words presented to them visually. Another 13 patients with PDS did not receive any therapy and 13 fluent controls were included in the analysis.

Using magnetic resonance imaging (MRI) scans, the subjects underwent screening prior to and one week after the intervention in order to assess the resting-state functional connectivity (RSFC) and cortical thickness.

Before the intervention, the researchers documented significant RFSC and cortical thickness reductions in the left pars-opercularis (PO) compared with the fluent controls. By contrast, the RSFC was significantly increased in the cerebellum of stutterers compared with those who did not stutter.

After just one week of treatment, there was an effective reduction in stuttering in the PDS patients. On MRI, the intervention reduced the activity of the RSFC in the cerebellum to the level of fluent controls.

Importantly, Lu and colleagues report that the treatment was specific to the PDS patients as it was not observed in healthy controls without the speech deficit.

The therapy was ineffective at altering the RSFC and cortical thickness in the left PO, which remained at levels recorded prior to the intervention. According to the researchers, these results show that PO structure of the brain is altered in people with stuttering.

Previous studies have shown that the degree of activation of the left PO in normal speakers and damage to the area in aphasic speakers is associated with performance in speech performance tasks. It is also associated with lexical selection, phonologic processing, and phonetic encoding.

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