Summary: A new study has identified a common brain network responsible for stuttering, regardless of the cause. Researchers have found that stuttering-causing strokes and developmental stuttering both affect the same areas of the brain.
These findings could lead to targeted treatments, such as brain stimulation, to help people who stutter. The study highlights key brain regions involved in motor function and emotion regulation.
Highlights:
- Common network: Stuttering from different causes affects the same brain network.
- Key regions of the brain: Putamen, amygdala and claustrum are crucial in stuttering.
- Treatment potential: The results open possibilities for targeted brain stimulation treatments.
Source: University of Turku
Stuttering is a speech rhythm disorder characterized by involuntary repetitions, prolongations, or pauses in speech that prevent typical speech production.
About 5 to 10 percent of young children stutter, and about 1 percent continue to stutter as adults. Severe stuttering can have a profound negative impact on the affected person’s life.
“Stuttering was once considered a psychological disorder. However, through further research, it is now a brain disorder linked to the regulation of speech production,” explains neurology professor Juho Joutsa from the University of Turku.
Stuttering can also be acquired as a result of certain neurological diseases, such as Parkinson’s disease or stroke. However, the neurobiological mechanisms of stuttering are not yet fully understood and its origin in the brain remains unclear.
The results of brain imaging studies are partly contradictory, and it is difficult to determine which changes cause stuttering and which are just associated phenomena.
Stuttering located in the same brain network whatever its cause
Researchers from Finland, New Zealand, the United States and Canada have developed a new research model that could provide a solution to this problem. The study looked at people who had suffered a stroke, some of whom developed stuttering immediately afterward.
The researchers found that although the strokes were located in different parts of the brain, they were all located in the same brain network, unlike strokes that did not cause stuttering.
In addition to people who had strokes, researchers used magnetic resonance imaging (MRI) to scan the brains of 20 people with developmental stuttering. In these individuals, stuttering was associated with structural changes in brain network nodes initially identified in relation to causal lesions of stroke – the greater the changes, the more severe the stuttering.
This finding suggests that stuttering is caused by a common brain network, regardless of etiology (developmental or neurological).
The key nodes in the network identified by the researchers were the putamen, amygdala and claustrum located deep in the brain, and the connections between them.
“These findings explain well-known characteristics of stuttering, such as motor difficulties in speech production and significant variability in stuttering severity across emotional states.
“As the major nuclei of the brain, the putamen regulates motor function and the amygdala regulates emotions. The claustrum, in turn, acts as a node for multiple brain networks and relays information between them,” explains Joutsa.
The study results provide unique insight into the neurobiological basis of stuttering. Locating stuttering in the brain opens up new possibilities for medical treatment.
Researchers hope that in the future stuttering can be treated effectively, for example through brain stimulation specifically targeting the now identified brain network.
About this research news on stuttering and neuroscience
Author: Tuomas Koivula
Source: University of Turku
Contact: Tuomas Koivula – University of Turku
Picture: Image is credited to Neuroscience News
Original research: Free access.
“Localization of stuttering based on causal brain lesions” by Juho Joutsa et al. Brain
Abstract
Localization of stuttering based on causal brain lesions
Stuttering affects approximately 1 in 100 adults and can cause significant communication problems and social anxiety. It is most often a developmental disorder, but can also be caused by focal brain damage.
These latter cases may provide unique insight into the regions of the brain that cause stuttering.
Here, we investigated the neuroanatomical substrate of stuttering using three independent datasets: (i) case reports from the published literature on neurogenic stuttering acquired following stroke (not = 20, 14 men/six women, 16-77 years); (ii) a unique clinical study cohort presenting with neurogenic stuttering acquired following a stroke (not = 20, 13 men/seven women, 45 to 87 years); and (iii) adults with persistent developmental stuttering (not = 20, 14 men/six women, 18-43 years).
We used the first two datasets and lesion network mapping to test whether the lesions causing acquired stuttering corresponded to a common brain network. We then used the third dataset to test whether this lesion-based network was relevant to developmental stuttering.
In our literature dataset, we found that the lesions causing stuttering occurred in several heterogeneous brain regions, but that these lesion locations were all functionally connected to a common network centered around the left putamen, including the claustrum, the area amygdalostriatal transition and other adjacent areas.
This result was found to be specific to stuttering (P.FWE P.FWE
Within the common network of acquired stuttering, we found a significant association between gray matter volume and stuttering impact in adults with persistent developmental stuttering in the left posteroventral putamen, extending to the adjacent claustrum and at the amygdalostriatal transition zone (P.FWE
We conclude that lesions causing acquired neurogenic stuttering correspond to a common brain network, centered on the left putamen, claustrum and amygdalostriatal transition zone. The association of this lesion-based network with symptom severity of developmental stuttering suggests a shared neuroanatomy across etiologies.
News Source : neurosciencenews.com
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