During the 1990s , Maguire and colleagues were among the first to use a certain kind of brain scan , positron emission tomography , on people who stutter . They found too much dopamine activity in these people ’ s brains . That extra dopamine seems to stifle the activity of some of the brain regions that Chang and others have linked to stuttering .
Backing up the dopamine connection , other researchers reported in 2009 that people with a certain version of the D2 receptor gene , one that indirectly enhances dopamine activity , are more likely to stutter .
So Maguire wondered : Could blocking dopamine be the answer ? Conveniently , antipsychotic drugs do just that . Over the years , Maguire has conducted small , successful clinical studies with these medications including risperidone , olanzapine and lurasidone . ( Personally , he prefers the last because it doesn ’ t cause as much weight gain as the others .) The result : “ Your stuttering won ’ t completely go away , but we can treat it ,” he says .
None of those medications are approved for stuttering by the US Food and Drug Administration , and they can cause unpleasant side effects , not just weight gain but also muscle stiffness and impaired movement . In part , that ’ s because they act on the D2 version of the dopamine receptor . Maguire ’ s new medication , ecopipam , works on the D1 version , which he expects will diminish some side effects — though he ’ ll have to watch for others , such as weight loss and depression .
In a small study of 10 volunteers , Maguire , Yaruss and colleagues found that people who took ecopipam stuttered less than they did pre-treatment . Quality-of-life scores , related to feelings such as helplessness or acceptance of their stutter , also improved for some participants . Ecopipam isn ’ t the only treatment under consideration . Back in Michigan , Chang hopes that stimulation of specific parts of the brain during speech could improve fluency . The team uses electrodes on the scalp to gently stimulate a segment of the hearing area , aiming to strengthen connections between that spot and the one that manages speech movements . ( This causes a brief tickle sensation before fading , Chang says .) The researchers stimulate the brain while the person undergoes traditional speech therapy , hoping to enhance the therapy ’ s effects . Because of the Covid-19 pandemic , the team had to stop the study with 24 subjects out of a planned 50 . They ’ re analyzing the data now .
Connecting the dots
Dopamine , cellular waste disposal , neural connectivity — how do they fit together ? Chang notes that one of the brain ’ s circuits involved in stuttering includes two areas that make and use dopamine , which might help explain why dopamine is important in the disorder .
She hopes that neuroimaging can unite the different ideas . As a first stab , she and collaborators
Ten adult volunteers who stuttered were given ecopipam , a drug that blocks one version of the dopamine receptor , for 8 weeks . They stuttered significantly less when they were on the drug than they had before the treatment .
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