[ti:Researchers Look for Biological Reasons Behind Stuttering] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]Researchers are looking into the biological causes of stuttering. [00:05.32]Stuttering is a speech problem that causes the speaker [00:09.12]to repeat the beginning sound of some words. [00:13.32]For centuries, people have feared being judged for stuttering. [00:17.64]It is a condition often misunderstood as a psychological problem [00:22.64]caused by things like bad parenting or emotional trauma. [00:27.28]But research presented at a recent science conference [00:31.28]explores its biological causes: genetics and brain differences. [00:37.20]Stuttering affects 70 million people around the world, [00:41.12]including U.S. President Joe Biden. [00:44.36]Biden has spoken publicly about being bullied [00:47.80]by classmates for his speech problem. [00:50.76]He has said that overcoming his stutter [00:53.60]was one of the hardest things he ever did. [00:56.92]After a campaign event in 2020, he met a New Hampshire teenager [01:02.36]who also stuttered, Brayden Harrington. [01:05.60]They ended up talking for an hour. [01:08.56]Living with a stutter has not been easy, Brayden told The Associated Press. [01:14.64]"I want to carry on what Joe Biden said to me," he said. [01:18.52]"That this does not define you [01:20.56]and that you can be much more than you see yourself as." [01:25.40]Stuttering has been recorded as far back as ancient China, Greece and Rome. [01:31.20]But no one really knew what caused it until modern genetic science [01:36.44]and brain imaging helped provide some answers. [01:40.56]Researchers identified the first genes [01:43.52]strongly linked to stuttering more than a decade ago. [01:47.64]Imaging studies looked at brains of adults and older children. [01:52.48]And in the last few years, University of Delaware researcher Ho Ming Chow [01:58.76]started looking at 3- to 5-year-olds. [02:02.20]That is around the age many kids begin stuttering, [02:06.08]with about 80 percent outgrowing it. [02:09.08]Chow said the imaging shows small brain differences [02:13.44]in young children who keep stuttering, [02:15.88]compared with those who recover or those who never stuttered. [02:20.00]He discussed his research earlier this month [02:23.32]at a conference of the American Association for the Advancement of Science. [02:28.00]For example, Chow and his team [02:31.48]found that genetic mutations related to stuttering [02:34.96]are linked to structural problems in the corpus callosum [02:39.16]and thalamus areas of the brain. [02:41.68]The corpus callosum is an area that connects the two sides of the brain [02:46.76]and helps them communicate. [02:48.60]The thalamus sends sensory information to other parts of the brain. [02:53.48]Past research has also linked stuttering to the basal ganglia, [02:58.76]a group of brain structures involved in body movements. [03:02.56]Though several genes may be involved [03:05.96]and the exact genetic causes may vary by child, [03:09.68]"they probably affect the brain in a similar way," Chow said. [03:15.36]Still, many people incorrectly believe that people stutter [03:19.40]because they are nervous or suffered childhood trauma. [03:23.00]Some also think stutterers could stop if they just tried harder. [03:28.76]"We have a long way to go" to change such beliefs, [03:32.32]said University of Maryland researcher Nan Bernstein Ratner. [03:38.16]Speech therapy is currently the main way to treat stuttering. [03:41.96]But the medications now being tested [03:45.32]could be approved for stuttering in the next few years. [03:49.36]Studies have suggested that stuttering may be related [03:52.72]to high levels of a chemical in the brain called dopamine. [03:56.76]Some medicines reduce dopamine activity or block its action. [04:02.68]Holly Nover is a speech pathologist [04:05.76]and member of the National Stuttering Association. [04:08.72]She grew up trying to hide her stutter. [04:12.32]Her 10-year-old son, Colton, also has a speech problem. [04:17.16]She said many people will surely be interested [04:20.20]in trying stuttering medications. But not her. [04:23.92]She is happy with her life as it is [04:27.04]and says she has accepted her stuttering. [04:30.20]If Colton were struggling [04:31.96]and wanted to try medication as a teenager, however, [04:35.48]she would be open to the idea. [04:38.28]Brayden, who is now 14, does not plan to try medication. [04:43.64]Taking medicine is "just taking away a part of you... [04:47.32]taking away part of your personality," he said. [04:51.44]I'm Dan Novak. 更多听力请访问51VOA.COM