Causes of stuttering?

Dear Murray,

Unfortunately, experts don’t fully understand what causes a stutter to occur and why it persists for some and resolves for others. In general, researchers agree that stuttering arises from a combination of genetic and environmental factors. Beyond this, not much else is known for sure. Read on for the rundown on what researchers do know.

Before more extensive studies were conducted, stutters were thought to arise from emotional or psychological trauma, called psychogenic stuttering. Some experts now believe that psychogenic stuttering is extremely rare, while others don't accept it as an explanation at all. In fact, most research concludes that emotional reactions to a preexisting stutter and avoidance behaviors may potentially exacerbate the stutter. With that said, the two common types of stuttering include:

• Developmental: This common type of stuttering is likely experienced by just about everyone. It occurs when a roadblock forms in the language development process. Small children learning to speak often repeat a letter sound, word, or phrase ("and ummm,... and ummm,... and ummm") as they mentally search for the next thought or word. This type of stutter often occurs between the ages of two and five, with most individuals outgrowing it as language skills and muscle coordination become more practiced and fluent. It’s possible that developmental stutters occur as a result of the brain learning to work as fast as the muscles in the face and mouth.
• Neurogenic: This type of stuttering usually occurs, in adults, after a traumatic brain injury or stroke. Speech difficulty arises from signaling problems between the brain and the nerves or muscles used when talking.

It’s also possible that there’s a genetic component to stuttering. Research has found mutations in three genes among those who stutter — GNPTAB, GNPTG, and NAGPA specifically. While genes may be implicated, they don’t explain why stuttering persists or describe why it might happen at different points in a person’s life. However, researchers with the National Institute on Deafness and Other Communication Disorders (NIDCD) identified four potential genetic variants that are responsible for proteins that help direct traffic within a cell. These proteins make sure that cell components get to the right location at the right time. If these proteins are altered, it could create difficulties with speech fluency. All that being said, more research is needed in order to conclusively support this theory.

Regardless of the cause, people who’ve had problems with stuttering for more than six months, avoid speaking, or experience emotional distress due to their stuttering may want to consult a speech-language pathologist. A professional will be able to use clues from the onset and history of stuttering to pinpoint the cause and assess the individual’s speech and language ability to develop a treatment plan. Strategies to help reduce stuttering and tension when experiencing a stuttering block are often taught and then practiced at home. These strategies may include appropriate use of pauses, slowing the rate of speech, and identifying habits and behaviors used to avoid stuttering. Treatment is successful in many cases, and with the proper tools and resources, people who stutter may lead happy and productive lives.

For more information about diagnosis and treatment, you can review the NIDCD website. They also have some information regarding ongoing research. It's great that you're asking these questions as new research is continuing to come out. To get more information about support groups, self-help strategies, and additional resources, you may want to visit the National Stuttering Association and the Stuttering Foundation websites. To find a speech-language pathologist near you, check out the American Speech-Language-Hearing Association’s website.