Stuttering: Understanding the neurobiology, psychology, and treatment options

Stuttering is a speech disorder characterized by the involuntary disruption of verbal fluency. It is relatively common, with an estimated 55 million people affected by the condition worldwide. For some, the condition can be relatively mild and is barely noticeable unless one is feeling especially anxious. In more severe cases, the disorder can be virtually debilitating. Stuttering not only impairs communication, it can also have a devastating effect on one’s confidence, as well as one’s social and professional lives.

The good news is that stuttering is manageable. This is true for adults as well as children. In fact, some children may recover from the disorder without treatment by the time they reach adulthood without speech therapy or other treatment. However, there are no scientific means of predicting if a child will overcome their stutter without assistance. One should take proactive measures and not merely hope for the best.

However, before exploring treatment options, it is necessary to understand what causes stuttering. Persistent developmental stuttering, the kind that does not arise because of a singular event like a stroke or an injury that involves head trauma, does not have one cause. Rather, there are numerous genes that, if active, can increase one’s predisposition for developing a stutter.

More important, one should remember that stuttering is a symptom, not a disease, and that it rarely exists in isolation. Research has shown that it tends to occur in conjunction with a variety of other disorders: Concurrent conditions were observed in 62.8% of the 2,628 children with stutters who took part in a 2003 mail survey. These conditions included articulation disorders (33.5%), learning disabilities (15.2%), phonology disorders (12.7%), literacy disorders (8.2%), and attention deficit disorder (5.9%), among others.

What causes stuttering?

Stuttering may seem to be an issue that is largely muscular and aggravated by environmental stressors. However, recent research has found that this is not the case, and that the disorder may be similar in some regards to Tourette syndrome, a neurological disorder characterized by involuntary tics that are either verbal or non-verbal. Tourette syndrome has long been associated with elevated levels of dopamine, a chemical in the brain that is vital to the function of the basal ganglia, the network of brain structures that control movement.

Medications that address the hyperactivity of the dopaminergic system have reduced the symptoms of Tourette syndrome. When patients with stuttering disorders were provided similar medications, the effects were equally positive. This suggests that stuttering is more closely tied to Tourette syndrome than previously thought.

Dopaminergic hyperactivity has also been shown to correspond with anxiety and panic states. This suggests that episodes of high anxiety can lead to overactivity within the dopaminergic system, which in turn can make one’s stuttering more intense. If one develops social anxieties because of their stutter, this can create a positive feedback loop that increases both one’s anxiety and one’s stutter.

Dopamine may play a significant role in stuttering disorders, but studies that rely on noninvasive brain imaging techniques have revealed that there are also structural components to stuttering disorders that arise as the brain develops. These studies have shown that the right hemisphere of the brain in stutterers is hyperactive, and that this hyperactivity is likely taking place as a form of compensation because of signal misfires in the left hemisphere between the central and the frontal cortices. Surprisingly, researchers have discovered that the manner in which these parts of the brain communicate can be effectively recalibrated by introducing an external auditory signal—whether through chorus reading, metronomic reading, or singing. These external cues have been shown to allay the effects of the misfires and to cause an instantaneous reduction in stuttering.

Treatment

Treatments for stuttering may include speech therapy and talk therapy, as well as medications designed to mitigate hyperactivity of the dopaminergic system. While there are currently no medications approved for stuttering based on the hyperdopaminergic hypothesis, the same medicines that have been used to block dopamine receptors in patients with other disorders can be used.

When a medical professional prescribes a drug for a condition or demographic other than the one for which it was approved, it is often referred to as an “off label use.” This is not uncommon: A 2006 study found that 20% of all medications were prescribed off-label. These medications may restore verbal fluency to varying degrees and improve patient quality of life. However, because the rate of side effects for off-label drugs is notably higher than when these medicines are used in the manner for which they have been approved, their use should be reserved for adults who have not benefited from conventional treatments.

Because numerous factors give rise to stuttering, there is not a single, universal way to treat a stuttering disorder. Further, because stuttering rarely occurs without concurrent speech or learning disorders that may not be readily apparent, one needs to be examined by a medical professional who can diagnose what may be several conditions. Only by understanding the issue can one decide upon an effective and holistic treatment plan. Moreover, by addressing these problems simultaneously, it is more likely that one can overcome their stutter, as well as any concurrent disorders, and improve their confidence in social and professional settings.

Samoon Ahmad is a professor of psychiatry, NYU Grossman School of Medicine, and founder, the Integrative Center for Wellness. He can be reached on Twitter @SamoonAhmadMD, LinkedIn, Instagram, and Facebook.

Image credit: Shutterstock.com

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