What is neurogenic stuttering?
Neurogenic stuttering is a fluency disorder that is a result of damage to the nervous system. In order to have neurogenic stuttering, the person must be someone who did not stutter previously and then had some damage to the nervous system; whether it was the brain or spinal cord. The person stutters as a result of the damage to the nervous system. It might occur following a stroke, brain trauma, surgery, or drug use. It may involve one or both hemispheres of the brain, depending on the damage that was done or where the stroke or lesion happens. There must be damage to the nervous system for neurogenic stuttering to occur.
With neurogenic stuttering there is a high frequency of words stuttered. The dysfluency rate tends to be very high but there will not be many, if any secondary behaviors. Dysfluencies will occur on initial, medial, and final sounds as well as on content and function words. The speaker is not usually anxious about their speech.
There is no real adaptation effect. The adaptation effect is when a person is given the same passage to read over and over again; he/she will stutter less and less with each reading. Adaptation is typically seen in individuals with childhood onset stuttering but not with neurogenic stuttering. For example, if a person with neurogenic stuttering was asked to read a passage five times, he would stutter about the same way each time. His rate of stuttering would not greatly decrease each time like it would for someone who has childhood onset stuttering.
There is also an interesting symptom called “final sound dysfluency”. If a child repeats the final sound of words (e.g., “I went to the store-ore-ore”), it really stands out. From my experience, final sound dysfluency can occur for a few reasons. I have seen this occur in children with Tourette’s, obsessive-compulsive disorder (OCD), and autism spectrum disorder. I have also seen it in children who just have stuttering when they are really blocking on the next word, but are using the final part of the previous word to springboard themselves into the next word. “I went to the store-ore-ore-ore to get some milk” is very different than, “I went to the store-ore-ore.” In the second case, nothing is being said after the word, "store." That was not just word-final dysfluency; it was an utterance-final dysfluency. It suggests that this is not someone who is stuck on the next word and blocking; rather something else is going on. That should send a red flag to start looking for characteristics of other neurogenic, autistic or OCD mannerisms.
One of the other interesting findings is that someone with neurogenic stuttering often has some other speech and language component. If there is damage to neurological system to the point where it is causing the person to stutter, it is also possible that it is affecting speech sound production and language. Being able to weed that out and separate what component is based on the dysfluency, what the speech component is, and what the language component is can be helpful. For someone who has a neurogenic etiology, you may see all three of those issues and will work on all of them in treatment.
Craig Coleman, MA, CCC-SLP, BCS-F, is an assistant professor at Marshall University and a Board-Certified Specialist in Fluency Disorders. Coleman is currently serving as coordinator of ASHA SIG 4 (Fluency) and as a member of the ASHA ad-hoc committee to revise the scope of practice in speech-language pathology. Craig is an adjunct instructor at Indiana University of Pennsylvania and Co-Director of the Stuttering U. summer program for children who stutter, their families, and SLPs.