What Stuttering Therapies Are Effective?
Three "meta-reviews" examined more than 200 published studies of stuttering treatments published between 1970 and 2005:
- 31 studies of pharmaceutical treatments for stuttering. [1]
- 17 studies of altered auditory feedback (AAF) treatments for stuttering. [2]
- 162 studies of "behavioral, cognitive, and related approaches," [3] mostly clinic-based stuttering therapies.
The meta-reviews of medications and technology are covered in other articles on this website so this article will focus on the meta-review of clinic-based therapies.
The main conclusion of the review was that most stuttering treatment research is poor quality. Studies were assessed on a five-point scale for "trial quality," i.e., how scientific the study was. This included whether speech samples were recorded outside of speech clinics and whether speaking rate and speech naturalness were measured. Studies were also assessed on a four-point scale for "treatment outcomes," i.e., how effective the therapy was. This included how much stuttering was reduced immediately post-therapy and six months later, and whether psychological effects ("social, emotional, and cognitive measures") were measured.
On average, the 162 studies scored only 2.5 out of 5 on the "trial quality" scale and 1.1 out of 4 on the "treatment outcomes" scale.
39 articles that scored 4 or better out of 5 on the "trial quality" scale were examined more closely (i.e., 123 less-than-scientific studies were thrown out). These 39 articles averaged 1.4 out of 4 on the "treatment outcomes" scale.
This article first presents the stuttering therapies found to be effective in the review of 162 stuttering therapies. (I.e., this article leaves out the ineffective therapies.) Then this article discusses why stuttering treatment research is generally poor quality, and some things you can do to improve future stuttering treatment research.
Prolonged Speech
Prolonged speech stuttering therapy begins with slowing down a stutterer's speech five to ten times, holding each syllable one to two seconds by stretching the vowel. When the stutterer can speak fluently at this very slow speaking rate, the speaking rate is gradually increased until the stutterer is speaking fluently at a normal speaking rate. Prolonged speech stuttering therapy is also called "fluency shaping" in the United States and "smooth speech" in Australia. It is the most widely practiced stuttering therapy and has the most research studies.
13 studies of prolonged speech stuttering therapy met the trial quality criterion (scoring at least four on a five-point scale). All 13 studies were effective, reducing stuttering below 5%. 7 studies provided follow-up data at least 6 months after the treatment program was completed. Most studies included beyond-clinic speech samples. 4 studies included psychological (SEC) measures (even though none of the programs included psychological treatment). Two of the studies were among the three studies that met all of the "trial quality" and "treatment outcomes" criteria.
Perhaps the best studies were of the Institute for Stuttering Treatment and Research (ISTAR) program in Edmonton, Alberta. A 1994 study followed 42 adult and teenage stutterers through the three-week residential program. In addition to prolonged speech stuttering therapy, the program also works on reducing fears and avoidances, discussing stuttering openly, and changing social habits to increase speaking. The program includes a maintenance program for practicing at home. The program reduced stuttering from about 15-20% stuttered syllables to 1-2% stuttered syllables. Twelve to 24 months after therapy, about 70% of the stutterers had satisfactory fluency. About 5% were marginally successful. About 25% had unsatisfactory fluency. A 2010 study found similar results up to five years post-treatment. [7]
Ages of the subjects ranged from 7 to 58 years old. Prolonged speech stuttering treatment is also used with younger children but is generally seen as a treatment for school-age and adult stutterers.
Electromyography
Electromyography (EMG) uses electrodes taped to the user's skin to monitor muscle activity. Articulation muscles such as lips and jaws are easily monitored. Vocal folds are too deep in the neck to be monitored with surface electrodes.
Craig and Hancock [4] divided 98 school-age stutterers into four groups: one group went to a speech clinic for prolonged speech stuttering therapy with a SLP; in the second group, the parents went to the speech clinic and learned to do the same speech therapy with their children; the third group went to the speech clinic and did the same therapy using computer-based EMG biofeedback and relatively little interaction with SLPs; and the fourth group received no therapy. At the end of each therapy program, all three therapies reduced stuttering below 1% on average. One year after the therapy program, the children who'd done the EMG biofeedback were the most fluent (71% under 2% stuttering and 44% under 1% stuttering); the children whose parents who been involved were a close second (63% and 37%); and the children who'd had therapy with a speech-language pathologist were a distant third (48% and 10%). This was one of only three studies reviewed that met all of the "trial quality" and "treatment outcomes" criteria.
While the results of this study were impressive, and the reviewers found several other effective studies of EMG biofeedback, the therapy has never caught on. The inability to monitor vocal fold activity is an important shortcoming. Another problem is false positive readings from smiling and swallowing. Another problem is the electrodes and wires all over a stutterer's throat and face. EMGs are expensive, difficult to use, and don't improve stuttering therapy enough to justify the required time and expense, i.e., training parents to do therapy at home was almost as big an improvement as EMG biofeedback.
Response Contingencies
In the Lidcombe Program, speech-language pathologists train the parents of pre-school children who stutter to respond to their child's fluent speech positively, e.g., saying "good," and when the child stutters to respond with a gentle, "Whoops, that was a bumpy word." The reviewers classified this as response contingencies, are also known as operant conditioning, based on the work of psychologist B.F. Skinner. I would classify the Lidcombe Program as a program in which the parents become the primary therapy providers, along with the Craig and Hancock study (above, in the EMG section) that found that children do better when their parents provide speech therapy instead of relying on speech-language pathologists.
Several large, well-designed studies found the Lidcombe Program to be effective with young children who stutter. For example, one study had 29 children doing therapy with their parents and 27 children in a control group, who didn't do therapy. Speech samples were collected outside the speech clinic. Stuttering was reduced from 6.4% stuttered syllables (SS) to 1.5% SS in children who received therapy, vs. 6.8%SS to 3.9%SS in the control group. Note that many of the children who didn't receive therapy spontaneously improved their speech.
GILCU and DAF
Gradual increase in length and complexity of utterance (GILCU) stuttering therapy uses verbal positive reinforcement (e.g., "good") for fluent speech, beginning with single-syllable words and progressing to 5-minute conversations. A 1995 study compared GILCU to delayed auditory feedback (DAF) stuttering therapy. 24 children, ages 7 to 17, participated. 12 received GILCU stuttering therapy and 12 received DAF stuttering therapy. Both stuttering therapies were effective. Both established fluency (near-zero stuttering) in about 8 hours of treatment. The programs then included about ten hours of transfer and maintenance. The children maintained this fluent speech 14 months after completing the therapy programs. [5]
A second GILCU study found similar results with 4 children. A third study of fifteen 6-to-8-year-olds found that a 40-hour therapy program was successful for all the children. The children maintained their fluency over the next 18 months. [6]
Summary: What Works for Children and Adults
Based on the review of 162 studies, it appears that pre-school children should do the Lidcombe Program with their parents; school-age children should do prolonged speech stuttering therapy or GILCU stuttering therapy, preferably with their parents and with either a DAF device or an EMG device; and teenagers and adults should do prolonged speech. I will add more recommendations below.
A Different Perspective
When I consider which stuttering treatments to recommend, I also look at the cost of a treatment, in terms of money and time; and whether there is a downside. Consider my recommendation of vitamin B-1. The one published study was done in 1951 and hardly meets modern standards. The only other study hasn't been published. I recommend vitamin B-1 because it works for me and it's cheap, easy, and there's no side effects. You can buy vitamin B-1 at any drugstore. You'll either see the effects in a few days, or you won't. If it doesn't work for you, you've lost only $5 and ten minutes of your time.
I also recommend AAF devices. You can download DAF/FAF software free and try it right now on your computer. If it helps, most Americans can get DAF/FAF devices free from state programs, health insurance, or other third-party payers. If you have to pay for a device out of pocket, most companies have trial periods with money-back guaranties.
In contrast, most of the stuttering therapy programs in the 162 studies involved going to a speech clinic several times a week for weeks or months. Some programs, such as ISTAR, are residential programs lasting two or three weeks and costing thousands of dollars. Obviously before you invest that much time and money in a treatment you want to see a published study showing that the treatment is effective. But my standards are lower for treatments that are quick, easy, and inexpensive.
Why Stuttering Treatment Research Is Poor Quality
Money is why stuttering treatment research is poor quality. Clinical trials and expensive and time-consuming, costing $50,000 or more and requiring years of work. There's no profit in developing a better treatment for stuttering. Government grant providers such as the National Institute for Deafness and Communication Disorders (NIDCD) prefer to fund research that meets high scientific standards, and stuttering treatment research is messy. The Stuttering Foundation of America and National Stuttering Association don't provide grants for stuttering research.
Consider the pagoclone study, funded by Indevus. 300 stutterers are taking the medication for eight months. In comparison, most stuttering treatment studies have five to ten subjects. Many studies had one or two subjects. 300 subjects is a small study in the pharmaceuticals industry, but bigger than all the prolonged speech stuttering therapy studies combined.
Most stuttering research is done by professors hoping to publish a paper and get tenure. Given the time, expense, and messiness of stuttering treatment research professors instead chose to do etiology research (about the nature and origin of stuttering, not about treating stuttering). Another survey found that 93% of studies about stuttering were etiology, and 7% were about treatments.
Another issue is that consumers don't care whether stuttering treatments have been proven effective or not. An endorsement from a television news or talk show host is worth infinitely more than a well-researched study in the Journal of Fluency Disorders. The speech-language pathologists who treat stuttering, who usually have masters degrees, tell me they don't read the scientific journals because there's rarely anything useful published. The Ph.D. speech-language pathologists don't seem to read many studies either, judging from the mistakes I see in the papers and books they write.
Three Ways To Improve Stuttering Treatment Research
First, a non-profit foundation to provide grants for stuttering treatment research is needed. These could be small, seed grants. I've been told by NIDCD reviewers that to get a grant to develop a new stuttering treatment and run a clinical trial they need me to develop the new stuttering treatment and run a clinical trial, proving effectiveness, and then they'll consider giving me a grant. A private foundation could give out small grants to help researchers get a foot on the first rung of the grants ladder (eventually leading to bigger, government grants).
Second, we need standardized procedures for stuttering treatment research. The review of 162 studies listed nine criteria that every stuttering treatment study should include, but more detail is needed. E.g., instead of requiring "beyond-clinic" speech samples, a protocol could explain how to make telephone calls to local businesses (the only stressful but standardized speaking situation I know of). Research budgets should also be standardized. What is the normal cost to record and analyze a three-minute speech sample? The pharmaceuticals industry has a huge sub-industry just for clinical trials of new medications, with standardized procedures, budgets, and personnel who do this for a living every day for years. In contrast, stuttering treatment research is almost entirely done by people whose real job is something else (teaching classes about stuttering or treating stutterers isn't the same as running a large research study). When we apply for grants we look like amateurs competing against professionals from other fields.
Third, my company's iStutter iPhone app records your speech data during the day, then e-mails the data to a researcher when you plug in your iPhone to recharge at night. The technology can't yet count how many times you stutter each day, but perhaps in a few years stutterers will walk around with their smartphones collecting data for researchers.
Three Things You Can Do To Improve Stuttering Treatment Research
Volunteer to participate in a stuttering treatment research study. One of the hardest parts of stuttering treatment research is finding subjects. I'll set up a database on this website where you can volunteer as a subject.
Then volunteer to help analyze speech samples. I hope to set up an area of this website where researchers can upload speech samples (audio or video). Volunteers will then watch a video teaching them to analyze speech samples. Then they'll login and analyze a speech sample. Each speech sample can be analyzed by two or three volunteers. You'll be able to help with stuttering treatment studies as easily as you know watch YouTube.
Third, read the studies. When you're choosing between stuttering treatment options ask the treatment provider for copies of studies. Any respectable stuttering treatment provider will be happy to give you these. In the nearly twenty years since I founded Casa Futura Technologies only a handful of people have asked to see our studies. (We now have twenty studies!)
References
[1] Bothe, A., Davidow, J., Bramlett, R., & Ingham, R. (2006). Stuttering treatment research 1970–2005: I. Systematic review incorporating trial quality assessment of behavioral, cognitive, and related approaches. American Journal of Speech-Language Pathology, 15, 321-341; 1058-0360/06/1504-0321.
[2] Bothe, A., Davidow, J., Bramlett, R., Franic, D., & Ingham, R. (2006). Stuttering treatment research 1970–2005: II. Systematic review incorporating trial quality assessment of pharmacological approaches. American Journal of Speech-Language Pathology, 15, 342-352; 1058-0360/06/1504-0342.
[3] Lincoln, M., Packman, A., & Onslow, M. (2006) Altered auditory feedback and the treatment of stuttering: A review. Journal of Fluency Disorders, 31, 71-89.
[4] Craig, A., Hancock, K., Chang, E., McCready, C., Shepley, A., McCaul, A. & Reilly, K. (1996). A controlled clinical trial for stuttering in persons aged 9 to 14 years. Journal of Speech and Hearing Research, 39:4, 808-826. Hancock, K., Craig, A., McCready, C., McCaul, C., Costello, D., Campbell, K., & Gilmore, G., (1998). Two- to six-year controlled-trial stuttering outcomes for children and adolescents. Journal of Speech and Hearing Research, 41, 1242-1252.
[5] Ryan, B. P. & B. Van Kirk Ryan (1995). "Programmed stuttering treatment for children: comparison of two establishment programs through transfer, maintenance, and follow-up." Journal of speech and hearing research 38(1): 61-75.
[6] Druce, T., Debney, S., & Byrt, T. Evaluation of an Intensive Treatment Program for Stuttering in Young Children. Journal of Fluency Disorders, 22, August 1997, 169-186.
[7] Boberg, E., & Kully, D. (1994). Long-term results of an intensive treatment program for adults and adolescents who stutter. Journal of Speech and Hearing Research, 37, 1050-1059. Marilyn Langevin, Deborah Kully, Shelli Teshim, Paul Hagler, & N.G. Narasimha Prasad. (2010). Five-year longitudinal treatment outcomes of the ISTAR Comprehensive Stuttering Program. Journal of Fluency Disorders, 35:2, 123-140, doi:10.1016/j.jfludis.2010.04.002.
