Puh-tuh-kuh is making a come-back! The use of the diadochokinetic (DDK) rate has been described as “the simplest way to recognize motor speech difficulties.” (Williams, P. et al; 2000)
Actually, for me, it never really left. I’ve always liked doing repetitive syllable analysis with my therapy-kids because I glean so much information from it.
I admit, I don’t do it the way Sam Fletcher suggested in 1972. I’ve modified it through the years and made it my own.
I’ll share it with you today.
But first, a little perspective and, a little history. Diadochokinesis goes back even further than 1972. The term was introduced into our field in 1950 by Lundeen. And then, a full twenty-two years later Dr. Fletcher created and normed his DDK “Time-by-Count” measurement. Many of us are familiar that syllable rate-task. But if you’re not, here a brief description.
The Normed Diadochokinetic (DDK) Rate Analysis
SLPs do the diadochokinetic rate activity to analyze the ability to make rapidly alternating speech movements. It’s about rate of movement.
Here’s a brief description of how to determine the diadochokinetic rate. Three syllables are used: puh, tuh, and kuh (the lips, front-tongue vertical movement, back-tongue vertical movement). Each one is repeated rapidly then together, puhtuhkuh. The norms, for ages 6 to 13 years, specify the number of seconds it takes to say 20 sound repetitions.
For each of the single-sound repetitions the normal amount of time incrementally decreases from the younger child to the older child from around 5 seconds down to around 3 seconds.
For the combined repetitions, puhtuhkuh, the normal amount of time incrementally decreases from the younger child to the older child, from around 10 seconds down to around 6 seconds.
Honestly, I always had trouble keeping track of the number of syllables the kid did (supposed to be 20),and simultaneously click the stop watch when he was done. I never mastered that.
Char’s Modified Diadochokinetic (DDK) Analysis Task
Consider doing amodified DDK task that does not yield numbers but reveals oral capability information about differentiation skills (the ability to move one articulator without significant movement from other non-involved articulators), and oral control—via your observations.
The same syllables are used (puh, tuh, kuh, and, combined), but, we look beyond the sound-of-the-sound, and into what he is physically doing and not doing.
Like the original task, begin with puh. Briefly model the syllable production and ask him to continue saying it quickly until you say stop. Encourage him to continue for at least 10 seconds. Then do the tuh, then the kuh, then put the three together for puhtuhkuh. Make note of your observations.
Yes, we’re still looking his rate, but there’s no counting. Most of us are able to perceive when a child is significantly slow, or within normal limits.
Observe him closely and look for the following capability characteristics of the lips, tongue, and jaw.
Labial stabilization and mobilization:
During bilabial speech sound production, the “corners” of the lips contract (stabilize) as the mid-portion of the lips move in a refine, small manner to make the sound. Make note if he stabilizes and mobilizes appropriately, or if the jaw does most of the up-down movement.
The tongue’s operating zone:
In what general area of the mouth does his tongue move? Is it low and forward? Is it low, and synergistically moves up and down with the jaw? Or, is it appropriately “up” within the dental arch? If it appears to be in that region, lateral margin stabilization is possible and probable. That’s a good thing.
The tongue’s plane of movement:
For the lingual sounds, does his tongue move horizontally or vertically or just go along with the jaw’s up-down movements?
Is the front-tongue capable of moving vertically?
When doing the tuhs do you see his front-tongue moving vertically or horizontally and touching the front teeth, or, is the tuh jaw-driven (up-down movements)? A “jaw-driven” speech sound is when the jaw is the primary articulator (the primary mover) instead of the tongue or lips. That’s what happens in babbling.
Is the back-tongue capable of moving vertically?
When doing the kuhs do you see (or feel outside on his throat area) his back-tongue moving vertically, or is the whole tongue moving horizontally and contacting the front teeth, or, is the kuh jaw-driven?
Do the syllables sound connected or disconnected? Are his productions choppy and irregular or consistent? Most multiple-artic kids say the sounds uneven and erratic.
His breathing pattern. Does he breathe appropriately (take a breath then say several sounds in a row), or does he take a breath between each syllable?
The size of his oral movements for speech, i.e. the range of motion of his articulators. Do his movements look large and effortful, or small and refined (like speech is supposed to be)? Larger oral movements usually yield a low number of productions in Fletcher’s Time-by-Count measurement.
His production rate. Excessively slow productions typically indicate effortful productions that are not stabilized appropriately; or there is a neuro-muscular issue. Further investigation would be needed.
His comfort level. Ask him what he thinks of the task, pretty-easy and effortless, or harder and more effortful.
His level of fatigue. To you, do his oral movements appear to be abnormally effortful? For example, does he get tired after doing 5 seconds and needs to rest? This can be indicative of poor lingual muscular endurance—and we know, connected speech is an endurance task. Also, if he is trying to do whole tongue, unstabilized productions, repetitive movements can be tiring. One influences the other.
If you add this to your analysis protocol, let me know how it works out. Also, if you have a “modified” analysis that you do and really like, feel free to send it to me, and if you want, we’ll share it with others.
There have been several newer research articles done in the past 20 years. A few have been in our Speech Pathology field, but many have been conducted in the Clinical Linguistics field. If you are interested, you may want to Google them.
These are the ones I mentioned:
Fletcher S.G. (1972). Time-by-count measurement of DDK syllable rate. Journal of Speech and Hearing Research. Vol. 15, 763-770. Sam Fletcher did the research, formulated a structure, and generated DDK norms. It has stood the test of time.
Lundeen D.J. (1950). The relationship of diadochokinesis to various speech sounds. Journal of Speech Hearing Disorders. Vol. 15 (1),54-59. Dale Lundeen was the one responsible for initially introducing DDK within our field. The article is about normal speaking adults and 10 consonant sounds. Dr. Fletcher ended up with something quite different 22 years later. It’s a fun article to read and gives insight as to how they thought 70 years ago. Also, unlike some articles of today, it’s quite readable.
Williams P. et al. (2000). Rate, accuracy and consistency: DDK performance of young, normally developing children. Clinical Linguistics and Phonetics. Vol 14 (4),267-293.
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