What is the diadochokinetic rate?
The diadochokinetic (DDK) rate is a measurement that speech-language
pathologists (SLPs) can make. These professionals help people with
communication problems. They can use the DDK rate to assess, diagnose, and
treat speech and language problems. The DDK rate is also known as the “Fletcher
time-by-count test of diadochokinetic syllable rate.”
The DDK rate measures how quickly you can accurately repeat a series of
rapid, alternating sounds called “tokens.” They’re designed to test how well
you can make sounds with different parts of your mouth, tongue, and soft
palate. The tokens contain one, two, or three syllables, such as:
The DDK rate is a measure of the repetitions of sounds within a designated
amount of time. For example, your test results will show how many seconds it
takes you to repeat a token 10 times.
Established DDK-rate norms exist for each year of age throughout childhood. Norms
for adults with various underlying conditions also exist. Experts have
developed an index of comparative norms through clinical trials. The process of
perfecting the index continues today.
Your SLP may use other diagnostic tests, along with the DDK rate, to assess
speech and language problems that you may have.
When is the diadochokinetic rate used?
Your doctor may refer you to an SLP if you have problems with the following
types of skills:
- oral motor
Your SLP can use the DDK rate to help determine the severity of your
communication problems, their underlying cause, and the best course of
Multiple parts of your body control or affect your ability to speak,
- cerebellum, or the bottom back portion of your
- central nervous system
- muscle and bone structures in your face, mouth,
Conditions that can affect your speech and language include:
- neurological disorders, such as a stroke or brain
- neurological diseases, such as cerebral palsy or
- birth defects, such as cleft palate
- head, neck, or mouth cancer
- impairments after surgery
Your SLP can use the DDK rate
to detect specific speech variations associated with different underlying
conditions. Common variations and associated disorders include the following:
- Ataxia is abnormal and uncoordinated control during
voluntary movements that may affect your arms, legs, fingers, and hands,
as well as speaking and swallowing. It occurs due to damage to your
cerebellum or a defective gene.
- Dysarthria is a motor speech disorder that causes slow
or limited movement of your mouth, face, and respiratory system. It’s
often a result of stroke or other brain injury.
- Childhood apraxia of speech is an uncommon speech
disorder in which your brain struggles to plan speech and control your mouth
muscles. It can be caused by a stroke, brain injury, genetic disorders, or
- Aphasia is a disorder marked by speaking in short
phrases that make sense but are produced with great effort. It occurs due
to damage to the left hemisphere of your brain.
- Oropharyngeal disorders cause difficulties in
swallowing. They usually result from throat damage, which can occur due to
throat cancer and subsequent surgeries.
Your SLP may also use the exercises used to measure your DDK rate during
speech therapy sessions to help improve your speaking skills.
How is your DDK rate measured?
Your SLP can usually measure your DDK rate in a single session, lasting
about 30 minutes. They will administer a series of carefully timed tests and
score your results.
During each test, they’ll ask you to produce a different sound or
combination of sounds. For example, they may ask you to say the “a” sound 20
times very quickly. Then, they may ask you to repeat the sound, starting at a
whisper and getting louder. Before each test begins, your SLP will demonstrate
the sounds. You can then practice making the sounds several times.
Your SLP may also use other tests of oral mechanisms, such as singing to test your perceptual
ability or blowing through a straw submerged in water to test your breath control.
For people who have brain damage and for children, the SLP may use familiar
words like “patty-cake” or “buttercup” in place of nonsense syllables.
What do the results mean?
Your SLP will compare the results of your test to standard normalcy
measurements, using the DDK rate system. For example, a typical 10-year-old
produces 20 repetitions of the syllable “puh” in 3.7 seconds.
Your SLP will use any deviations from the standard normalcy measurements to
assess and diagnose your condition. Ask your SLP for more information about
your specific results, diagnosis, and treatment plan.
If you’re experiencing speech or language problems, your SLP may measure
your DDK rate by asking you to repeat certain sounds during a timed test. The
results can help them assess the severity or your speech or language problems,
diagnose the underlying cause, and prescribe appropriate treatment.