How to conduct a Stimulability Test
This is a simple test which is used to determine whether or not a person may have difficulties articulating particular speech sounds. It is quick (no more than 10 minutes) and easy to administer, as follows:
Choose a quiet place to work – one without any distractions (e.g. children playing nearby, telephones that are likely to ring, too many interesting objects in the room).
Sit opposite the person being tested so that they can see your face clearly.
Ask them to, ‘Look at me and listen carefully. I’m going to say some sounds and I want you to say them back to me.’
Then go through the whole list of 24 English consonant sounds in Table 1, saying them clearly one at a time. So, you would start by saying ‘p’ and have the person repeat the sound back to you. Then you would say ‘b’ and have the person repeat the sound back to you…and so on.
Remember to say each consonant in isolation, i.e. do not add a vowel to the sound. For example, ‘p’ should not be said as ‘puh’, but simply as ‘p’; ‘v’ should not be said as ‘vuh’ but simply as the long sound ‘vvvvvv’.
Make a note of whether or not the person being tested is able to imitate a sound properly by placing a tick in the appropriate cell in Table 1.
If a sound is not produced correctly, make a note of which sound (if any) they produced instead.
If the person being tested does not respond to any particular sound, gently persuade them to repeat it by saying, “Listen again. This is the sound I want you to say.” If they still do not respond, do not pressurize them to imitate the sound. Simply record this as ‘NR’ (no response) and move on to the next sound in the list.
|IPA||International Phonetic Alphabet.|
|SI||Consonant in syllable-initial position.|
|SF||Consonant in syllable-final position.|
|*||The consonant /r/ does not appear in syllable-final position in standard British English but does appear, for example, in American English.|
Table 1. Stimulability Test (download a printable form)
Interpreting the results
If the person is able to articulate a particular speech sound then he or she cannot have a so-called phonetic disorder. Only if the person can not articulate a sound would they be described as potentially having an articulation disorder or articulation difficulty, i.e. a phonetic difficulty.
Of course, the Stimulability Test presented above only assesses consonants. It is possible that a person may have difficulties articulating vowels. Since vowels are open sounds that are produced with no obstruction to the airflow from the lungs as is escapes through the vocal tract, such difficulties are less common. However vowel distortion can be a feature of dyspraxia (the reduced ability to perform purposeful movements of the vocal tract that cannot be attributed to impairments of motor or sensory functions) and dysarthria (reduced precision, range and speed of movement of the vocal apparatus due to a neurological impairment). Note: As dyspraxia is often characterized by a reduced ability to perform previously learned skills, some authorities classify oral dyspraxia (verbal dyspraxia; developmental articulatory dyspraxia) as a cognitive disorder.