Ultrasound Visual Feedback
Within the past decade, there has been interest in the clinical application of ultrasound to individuals with speech disorders. By holding an ultrasound transducer under the chin, we can observe real-time images of the tongue. These images can be used to provide both the client and the clinician with information about tongue position and configurations during production of certain speech sounds or during sequences of sounds. Speech-language pathologists can use this information to provide cues to their clients about how to change the tongue position or shape. Ultrasound imaging of the tongue can be used to address articulation of sounds such as /t, d, n, s, z, l, r, k, g/ and vowels.
The ultrasound device that has been used in most studies (and the one used in our research) is the Seemore PI 7.5 MHz probe by Interson. This is a relatively inexpensive USB-powered device that plugs into a PC. It is very portable and can be used with windows-based laptops. However, many other ultrasound devices would work well for purposes of visualizing the tongue.
Clinical practice and research involving ultrasound visual feedback is conducted at Montclair State University, Southern Connecticut State University, the University of Cincinnati, University of British Columbia and the University of Sydney (AU), among others.
We have recently provided some clinical training for speech-language pathologists at Haskins Laboratories.
A question that is commonly asked is if there are any known risks associated with the use of ultrasound imaging. There are no known harmful effects of ultrasound imaging of the tongue. Ultrasound uses sound waves to generate the images we see (using frequencies much higher than our ears can hear). Ultrasound does not involve ionizing radiation, as found in x-rays. The type of ultrasound we use is considered “diagnostic ultrasound” using a low-intensity B-mode transducer. The most common complaint from individuals who have undergone ultrasound visual feedback as part of speech therapy is that the gel is cold or gooey, and that the ultrasound transducer can be slightly uncomfortable when it is placed tightly under the chin. Although there are no known harmful effects, we always follow the ALARA (as low as reasonably achievable) principle to limit exposure, and we allow breaks anytime a participant requests it. See Aium Official Statement.
In speech therapy, our laboratory uses ultrasound visual feedback within the context of motor learning theory. The visual display provided by the ultrasound provides “knowledge of performance” for the learner; that is, it offers information about the specific movements that are happening. Our “speech lessons” make an attempt to adhere to principles of motor learning by incorporating many practice trials (approximately 200 trials within an hour long session), practice variability (practicing more than one sound variant of each target), reducing the amount of feedback over time, and changing the type of feedback (from primarily knowledge of performance to primarily knowledge of results). Additionally, when incorporated into treatment, ultrasound is not used for the entire session. Periods of ultrasound and no-ultrasound treatment are included in each session, and less than half of the hour long session is spent with the ultrasound. As the speaker becomes more accurate, practice moves to higher levels of complexity (from syllables to monosyllabic words to multisyllabic words to phrases) and the amount of ultrasound visual feedback is faded over time. An example of the data sheet used to guide the structure of our treatment can be found here.
Below is a video demonstrating the structure of our current speech therapy sessions.
This video has been published in the Journal of Visualized Experiments." [link to: http://www.jove.com/video/55123/ultrasound-images-tongue-tutorial-for-as... ]
Preston, J. L., McAllister Byun, T., Boyce, S. E., Hamilton, S., Tiede, M., Phillips, E., Rivera-Campos, A. & Whalen, D. H. (2017). Ultrasound images of the tongue: A tutorial for assessment and remediation of speech sound errors. Journal of Visualized Experiments, (119), e55123. doi:10.3791/55123