VAST is a technique for treatment of acquired apraxia of speech (AoS). It was developed by Speech-Language Pathologist Darlene Williamson, through her work at the Stroke Comeback Center, and in collaboration with her son, Jeff Williamson.

It has also been utilized and referred to as “speech entrainment” (Fridriksson, et al, 2012) and “auditory-video word presentation” (Ball, de Riesthal, Steele, 2018) an evidence-based, combined approach to addressing AoS by:

  • Using multi-modal stimulation; audio, articulation video-visual and written cues to facilitate imitation of model production
  • Integrating the principles of motor learning by providing opportunity for unlimited repetitions of practice and feedback
  • Varying the complexity of target stimuli as appropriate
    • Beginning with familiar, serial tasks (counting, days of the week) and expanding to word combinations, contrasts, compound words, phrases and sentences
  • Incorporating relevant vocabulary and script training as appropriate
  • Providing easy access for practice/orthotic use via mobile platforms


Ball, A.L., de Riesthal, M., & Steele, R.D. (2018). Exploring treatment fidelity in persons with aphasia autonomously practicing with computerized therapy materials. American Journal of Speech-Language Pathology, 27, 454-463. 

Fridriksson, J., Hubbard, H. I., Hudspeth, S. G., Holland, A. L., Bonilha, L., Fromm, D., & Rorden, C. (2012). Speech entrainment enables patients with Broca’s aphasia to produce fluent speech. Brain, 135 (12), 3815-3829. 

Download a Free Info Sheet on Informal Probes to Assess Apraxia of Speech

What the Implementation of VAST Has Shown

  • Confidence in using the technique appears to be a larger contributor to success than the number of repetitions practiced
  • All levels of severity can benefit from the use of this technique, however; individuals with more severe AoS will continue to have diminished intelligibility
  • Improved production when the client is provided with the audio + articulation video-visual vs. the audio + visual drawing cue alone
  • The ability to produce personal information generalized after practicing video scripts

How to Begin Implementing VAST

Lingraphica SmallTalk™ video apps and TalkPath™ Therapy speech articulation video exercises are free to download and a great way to begin implementing this technique among clients who are a good fit. Additionally, articulation videos are also included on Lingraphica AAC devices, and allow you to create your own, personalized articulation videos with/for your clients for therapeutic/orthotic communication on the devices as well.


Adult Acquired Apraxia of Speech: Basics and Beyond

To learn more about the development and application of the VAST technique, watch our free CE course presented by Darlene Williamson, “Adult Acquired Apraxia of Speech: Basics and Beyond”.

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