Ultrasound visual feedback for acquired apraxia of speech: A case report

Background: Individuals with acquired apraxia of speech (AOS) can lose precision of articulatory movements, including the ability to achieve correct production of specific sounds or sound sequences. Novel treatment approaches should be explored to enhance treatment outcomes.Aims: To evaluate the clinical feasibility of ultrasound visual feedback of the tongue for addressing errors on rhotics in a patient with AOS. Ultrasound visual feedback was used to provide knowledge of performance to the participant.Methods & Procedures: A multiple baseline single case report is presented to evaluate a treatment programme that uses visual feedback of the participant's tongue from real-time ultrasound images. A blocked practice schedule was implemented during 12 one-hour therapy sessions; 30 minutes involved ultrasound visual feedback (10 minutes of pre-practice and 20 minutes of practice) and 20 minutes involved non-ultrasound practice. Cues were provided to modify tongue shape to achieve perceptually accurate production of rhotics, along with practice trials with increasing levels of phonetic complexity. The feedback type (verbal knowledge of performance and knowledge of results) and feedback frequency (number of trials with feedback) were structured to adhere to principles of motor learning.Outcomes & Results: The participant demonstrated moderate evidence of acquisition of prevocalic rhotics and strong evidence of acquisition of postvocalic rhotics during treatment. There was evidence of retention and generalisation only for postvocalic rhotics. An untreated context was probed regularly and showed no evidence of improvement.Conclusion: The results provide preliminary support for the feasibility of this treatment approach for improving speech accuracy in adults with acquired AOS. The improvements in stimulability for the treated sound sequences could be used to foster further motor learning.