Ultrasound Images of the Tongue: A Tutorial for Assessment and Remediation of Speech Sound Errors

Summary

Ultrasound imaging can be used to display the shape and movements of the tongue in real time during speech. The images can be used to determine the nature of speech sound errors. Visual feedback of the tongue can be used to facilitate improvements in speech sound production in clinical populations.

Abstract

Diagnostic ultrasound imaging has been a common tool in medical practice for several decades. It provides a safe and effective method for imaging structures internal to the body. There has been a recent increase in the use of ultrasound technology to visualize the shape and movements of the tongue during speech, both in typical speakers and in clinical populations. Ultrasound imaging of speech has greatly expanded our understanding of how sounds articulated with the tongue (lingual sounds) are produced. Such information can be particularly valuable for speech-language pathologists. Among other advantages, ultrasound images can be used during speech therapy to provide (1) illustrative models of typical (i.e. "correct") tongue configurations for speech sounds, and (2) a source of insight into the articulatory nature of deviant productions. The images can also be used as an additional source of feedback for clinical populations learning to distinguish their better productions from their incorrect productions, en route to establishing more effective articulatory habits.

Ultrasound feedback is increasingly used by scientists and clinicians as both the expertise of the users increases and as the expense of the equipment declines. In this tutorial, procedures are presented for collecting ultrasound images of the tongue in a clinical context. We illustrate these procedures in an extended example featuring one common error sound, American English /r/. Images of correct and distorted /r/ are used to demonstrate (1) how to interpret ultrasound images, (2) how to assess tongue shape during production of speech sounds, (3), how to categorize tongue shape errors, and (4), how to provide visual feedback to elicit a more appropriate and functional tongue shape. We present a sample protocol for using real-time ultrasound images of the tongue for visual feedback to remediate speech sound errors. Additionally, example data are shown to illustrate outcomes with the procedure.

Introduction

Both clinical and research settings have seen an increase in the use of ultrasound imaging to provide visual biofeedback intervention to individuals with speech disorders. One important use of ultrasound imaging for speech-language pathologists is as a visual biofeedback tool during intervention for individuals with speech disorders. With the guidance of a speech-language pathologist, learners can observe real-time video of the shape and movements of their tongue and discuss how these images may differ from the tongue movements needed to properly articulate a speech sound. To conduct such interventions, it is important for users to be competent in the interpretation o....

Protocol

Ethics Statement. When used in research, informed consent and/or assent from children is always required before collecting ultrasound images. When used clinically, clients should be informed of the purpose of the ultrasound imaging. Although diagnostic ultrasound imaging is considered "minimal risk" ³⁰, users should always follow the ALARA principle when using ultrasound, meaning exposure to ultrasound should be as "As Low As Reasonably Achievable"³¹. This involves limiting acoustic power during imaging and also limiting exposure time. For example, if ultrasound is being used for visual feedback but the participant is not attendin....

Results

Figure 1 presents sample sagittal images of correct /r/ in a 9-year-old female. The ultrasound images are paired with magnetic resonance images from the same speaker to demonstrate the similar tongue shape that can be viewed with both technologies.

Discussion

Critical Steps within the Protocol

It is essential to obtain clear, interpretable images as described in steps 1.3 and 1.6. Poor image quality renders the procedures meaningless. Additionally, participants must be fully aware of what they are seeing on the screen. Therefore, orienting the participant to the image as described in 3.2 is a step that should be emphasized prior to providing visual feedback training. Additionally, step 3.10, which involves clearly describing differences in tongue shap.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
ACUSON X300  ultrasound with C6-2 probe	Siemens	Acuson X300
Trasceptic Spray	Parker labs	PLI 09-25
Acquasonic 100 ultrasound gel	Parker labs	01-08