EPG research and therapy: further developments.

Electropalatography (EPG) has been used in the past 50 years for studying the patterns of contact between the tongue and the palate during speech production in typical speakers and those with speech disorders due to different causes. At the 7th EPG Symposium in Japan that was held online on 24 January 2021 (see: https://epg-research.sakura.ne.jp/), a panel of invited experts discussed their views regarding further developments and application of the technique. This paper provides a summary of this discussion. EPG offers information on articulation which cannot be replaced by other instrumental measures of speech. Identified areas for further hardware development are thinner EPG plates, better dental and palatal coverage, wireless connectivity, and sensors that provide additional articulatory information (e.g. tongue pressure, tongue-palate distance). EPG can serve as a resource for teaching speech disorders and phonetics. Furthermore, EPG therapy can be combined with telepractice in the speech therapy of clients with speech disorders.

Electropalatography (EPG) activities in Japan and the impact of the COVID-19 pandemic on EPG research and therapy: A report of presentations at the 7th EPG Symposium.

BACKGROUND: At the 7th Electropalatography Symposium in Japan, held online on the 24 January 2021, a few speakers were invited to talk about how the COVID-19 pandemic had impacted their research and/or speech therapy that involved the use of electropalatography (EPG) as well as the procedures adopted in order to continue their work in a safe manner. The information on protective measures when using instrumental techniques in speech research and therapy may be useful for colleagues in research and the clinic. AIMS: The primary aims are: (1) to find out whether there are any published recommendations regarding protective measures for using EPG in research and clinic settings; (2) to discuss the impact of the pandemic and the corresponding restrictions and general protective measures directed (or advised) by local government and professional bodies at each stage of EPG work; and (3) to share experiences in using modified procedures for face-to-face EPG therapy sessions and combined EPG teletherapy. In addition, a brief overview of EPG and a summary of EPG research and clinical activities in Japan presented by one of the symposium organizers at the symposium are included. METHODS & PROCEDURES: A review of the literature regarding protective measures recommended for using EPG for speech assessment and treatment or research, supplemented by a discussion of our own experiences. MAIN CONTRIBUTION: The literature review showed that there are no guidelines regarding protective measures for using EPG, but there is some advice regarding speech recording using microphones. Most published articles related to speech and language therapy (SLT) service during COVID-19 are about telepractice or general clinical guidelines for face-to-face speech therapy sessions. The protective measures for using EPG developed based on the general guidelines recommended by local government and professional bodies (e.g., using visors, transparent acrylic board) were described. Using EPG in telepractice was discussed as well. CONCLUSIONS: It has been challenging to continue EPG research and therapy during the pandemic. In order to deal with this crisis, available knowledge regarding infection control and recommendations from local government and professional bodies were applied to design methods and procedures that allowed EPG research and therapy to continue. WHAT THIS PAPER ADDS: What is already known on the subject There are general protective measures recommended by local government and professional bodies regarding speech therapy sessions (e.g., using personal protective equipment (PPE), social distancing), but little is known about the measures for using instrumental techniques in speech research and therapy, particularly EPG. The equipment of each instrumental technique is different, so measures that are appropriate for one may not be suitable for others. Hence, specific recommendations are needed for EPG. What this paper adds to existing knowledge This paper provides pointers to information about recommendations regarding protective measures for speech research and therapy, supplemented with suggestions specific to EPG provided by experienced users based on actual experience. What are the potential or actual clinical implications of this work? In evaluating the impact of the COVID-19 pandemic on EPG research and therapy, an analytical approach was taken to break down the steps involved in carrying out those activities, and the challenges we faced and the possible alternatives for completing the tasks were discussed. A similar approach can be applied to evaluate other aspects of speech therapy service.

Tongue model construction based on ultrasound images with image processing and deep learning method.

PURPOSE: The purpose of this paper is to construct a 3D tongue model and to generate an animation of tongue movement for speech therapy in patients with lateral articulation (LA). METHODS: The 3D tongue model is generated based on ultrasound (US) images, which are widely used in many clinics. A tongue model is constructed by extracting the tongue surfaces from US images with the help of image processing techniques and a deep learning method. A reference tongue model is generated first using US images of a normal speaker, and a model of an LA patient is then constructed by modifying the reference tongue model. An animation of the tongue movement is generated by deforming the model according to a time sequence. RESULTS: The accuracy of the tongue surfaces estimated by a deep learning method were 22/45 = 49% and 29/45 = 64% for US images of a normal speaker and an LA patient, respectively. In addition, the maximum vertical errors between the ground truth and the estimated spline curves were 1.01 and 1.03 mm for US images of a normal speaker and an LA patient, respectively. CONCLUSION: We have constructed a tongue model and generated a tongue movement animation of an LA patient using US images. The maximum vertical error between the ground truth and the estimated spline curves was only 1.03 mm, and we have confirmed that the generated tongue model is very useful for speech therapy in LA patients.

Accuracy of cervical auscultation in detecting the presence of material in the airway.

Several studies have investigated the accuracy of cervical auscultation (CA). However, both the sensitivities and the specificities of CA in detecting dysphagic conditions varied widely among these studies. These wide variations of the accuracy of CA might be caused by differences of the targeted sounds, such as the expiratory sound (ES) and/or swallowing sound (SS). Forty-six dysphagic patients were served as subjects. Patients who had unoccluded tracheostoma and patients who could not follow the instructions were excluded. During the videofluorographic swallowing study (VFSS), the subjects swallowed 3 ml of yogurt containing barium sulfate. The VFSS images were recorded with acoustic signals including both the swallowing and respiratory sounds detected by our method. Classification of the VFSS images was decided by consensus of the three dentists using a penetration-aspiration scale (PAS). Recorded VFSS images were classified into the following 2 groups based on PAS: "no or minimum risk group": PAS1-2; and "possible risk group": PAS3-8. As a result of the classification of VFSS findings, 30 samples were evaluated as no or minimum risk group and 16 as possible risk group. Twelve observers including 10 dentists other than 3 dentists who evaluated VFSS images and 2 speech pathologists auditorily diagnosed "negative" and "positive." Sensitivity, specificity, and intra-rater reliability was calculated for the 3 types of acoustic samples. The sensitivity of the intra-rater reliability was 60.3% for ES, 76.6% for SS, and 89.9% for ES + SS. The sensitivity of intra-rater reliability of ES + SS samples was significantly higher than that of ES (p < .01) and SS (p < .05). The sensitivity of intra-rater reliability of SS was significantly higher than that of ES (p < .01). The specificity of the intra-rater reliability was 53.7% for ES, 50.3% for SS, and 44.5% for ES + SS. ES + SS might be most useful for detecting the presence of material in the airway.

Clinical inter-rater reliability of postural control techniques.

Effectiveness of postural control techniques to compensate for oropharyngeal dysphagia have been recommended and used by several clinicians. However, the inter-rater reliability of these techniques is not well understood. The purpose of this study was to clarify the ambiguity of postural control techniques using statistical analyses. A total of 50 clinicians involved in dysphagia treatment participated in this study, where a healthy male served as the simulated patient. The following clinically used postures were measured by two investigators on two separate days: chin down, right/left incline, and right/left rotation. Postural angles were measured twice by two investigators on each day. Data obtained for the angle of each posture were visually displayed. Data from both investigators were assessed for each posture using the Youden plot, which analyzes data variability for systematic errors and accidental errors separately. The correlation coefficient for examining the measurement error between investigators was calculated. The results showed considerable variation between clinicians regarding the postures used, and significant differences were noted each day. The correlation coefficient for a total of four measurements was more often lower on Day 2 than that on Day 1. The details of the instructions provided by clinicians were not fixed, and the same specified posture was not reproduced even when instructions were provided to the same subject. These findings suggest poor inter-rater reliability because of the variability of selected postures when using statistical analyses. Therefore, standardized postures need to be developed that can be easily measured and reproduced.