Electropalatography and the Linguagraph system

Inertial Measurements for Tongue Motion Tracking Based on Magnetic Localization with Orientation Compensation

Permanent magnet localization (PML) is designed for applications requiring non-line-of-sight motion tracking with millimetric accuracy. Current PML-based tongue tracking is not only impractical for daily use due to many sensors being placed around the mouth, but also requires a large training set of tracer motion. Our method was designed to overcome these shortcomings by generating a local magnetic field and removing the need for the localization to be trained with tracer rotations. An inertial measurement unit (IMU) is used as a tracer that moves in a local magnetic field generated by a magnet strip. The magnetic strength can be optimized to enable the strip to be placed further away from the tracer, thus hidden from view. The tracer is small (6×6×0.8 mm³) to reduce hindrance to natural tongue movements, and the strip is designed to be worn as a neckband. The IMU's magnetometer measures the local magnetic field which is compensated for the tracer's orientation by using the IMU's accelerometer and gyroscope. The orientation-compensated magnetic measurements are then fed into a localization algorithm that estimates the tracer's 3D position. The objective of this study is to evaluate the tracking accuracy of our method. In a 8×8×5 cm³ volume, positional errors of 1.6 mm (median) and 2.4 mm (third quartile, Q3) were achieved on a tracer being rotated ±50° along both pitch and roll. These results indicate this technology is promising for tongue tracking applications.

The technology of tongue and hard palate contact detection: a review

The tongue and hard palate play an essential role in the production of sound during continuous speech. Appropriate tongue and hard palate contacts will ensure proper sound production. Electropalatography, also known as EPG, is a device that can be used to identify the location of the tongue and hard palate contact. It can also be used by a speech therapist to help patients who have a speech disorder. Among the group with the disease are cleft palate, Down syndrome, glossectomy, and autism patients. Besides identifying the contact location, EPG is a useful medical device that has been continuously developed based on the patient's needs and treatment advancement. This article reviews the technology of electropalatography since the early introduction of the device. It also discusses the development process and the drawbacks of the previous EPG systems, resulting in the EPG's upgraded system and technology. This review suggests additional features that can be useful for the future development of the EPG. The latest technology can be incorporated into the EPG system to provide a more convenient method. There are some elements to be considered in the development of EPG's new technology that were discussed in this study. The elements are essential to provide more convenience for the patient during speech therapy. New technology can accelerate the growth of medical devices, particularly on the development of speech therapy equipment that should be based on the latest technological advancements available. Thus, the advanced EPG system suggested in this article may expand the usage of the EPG and serve as a tool to provide speech therapy treatment services and not limited to monitoring only.

Evaluation of a Wireless Tongue Tracking System on the Identification of Phoneme Landmarks

OBJECTIVE

Evaluate the accuracy of a tongue tracking system based on the localization of a permanent magnet to generate a baseline of phoneme landmarks. The positional variability of the landmarks provides an indirect measure of the tracking errors to estimate the position of a small tracer attached on the tongue. The creation of a subject-independent (universal) baseline was also attempted for the first time.

METHOD

2,500 tongue trajectories were collected from 10 subjects tasked to utter 10 repetitions of 25 phonemes. A landmark was identified from each tongue trajectory, and tracking errors were calculated by comparing the distance of each repetition landmark to a final landmark set as their mean position.

RESULTS

In the subject-dependent baseline, the tracking errors were found to be generally consistent across all phonemes, and subjects, with less than 25% of the errors reported to be greater than 5.8 mm (median: 3.9 mm). However, the inter-subject variability showed that current limitations of our system resulted in appreciable errors (median: 55 mm, Q3: 65 mm).

CONCLUSION

The tracking errors reported in the subject-dependent case demonstrated the potential of our system to generate a baseline of phoneme landmarks. We have identified areas of improvement that will reduce the gap between the subject-dependent, and universal baseline, while lowering tracking errors to be comparable to the gold standard.

SIGNIFICANCE

Creating a baseline of phoneme landmarks can help people affected by speech sound disorders to improve their intelligibility using visual feedback that guides their tongue placement to the proper position.

Color change of airborne particle-abraded acrylic resin surfaces: A palatography method

STATEMENT OF PROBLEM

A palatogram aids prosthodontists and speech pathologists in evaluating the precise prosthetic treatment needed and the effectiveness of such treatment to improve speech intelligibility. Powder is commonly used to visualize tongue-palate contact, where wetted areas of powder in the oral cavity reveal such contact during palatography. However, discomfort and the risk of aspiration are among the shortcomings of this method, and an improved method is needed.

PURPOSE

The purpose of this in vitro study was to examine the feasibility of a new method of palatography that uses airborne-particle-abraded acrylic resin so that wet areas can be easily distinguished from dry areas.

MATERIAL AND METHODS

Seventy-two specimens of heat-polymerized acrylic resin were prepared in 6 different resin colors. After the specimens had been airborne-particle abraded, CIELab color values for each specimen were measured using a colorimeter under dry and wet conditions and recorded. Color difference (ΔE) was then computed, and a paired Student t test, 1-way analysis of variance, and multiple comparison using the Tukey post hoc analysis were applied (α=.05).

RESULTS

A significant color difference was found between the 2 conditions in all acrylic resin specimens examined. Mean ΔE ranged from 5.58 to 6.76.

CONCLUSIONS

The results indicated that an airborne-particle-abraded acrylic resin surface can show color differences made by wetting on palatograms.

A pressure-sensitive palatograph for speech analysis

Electropalatography (EPG) is a clinical technique used to monitor contacts between the tongue and the hard palate, thus promoting correct articulation mechanisms. Currently, employed commercial tools have a good resolution but they do not provide contact pressure information. In this work, textile-based sensing technologies were employed to realize an innovative EPG tool able to both maintain the proper spatial resolution and perform quantitative pressure detection. The single sensing unit was developed using a thin polymeric sheet with a central hole, sandwiched between two piezoresistive fabric layers. Under load application, the two textile layers come into contact and the resistance of the sensor reduces significantly, measuring pressure in the range from 0 to 30 kPa. The complete prototype is composed of 62 sensing units disposed in a matrix structure: the dielectric layer contains all the sites arranged in rows and columns, according to the topography of the traditional tools, and this layer presents on both sides strips of piezoresistive textile. The entire system was covered with a thin latex membrane and fixed on a hard custom acrylic palate for the experimental characterization. The system was tested on a healthy subject, confirming the adequacy and effectiveness of the soft sensing technologies for the measuring of the tongue pressure during speech.

Interventions for dysarthria due to stroke and other adult-acquired, non-progressive brain injury

BACKGROUND

Dysarthria is an acquired speech disorder following neurological injury that reduces intelligibility of speech due to weak, imprecise, slow and/or unco-ordinated muscle control. The impact of dysarthria goes beyond communication and affects psychosocial functioning. This is an update of a review previously published in 2005. The scope has been broadened to include additional interventions, and the title amended accordingly.

OBJECTIVES

To assess the effects of interventions to improve dysarthric speech following stroke and other non-progressive adult-acquired brain injury such as trauma, infection, tumour and surgery.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (May 2016), CENTRAL (Cochrane Library 2016, Issue 4), MEDLINE, Embase, and CINAHL on 6 May 2016. We also searched Linguistics and Language Behavioral Abstracts (LLBA) (1976 to November 2016) and PsycINFO (1800 to September 2016). To identify further published, unpublished and ongoing trials, we searched major trials registers: WHO ICTRP, the ISRCTN registry, and ClinicalTrials.gov. We also handsearched the reference lists of relevant articles and contacted academic institutions and other researchers regarding other published, unpublished or ongoing trials. We did not impose any language restrictions.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) comparing dysarthria interventions with 1) no intervention, 2) another intervention for dysarthria (this intervention may differ in methodology, timing of delivery, duration, frequency or theory), or 3) an attention control.

DATA COLLECTION AND ANALYSIS

Three review authors selected trials for inclusion, extracted data, and assessed risk of bias. We attempted to contact study authors for clarification and missing data as required. We calculated standardised mean difference (SMD) and 95% confidence interval (CI), using a random-effects model, and performed sensitivity analyses to assess the influence of methodological quality. We planned to conduct subgroup analyses for underlying clinical conditions.

MAIN RESULTS

We included five small trials that randomised a total of 234 participants. Two studies were assessed as low risk of bias; none of the included studies were adequately powered. Two studies used an attention control and three studies compared to an alternative intervention, which in all cases was one intervention versus usual care intervention. The searches we carried out did not find any trials comparing an intervention with no intervention. The searches did not find any trials of an intervention that compared variations in timing, dose, or intensity of treatment using the same intervention. Four studies included only people with stroke; one included mostly people with stroke, but also those with brain injury. Three studies delivered interventions in the first few months after stroke; two recruited people with chronic dysarthria. Three studies evaluated behavioural interventions, one investigated acupuncture and another transcranial magnetic stimulation. One study included people with dysarthria within a broader trial of people with impaired communication.Our primary analysis of a persisting (three to nine months post-intervention) effect at the activity level of measurement found no evidence in favour of dysarthria intervention compared with any control (SMD 0.18, 95% CI -0.18 to 0.55; 3 trials, 116 participants, GRADE: low quality, I² = 0%). Findings from sensitivity analysis of studies at low risk of bias were similar, with a slightly wider confidence interval and low heterogeneity (SMD 0.21, 95% CI -0.30 to 0.73, I² = 32%; 2 trials, 92 participants, GRADE: low quality). Subgroup analysis results for stroke were similar to the primary analysis because few non-stroke participants had been recruited to trials (SMD 0.16, 95% CI -0.23 to 0.54, I² = 0%; 3 trials, 106 participants, GRADE: low quality).Similar results emerged from most of the secondary analyses. There was no evidence of a persisting effect at the impairment (SMD 0.07, 95% CI -0.91 to 1.06, I² = 70%; 2 trials, 56 participants, GRADE: very low quality) or participation level (SMD -0.11, 95% CI -0.56 to 0.33, I² = 0%; 2 trials, 79 participants, GRADE: low quality) but substantial heterogeneity on the former. Analyses of immediate post-intervention outcomes provided no evidence of any short-term benefit on activity (SMD 0.29, 95% CI -0.07 to 0.66, I² = 0%; 3 trials, 117 participants, GRADE: very low quality); or participation (SMD -0.24, 95% CI -0.94 to 0.45; 1 study, 32 participants) levels of measurement.There was a statistically significant effect favouring intervention at the immediate, impairment level of measurement (SMD 0.47, 95% CI 0.02 to 0.92, P = 0.04, I² = 0%; 4 trials, 99 participants, GRADE: very low quality) but only one of these four trials had a low risk of bias.

AUTHORS' CONCLUSIONS

We found no definitive, adequately powered RCTs of interventions for people with dysarthria. We found limited evidence to suggest there may be an immediate beneficial effect on impairment level measures; more, higher quality research is needed to confirm this finding.Although we evaluated five studies, the benefits and risks of interventions remain unknown and the emerging evidence justifies the need for adequately powered clinical trials into this condition.People with dysarthria after stroke or brain injury should continue to receive rehabilitation according to clinical guidelines.

Speech intelligibility after gingivectomy of excess palatal tissue

To appreciate any enhancement in speech following gingivectomy of enlarged anterior palatal gingiva. Periodontal literature has documented various conditions, pathophysiology, and treatment modalities of gingival enlargement. Relationship between gingival maladies and speech alteration has received scant attention. This case report describes on altered speech pattern enhancement secondary to the gingivectomy procedure. A systemically healthy 24-year- female patient reported with bilateral anterior gingival enlargement who was provisionally diagnosed as “gingival abscess with inflammatory enlargement” in relation to palatal aspect of the right maxillary canine to left maxillary canine. Bilateral gingivectomy procedure was performed by external bevel incision in relation to anterior palatal gingiva and a large wedge of epithelium and connective tissue was removed. Patient and her close acquaintances noticed a great improvement in her pronunciation and enunciation of sounds like “t”, “d”, “n”, “l”, “th”, following removal of excess gingival palatal tissue and was also appreciated with visual analog scale score. Exploration of linguistic research documented the significance of tongue-palate contact during speech. Any excess gingival tissue in palatal region brings about disruption in speech by altering tongue-palate contact. Periodontal surgery like gingivectomy may improve disrupted phonetics. Excess gingival palatal tissue impedes on tongue-palate contact and interferes speech. Pronunciation of consonants like “t”, “d”, “n”, “l”, “th”, are altered with anterior enlarged palatal gingiva. Excision of the enlarged palatal tissue results in improvement of speech.

Speech and language therapy for dysarthria due to non-progressive brain damage

BACKGROUND

Dysarthria is a common sequel of non-progressive brain damage (typically stroke and traumatic brain damage). Impairment-based therapy and a wide variety of compensatory management strategies are undertaken by speech and language therapists with this patient population.

OBJECTIVES

To determine the efficacy of speech and language therapy interventions for adults with dysarthria following non-progressive brain damage.

SEARCH STRATEGY

We searched the trials registers of the following Cochrane Groups: Stroke, Injuries, Movement Disorders and Infectious Diseases. We also searched the trials register of the Cochrane Rehabilitation and Related Therapies Field. The trials registers were last searched in September 2004. The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2004), MEDLINE (1966 to September 2004), EMBASE (1980 to September 2004), CINAHL (1983 to September 2004), PsycINFO (1974 to October 2004), and Linguistics and Language Behavior Abstracts (1983 to December 2004) were searched electronically. We handsearched the International Journal of Language and Communication Disorders (1966 to 2005, Issue 1) and selected conference proceedings, and scanned the reference lists of relevant articles. We approached colleagues and speech and language therapy training institutions to identify other possible published and unpublished studies.

SELECTION CRITERIA

Unconfounded randomised controlled trials (RCTs).

DATA COLLECTION AND ANALYSIS

One author assessed trial quality. Two co-authors were available to examine any potential trials for possible inclusion in the review.

MAIN RESULTS

No trials of the required standard were identified.

AUTHORS' CONCLUSIONS

There is no evidence of the quality required by this review to support or refute the effectiveness of speech and language therapy interventions for dysarthria following non-progressive brain damage. Despite the recent commencement of a RCT of optimised speech and language therapy for communication difficulties after stroke, there continues to be an urgent need for good quality research in this area.