Artificial Palate Research Articles

DEVELOPMENT AND DESIGN OF ARTIFICIAL PALATE MATERIALS FOR SPEECH TREATMENT: A REVIEW

With the advancement of technology, various denture base materials have been developed with enhanced mechanical and physical properties. Because the mechanical properties of the denture base play a significant role in its clinical lifespan, this systematic review aims to examine the effects of various additives added to polymethyl methacrylate (PMMA) denture base materials on the physical (surface properties, water sorption) and mechanical (flexural strength, impact strength, thermal conductivity) properties of the denture base and can then be used to produce artificial palates. An electronic database search of peer-reviewed published papers in English was conducted using relevant keywords between the 23rd of August 2016 and the 24th of August 2022. The database yielded 1048 relevant published articles. However, 21 articles were qualified for this study after considering the inclusion and exclusion criteria. A substantial body of literature demonstrates that zirconium ZrO2 is widely used as an additive in the modification of PMMA. Meanwhile, flexural strength is the most conducted test based on the literature.

Effectiveness of the novel impression tray "cleftray" for infants with cleft lip and palate: a randomized controlled clinical trial.

ObjectivesCleft lip and palate (CLP) is one of the most common congenital deformities with worldwide prevalence. It causes a range of issues for infants that mainly involve difficulty in feeding due to abnormal oronasal communication. For this purpose, feeding plates are provided to infants to act as an artificial palate to aid in feeding. The most crucial procedure in fabrication of a feeding plate is creation of the impression using the traditional finger technique or impression trays. This preliminary research aims to compare the effectiveness of novel impression trays with that of the traditional finger technique for recording impressions of infants with CLP.Materials and MethodsThis randomized controlled trial was conducted among 30 infants who were divided into two groups based on the method of obtaining impressions Group I, finger technique; Group II, specialized acrylic tray (cleftray).ResultsUse of cleftray required less impression time, a reduced amount of material, no incidence of cyanosis/choking in infants, and lower anxiety among doctors compared to the traditional method. Additionally, there was no distortion of cleft impressions, recorded maxillary tuberosity, or other fine details. Therefore, the novel impression tray (cleftray) exhibited superior outcomes in all the parameters compared to the finger technique.ConclusionWithin the limitations of this study, we conclude that impression trays are superior to the traditional finger, spoon, or ice cream stick methods of creating impressions of CLP. However, it is necessary to conduct more clinical trials on a larger population based on other parameters to compare the effectiveness of the two techniques to draw definitive conclusions.

Articulating Alternatives: Moving Past a Plug-and-Play Prosthetic Media Model

Articulating Alternatives: Moving Past a Plug-and-Play Prosthetic Media Model

Contact Pattern of Alveolar Consonants in the Malay Consonants of Paralysis Subject using Electropalatography

Place of articulation plays an important part to produce different sounds. Besides the place of articulation, tongue is also an active articulator during a continuous speech. During the speech, the tongue moves around creating different sounds when it is placed at different place of articulation. The movement of tongue is controlled by muscles. The lack of muscle movement will produce inactive tongue movement. Paralysis is an example of the muscle weakness in a person resulting in difficulties to move. Paralysis may occur due to several factors including stroke and spinal cord injury (SCI). One of the indirect effects of paralysis is slurred speech and difficulty in speaking. This study aims to determine the contact pattern of five paralysed subjects during speech production of alveolar consonants in the Malay Language. The subjects had paralysis due to different aetiologies and with different medical history backgrounds. All participants were required to produce five single consonants; /d/, /t/, /l/, /n/ and /s/. The data recording was done in a studio laboratory with a soundproof system. The device used for detecting the tongue and hard palate contact in this study was electropalatography (EPG). Subjects were required to wear the artificial palate consists of 62 sensors to detect the tongue and hard palate contact. The speech contact was analysed using Articulate Assistant 1.18TM. The results were then compared with the average contact pattern of Malay speaker which had been obtained in the previous study. In conclusion, the subjects who had frequent treatments produced better articulation and the subjects with positive attitudes produced better articulation during the treatment process.

Visualisation and Analysis of Speech Production with Electropalatography.

The process of speech production, i.e., the compression of air in the lungs, the vibration activity of the larynx, and the movement of the articulators, is of great interest in phonetics, phonology, and psychology. One technique by which speech production is analysed is electropalatography, in which an artificial palate, moulded to the speaker’s hard palate, is introduced in the mouth. The palate contains a grid of electrodes, which monitor the spatial and temporal pattern of contact between the tongue and the palate during speech production. The output is a time sequence of images, known as palatograms, which show the 2D distribution of electrode activation. This paper describes a series of tools for the visualisation and analysis of palatograms and their associated sound signals. The tools are developed as Matlab® routines and released as an open-source toolbox. The particular focus is the analysis of the amount and direction of left–right asymmetry in tongue–palate contact during the production of different speech sounds. Asymmetry in the articulation of speech, as measured by electropalatography, may be related to the language under consideration, the speaker’s anatomy, irregularities in the palate manufacture, or speaker handedness (i.e., left or right). In addition, a pipeline for the segmentation and analysis of a three-dimensional computed tomography data set of an artificial palate is described and demonstrated. The segmentation procedure provides quantitative information about asymmetry that is due to a combination of speaker anatomy (the shape of the hard palate) and the positioning of the electrodes during manufacture of the artificial palate. The tools provided here should be useful in future studies of electropalatography.

Use of artificial palate for improving facial support in the fabrication of a maxillary obturator: A case report

Use of artificial palate for improving facial support in the fabrication of a maxillary obturator: A case report

Motor Equivalent Strategies in the Production of German /∫/ under Perturbation

The German sibilant /∫/ is produced with a constriction in the postalveolar region and often with protruded lips. By covarying horizontal lip and tongue position speakers can keep a similar acoustic output even if the articulation varies. This study investigates whether during two weeks of adaptation to an artificial palate speakers covary these two articulatory parameters, whether tactile landmarks have an influence on the covariation and to what extent speakers can foresee the acoustic result of the covariation without auditory feedback. Six German speakers were recorded with EMA. Four of them showed a covariation of lip and tongue, which is consistent with the motor equivalence hypothesis. The acoustic output, however, does not stay entirely constant but varies with the tongue position. The role of tactile landmarks is negligible. To a certain extent, speakers are able to adapt even without auditory feedback.

Electropalatography data from Central Arrernte: A comparison of the new Articulate palate with the standard Reading palate

This paper presents electropalatography (EPG) data from two female speakers of Central Arrernte, a language with six places of articulation, including four coronal contrasts. Both speakers were recorded reading the same list of words using two different types of artificial palate: the standard Reading palate, and the new Articulate palate. Data are presented from seventeen lingual consonants of this language. It is suggested that since the Articulate palate provides more coverage of the velar and dental regions, it may be able to better capture the crucial laminal and apical distinctions that exist in Australian languages such as Central Arrernte. However, caution is advised in interpreting the results from the two different types of artificial palate, since for many consonants, palatograms as well as values for standard analysis measures differ greatly between the two palate types.

Articulatory and acoustic adaptation to palatal perturbation

Previous work has established that speakers have difficulty making rapid compensatory adjustments in consonant production (especially in fricatives) for structural perturbations of the vocal tract induced by artificial palates with thicker-than-normal alveolar regions. The present study used electromagnetic articulography and simultaneous acoustic recordings to estimate tongue configurations during production of [s š t k] in the presence of a thin and a thick palate, before and after a practice period. Ten native speakers of English participated in the study. In keeping with previous acoustic studies, fricatives were more affected by the palate than were the stops. The thick palate lowered the center of gravity and the jaw was lower and the tongue moved further backwards and downwards. Center of gravity measures revealed complete adaptation after training, and with practice, subjects' decreased interlabial distance. The fact that adaptation effects were found for [k], which are produced with an articulatory gesture not directly impeded by the palatal perturbation, suggests a more global sensorimotor recalibration that extends beyond the specific articulatory target.

Dependency of compensatory strategies on the shape of the vocal tract during speech perturbed with an artificial palate.

When adapting to an articulatory perturbation, different speakers may use different strategies. This study investigates the hypothesis that the choice of strategy depends on vocal tract shape. Vowel production was perturbed with prostheses that changed palatal shape. Three speakers had a prosthesis that effectively moved the alveolar ridge posteriorily; three others had a prosthesis that effectively flattened the palate. EMA recordings of speakers’ adaptive behavior showed that during the production of the vowel /y/, the speakers with the alveolar prosthesis compensated by using increased lip protrusion. The speakers with the flat prosthesis used about the same amount of lip protrusion as without perturbation. We hypothesize that this is because for the first group of speakers the main constriction in the vocal tract was moved forward due to the changed palatal outline: the front cavity became too short, which was compensated for by more lip protrusion. This hypothesis is being explored by determining whether the DIVA speech production model will produce compensations like the subjects when the model’s vocal tract is adapted to fit individual vocal tract shapes using detailed information about the subjects’ vocal tracts from MRI recordings. Complete results will be reported and discussed. [Work supported by DAAD, NIH.]

Application of palatal RB obturator in babies with isolated palatal cleft

Isolated cleft of secondary palate has a specific clinical picture due to a wide communication between the mouth and nose cavity. As a consequence of that, babies born with this malformation are often subject to infections of the upper bronchial tubes, middle ear, speech disorders, and certainly the most difficult existential problem they face at the very beginning of their lives, the impossibility of suckling (breast feeding). Such babies have to be fed with gastric probe. The difficulties in their nutrition have often been described in literature, yet a singular attitude toward early orthodontic therapy has not been adopted still. The aim of the paper was to describe a design and application of obturator immediately after the birth of a baby with isolated palatal cleft, and the role in feeding. We presented a female neonate, born on 27th December 2007, with a wide fissure in the shape of the letter U over the entire secondary palate. The baby was referred to the Stomatology Clinic due to nutrition impossibility. To avoid feeding with gastric probe, the formation of RB obturator was performed (artificial palate). Hereby, the procedure of obturator making with an explanation of its function is presented. The application of RB obturator and the necessary education of parents have a major role in shortening the time of breast feeding and increasing the amount of food intake and, thus, for the normal growth and development of newborn infants with isolated palate cleft.

Influence of a Standard Electropalatography Artificial Palate Upon Articulation

Objective: This study investigated the influence of a standard electropalatography (EPG) palate upon speech articulation in 3 normal speakers under standard EPG testing conditions. Patients and Methods: Three adult females aged 26, 31 and 34 years read the experimental phrase ‘say CV again’ 5 times under 3 experimental conditions: normal speech (without a palate in situ), 45 min after EPG palate insertion and 3 h after EPG palate insertion. Consonants and vowels commonly used in EPG research were studied and included /t/, /s/ and /∫/ in the /i/, /a/ and /u/ vowel environments. Perceptual and acoustic analysis of the data was completed. Results: The results revealed varied patterns of adaptation across the 3 participants. Perceptual analysis suggested that 2 of the participants adapted to the presence of the palate; however, 1 did not. The presence of the palate resulted in significant changes to consonant duration for all 3 participants. Spectrally, production of /t/ was unaffected by the presence of the palate, while articulation of fricatives varied across the participants. Conclusion: Paired with a previous study examining the effects of an EPG palate upon speech articulation [McLeod S, Searl J: Am J Speech Lang Pathol 2006;15:192–206], the present data suggest that researchers and clinicians alike should be aware of the potential perturbing effects of the palate.

Electropalatographic (EPG) assessment of tongue‐to‐palate contacts in dysarthric speakers following TBI

The aim of the investigation was to compare EPG‐derived spatial and timing measures between a group of 11 dysarthric individuals post‐severe TBI and 10 age‐ and sex‐matched neurologically non‐impaired individuals. Participants of the TBI group were diagnosed with dysarthria ranging from mild‐to‐moderate–severe dysarthria. Each participant from the TBI and comparison group was fitted with a custom‐made artificial acrylic palate that recorded lingual palatal contact during target consonant production in sentence‐ and syllable‐repetition tasks at a habitual rate and loudness level. Analysis of temporal parameters between the comparison and TBI groups revealed prolonged durations of the various phases of consonant production, which were attributed to articulatory slowness, impaired speech motor control, impaired accuracy, and impaired coordination of articulatory movements in the dysarthric speakers post‐TBI. For the spatial measurements, quantitative analysis, as well as visual inspection of the tongue‐to‐palate contact diagrams, indicated spatial aberrations in dysarthric speech post‐TBI. Both the spatial and temporal aberrations may have at least partially caused the perceptual judgement of articulatory impairments in the dysarthric speakers.

Acoustic and perceptual analysis of speech adaptation to an artificial palate

The study investigated adaptation to a standard electropalatographic (EPG) practise palate in a group of eight adults (mean age = 24 years). The participants read the phrase “a CVC” over four sampling conditions: prior to inserting the palate, immediately following insertion of the palate, 45 minutes after palate insertion, and 3 hours after insertion of the palate. Perceptual and acoustic analyses were conducted on the initial CV portion of the stimuli. Consonants examined included: /t/, /k/, /s/, and /∫/ followed by the /i/, /a/, and /u/ vowels. Results revealed that individuals within the group were able to adapt their speech articulation to compensate for the presence of the artificial palate. Perceptually, mild consonant imprecision was observed upon insertion of the palate; however, this resolved following 45 minutes to 3 hours of adaptation. Acoustic findings indicated that the palate did not affect segment durations or vowel formant frequencies. However, a significant reduction in M1 for /s/ persisted across the sampling periods. Overall, the results suggest that a period of between 45 minutes and 3 hours of adaptation is generally suitable for participation in EPG studies.

Adaptation of speech production to palatal perturbation: Kinematic analysis using electromagnetometry

The extent to which adults are able to flexibly adapt their speech production to altered sensory-motor conditions has considerable implications for oral-motor rehabilitation, yet it remains poorly understood. Previous studies have explored the effects of different physical and perceptual perturbations on speech production, yielding mixed results with respect to the timecourse and extent of adaptation. A major limitation of these studies has been their reliance on acoustical measures as the sole index of motor adaptation. The difficulty with such an approach is the potentially complex relationship between acoustic changes and their underlying articulatory patterns. In the present study, speech adaptation to a palatal perturbation (5-mm thickened alveolar ridge) was investigated by directly measuring articulatory kinematics using electromagnetometry. In contrast to previous claims, subjects were found to produce a significant change in speech-related tongue movement immediately upon insertion and removal of the artificial palate. In addition, subjects gradually fine-tuned their tongue position with continued practice. The observed patterns are consistent with the idea of two independent adaptation processes: a rapid adaptation process that is driven by the mere presence of the false palate and a slower adaptation process driven by the continued presence of the palatal perturbation.

Electropalatographic, acoustic, and perceptual data on adaptation to a palatal perturbation

Exploring the compensatory responses of the speech production system to perturbation has provided valuable insights into speech motor control. The present experiment was conducted to examine compensation for one such perturbation-a palatal perturbation in the production of the fricative /s/. Subjects wore a specially designed electropalatographic (EPG) appliance with a buildup of acrylic over the alveolar ridge as well as a normal EPG palate. In this way, compensatory tongue positioning could be assessed during a period of target specific and intense practice and compared to nonperturbed conditions. Electropalatographic, acoustic, and perceptual analyses of productions of /asa/ elicited from nine speakers over the course of a one-hour practice period were conducted. Acoustic and perceptual results confirmed earlier findings, which showed improvement in production with a thick artificial palate in place over the practice period; the EPG data showed overall increased maximum contact as well as increased medial and posterior contact for speakers with the thick palate in place, but little change over time. Negative aftereffects were observed in the productions with the thin palate, indicating recalibration of sensorimotor processes in the face of the oral-articulatory perturbation. Findings are discussed with regard to the nature of adaptive articulatory skills.

Speech production in Parkinson's disease: I. An electropalatographic investigation of tongue‐palate contact patterns

Previous studies have indicated that consonant imprecision in Parkinson's disease (PD) may result from a reduction in amplitude of lingual movements or articulatory undershoot. While this has been postulated, direct measurement of the tongue's contact with the hard palate during speech production has not been undertaken. Therefore, the present study aimed to use electropalatography (EPG) to determine the exact nature of tongue‐palate contact in a group of individuals with PD and consonant imprecision (n = 9). Furthermore, the current investigation also aimed to compare the results of the participants with PD to a group of aged (n = 7) and young (n = 8) control speakers to determine the relative contribution of ageing of the lingual musculature to any articulatory deficits noted. Participants were required to read aloud the phrase ‘I saw a ___ today’ with the artificial palate in‐situ. Target words included the consonants /l/, /s/ and /t/ in initial position in both the /i/ and /a/ vowel environments. Phonetic transcription of phoneme productions and description of error types was completed. Furthermore, representative frames of contact were employed to describe the features of tongue‐palate contact and to calculate spatial palatal indices. Results of the perceptual investigation revealed that perceived undershooting of articulatory targets distinguished the participant group with PD from the control groups. However, objective EPG assessment indicated that undershooting of the target consonant was not the cause of the perceived articulatory errors. It is, therefore, possible that reduced pressure of tongue contact with the hard palate, sub‐lingual deficits or impaired articulatory timing resulted in the perceived undershooting of the target consonants.

Variation in articulatory timing of three English consonants: an electropalatographic investigation

Increasingly, electropalatography (EPG) is being used in speech pathology research to identify and describe speech disorders of neurological origin. However, limited data currently exists that describes normal articulatory segment timing and the degree of variability exhibited by normal speakers when assessed with EPG. Therefore, the purpose of the current investigation was to use the Reading EPG3 system to quantify segmental timing values and examine articulatory timing variability for three English consonants. Ten normal subjects repeated ten repetitions of CV words containing the target consonants /t/, /l/, and /s/ while wearing an artificial palate. The target consonants were followed by the /i/ vowel and were contained in the carrier phrase 'I saw a _'. Mean duration of the approach, closure/constriction, and release phases of consonant articulation were calculated. In addition, inter-subject articulatory timing variability was investigated using descriptive graphs and intra-subject articulatory timing variability was investigated using a coefficient of variation. Results revealed the existence of inter-subject variability for mean segment timing values. This could be attributed to individual differences in the suprasegmental features of speech and individual differences in oral cavity size and structure. No significant differences were reported for degree of intra-subject variability between the three sounds for these same phases of articulation. However, when this data set was collapsed, results revealed that the closure/constriction phase of consonant articulation exhibited significantly less intra-subject variability than both the approach and release phases. The stabilization of the tongue against the fixed structure of the hard palate during the closure phase of articulation may have reduced the levels of intra-subject variability.

Compensatory responses of articulators to unexpected perturbation of the palate shape

This paper describes compensatory articulatory behavior in response to an unexpected perturbation of the oral cavity. A mechanical device was used to change dynamically the thickness of an artificial palate; the thickness of the un-inflated artificial palate was increased or the thickness of the already inflated artificial palate was decreased. The palatal perturbations were introduced under conditions of normal and masked auditory feedback. Acoustic, perceptual, and speech movement changes were examined in response to the experimental conditions. An EMA system was used to look for evidence of compensatory articulation during the utterance of repeated CV syllables containing fricative /∫/ and affricate /t∫/. When perturbation by palatal inflation was randomly given just before the initial syllable in the repeated fricative syllable, there was frequent overshoot of the tongue in forming the constriction, causing speech errors in the first syllable with the fricative. Compensation by the tongue for the unexpected palatal inflation became evident around the second syllable and the speech error disappeared in the successive syllables. Even when auditory feedback was masked, rapid compensatory articulation of the tongue was observed around the second syllable, but speech errors randomly occurred in the successive syllables. This fact suggests that tactile feedback gathered by sensing contact between tongue and inflated artificial palate is primarily used to develop the rapid compensation, and that auditory feedback is used in finely adjusting articulation with a longer time lag.

Compensatory articulatory behavior to immediate structural perturbation of the oral cavity

Speech compensation to the structural perturbation of the oral cavity was investigated by using an artificial palate whose thickness in the alveolar region is dynamically changeable. The artificial palate was constructed with a base and thin rubber attached to the base, and the rubber balloon was dynamically controlled by means of an external air flow. The articulatory behavior with the structural perturbation was recorded using an electromagnetic articulographic system. A set of VCV syllables uttered in the carrier sentence, containing the consonants /s, sh, t, n/ and the vowels /a, i, u/, was used for the test. Unexpected perturbation of the palate shape, a change in thickness of 1 to 4 mm, caused significant speech articulation errors for the fricative consonants, fictive consonants /s, sh/ changed to the stop consonants /t, ch/. On the contrary, the stop consonant /t/ was very robust to unexpected perturbation. After five to seven speaking trials with the modified palate shape with or without audio feedback, these articulation errors disappeared and the subject could produce correctly perceived consonants. Then, the articulatory compensation in the alveolar region significantly appeared in the tongue tip position but was small in the jaw and the lip positions.