Introduction
Speech and articulation disorders do not necessarily lead to disability but these disorders definitely affect an individual in a multitude of ways. An individual suffering from the congenital disorder cleft palate for example, would most likely exhibit obvious signs and symptoms of speech and articulation impairments, mainly because of the anatomical distortion of the muscles and other facial structures used in articulation. These individuals’ speech may well be distorted for the rest of their lives if left untreated because there is no natural way of repairing damaged articulation structures. There is a statistically significant portion of the infant population suffering from disorders such as the cleft palate and other disorders or diseases that cause malfunction and malformation of the oral and facial structures used in speech and articulation. One of the aims and goals of medicine is to make the lives of patients suffering from practically all forms of disorders, easier and generally, for these people to have a higher quality of life. The thing is that there are still a significant percentage of discerned diseases and disorders that physicians and even surgeons cannot do something about. Well, this idea may actually be partly true if we are still in the early 20th century, a time which was bombarded with a lot of scientific and medical discoveries. Now, thanks to the continuous efforts of medical researchers, more and more advancements—some may even be considered breakthroughs in their respective fields, are being discovered. Add the fact that the vast improvement in technology has also brought machines that make the life of the medical professionals a lot easier not only in terms of addressing medical conditions but also in diagnosing them, and there is no stopping the field of medicine from advancing anymore.
Having a speech or articulation disorder can be quite disturbing especially for an individual who is in the process of transitioning from the late childhood to the early adolescent stage of development. An individual with a cleft palate for example would most likely suffer from low values of self-esteem which can be a result of a lot of social and psychological, and even external factors such as bullying, mockery, etc. The contribution of such factors has so far been proven and is actually already established. In fact, these have been one of the major reasons why experts are pushing themselves on working on finding a solution that would address the speech and articulation that cleft palate patients typically have.
This paper will focus on the recent discoveries related to the diagnosis of distortions in the normal speech and articulation mechanism among patients with speech and articulation disorders. The discussion will mainly focus on Electropalatography (EPG), which has something to do with the mechanism wherein the tongue touches the different surfaces of the mouth, particularly the palates, during speech and enunciation of words . The use of this procedure involves the putting of custom-made thin acrylic pseudo-plates which are mounted in thin electrodes, which can be comparable in size to those used in electric therapy. A typical electropalatography session usually involves the use of 62 electrodes, all of which are placed in approximated areas of the mouth. Most of the electrodes are placed under the hard palate, mainly because it is the structure that the tongue most frequently hits . The 62 electrodes are basically placed inside the mouth, forming 8 horizontal rows and are arranged in a way that the spaces between the electrodes in the first four rows is one half the spaces between the first four rows of electrodes from the back . The special material covering all the 64 electrodes is the one responsible for the transmission of an electrical signal that, under normal conditions, is sent to an external processing unit, which analyzes the different parameters of the contact that exists between the tongue and the specific oral structure it hits—which is most probably covered by an electrode that is why the electrical transmission occurred in the first place. This essentially occurs every time the electrodes are tapped as a result of contact between the tongue and the palate, or basically any other oral surface that would have been covered with electrodes .
Electropalatography Explained
An electropalatograph is essentially an instrument that analyzes the different mechanisms involved during speech. It can analyze the location of the tongue in relation to all other structures used in speech and articulation. Whenever a word is pronounced, it can detect, in real time, where the tongue is, and with which it has contact. Aside from locating structures, it also enables the operator, provided that he is adept in using the electropalatograph, to identify the timing, the rhythm, phasing, and even the rate by which the tongue comes in contact with all the structures it can possibly come in contact with during speech and articulation. An electropalatography procedure provides a real time monitoring or analysis of the parameters of contact between the tongue and the hard palate. It also provides a visual feedback to the operator which generally helps him in diagnosing what type of speech or articulation disorder a patient suffers from by merely identify the phase or phases of normal articulation that is or is impaired in the patient’s case. The findings from an electropalatograph therefore, could well be used by experts in monitoring physically new gestures that may help or ultimately inhibit abnormal patterns exhibited by patients with speech and articulation disorders, or basically those who are undergoing speech therapy . There are simply a lot of things that an EPG can analyze, all of which, of course, must have been related to speech and articulation. It can record palatal, velar, alveolar, and post-alveolar placements with usually the tongue as the reference point, and it can also record and detect specific contact patterns for a wide range of speech and articulation sounds, and even consonants. To test whether an EPG can really detect abnormalities in the parameters of normal speech and articulation, a comparison test has been performed between a normal speaker and a non-normal speaker. The result was as expected. The EPG detected significant differences in the tongue to palate contact patterns and all other parameters between the normal and non-normal speakers. This only proves that using EPG in monitoring and analyzing speech abnormalities in non-normal speakers, or practically those with speech and articulation disorders can be an objective way of diagnosis; particularly, in objectively measuring the contact of the subject’s tongue with his hard palate .
Despite all of the objectivity and accuracy in analyzing the phases of speech and articulation that the procedure offers, this procedure has one limitation—it cannot specifically identify which part of the tongue comes in contact with the hard palate and in the same manner, it also cannot pin point which part of the hard palate comes in contact with the tongue. However, there are certain techniques that an operator knowledgeable in performing the procedure could do to arrive at a compromise. He can, for example, make inferences. Suppose that the monitor shows that the area of the hard palate being hit by the tongue is the anterior half where the first 4 tightly spaced rows of electrodes are most likely placed, the anterior half of the hard palate is actually comprised of the alveolar regions. When the electrodes placed in these regions generate electrical signals, the operator can then identify where the signals come from, provided that he knows the approximation of the electrode placements and which and where is which, and therefore, infer which area of the hard palate gets touched by the tongue. The same inferential principle is actually true and applicable to the posterior half of the hard palate or what is more formally known as the velar and palatal regions. When the tongue comes in contact with the posterior half of the hard palate, the electrodes there of course would react by sending electrical signals to the external processing unit which would then signal the operator what just happened. The rest is the same how an EPG operator can come up with an inference that the subject’s tongue just hit the posterior half of his soft palate during a certain speech or articulation activity. Knowing, this, it can be inferred that using EPG as one of the main diagnostic tools in ruling out speech and articulation disorders is not only promising but also practical and can actually be already regarded as accurate, although some studies suggest that further research should be done to identify more limitations that this diagnostic tool may have that are still unidentified.
An EPG operator, in order to manipulate the machine at its full potential, should have a working, and ideally an intensive knowledge of the anatomy of the muscles and other bodily structure commonly used and associated with speech and articulation, and the physiology by which they work. A comprehensive knowledge of the anatomy and physiology of the velar-pharyngeal mechanism is also of utmost importance to provide accurate assessments and treatment prescriptions for patients who are born with either a cleft lip or palate disorder. It has been established that individuals in their neonatal development changes up to their early adolescent age still experience a significant rate of growth and development, both anatomically and physiologically in their head and neck region, which well covers the muscles of mastication, swallowing, speech and articulation. An EPG operator should be well knowledgeable of these areas of studies because they would not be able to identify what is exactly wrong with the subject that hinders him from speaking or articulating normally or at least at a near-normal basis, if he was not. Being able to know all of the anatomical parts and knowing how to relate these parts to each other in response to a certain reaction—that is physiology. And most importantly, being able to differentiate a normal from an abnormal speech, articulation, anatomic, and physiological pattern of the structures involved is of utmost importance because these would serve as the operator’s main basis of diagnosing the patient and pin pointing the faulty mechanisms.
The posterior pharyngeal wall of the hard palate or what is more practically known as the roof of the mouth (because it basically separates the oral cavity from the nasal cavity) is lined with a tissue, that acts as a muscular valve that forms the velo-pharyngeal mechanism. Aside from this structure, the velo-pharyngeal mechanism is also comprised of the soft palate or the velum, the posterior pharyngeal wall or the back wall of the throat, and the lateral pharyngeal walls or the two sides of the throat . These structures work well together to serve as a tight seal between the pharyngeal walls and the velum to practically separate the nasal from the oral cavity. This of course is the basic description how it happens in a normal person and can vary greatly when we change the subject to an individual with a speech or articulation dysfunction, either functionally or structurally, such as cleft lip or cleft palate. Whenever a person speaks, the velo-pharyngeal mechanism gets activated. It closes tightly so that the person can produce normal sounds. The closure of these flaps is so important. In fact, almost all sounds used in the English language cannot be delivered normally without a normal velo-pharyngeal port mechanism except for m, n, and ng, because these sounds are produced with an open velo-pharyngeal port .
The velum can be anatomically located by examining the space between the uvula and the posterior nasal spine of the hard palate. Naturally, the flaps open when a person breaths, otherwise, that person would die of asphyxia. It is during the production of oral speech sounds that the velum becomes retracted and elevated so that it completely makes contact, in a tight manner, against the pharyngeal wall, a mechanism which makes use of the flow of air inside a tight space, against the posterior pharyngeal wall, producing a variation of sounds. When this happens, the air that would have flown into the nasal cavity after the initiation of the oral speech sound would have been directed towards the oral cavity because the oral and the nasal cavity have already been tightly separated by the enclosed velum. Closure of the velo-pharyngeal mechanism can actually be done by elevating and retracting the velum and vial the less common mechanism which is via the movement of the pharyngeal walls. Moving the lateral pharyngeal walls or contracting them for example, would result in a sphincter-like movement pattern that would of course, lead to a sound. The rest depends on the type of oral speech sound that an individual tries to make or initiate.
What happens with an individual who was born with a cleft lip or palate is that there is no midline tissue that maintains the integrity of the closure of the flaps, which is what makes the flow of the air to towards the nasal cavity impossible. There is a cleft in the tissue and so, the air flows into two directions—towards the nasal and the oral cavity, which normally should be separated because of the closure. Another result of the presence of the flap is the attachment of the muscles responsible for making the oral speech sounds to different areas. The most commonly affected muscle in this way in a person with cleft lip or palate is the Levator Veli Palatini muscle. Now, this muscle normally follows the alignment of the midline of the velum; but since this area or structure is absent in a person with cleft palate, the muscle becomes forcibly attached either or both onto the posterior and or lateral portions of the hard palate . Other muscles that get affected the same way this muscle gets affected are the Palatoglossus and the Palatopharyngeus muscles. One of the muscle groups not typically affected in a person with cleft palate are the superior pharyngeal constrictor muscles and the Salphinopharyngeus muscles.
An EPG can well detect the present abnormalities present in a patient with cleft palate . In fact, this is what an EPG perfectly does. According to a study authored by Lohmander et al. (2011), an EPG assessment is recommended for any patient suffering from any speech and articulation defect before proceeding directly into EPG therapy because this is where the problematic areas of the contact between the areas of the tongue and soft palate are identified, as in the case study conducted by Lohmander et al. (2011) wherein an 11 years old Swedish girl with an isolated cleft palate was analyzed via EPG assessment. What has been discovered about the girl is that she has difficulty forming the consonant t and s sounds because of relatively small velo-pharyngeal impairment, specifically, only the top two rows of the electrodes on the alveolar area are reached. The girl patient as of course immediately referred to EPG therapy and after two months of continuous treatments, “there was a more forward place of articulating whereby the place of articulation was anterior with clearly reduced tongue to palate contact” . The significant improvement after two months of training was reduced after another month of EPG training was conducted to address all the remaining problems. Nonetheless, the improvements with the patient’s ability to articulate sounds were remarkable which makes EPG an effective diagnostic and therapeutic tool in addressing speech and articulation disorders among patients with cleft palate and other related disorders. An example of another related disorder would be cerebral palsy. Cerebral palsy is usually described as a non-progressive insult to one o some neurological structures in the central nervous system which may well include those that are involved in speech production . Research has shown that using an EPG to diagnose any affectation on areas involved in speech and articulation is more than recommended.
Down syndrome may also be well diagnosed and treated using EPG. Wood et al. (2009) studied a child that would produce the sound s as if it was “CH.” They have concluded that even if the patient may be able to accurately pronounce the s, it would get mixed in with responses that were not accurate and were variable which signifies lack of motor control .
Sound System Disorder is another group of disorders that can be well diagnosed and addressed by EPG. “Sound system disorders refer to the heterogeneous group of speech disorders with unknown origins” . In a case presented by Gibbon et al. (1999), a patient named Robbie suffered from this particular group of disorders. Through the use of EPG guided diagnosis and therapy, as well as other interventions such as occupational retraining, his problems in articulating t and d consonants were addressed.
Limitations
Despite the tons of advantages such as the precision and accuracy of EPG findings which could well contribute to the improvements of the patients’ speech and articulation conditions, EPG can also have some limitations. Firstly, it is considerably expensive compared to other more conventional methods of speech and articulation diagnosis and treatment. In fact, even some clinics dedicated to address speech disorders do not have the software and hardware and maintenance capabilities to utilize this kind of equipment. The second limitation is related to the first one. Because of the equipment’s inaccessibility, patients would be prompted to travel to possibly faraway places just to have access to this machine, which in some instances, may prove to be impractical. Thirdly, to achieve a high EPG diagnostic accuracy rate, the patients must be able to provide feedback. Unfortunately, for them to provide feedback, they basically have to understand what happens when and how the machine operates, which can be a very daunting task for the operators . Lastly, the limitation brought about by the continuous growth and development of the oral cavity which results in problems of fitting the pseudo palate would always be present considering the fact that most patients are children.
Conclusion
Gone are the days when patients with speech and articulation defects would have to live with their impairments because through the use of EPG, the problematic areas of their speech and articulation can be easily identified and treated. The accuracy and precision of using this tool or technique has already been proven in the industry. The only factors that limit its widespread use are the expensive price and the steep learning curve both from the operators and the clients’ perspective that has to be undergone before the machine could be used.
References
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Gibbon, F., Stewart, F., Hardcastle, W., & Crampin, L. (1999). Widening access to electropalatography for children with persistent sound system disorders. American Journal of Speech Language Pathology, 319-334.
Lee, A., Gibson, F., & Law, J. (2008). Electropalatography for articulation disorders associated with cleft palate: A Systematic Review. ASHA Conventio.
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Pantelemidou, V., Herman, R., & Thomas, J. (2003). Efficacy of Speech INtervention Using Electropalatography with a Cochlear Implant User. Clinical Linguistics and Phonetics, 383-392.
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Wood, S., Wisehart, J., Hardcastle, W., Cleland, J., & Timmins, C. (2009). The Use of Electropalatography in the Assessment and Treatment of Motor SPeech Disorders in Children with Down's Syndrome. Developmental Neurorehabilitation, 66-75.
