Cleft palate is a common congenital malformation, with a reported incidence of about 0.182%. Due to the presence of abnormalities in physiological structure and multiple functions, it causes impairment in feeding, swallowing, language development, and speech in children with cleft palate, especially the abnormalities in cleft palate speech, which has serious impact on patients’ social, psychological, work and study. In recent years, with the intensive development of sequential cleft lip and palate treatment, there is a growing recognition that cleft palate treatment is not only about restoration of anatomical form, but more importantly, improvement of speech function. The responsibilities of the speech therapist within the medical professional team have also become increasingly clear and important. In addition to preoperative and postoperative functional assessment and training, intervention has expanded to address the entire spectrum of language development and communication skills.
Patients with cleft palate have unique phonological characteristics that require a corresponding understanding of the physiological and pathological basis of cleft palate, on the basis of which their abnormal speech can be evaluated and prepared for speech correction.
1. Anatomical and physiological characteristics of the palate
The palate is anatomically divided into the hard palate and the soft palate, which have very different structures and functions.
1.1 Hard palate
The main structure of the hard palate is bone, located in the anterior part, between the nasal cavity and the oral cavity, shaped like a flat dome, can not move. Its main function is to separate the nasal cavity from the oral cavity to avoid food entering the nasal cavity and nasal secretions flowing into the oral cavity.
The bones that make up the hard palate are mainly the palatine process of the maxilla and the horizontal plate of the jaw. The horizontal plate is thin and has fibers attached to the posterior edge of the palatal tendon membrane of the soft palate and other muscles that support the soft palate and play an important role in the palatopharyngeal closure function of the soft palate by lifting, retreating, and contacting the pharyngeal wall.
Patients with cleft palate will have morphological and structural abnormalities of the hard palate, which are mainly manifested by: clefting of the palatal fornix, the presence of clefts of varying degrees, which can reach the incisal foramen anteriorly and even reach the alveolar process; the hard palate at the cleft site is not connected to the nasal septum, causing the mouth and nasal cavity to be connected; in volume, the hard palate on the affected side will be smaller than on the healthy side.
1.2 Soft palate
The main structure of the soft palate is a muscular, posteriorly located, mantle-like soft tissue structure with a very flexible motor function. The upper edge of the soft palate is the palatal tendon membrane, which allows the soft palate to attach to the posterior edge of the hard palate. Its lower edge is the free edge. In the middle of the free edge is the palatal lobe, flanked by the palatolingual and palatopharyngeal arches. The palatolingual arch is anterior and is connected to the root of the tongue. The palatopharyngeal arch is posterior and is connected to the lateral wall of the pharynx.
The soft palate is mainly composed of the palatopharyngeal muscle, palatoglossus, palatofantoid, palatofantoid and palatopelvic muscles, and is connected to the muscle fibers of the supraglossus, which are distributed in the lateral and posterior pharyngeal walls, forming a complete muscle ring. When pronouncing, due to the contraction of the muscle flap, the soft palate is elevated, the middle and rear 1/3 part of the soft palate approaches the posterior pharyngeal wall and lateral pharyngeal wall, while the supraglottis muscle contracts, making the passage between the oral cavity and the nasal cavity partially or completely temporarily isolated, forming the so-called “palatopharyngeal closure”. Then, through the cooperation of the tongue, lips, teeth and other organs, various speech sounds can be produced.
The muscle composition of the soft palate in cleft palate patients is the same as that of normal people, but due to the different degrees of clefting of the soft palate, the muscle fibers of the five pairs of soft palate muscles are intertwined in the midline of the soft palate in an arch-shaped structure, so that they are attached to the posterior edge of the hard palate and the posterior nasal ridge in a bundle along the edge of the cleft, thus interrupting the complete muscle ring of the palatopharynx. As a result, patients with cleft palate cannot form a “palatopharyngeal closure” and the oral and nasal cavities are connected.
2.Clinical classification of cleft palate
There is no uniform classification method so far, and the common clinical classification is as follows.
2.1 Soft cleft palate Only the soft palate is cleft, sometimes limited to the palatal lobe.
2.2 Incomplete cleft palate Complete clefting of the soft palate with partial clefting of the hard palate; sometimes accompanied by unilateral partial (incomplete) cleft lip, but the alveolar process is often intact.
2.3 Unilateral complete cleft palate The cleft is completely cleft from the palatal lobe to the incisal foramen and is obliquely directed laterally to the alveolar ridge and connected to the alveolar cleft; the margin of the cleft on the healthy side is connected to the nasal septum; the alveolar cleft can be wide with a cleft only; it is often accompanied by ipsilateral cleft lip.
2.4 Bilateral complete cleft palate Often occurs at the same time as bilateral cleft lip; the cleft is in the anterior maxillary portion, each with an oblique cleft to the sides, reaching the alveolar process; the nasal septum, anterior maxillary process and anterior lip portion are isolated in the center.
A few atypical cases are also seen clinically, such as complete cleft palate on one side and incomplete cleft palate on the other side, submucosal cleft (cryptic cleft), missing palatal lobe, and partial cleft of hard palate.
3, Clinical presentation and characteristics of cleft palate
3.1 Abnormalities in the anatomical morphology of the palate The soft and hard palate is completely or partially cleft from back to front; patients with complete cleft palate are seen to have different degrees of fracture and malformation of the alveolar ridge; clinically, some palatal mucosa appears to be intact but is filiform and the bone tissue is missing; such patients have poorly developed soft palate muscles and a deep and large palatopharyngeal cavity, which often manifests itself in the form of syndromes mostly, such as Robin syndrome.
3.2 Sucking dysfunction Because of the cleft palate, which makes the mouth and nose connected, negative pressure cannot be generated in the oral cavity, so the child is unable to suck, or milk overflows from the nostrils, or even chokes on milk, which affects feeding, causing feeding difficulties for the child, and also easily induces respiratory infections, which to some extent affects the healthy development of physical growth of the child. For newborns with sucking difficulties, examination of the palate and pharynx is needed to exclude abnormalities such as cleft palate, cleft palate occlusion, and palatal motor nerve palsy.
3.3 Cleft palate speech Cleft palate speech is characterized by excessive nasality, nasal leakage, compensatory speech, and some other abnormal speech. Cleft palate voice is an important factor affecting the quality of life of cleft palate patients. Even through surgical treatment, the abnormal state of voice cannot be completely improved and corresponding voice therapy is needed.
3.4 Alteration of the self-cleaning environment of the oral and nasal cavities Cleft palate causes direct communication between the oral and nasal cavities.
3.5 Malocclusion Complete cleft palate is often accompanied by a complete or incomplete cleft lip with a wide alveolar cleft. After the repair of cleft lip, the alveolar process on the affected side collapses inward and the dental arch is abnormal.
3.6 Hearing impairment In patients with cleft palate, some muscular damages, especially abnormal attachment and reduced mobility of palatal sail tensor and palatal sail raphe, lead to poor opening ability of the eustachian tube and affect the balance of middle ear airflow, making patients susceptible to exudative otitis media. At the same time, due to the inability to form palatopharyngeal closure, food reflux often occurs during swallowing, which can easily cause infection of the eustachian tube and middle ear.
3.7 Maxillary developmental disorders A significant number of patients with cleft palate often have maxillary hypoplasia, which becomes more pronounced with age, resulting in reverse B or open B and midface depression deformities. In addition, there are also some patients with overdeveloped mandibles. These patients have oversized mandibular angles, oversized chin points, and a wrong B sometimes in the form of an open B, which aggravates the depressed deformity of the midface.
4, classification of cleft palate dysarthria
At present, most domestic reference to the classification method of Shanghai Jiaotong University Cleft Lip and Palate Treatment Center, the cleft palate dysarthria is divided into two major categories.
4.1 Speech disorders caused by palatopharyngeal closure insufficiency
4.1.1 Vocal hilar burst foreign speech pathologists consider vocal hilar burst to be representative of cleft palate speech; it is more common in older patients in China.
4.1.2 Pharyngeal fricative sound Clinically, it is often accompanied by the same degree of vocal fold burst sound, which is considered to be representative of abnormal speech after cleft palate surgery in China.
4.1.3 Pharyngeal bursting sounds Simple or typical pharyngeal bursting sounds are not very common in our clinic.
4.2 Speech disorders caused by non-palatopharyngeal closure insufficiency
This is a category of voice disorders that was only gradually recognized and acknowledged by speech pathologists in developed countries in the 1980s
It is a type of abnormal speech that occurs in patients after cleft palate surgery. With the introduction of cleft palate surgery in younger patients, the number of patients with non-palatopharyngeal insufficiency voice disorders is increasing, with an increasing trend in China this year.
4.2.1 Palatalized Constructed Speech It has been reported in foreign literature that such abnormal speech can occur in up to 82% after undergoing cleft palate surgery at a young age. Because it is clinically very different from traditional post-operative cleft palate patients with high speech intelligibility and no clinical symptoms such as excessive nasality, it is often easily overlooked, thus missing the ideal time for treatment.
4.2.2 Lateralized constructions are currently more common in clinical abnormal speech, and a functional abnormal speech is also more common in the normal population in clinical practice.
4.2.3 Nasal diction Very rare in patients with simple postoperative cleft palate and easily mistaken for abnormal speech caused by palatopharyngeal closure insufficiency in clinical practice.
In the last three decades, despite continuous innovations and improvements in surgical procedures and skills for cleft palate patients, a significant proportion of patients still present with palatopharyngeal closure insufficiency after cleft palate surgery, with up to 78% reported recently in China. The assessment of speech intelligibility in patients with cleft palate is still based on human auditory hearing, and there is no domestic or foreign instrument that can replace the auditory examination by professionals.