Calnan [6] defined SMCP as the imperfect union of muscles that cross the soft palate, and patients with SMCP have shown soft palate shortness and velopharyngeal closure, which resulted in hypernasality and unintelligible speech [2]. This report established Calnan’s triad as criteria for diagnosis SMCP, which included bifid uvula, clear lining in the middle of the soft palate, and the absence of a bony notch in the posterior margin of the hard palate, as found in patient with SMCP [7]. However, not all patients with SMCP show this triad of signs; some patients present only one or two signs.
Also, cleft palate muscle malposition may occur in the absence of the triad signs, which is a condition that has been identified as occult submucous cleft palate (OSCP). OSCP is difficult to recognize by oral examination alone but can be confirmed during surgery [2, 8].
The major symptoms of SMCP are hypernasality (51%) due to motile incompetence in the soft palate and pharyngeal muscles, as well as conductive hearing loss (45%) [3, 9]. Palatoplasty is performed to connect palate muscles to stretch the length of the soft palate. However, the postoperative frequency of VPI has been reported to range from 20 to 50%, even with successful surgery [10]. Accordingly, it is necessary to proceed with prosthetic treatment using a combination of speech aid and speech therapy to provide an ideal treatment [9].
Sphincteric interaction of the palate in the pharynx is very important for producing intelligible speech [10]. Speech problems that include hypernasality may arise when these palate muscles function inappropriately. There are mainly three muscles that affect velopharyngeal closure. First, during the contraction of levator veli palatini muscles, the soft palate is lifted and conveyed into the posterior direction. Superior pharyngeal constrictor muscles move to constrict the pharyngeal cavity in a circular shape by moving forward and to the inside of the pharynx’s lateral wall. Last, uvula muscles provide thickness at the posterior position [4].
Velopharyngeal dysfunction (VPD) is a general term that describes an inappropriate function of velopharyngeal port [11]. Velopharyngeal insufficiency (VPI) is a congenital or acquired condition in which the velopharynx has not closed due to a lack of soft tissue. The most common cause of VPI is cleft palate, including SMCP and occult submucous cleft palate. These patients present hypernasality, nasal emission, and reduced speech intelligibility [4]. Velopharyngeal incompetence refers to a functional velopharyngeal impairment that is due to neuromuscular diseases, such as cerebral palsy, myotonic dystrophy, and cerebral vascular accidents. Also, velopharyngeal mislearning (VPM) indicates speech problems with learning a language, which are not caused from anatomical or neurophysiological reasons [12].
In order to treat velopharyngeal insufficiency and incompetence, surgical intervention should be considered combined with prosthetic treatment and speech therapy. And surgical intervention is the first line of treatment. Although there are various surgical procedures, the operation has a success rate of about 50%. Speech aids can be a good alternative when surgical treatment is not considered.
Speech aid consists of the maxillary portion (palatal portion) covering the palate, the pharyngeal portion (functional part), and the palatal extension that connects between of them. Speech aids can be divided into speech bulbs and palatal lift depending on the functional part [2]. The functional part of speech bulb directly closes the opened velopharyngeal port during pronouncing [13]. The functional part of palatal lift is placed on the soft palate and elevates the soft palate to the posterosuperior position [12].
During treatment with speech aids, periodic speech therapy and assessment are essential, and if the nasality and speech intelligibility of the patients are normal without nasal emission, time-based reduction program of the functional part can be initiated [11]. Finally, when the patient sounds the same whether the appliance is worn or removed, the appliance may then be removed permanently.
After reduction therapy, if the appliance cannot be reduced additionally or removed entirely, an appropriate surgical procedure may then replace it.
In this case, the patient showed much progress in nasalance and speech intelligibility using palatal lift and speech therapy without any surgical intervention. It suggests that conservative treatment without surgical intervention may be an effective treatment for SMCP patients with VPI.