Magnetic resonance imaging in the evaluation of occult submucous cleft palate.

OBJECTIVE: To explore the application of magnetic resonance imaging (MRI) in the evaluation of patients with occult submucous cleft palate and to use the MRI information obtained to aid in the treatment decision to perform surgery versus behavioral speech therapy. DESIGN: Prospective study with magnetic resonance (MR) images of subjects suspected of having occult submucous cleft palate. SETTING: Hospital and university-based. PATIENTS: Two girls who were 4 years old at the time of palatal surgery. INTERVENTION: Furlow double-opposing Z-plasty. MAIN OUTCOME MEASURES: MR images and clinical speech evaluations. RESULTS: MR images provided evidence of an interruption of levator veli palatini muscle tissue in the midline and a substantial attachment of levator muscle tissue to the posterior border of the hard palate. In addition, MR images for both subjects demonstrated remarkably similar bilateral encapsulating sheaths that contained nonmuscular tissue, as confirmed subsequently during surgery. The encapsulating sheaths interrupted the normal progression of the levator muscle sling across the midline. The MR images led to the decision to perform surgery instead of speech therapy. Hypernasality was markedly reduced in both subjects after surgery. CONCLUSIONS: MRI is an effective technique for diagnosing occult submucous cleft palate and may be an important aid in the treatment decision regarding surgery versus behavioral speech therapy for patients diagnosed with occult submucous cleft palate.

Induced fatigue effects on velopharyngeal closure force.

This investigation studied the effects of induced velopharyngeal fatigue in speakers with normal mechanisms. Five adult female and 5 adult male subjects were used. A force sensing bulb was placed in the velopharynx to measure velopharyngeal closure force and intramuscular electrodes were inserted in the levator veli polatini muscle to sample muscle activation levels. The subjects' task was to repeat the syllable /si/100 times while an external load was placed on the velopharyngeal mechanism. The external load consisted of various levels of air pressure (0 as a control, 5, 15, 25, and 35 cm H2O relative to atmospheric pressure) delivered to the nasal passages via a tube and nasal mask assembly. Fatigue was defined as a declination of force across the series of syllables within a pressure condition and was depicted as the slope of a linear regression line that was fit to the data. The more negative the slope, the greater was the rate of fatigue. Within each experimental pressure condition, small cyclic variations in force were noted about each regression line that corresponded to individual breath groups. This type of declination, within breath groups, has been reported in the literature previously. Overall declination in force over an entire series of syllables and over several breath groups is a new finding. It was possible to induce such fatigue in most subjects, and greater rates of fatigue generally occurred at the higher levels of external loading, i.e., at 25 and 35 cm H2O. Two subjects, 1 male and 1 female, reached exhaustion. The female subject could not perform the syllable repetition task at 25 cm H2O, and the male subject could not complete the task at 35 cm H2O. Three subjects, 1 female and 2 males, exhibited virtually no force declination even at the highest level (35 cm H2O) of external loading. There were no discernable differences in patterns of fatigue or in initial velopharygeal closure force values between the male and female subjects.

A finite element model of the soft palate.

OBJECTIVE: As a step toward better understanding of normal and abnormal velar control, a finite element model of the soft palate was developed. DESIGN: A static two-dimensional midsagittal model of the velum was given physical dimensions to match that of a 10-year-old boy. Biomechanical properties of the tissues were inferred based on previous histologic studies. Velar movements were induced by the influence of three extrinisic velar muscles: the levator veli palatini, the palatoglossus, and the palatopharyngeus, which were simulated as external forces acting on the velar model. RESULTS AND CONCLUSIONS: Velopharyngeal opened and closed positions were simulated as well as a variety of intermediate steps between the two configurations. Velopharyngeal closure was also simulated in a manner appropriate for both high and low vowels. Future extensions of the model will incorporate the muscles as an intrinsic component of the model and will include a full time-dependent implementation, including inertial effects. Future studies will compare model predictions with experimental data from the laboratory, including both kinematic data and velopharyngeal closure forces.

An anatomic study of the tensor veli palatini and dilatator tubae muscles in relation to eustachian tube and velar function.

In a gross anatomic study of 20 sides in 16 human head specimens, the tensor veli palatini, the dilatator tubae, and the tensor tympani muscles were studied. The tensor veli palatini was observed to insert onto the anterior one-third of the pterygoid hamulus, whereas the dilatator tubae rounded the middle one-third of the pterygoid hamulus without an insertion. Thus, the dilatator tubae, not the tensor veli palatini, could serve to tense the anterior velum. An insertion from the superior pharyngeal constrictor muscle onto the posterior one-third of the hamulus could provide a curbing function for the dilatator tubae muscle. Adipose tissue, located at the hamulus, could provide lubrication for the tendinous fibers of the dilatator tubae as they round the hamulus. The dilatator tubae was observed to attach to the hook of the eustachian tube and is accepted as the tubal dilator. Observed on 13 of 20 sides in 11 specimens, the bulk of the dilatator tubae remained distinct from the tensor veli palatini despite a connective tissue alliance and intermingling of some muscle fibers. On 5 of 20 sides in 5 specimens, fibers of the dilatator tubae intermingled extensively with the tensor veli palatini. Of the 20 dilatator tubae muscles dissected, 2 were observed to be deficient. The tensor veli palatini was observed to be continuous with the tensor tympani. Full color versions of the figures are available at the following website: http://www.shc.uiowa.edu/papers/tensor/.

Velopharyngeal closure force and levator veli palatini activation levels in varying phonetic contexts.

The purpose of this study was to measure velopharyngeal closure force in varying phonetic contexts for normal men and women subjects. Levator veli palatini muscle activity was measured as well. Place and manner of articulation, voicing, and the effects of consonant sequencing were studied in different vowel contexts. When the data were grouped by sex of subject, no differences were found in absolute values of velopharyngeal closure force for the men versus women subjects. As expected, nonnasal consonants were produced with greater velopharyngeal closure force than nasal consonants. High vowels were produced with greater closure force than low vowels. Closure force was greater for voiceless than for voiced consonants but only for the men and only within /i/ and /u/ contexts. The lingua-dorsal consonant was associated with greater closure force than the lingua-apical consonant but only for the men and only in the high-back vowel environment. Significant differences in closure force were not found between fricatives or stops. A tendency for greater closure force for the fricative consonant was observed when the fricative followed rather than preceded the nasal consonant. Vowel identity had an effect on closure force during consonant production in the men in that closure force was greater for /s/ and /n/ in high versus low vowel contexts. Men exhibited a larger number of significant differences in closure force than did the women. The results suggest that velopharyngeal closure force is not controlled by a single muscle (the levator veli palatini) but that other muscles and mechanical factors are likely contributors.

Levator veli palatini muscle activity in relation to intraoral air pressure variation in cleft palate subjects.

A comparison of the ranges of levator veli palatini EMG activity for speech versus a nonspeech task for subjects with cleft palate was the focus of this study. EMG values are also compared with subjects without cleft palate obtained in a previous study. Hooked-wire electrodes were inserted into the levator muscle of five adult subjects with cleft palate exhibiting mild hypernasality. Intraoral air pressure was measured concurrently. A blowing task was used to determine the subject's operating range for the levator muscle. Both the nonspeech and speech tasks were designed to sample the widest possible ranges of levator EMG activity. It was found that the subjects with cleft palate used a relatively high activation level for the levator muscle during speech, in relation to their total activation range, compared with the subjects without cleft palate. Implications are discussed in relation to possible anatomic and physiologic differences for cleft palate subjects compared to normal.

Levator veli palatini muscle activity in relation to intraoral air pressure variation.

The purpose of this investigation was to study the operating range of the levator veli palatini muscle for a nonspeech task (blowing) and to determine where in that range levator activity for speech lies. Ten adult subjects without speech or velopharyngeal abnormalities participated. Levator EMG activity for speech occurred in the lower region of the total range for blowing. In two subsequent experiments involving a subset of 4 subjects, it was found that overall effort may have had a small effect on levator activity apart from its role in velopharyngeal closure for aerodynamic purposes. The results of the main experiment are discussed in relation to the concept of threshold of fatigue as it may influence velopharyngeal control mechanisms.

Measurement of velopharyngeal closure force during vowel production.

The purposes of this study were to (a) design and test a new velopharyngeal closure force sensing bulb, and (b) use the closure force bulb to gather additional information on the variations in closure force associated with different vowels. The closure force sensing bulb possessed a flat frequency response to 30 Hz. Its output was highly linear relative to applied gram force. Reliable placement of the bulb in human subjects was achieved following prescribed placement criteria. The bulb was sensitive to small variations in velopharyngeal closure force. In agreement with some previous reports, high vowels were associated with greater velopharyngeal closure forces than low vowels. The results of this investigation support the notion that articulatory goals are specified for vowels. This vowel specificity was observed during production in both isolation and in context.

A quantitative histologic study of the normal human adult soft palate.

This study was designed to re-examine the same soft palates studied qualitatively in a previous investigation (Kuehn and Kahane, 1990), using a true-color image analysis system. The quantified measures of the areas of specific tissue types are reported. The results indicate that: (a) tendinous tissue is prominent anteriorly and comprises about 10% of total tissue in that region, (b) the relative proportion of glandular and connective tissue is fairly uniform across the length of the soft palate, averaging 22% and 36% respectively, (c) muscle tissue shows a pattern of increasing then decreasing amount from anterior to posterior with a maximum proportion of 23% in the midportion of the soft palate, (d) adipose tissue comprises 22% of total tissue area in the anterior segment and 17% of total tissue area in the posterior segment of the soft palate, (e) other tissue, primarily epithelium and vascular tissue, was found to be fairly constant anteriorly and increased in relative proportion to almost 30% of the total tissue area at the uvular base. The functional implications of these findings are discussed.

Levator veli palatini muscle activity in relation to intranasal air pressure variation.

Continuous positive airway pressure (CPAP) therapy can be used to reduce hypernasality by elevating the air pressure in the nasal cavities during speech. The purpose of this study was to determine whether increased intranasal air pressure loads the major muscle of velopharyngeal closure, the levator veli palatini. Nine subjects, four with cleft palate and five without cleft palate, were studied. Electromyographic activity was measured from the levator veli palatini muscle with several levels of air pressure delivered to the nasal cavities using a commercially available CPAP instrument. It was found that levator veli palatini activity was significantly greater for the positive air pressure conditions than for the atmospheric pressure conditions for both subject groups. This indicates that the levator veli palatini muscle acts against the resistive load produced by the increased intranasal air pressure. The results support the use of CPAP therapy as a method of resistance exercise for strengthening velopharyngeal closure muscles.

New therapy for treating hypernasal speech using continuous positive airway pressure (CPAP).

The purpose of this report is to introduce a new therapy technique for treating hypernasality. The instrumentation consists of a continuous positive airway pressure (CPAP) device that delivers air pressure by means of a hose and nasal mask assembly to the nasal cavities. This positive pressure is theoretically useful in providing resistance training to strengthen the velopharyngeal closure muscles. Speech drillwork is conducted in the patient's home and consists of production of VNCV syllables and short sentences with the nasal mask worn by the patient. Incremental changes in CPAP pressure and time per therapy session occur over an 8-week course of therapy. Six case studies are presented. The preliminary results suggest that CPAP therapy may be effective in reducing hypernasality in individuals exhibiting mild to moderate degrees of severity.

Muscle spindles in the velopharyngeal musculature of humans.

Seven muscles in the velopharyngeal region of humans were studied histologically to determine the presence of muscle spindles. Typical spindles were found in palatoglossus and tensor veli palatini with a greater number in the latter. Spindles were not found in levator veli palatini, palatopharyngeus, musculus uvulae, salpingopharyngeus, or the superior pharyngeal constrictor.

Speech status following uvulopalatopharyngoplasty.

The purpose of this study was to evaluate the adequacy of speech following uvulopalatopharyngoplasty surgery. Twenty UPPP subjects, all of whom exhibited obstructive sleep apnea syndrome, and 15 non-UPPP control subjects participated in the study. Evaluation included measures of nasal airflow, speech recordings with listener judgments, and a questionnaire survey. Nasal resonance in the UPPP subjects was found not to be deviant by a panel of four experienced judges. The UPPP subjects were differentiated from their non-UPPP pairs on the basis of significant phonation (voice) problems, and to a lesser extent, their articulation problems. It is suggested that dryness problems that remained in many subjects postoperatively may be related to the observed voice problems.

Histologic study of the normal human adult soft palate.

Detailed information about the tissue components of the soft palate is needed to construct biomechanical models that are functionally useful. Soft palates were removed from 10 adult cadavers, four males and six females. One-half of each palate was further divided into 10 blocks of equal anterior-to-posterior thickness. The face of each block was sectioned and stained using three different stains, thus providing a sample of 300 histologic slides. Each slide was carefully examined and major anatomic characteristics were noted and recorded. The results indicate that a typical adult soft palate consists of several major tissue layers including: (1) the oral aspect, which is glandular with a zone of adipose tissue located somewhat laterally; (2) the two middle layers are muscular with the more inferior layer consisting mainly of transverse levator veli palatini fibers and the overlying longitudinal layer of musculus uvulae fibers; (3) a superoanterior layer consisting of the tensor veli palatini tendon; and (4) a posteroinferior layer consisting of a mixture of tissue that is primarily glandular. The oral mucosa consists of stratified squamous epithelium with a basement membrane that is reinforced with a dense meshwork of elastic fibers. The nasal mucosa consists of pseudostratified ciliated columnar epithelium anteriorly and stratified squamous epithelium posteroinferiorly. The functional implications of these findings are discussed.

An electromyographic study of the musculus uvulae.

The musculus uvulae and the levator veli palatini muscle were studied with electromyography (EMG) in three normal young adult subjects. Patterns of EMG activity for the musculus uvulae were similar to those of the levator veli palatini for all three subjects. When differences in EMG activity between the two muscles were found, the tasks did not involve speech. The presence of the musculus uvulae along the nasal aspect of the velum may be important in filling the space between the elevated velum and the posterior pharyngeal wall. In addition, the musculus uvulae may function to modify stiffness of the tissue adjacent to the insertion of the levator veli palatini and to produce extension of the velum.

Early repair and breast-feeding for infants with cleft lip.

This study attempts to define the effect of early repair and breast-feeding on the outcome of cleft lip surgery. The first part deals with 100 consecutive cleft lip repairs categorized retrospectively by age at operation. Forty-nine patients were operated on during the first 3 weeks of life; 51 at an older age. There were no statistically significant differences in complication rate between the groups (14 and 18 percent, respectively). A subgroup of 26 infants was operated on at a week or less of age; these sustained significantly fewer complications (8 percent). There was no apparent difference in the operative results as defined by whether or not the child needed a subsequent revision. A second group of 60 mothers was offered the choice of breast-feeding their babies immediately following operation. Sixteen breast-fed for a minimum of 6 weeks, 22 were fed by means of a cup or syringe, and 22 started breast-feeding but converted to a bottle within 6 weeks. No complications attributable to breastfeeding were observed, and the rate of weight gain was definitely enhanced in the breast-feeding group. Hospital stay was shortened by an average of over a day (33 percent) as compared with those fed by cup. This effect was related to the easier transition from IV administration to oral intake when breast-fed. We are currently encouraging early repair and breast-feeding in the full-term baby as the optimum method of management of newborns with cleft lip.

Relationships between muscle activity and velar position.

Five normal subjects were used to study the relations between muscle activity and velar position. The speech sample consisted of the sustained sounds /i/, /u/, /s/, nonnasal /a/, and nasalized /a/. Velar position was determined using lateral-view x-rays. Electromyographic activity was measured from hooked-wire electrodes intended to record from the levator veli palatini, palatoglossus, palatopharyngeus, and the superior pharyngeal constrictor muscles. A transnasal approach was used to insert electrodes intended for superior constrictor. It was found that 1) the level of levator activity was not directly related to velar position, 2) for a given velar position the level of levator activity was related to palatoglossus and/or palatopharyngeus activity in most cases, and 3) superior constrictor was active during all speech samples studied, but the level of activity was inconsistent both within and between subjects.

Comparison of methods for measuring velar position from lateral-view cineradiography.

The purpose of this experiment was to compare methods of measuring velar position during speech movements from lateral-view cineradiographic films. Specifically, correlations were calculated between measurements from a radiopaque marker sutured to the oral surface of the velum and three velar measurements that do not involve a radiopaque marker. As the correlations with the marker measurements were relatively high, it is concluded that experimenters may be free to choose any of the measurement procedures. The attachment of radiopaque markers to the velum does not appear necessary for obtaining a reliable and valid estimate of velar movements during speech.