Intraoral Air Research Articles

Temporary obturation of anterior residual clefts: Preliminary clinical report

In bilateral cleft lip and palate children, reflux of liquids and food into the nasal cavity, hypernasality and other speech deficiencies, displacement and risk of traumatic injuries to the premaxilla may be consequences of delayed surgical closure of the anterior palate. To address these problems, temporary obturation was undertaken with a newly designed orthopedic plate. The plate was well accepted by the ten consecutively treated patients and obturation was achieved in a clinical sense. The position of the premaxilla was corrected and maintained. Speech and intraoral air pressure were assessed. Both abilities improved with training and time after insertion of the plate.

The effects of auditory feedback on the regulation of intraoral air pressure during speech

Previous experimental evidence has been interpreted as support for regulation of both acoustics and aerodynamics during speech production. One recent perspective is that although speech acoustics may be manipulated, regulation of aerodynamics is a central component of the processes that produce speech. From this perspective, it has been suggested that aerodynamic regulation is given priority over perceptual accuracy. The experiment attempted to test this hypothesis by forcing speakers into a choice between aerodynamic and acoustic regulation. The intensity level of frication (embedded in a carrier phrase) was selectively amplified or attenuated and fed back to the speaker on line. Intraoral air pressure was recorded in order to assess whether or not perturbed auditory feedback would result in aerodynamic compensation. Although compensatory changes in peak intraoral air pressure, pressure duration, and pressure curve area were seen in response to 30-dB alterations of frication, no systematic effects were seen for smaller auditory manipulations. Further, the compensations were less than what one might expect from a system controlling auditory output. Explanations of these findings and their implications for the control of speech production are offered.

Cheek and lip pressure against maxillary dental arch during dummy sucking

The sucking pattern and intra-oral negative air pressure were studied simultaneously with the cheek/lip pressure in 12 children when sucking a dummy. The cheek/lip pressure was measured at the canine and at the second primary molar on the right side of the upper dental arch. The cheek/lip pressure peaks followed the intra-oral negative air sucking pressure peaks continuously. In the canine region the mean value of maximum cheek/lip pressure was 54 g/cm2. The corresponding value at the second primary molar was 21 g/cm2. During dummy sucking the mean cheek/lip pressure was 3.4 times higher against the canine compared to the second molar (P less than 0.001). The intra-oral negative air pressure was approximately the same whether the cheek/lip pressure was measured at the canine or at the second primary molar. The results indicated that the circumoral muscles were especially active during dummy sucking, in addition to the cheek pressure in the canine region.

A Comparison of Selected Phonatory Behaviors of Healthy Aged and Young Adults

Selected phonatory behaviors of healthy aged and young men and women were compared. Inverse-filtered air flow, electroglottograph (EGG), and intraoral air pressure signals were recorded as subjects phonated in each of four conditions: normal, soft, loud, loud/high pitched. Minimum flow offset, flow amplitude, air flow duty cycle, EGG duty cycle, estimated subglottal pressure, and fundamental frequency were derived from the recorded signals and compared among age/gender groups. Males had significantly greater flow amplitude than females regardless of age. Significant Age x Sex interactions were found for fundamental frequency and duty cycle measures. Duty cycles and fundamental frequency increased for males and decreased for females with aging. For the normal phonatory condition, aged men had significantly greater duty cycle measures, flow amplitude, and estimated subglottal pressure than young men. There were significant differences in fundamental frequency and EGG duty cycle between aged and young women during normal phonation. It was concluded that the effects of aging on phonatory behaviors are different in degree and kind for men and women. Fewer significant age-related differences in phonatory measures for women than men were consistent with reports of less age-related laryngeal degeneration in females than males.

Pneumoparotid: A case report

Pneumoparotid is an unusual condition resulting from air being forced into the parotid ductal system. When it develops, it is a result of increased intraoral air pressure. Diagnosis is based on the etiologic factor, palpatory evidence of tissue emphysema, the escape of frothy saliva from the involved duct, and the sialographic finding of retained ductal air and ductal infection.

A system for signal processing and data extraction from aerodynamic, acoustic, and electroglottographic signals in the study of voice production

A software system, implemented in the MITSYN languages, is described for signal processing and data extraction from oral airflow, intra-oral air pressure, vocal fold contact area (EGG) and sound pressure signals. Signal processing algorithms are specified in the form of block diagrams; examples are shown for demultiplexing signals into bandwidth-specific, time-aligned signal stream files and for inverse filtering the oral airflow waveform to obtain an approximation of the glottal airflow waveform. Interactive and algorithmic data extraction is performed with a menu-driven procedure that displays the stages of analysis, graphical indications of the results of algorithmically made decisions, and derived results. The system has proven to be useful for obtaining quantities of detailed data on voice production.

The dental amalgam issue. A review

Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included. New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included. It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.

Exposure to mercury vapor during setting, removing, and polishing amalgam restorations

The level of mercury vapors in the oral cavity was determined by analyzing 242 samples of intra-oral air before and after removing, setting, and polishing dental amalgam. The analysis was effected using atomic absorption spectrometry in cold vapors with the detection limit of 6 micrograms/m3. A score of 1 to 3 was assigned to each restoration to adjust the differences of the amalgam sizes. The present study showed that the vapor was released during any procedure: removing, setting, and polishing amalgam. The mean levels were between 85 and 326 micrograms/m3. However, before the restorative procedures, no mercury vapors had been detected in the oral cavity. This investigation has also demonstrated a significant direct correlation between Hg vapor concentrations in intra-oral air and the sizes of amalgam restorations during each procedure: removing, setting, and polishing. The statistic analysis showed no significant difference of mercury vapors in the oral cavity between the use or nonuse of water coolant during the amalgam polishing.

Regulation of intraoral air pressure during speech

Speakers with velopharyngeal dysfunction produce higher intraoral air pressure than that obtained by simulating velopharyngeal openings using a passive mechanical model of the vocal tract and a compressed air source. It has been inferred that, in order to maintain air pressures within a regulated range, speakers with velopharyngeal dysfunction compensate for the leakage of air through the velopharyngeal port by altering their respiratory or vocal tract movements. An alternative explanation may be that, instead of depending on an active compensation, the pressure is maintained by the characteristics of the respiratory system. Previous modeling experiments have used an air source with constant flow into the vocal tract. However, it may be that the respiratory system acts more like a constant pressure source than a constant flow source, in which case the intraoral pressures would not be changed by the presence of a velopharyngeal leak. Experiments are reported comparing mechanical models of speech aerodynamics with constant flow and constant pressure inputs. Also reported on are experiments comparing vocal tract aerodynamics measured during speech with data from constant‐flow and constant‐pressure models.

Simultaneous measurement of respiratory and laryngeal function during comfortable, soft, and loud speech

It is well known that both respiratory and laryngeal mechanisms are involved in changing vocal intensity [T. J. Hixon, JSHR 16, 78–115 (1973); N. Isshiki, JSHR 7, 17–29 (1964)], although these have generally been studied separately. The present investigation studied these functions simultaneously while adult speakers produced comfortable, soft, and loud speech. Respiratory function was measured using linearized magnetometers. Laryngeal function was assessed using an electroglottograph and circumferentially vented pneumotachograph. An intraoral air pressure tube was used for estimating subglottal pressure. Analysis of preliminary respiratory data showed the following trends: increased ribcage‐, abdominal‐, and lung‐volume initiations, terminations, and excursions for loud as compared to soft and comfortable speech. Preliminary laryngeal function data indicate that open quotient decreased and estimated laryngeal resistance increased for loud as compared to comfortable and soft speech. Intraoral air pressure values doubled from comfortable to loud speech. Results indicate that respiratory and laryngeal systems are synchronized to produce changes in vocal intensity. Individual subject variability will be discussed in the presentation. [Work supported by NIH.]

Intra-oral air mercury vapor released from dental amalgam before and after restorative procedures: A preliminary study

The level of mercury vapor in the oral cavity was determined before and after the procedures of removing, setting and polishing dental amalgam. The samples were analyzed using atomic absorption spectrometry in cold vapors with a detection limit of 5·8 μg/m 3. Each restoration was assigned a score of 1 to 3 in order to adjust to the differences of the amalgam sizes. The present study showed that the procedures of removing, setting and polishing provoked the release of mercury vapor, as none had been detected in the oral cavity before the procedures. This investigation has also demonstrated a significant direct correlation between Hg vapor concentrations in intra-oral air and the sizes of amalgam restorations during removing, setting and polishing.

Dental amalgam and mercury

Mercury concentration in intraoral air and urine of seven females with dental amalgam was measured before and after intake of one hard-boiled egg. A considerable decrease in mercury concentration in intraoral air was found. Twenty women with about equal dental amalgam status, with or without subjective symptoms related to dental amalgam, were also studied. Mercury concentrations in intraoral air and urine were measured. For all the 27 women the basal intraoral air concentration of mercury ranged over 0.6-10.4 micrograms/m3 (median value 4.3 micrograms/m3). This corresponds to a release of 0.02-0.38 ng/s (median value 0.16 ng/s). In urine, the mercury concentration varied from less than 0.8-6.9 micrograms/g creatinine (median value 1.9 microgram/g creatinine). Data from both parameters were significantly correlated to the total number of teeth areas with dental amalgam. Protein values in urine indicated no renal damage. Maximum concentrations of mercury vapour in intraoral air for the 27 women who had chewed chewing gum for 5 min varied between 2-60 micrograms Hg/m3 (median value 19 micrograms Hg/m3). This corresponds to 0.07-2.20 ng Hg/s and a median value of 0.70 ng Hg/s.

Variations in velar position over time: a nasal videoendoscopic study.

Changes in velar position during production of nonnasal speech in two adults were measured using field-by-field videoendoscopic tracking procedures. The data suggested that the changes in velar position were coordinated with syllable production. Peak velar displacement occurred during maximum oral closure for oral consonant production and was followed by lowering of velar position during vowel production. This pattern of velar movement was not altered by changes in speaking rate or by jaw fixation. The timing of peak velar elevation relative to peak intraoral air pressure and peak jaw elevation was also examined. Timing of peak velar displacement was statistically associated with timing of peak intraoral air pressure in one subject. The data are discussed with regard to the potential value of studying variations in velar position during nonnasal speech in patients with marginal velopharyngeal incompetence.

Variability differences in the speech production in two age groups of adult females

The purpose of this study was to examine the variability between the speech produced by two age groups of adult females, a young adult group and a geriatric group. The 25 women in each group phonated three productions of the vowel /a/ for 5 s at three effort levels—maximum, comfortable, and minimum. Recordings of these productions were digitized and analyzed for mean intensity and intensity distribution. The women also repeated a series of CV, VCV, and VC syllables using the consonants /p/, /b/, /t/, /d/, /s/, and /z/ combined with the vowel /a/, in the carrier phrase “Speak_____again.” Intraoral air pressure and the voicing signal were recorded to provide vowel and consonant durations, voice onset times, and peak intraoral air pressure. The F‐max test for homogeniety of variance was used to compare the variability between the two age groups. The older speakers exhibited significantly greater variability than the younger speakers for the dependent variables, peak intraoral air pressure, consonant duration, vowel duration, voice onset time, and the minimum effort level of speech intensity. The greater variability of production exhibited by the older speakers could be a factor in the perception of older speakers.

Intraoral air pressure discrimination by normal-speaking subjects.

Intraoral air pressure discrimination by normal-speaking subjects.

An aerodynamic study of Korean stop consonants: measurements and modeling.

Measurements were made of intraoral air pressure and oral flow of ten native speakers uttering word pairs contrasting Korean fortis and lenis voiceless stop consonants in initial position. The production of fortis stops was found to be characterized by a higher intraoral pressure before release, yet a lower oral flow after release, than corresponding lenis stops. Possible reasons for this difference were explored with the use of a computer implemented aerodynamic model, giving an output of air pressure and flow. Input parameters were adjusted in accordance with known or hypothesized variations in glottal area function, vocal tract wall tension, respiratory muscle force, and supraglottal cavity volume, as given in the literature. In addition to the previously known differences in glottal area, it is inferred from the results of the modeling experiment that fortis stops are produced with greater vocal tract wall tension than lenis stops. Speaker-specific production strategies such as larynx lowering and heightened subglottal pressure during fortis stops and differences noted between word pairs are also discussed.

Laryngeal compensation following sudden oral perturbation

Recently, there have been a number of demonstrations of rapid goal‐directed compensation in remote articulators when an articulator is perturbed unexpectedly during ongoing speech. Much of this research, however, has involved articulators that cooperate to produce a single vocal tract constriction (i.e., tongue‐jaw, lips‐jaw). In this experiment, spatially more separate articulators are examined that are simultaneously active in the production of a phonetic segment (i.e., the larynx and the lip‐jaw complex). Three subjects produced the nonsense utterance “/ipip/ again” and the lower lip was unexpectedly loaded in the first vowel or during the closure for the first /p/ on a small proportion of the trials. Laryngeal behavior was monitored using transillumination and fiberoptic videotaping. In addition, intraoral air pressure just above the folds was monitored. Oral movements were recorded with a Selspot system. Acoustically, the first /p/ closure in “ipip” was shorter in duration and the voice onset times were longer in the perturbed trials. An examination of the laryngeal gestures during the production of the first /p/ revealed longer adduction durations in the perturbed conditions than in the control trials and a longer overall abduction/adduction cycle. The results will be discussed in terms of task‐dependent articulatory coupling. [Work supported by NINCDS.]

Age‐related differences in phoneme durations among females

Reduced speech rate has been consistently reported for geriatric speakers when compared to the speech of younger adults. Only recently have the specific aspects of the speech signal associated with reduced rate been identified. The purpose of this study was to examine vowel and consonant durations using certain physiologic measures to determine their effect on age‐related differences in speech rate. Two groups of 25 women—one 20–30 years old and another 75 years and older—who had no history of speech disorders and exhibited normal hearing (for age level) served as subjects. They repeated a series of CV, VCV, and VC syllables using the consonants /p/, /b/, /t/, /d/, /s/, and /z/ combined with the vowel /ɑ/, which were spoken in the carrier phrase “Speak 3♯ again.” Intraoral air pressure and the voicing signal were recorded to provide vowel and consonant temporal information. Consonant duration did not differ significantly between the two age groups. Conversely, vowel durations were greater for the older females. These results are in agreement with previous studies and will be discussed in relation to a general model of aging.

Intraoral air pressure and oral air flow under different bleed and bite-block conditions.

Intraoral pressures and oral flows were measured as normal talkers produced /p lambda/ and /si/ under experimental conditions that perturbed the usual aeromechanical production characteristics of the consonants. A translabial pressure-release device was used to bleed off intraoral pressure during /p/. Bite-blocks were used to open the anterior bite artificially during /s/. For /p/, intraoral pressure decreased and translabial air leakage increased as bleed orifice area increased. For /s/, flow increased as the area of sibilant constriction increased, but differential pressure across the /s/ oral constriction did not vary systematically with changes in its area. Flow on postconsonantal vowels /lambda/ and /i/ did not vary systematically across experimental conditions. The data imply that maintenance of perturbed intraoral pressure was more effective when compensatory options included opportunity for increased respiratory drive and structural adjustments at the place of consonant articulation rather than increased respiratory drive alone.

Relationship between intraoral air pressure and vocal intensity in children and adults.

Intraoral air pressure (Po) varies as a function of age. Specifically, children produce significantly higher Po values than adults. The higher Po produced by children has been discussed in relation to age-related volumetric differences of the subglottal and vocal tract, to lung compression differences, and to the fact that children's "comfortable" speaking level might exceed that of adults. The present study was undertaken to evaluate the hypothesis that children (vs. adults) and women (vs. men) produce higher Po values when sound pressure level (SPL) is held constant. Measurements were made of Po generated by children and adults during a connected speech task completed at three intensity levels. The findings of the study indicated that peak Po values increased as vocal intensity increased for all subject groups, peak Po values were higher for voiceless stops than for voiced stops, and peak Po values were not significantly different for adults than for children or for men than for women. These results were interpreted to show that despite physical and physiological differences between male and female, and between adult and child vocal tracts, all groups use the same Po mechanism for achieving a given vocal intensity level.