Lip Protrusion Research Articles

Intrafascicular multi-unit recordings from the human infra-orbital nerve.

Intrafascicular micro-electrode recordings were made from the human infra-orbital nerve close to the infra-orbital foramen. The fascicular organization was studied and multi-unit activity from low-threshold mechanoreceptive afferents was recorded during tactile stimuli, vibration and facial movements. Attempts were also made to record C-fibre activity. Innervation zones corresponding to 66 fascicles were mapped with tactile stimuli on facial hairy skin and the red zone of the lip. Most of these fields were located on the upper lip, where they overlapped, indicating a high innervation density. The fields had a median size of 3.8 cm2. Skin indentation evoked dynamic on- and off-responses and a much less pronounced static discharge. The afferent double-peaked responses to an oscillating probe applied to the peri-oral region induced similar grouping of the EMG activity during sustained lip protrusion. Contraction of facial muscles and stretching of the skin evoked on- and off-responses, whereas the static discharge was less pronounced, especially during sustained stretching. The dynamic sensitivity to minor variations in contraction and stretching was high, and during normal facial movements, as in speech, there was a barrage of impulses originating from mechanoreceptors within large facial areas. Functional implications of these sensorimotor interactions are discussed. Sympathetic C-fibre activity, frequently seen in recordings from the supra-orbital nerve, was never encountered in the infra-orbital nerve recordings, indicating a lack of such fibres. Failure to detect afferent C-fibre activity could be explained by methodological difficulties.

Controlling an articulatory model

Nobody knows what the brain tells the vocal organs to do when producing speech. As a starting point, a computer model has been built in which there are the following independent articulatory parameters: height and backness of the body of the tongue, lip height, lip width, lip protrusion, jaw opening, tip of tongue curling, tip of tongue advancing, tongue root advancement, tongue bunching, and larynx raising. An alternative specification of the body of the tongue uses front raising and back raising gestures, each of which can be combined with the other in different degrees. There are also several options for the interdependent action of the parameters. Instead of being independently specified, the lower lip and the jaw can be determined by the gesture required for the tongue, or the tongue height and lower lip position can be determined by the jaw position. Lip protrusion can be considered to be a coordinative structure that also specifies lipwidth. Larynx height and tongue root advancement can be considered to co-vary. These and other possibilities will be demonstrated in a model of articulatory-acoustic relations in a (public-domain) program on a Macintosh computer.

Articulator movement in anticipatory coarticulation

The results of previous studies examining EMG activity (and, to a smaller extent, articulator movement) in anticipatory gestures have not been consistent. In some studies, the onset of activity for a given feature was time locked, in that it began at a fixed interval prior to the acoustic onset of the corresponding segment. This suggests that timing plays an intrinsic role in the organization of speech production, and that segmental targets are dynamic. Other studies have shown evidence for feature spreading, where the onset of activity begins within the earliest preceding segment which makes no contradictory demands on the articulators, regardless of the length between the onset of activity and the acoustic onset of the relevant segment. This suggests that time is extrinsic to segmental specification, and that targets are represented as static. However, Gelfer, Bell-Berti, and Harris (1985) and Perkeli (1986) argue that the different findings may be due to experimental design: /s/ and /t/, the consonants used in such studies, may not be unspecified with regard to lip protrusion, as previously assumed. In the current study, the issue of feature specification for presumed neutral segments is considered. Pellet traces from selected bases of x-ray microbeam data were examined. The point of onset of lip protrusion with respect to the acoustic onset of the rounded vowel in VCnu utterances was measured. Velocity patterns of articulator movement were also considered.

Testing parameters of Vocal tract shape

In a mini‐version of a system for modeling the speech production process on a Macintosh computer, new algorithms have been devised for interpreting values of eleven control parameters: front‐back tongue movement; high‐low tongue movement; jaw opening; tip of tongue raising; tip of tongue advancing; lip height; lip rounding and protrusion; velic opening; advancing of the tongue root; rhotacization; and larynx raising. New algorithms have also been devised for converting the vocal tract shapes into sets of tubes, whose lengths and areas can be used as a basis for calculating the sounds that would be produced. The phonological features nasal and advanced tongue root can be given direct values in this set of commands. The features high‐low and front‐back can be interpreted as auditory specifications from which corresponding tongue shapes can be calculated. It is not known if it is possible to devise algorithms for interpreting other features in terms of these commands.

The “trough” phenomenon in Turkish and in English

Previous studies on several Indo‐European languages have shown that for strings of two rounded vowels separated by phonologically rounding‐neutral consonants, both EMG and lip protrusion movement traces show double peaks coincident with the two rounded vowels plus an intervening “trough” [Bell‐Berti and Harris, J. Acoust. Soc. Am. 71, 449–454 (1982); Perkell, Speech Commun. 5, 47–68]. This has been interpreted as due to independent rounding gestures associated with each vowel and as counterevidence to the claim that rounding coarticulation is anticipatory. In this paper, English speakers' production of nonsense words /kuktluk/, /kuktuk/, /kukuk/, /kutuk/, and /kuluk/ will be compared with that of speakers of Turkish, a language with strong constraints against the cooccurence of rounded and unfounded vowels in the same word. Both movement and EMG evidence will be used to argue that the trough phenomenon is more extensive in English than in Turkish. Implications for cross‐language differences in coarticulat...

Soft-tissue profile-fallacies of hard-tissue standards in treatment planning

The study was designed to test the efficacy of using a cephalometric dentoskeletal standard as a clinical tool to produce predictable and desirable facial esthetics. Thirty adolescent patients were randomly selected who, at the completion of treatment, had lower incisors positioned approximately 1.5 mm anterior to the A-pogonion plane. A normal sample of excellent faces (Indiana sample) was used for comparison. Both profile measurements of hard and soft tissues were made. The most striking observation was the large variation in the facial profiles even in cases successfully treated to a cephalometric dentoskeletal standard. The variation (2 standard deviations) of lip protrusion from the subnasale pogonion plane was 5 mm or a total of 10 mm. Similar variations were found in other soft-tissue measurements. The results suggest that any given dentoskeletal standard has questionable validity in producing either desirable esthetics or reproducible profiles following treatment.

Coarticulation strategies: preliminary implications of a detailed analysis of lower lip protrusion movements

A two-part experiment on protrusion movements of the lower lip for the vowel /u/ was conducted to investigate: (1) the production of ‘troughs’, i.e., diminution of lip protrusion during the intervocalic consonant in /uCu/ utterances, and (2) ‘time locking’, that is, movement onset at a fixed interval prior to onset of voicing of /u/, regardless of the number of ‘neutral’ consonants in /V unroundedC n u/ utterances. Two speakers of French, a speaker of Spanish and two speakers of English produced similar sets of nonsense utterances. A bite block was used to eliminate mandible movements as a source of lower lip movements. A detailed examination was made of relationships among events in movement and acoustic signals for each token of multiple repetitions of the test utterances. Results suggest that the production of troughs may be due in part to specific articulatory targets for the intervocalic consonants /s/ and /t/. Specific consonantal targets prevented the direct investigation of time-locking. Experimental limitations preclude firm conclusions, but the nature of the results suggests that a complex of factors, including “co-production of adjacent segments” and “context-dependent adjustments of articulatory targets” may underlie observed variation in articulatory behaviour.

A syllabic component of speech motor control?

Some recent experimental results appear to contradict the usual finding that anticipatory coarticulation crosses syllable boundaries. For example, averaged EMG records of the posterior genioglossus during /ipi/ and the orbicularis oris during /utu/ have shown a peak of activity for each vowel with a diminution or “trough” corresponding to the consonant. These and other findings have been interpreted as support for a syllable‐based component of speech motor control [cf., T. Gay, J. Acoust. Soc. Am. 62, 183–193 (1977); T. Gay in Segments and Syllables, edited by A. Bell and J. Hooper (North Holland, Amsterdam, 1978)]; however, other factors may be implicated. Measurements of lower lip protrusion for nonsense utterances containing the sequence /kuCnu/ (n = 1−3) were made on speakers of American English, French and Spanish. Movement records show considerable variation, including examples of trajectories with and without troughs. Quantitative analysis of trough depth as a percentage of the displacement for the entire rounding gesture suggests several possible sources of variation: Language, individual, consonant type, and cluster duration. Thus it seems premature to attribute the existence of troughs to any single factor. [Research supported by NIH Grant No. NS04332.]

Preservation of vocal tract length in speech. A negative finding.

A primary determinant of vowel quality is vocal tract shape; one aspect of which is vocal tract length. It has been suggested [Perkell, Physiology of Speech Production (MIT, Cambridge, 1969); Riordan, J. Acoust. Soc. Am. 62, 998-1002 (1977)] that vocal tract length is controlled directly, and that one mechanism for its regulation is a coordination between labial and laryngeal gestures. Riordan (1977) observed compensatory changes in the vertical position of the larynx when the characteristic lip protrusion of a rounded vowel was impeded. Although subjects in this study accurately produced the vowels /i/, /a/, /u/, and /delta/ with different amounts of lip protrusion, no compensatory larynx height adjustments were observed.

The effects of antagonistic gestures on temporal and amplitude parameters of anticipatory labial coarticulation

An attribute of the speech production system is the ability to anticipate articulatory targets. This study investigated how the presence and proximity of prior antagonistic versus neutral phonetic gestures affected anticipatory coarticulation for lip rounding. EMG activity was recorded from orbicularis oris superior (OOS)—the agonist for lip rounding; and risoris (RIS) the antagonist, for three subjects repeating the tokens /kikstu/, /kakstu/, /tiku/, and tuki/. Comparing a three-member cluster to a single consonant enabled us to test the notion of time-locked anticipatory coarticulation. Temporal onset values of OOS with respect to /u/ onset and in relation to cluster duration revealed earlier relative OOS onset for the neutral /kakstu/ environment versus the antagonistic lip spread environment in /kikstu/. All subjects revealed greater OOS amplitude as measured by averaged integrated EMG for /kikstu/ versus/kakstu/. Anticipatory coarticulation was found to be nontime locked and a function of number of intervening segments. Lip movement was measured and onset of lip protrusion preceded OOS onset illustrating the operation of elastic recoil of the lip in moving from a prior spread position to a protrusion.

Lippenrundung bei schwedischen Vokalen (Liprounding in Swedish Vowels)

Abstract Is there a steady transition between unrounded, ‘outrounded’, and ‘inrounded’ Swedish vowels, or are these distinct categories? By which articulatory parameters can these distinctions be described? These questions, actualised through confusion data in speech reading, are answered by means of articulatory measurements of lip-opening, lip protrusion, and jaw-lowering in 4 subjects. It is found, i.a., that rounded and unrounded vowels form clearly separated categories, and that unrounded vowels, including /o/, are distinguished from outrounded ones by their smaller lip-opening and, if long, by increased lowering of the jaw.

Vertical lip changes from maxillary incisor retraction

S oft-tissue profile changes incident to growth and orthodontic tooth movement have been the subject of intense investigation for many years.ip6 Researchers7-‘i have well documented the effects of anteroposterior movement of incisors on soft tissue in the sagittal dimension. Rudee7 found that the mean ratio of upper lip movement to upper incisor movement is approximately I : 3, with the mode, however, between 1: I and 1: 2. Therefore, more cases should have upper lip retraction equal to or one half the distance of incisor movement anteroposteriorly. In developing a soft-tissue prediction method for maxillary osteotomies, Harris’” found a significant correlation of upper lip movement to maxillary incisor retraction at a ratio of 0.66: I Although variation has been noted by all investigators, a ratio of approximately 0.7 : I for upper lip movement related to upper incisor retraction has been established as a norm with a significant degree of predictability. A ratio of lower lip movement to upper incisor retraction of I : I has also been established but is less predictable than the I : 1 relationship found between lower incisor and lower lip movement.7* ’ Predictability of vertical changes in the labial soft tissue has not been established in these previous studies. Subjective evaluation has determined that as incisors are moved distally the interlabial gap decreases and the lips become thinner as viewed from the frontal aspect, but that the changes were inconsistent relative to the amount of such retraction. Most orthodontists have seen, at one time or another, normally shaped but slightly protrusive lips being reduced to a thin line of vermilion border as incisors are retracted to a functional position and/or to dentoskeletal cephalometric “norms” in the sagittal dimension. The perplexed clinician has observed that for relatively the same amount of incisor retraction, lip “thinning” varied from one patient to another. Therefore, the purpose of this study was to evaluate the vertical changes in the labial soft tissue relative to maxillary incisor retraction in an effort to correlate such retraction to closure of the interlabial gap with a significant degree of predictability.

Control of vocal-tract length in speech.

Essential for the correct production of vowels is the accurate control of vocal-tract length. Perkell [Psychology of Speech Production (MIT, Cambridge, MA, 1969)] has suggested that two important determinants of vocal-tract length are vertical larynx position and lip spreading/protrusion, often acting together. The present study was designed to determine whether constraining lip spreading/protrusion induces compensatory vertical larynx displacements, particularly on rounded vowels. Upper lip and larynx movement were monitored photoelectrically while French and Mandarin native speakers produced the vowels /i,y,u/ first under normal-speech conditions and then with lip activity constrained. Significant differences were found in upper-lip protrusion and larynx position depending on the vowel uttered. Moreover, the generally low-larynx position of rounded vowels became even lower when lip protrusion was constrained. These results imply that compensatory articulations contribute to a contrast-preserving strategy in speech production.

Differential treatment planning for mandibular prognathism

The treatment records of thirty-eight cases of mandibular prognathism treated by orthodontics means only (ORTHO) were evaluated. The pretreatment records of twenty cases of mandibular subapical esteotomy (SUB) and twenty cases of mandibular setback (SET) were evaluated for comparison and contrast with the pretreatment ORTHO records and with each other. Dental, skeletal, and soft-tissue parameters in the vertical and horizontal planes of space were recorded. Statistical analysis of means of parameters of the pretreatment records provided documentation of the discriminant variables in each of the following paired groups: ORTHO-SUB, ORTHO-SET, and SUB-SET. Analysis of the data as indicated above led to the following conclusions: 1. Three discriminant groups of mandibular prognathism of various degrees of severity were discernible when comparisons of treatment categories simulating clinical decisions were made. The ORTHO group was distinguished from the SUB group in the horizontal plane and, more strongly, in the vertical plane. The ORTHO group was distinguished from the SET group in the vertical plane and, more strongly, in the horizontal plane. The SUB group was distinguished from the SET group in the horizontal plane. 2. The physiologic developmental status of the patient should be carefully evaluated. 3. Anteroposterior dysplasias should be assessed relative to the cant of the mandibular plane. True denture base discrepancies can be noted relative to the occlusal plane. 4. Documentation of vertical dysplasias should include measurements of craniofacial divergence (SN-MP, FH-MP, and OP-MP). 5. In assessing the profile evaluation of the patient with mandibular prognathism, particular attention should be focused on facial contour angle (FCA), nasolabial angle (NLA), and relative lower lip protrusion (LLP). 6. Any numerical values obtained in the evaluation of the dental, skeletal, or soft-tissue characteristics of mandibular prognathism should be considered only as descriptive, diagnostic guides and not as components of a diagnostic formula.

Control of vocal tract length in speech

Accurate control of vocal tract length is essential for the correct production of vowels. Vertical larynx movement and lip spreading/protrusion, often acting together, are important determinants of vocal tract length. The present study was designed to determine whether constraining lip spreading/protrusion will induce compensatory vertical larynx displacements, particularly on rounded vowels. Upper lip and larynx movement were monitored photoelectrically while French and Mandarin native speakers produced the vowels /i, y, u/ first under normal speech conditions and then with lip activity constrained. In agreement with the findings of Sundberg (1969), Benguerel (1974), and Ewan (1976), there were significant differences during normal speech in upper lip protrusion and larynx position as a function of the vowel and tone uttered, in particular a difference in lip protrusion between /u/ and /y/. Results further reveal that the generally low larynx position of rounded vowels becomes even lower than lip protrusion is constrained. This data has implications for the role of a contrast-preserving strategy in speech production. [Supported in part by the National Science Foundation. ] Also, Department of Languages and Linguistics, University of Essex, Colchester, England.

A cineradiographic study of articulation in two talkers with temporarily induced oral sensory deprivation.

Cineradiography was used to study the behavior of the lips, tongue, and mandible in two subjects talking normally and under the influence of trigeminal nerve-block anesthesia. The speech sample consisted of isolated words and sentences. The nerve block was administered to eliminate somesthetic sensation in all of the oral articulators except the jaw. Frame-by-frame measurements of lip protrusion, tongue position, and jaw placement were taken from the film data for selected stops, glides, fricatives, and vowels in the speech sample. Comparison of these measurements from the normal and nerve-block condition revealed the following changes in the nerve-block data: (1) reduction in context-appropriate lip protrusion and loss of precision in lip closure activity, which was more noticeable for the upper than the lower lip; (2) a reduction in the precision of tongue articulations particularly on contacts for lingua-alveolar and lingua-velar consonants, apical retroflexion on glides, and steady state postures for lingua-palatal fricatives and vowels; and (3) noticeable alterations in inferior/superior jaw position which was systematically closer to the maxilla for bilabial consonant closures and often reduced or extended in excursion for vowels and other consonants. The data are discussed in terms of the relative effects of an oral somesthetic feedback deficit on speech production, and also with respect to compensation within the articulatory system under conditions of sensory deprivation.

Is the Relationship between Acoustic and Articulatory Variables in Speech Intrinsically Linear?

The functional relationship between the acoustic parameters of speech and the positions of different articulators was investigated on a computer-simulated model of the vocal tract using nonlinear regression. The area function of the vocal tract in the model was specified by seven articulatory variables, namely, the area and location of the maximum constriction formed by the tongue body, the area and location of the tongue tip constriction, the area of the mouth opening, lip protrusion, and the length of the vocal tract. It was found that any one of the seven articulatory variables could be represented reasonably accurately by a polynomial function of the acoustic parameters of the vocal tract model. Two interesting properties of this relationship were observed. First, in estimating an artic-ulatory variable, knowledge of the other articulatory variables was not required; the articulatory variable was uniquely determined by the acoustic parameters alone. Second, any one of several different acoustic representations—such as predictor coefficients, formant frequencies, and their band widths, or power spectrum—could be used with equal success in determining articulatory variables. The applications of this method for determining positions of the articulators during speech production, for speech recognition, and for control of articulatory models for speech synthesis are discussed.

Coarticulation of upper lip protrusion in French.

Abstract This study investigates the temporal organization of upper lip protrusion in French. A photocell was used to transduce upper lip movement into a recordable electrical signal. The utterances under study were recorded by six native speakers of French. Three aspects of the protrusion gesture are examined: extent of protrusion, velocity, and transition time. Results indicate differences between these three measures for the production of /u/ as compared to /y/ as well as differences when upper lip movement is directed away from its target protrusion position as compared to when it is directed toward its target protrusion position. This study also includes an attempt to determine onset of protrusion in a consonant cluster followed by a rounded vowel. Results show that the protrusion movement due to the rounding of the second vowel of a group –VCC ... CV– starts as early as the first consonant of a cluster of 4–6 consonants. In some cases, it even starts during the vowel preceding the cluster. These results do not support Kozhevnikov and Chistovich’s model of a CC ... CV-type syllable. On the other hand, they are compatible with Henke’s articulatory model of speech production.

The Activity of the Lip in Articulation of a Japanese Vowel /O/: A Simultaneous EMG and Stroboscopic Study

Electromyographic (EMG) and stroboscopic studies were made to investigate the time relationship between the movement of the upper lip and electrical activity of the pertinent muscle, the orbicularis oris, with reference to the acoustic event of rounded Japanese vowel [o]. The EMG data were computer-processed to obtain averaged results. It was revealed that the peak position of the EMG signal always preceded the time moment of the maximum displacement of the lip. Further, an apparent discrepancy was found between the time moment for the maximum lip protrusion and the center of the pertinent vowel [o]. It was assumed that the protrusion of the lip does not entirely characterize the acoustic manifestation of the vowel [o] as a function of time.

Coarticulation of lip rounding.

We investigated the extent of coarticulation of lip rounding in selected speech strings. Meaningful sentences containing sequences of one to four consonants preceding the vowel /u/ were constructed, with word and syllable boundaries falling within the sequences in various ways. High-speed cinefluorographic films were taken of three subjects producing these sentences and measurements of lip protrusion were made from selected film frames. For most utterances, the lip rounding gesture began during the approach to the closure phase of the first consonant in the sequence, extending over as many as four consonants preceding /u/. Word and syllable boundaries within the sequences did not affect the amount or the starting points of protrusion. Generally, the tongue and, to a lesser extent, the lips failed to achieve target positions defined during prolonged articulation of /hu/. Our results are discussed in relation to various conceptual models of speech production. The data are consistent with models presuming phoneme-size input units as well as those involving some type of syllabic input units. Further studies of coarticulation, designed to differentiate between the two types of models, are suggested by these results.