Masayuki Sawashima

New Laryngoscopic Technique by use of Fiber Optics

A fiberscope with a thin flexible fiber‐optics cable is inserted through the nasal passage in order to observe the laryngeal states and movements during various phonatory and articulatory conditions. Sample photographs of this procedure are presented.

Laryngeal Gestures in Speech Production

This chapter describes the physiological mechanisms of laryngeal gestures for various phonetic distinctions in speech production. An orientation toward the basic laryngeal gestures is presented in Section II, and detailed experimental data are discussed in Section III.

XX An Experimental Study of Central Motor Innervation of the Laryngeal Muscles in the Cat

It is reasonable to consider that the functions of the larynx depend upon reflex and intentional movement of the laryngeal muscles which is well-organized by voluntary and autonomic innervation. It is generally accepted that the larynx is supplied with both motor and sensory nerve fibers by two pairs of nerves: superior and inferior laryngeal nerves. However, the central mechanism of the innervation of the laryngeal muscles is one of the most obscure problems in the field of laryngology.

Velar movements during speech in two Wernicke aphasic patients

The articulatory gestures of the velum in two Wernicke aphasic patients were examined to compare their performances with those of an apraxic patient by means of the fiberoptic technique. In contrast to the marked variability in the apraxic performance in terms of velum height and segmental duration, the two fluent aphasic subjects showed a relatively high degree of consistency in velar movements throughout several repetitions of nonsense syllables and meaningful words. In addition, both patients exhibited a normal pattern of anticipatory coarticulation. Analyses of the velar movement patterns during the speech-sound error processes of both patients suggested that these errors were not due to an impairment at the level of articulatory programming but to an error in the selection of a target phoneme.

Interaction between Articulatory Movements and Vocal Pitch Control in Japanese Word Accent

In order to investigate the interaction between articulatory and vocal pitch controls, EMGs of the cricothyroid (CT) and sternohyoid (SH) muscles were recorded during utterances of two-mora Japanese words with rising and falling accent types in the Tokyo dialects. The test words consisted of combinations of open and closed vowels. It was revealed that the changes in CT activity were consistently observed in correspondence with the F0 shift according to the accent types, while the SH muscle was observed to be active both for jaw opening and F0 lowering, with some subject-to-subject difference. It was also observed that the time lag between the decrease in CT activity and the F0 fall varied with a shift in the relative timing of SH activity in one subject, but not in the other. Articulatory jaw opening with SH activation was considered to positively contribute to F0 lowering, but the use of this mechanism appeared to be optional at least in the Tokyo accent.

Cinegraphic Observations of the Larynx during Voiced and Voiceless Stops

Observations of laryngeal operation in running speech were made with a flexible fiberoptics bundle passed through the nose and coupled to a cinecamera. A previous report based on observations of a single subject concluded that English sounds with predominant noise source, i.e., the aspirated stops and voiceless fricatives, are produced with separation of the arytenoids, and that sounds with predominant quasiperiodic source are produced without such opening. The present paper extends our study to three speakers of American English, but limits attention to sounds not always distinguishable on the basis of earlier observations: unaspirated /p,k/ and /b,g/. Our present data indicate that these two classes are almost always different in respect to positioning of the arytenoids. The few anomolous cases include both /b,g/ with slight separation of the arytenoids and pulsing interruption, and /p,k/ with neither of these phenomena. Aside from articulatory “noise,” these cases may be explained by reference to facto...

Relationship between vowel articulation and pitch control

Extrinsic muscles of the tongue and larynx influence laryngeal function through their effects on the hyoid‐larynx complex, and thus cause interaction between vowel articulation and fundamental frequency. It has been argued that the mechanism for pitch control by the extrinsic frame of the larynx is related to vertical movement of the larynx, although physiological data has not always supported this view. In this study, positional control of the hyoid bone was examined by monitoring electromyographic activity from suprahyoid muscles and displacements of the hyoid bone. A speaker produced Japanese two‐mora words /ia/ and /at/ with different accent types. The data showed that activity of at least one anterior suprahyoid muscle, the geniohyoid, actively participated in pitch raising by producing anterior movements of the hyoid bone. This result suggests that horizontal rather than vertical movements of the hyoid bone caused by contractions of anterior suprahyoid muscles are used to tilt the thyroid cartilage ...

Some Notes on the Physiology of Speech Production.

Three different topics in speech research are discussed from the point of view of the physiology of the speech production mechanism. Concerning the problem of the laryngeal adjustments for the voicing distinction, fairly clear physiological evidence has been obtained about the abduction-adduction dimension of the glottis, while the tenseness feature of the vocal folds is still to be examined. Detailed analysis of the articulatory movements in syllable repetition is considered to be a promising approach for the study of articulatory dynamics in both normal and pathological cases. Neurophysiological studies of the cerebro-cerebellar communication system as a control mechanism of skilled voluntary movements should be referred to in the study of motor control of speech production.

Observation of the Larynx by a Fiberscope Inserted through the Nose

A specially devised fiberscope by use of a thin flexible fiber‐optics cable was inserted through the nose in order to observe the laryngeal conditions in the course of unperturbed speech utterances. Glottal conditions during various phonatory and articulatory activities have been visually inspected and photographed. The flexible optical cable with its tip is 5.6 mm in diameter. The hard tip, 15 mm in length, houses inside an objective lens designed for a straightforward view. Glass fibers of 15 μ are used for an image guide, and the size of the image on the photographic film is 5.6×5.6 mm2. The insertion of the optical cable does not cause any discomfort unless the nasal cavity of the subject is particularly narrow. When the scope reaches near the level of the epiglottis, the larynx is readily visible and the scope can be kept in position with a good stability. Cinefilm of the larynx obtained by this fiberscope with simultaneous sound recording will be shown at the meeting.

Laryngeal muscle activities in relation to glottal shape in voiceless sound production

Simultaneous EMG recording of the laryngeal abductor (PCA) and adductor (INT) muscles with laryngeal filming by use of a fiberscope was made with two subjects during utterances of various voiceless sounds and sound sequences in Japanese words in a frame sentence. For each of the utterance samples, the activity patterns of the two muscles were observed in correspondence with the opening and closing movements of the glottis. There was a reciprocal pattern of activity between the two muscles in relation to glottal abduction and adduction during speech, this finding being consistent with previous reports. There was, however, a difference between the subjects in that the time course of the glottal movements was predominantly controlled by the PCA in one subject, while the INT as well as the PCA appeared to actively control the glottal condition in the other subject. [Work supported by Ministry of Education Grant‐in‐Aid for Scientific Research, No. 239005.]