Tatsujiro Ushijima

Velar movements during speech in a patient with apraxia of speech.

Abstract A fiberscopic observation of velar movements during speech was made of a patient diagnosed as having apraxia of speech. Repeated utterances of the same word showed a marked variability in terms of the pattern of velar movements accompanied at times by a phonetic change. In spite of such a variability, the general successional pattern of velar gestures for a given phonetic context approximated the normal pattern. During the production of nasal and nonnasal consonants the velum tended to take “neutral” positions. Anticipatory coarticulation was present, but some deviation from normal patterns was occasionally observed. Based on these observations, possible mechanisms responsible for the syndrome called apraxia of speech were discussed.

Abnormal articulatory dynamics in a patient with apraxia of speech: X-ray microbeam observation☆

Abstract The temporal organization of articulatory movements in a patient diagnosed as having apraxia of speech was explored by means of pellet tracking techniques using an X-ray microbeam system. The results indicated that the temporal organization among different articulators of the patient was sometimes disturbed in his production of a meaningful Japanese word /deenee/. It was also observed that the pattern and velocity of the articulatory movements of the patient in repetitions of monosyllables were different from those of typical dysarthric patients.

Effect of Speaking Rate on Labial Consonant‐Vowel Articulation

This paper describes the results of a study of the effect of speaking rate on the articulation of the consonants /p,w/, in combination with the vowels /i,a,u/. Two subjects read a list of nonsense syllables containing /p,w/, in all possible VCV combinations with /i,a,u,/ at both moderate and fast speaking rates. EMG recordings from muscles that control movements of the lips, tongue, and jaw were recorded simultaneously with high‐speed lateral‐view x‐ray films of the tongue and jaw, and high‐speed full‐face motion pictures of the lips. For labial consonant production, an increase in speaking rate is accompanied by an increase in the activity level of the muscle (orbicularis oris) and slightly faster rates of lip movement (both closing and opening). Vowel production, however, shows opposite effects: an increase in speaking rate is accompanied by a decrease in the activity level of the genioglossus muscle and, as shown by the x‐ray films, evidence of target undershoot. Jaw movement data show more variable, c...

Laryngeal control for voicing distinction in Japanese consonant production.

The aim of the present study was to investigate the laryngeal adjustments for voiced versus voiceless distinction in Japanese consonant production by means of laryngeal electromyography (EMG) and fiberoptic observation. Multichannel EMG recordings were taken of a Japanese subject and the data were computer-processed to obtain the averaged activity patterns of the five intrinsic laryngeal muscles with special reference to the voicing distinction in consonant production in various phonetic environments. It was found that there were apparent reciprocal patterns in the posterior cricoarytenoid (PCA) and the interarytenoid (INT) in terms of significant negative correlation, and active control of PCA for voicelessness was demonstrated. The patterns of the thyroarytenoid and the lateral cricoarytenoid were different from that of INT even though these two muscles are usually classified as the members of the adductor group, and their activity levels were apparently influenced by the phonetic environment. A possible contribution of the cricothyroid (CT) to the voicing distinction was also pointed out but further investigations on acoustic parameters seem to be mandatory in more critical interpretation of CT activity in speech.