Masanobu Kumada

Morphological and histochemical studies of the genioglossus muscle.

The purpose of this preliminary study was to assess the histoanatomic composition of the genioglossus muscle fibers. The genioglossus muscles were obtained from 4 cadavers and 1 autopsy specimen. On morphological study, the average diameters of the muscle fibers were seen to gradually increase, from the fibers that ran anteriorly to the dorsum of the tongue, to the fibers that ran posteriorly to the root of the tongue. Histochemical study revealed that type II fibers were significantly predominant in the anterior portion; there was no dominant fiber type in the posterior portion. Gradual changes in diameter were independent of fiber type. These findings may suggest that the fibers of the anterior portion are suitable for phasic action, and that the posterior is relatively tonic; and the posterior has larger absolute muscle strength than the anterior. It is thought that the fibers of the posterior portion might contribute to the maintenance of the mesopharyngeal airway and to vowel production, and that the anterior fibers might contribute to some fine movements and to consonant production.

Botulinum Toxin Treatment for Spasmodic Dysphonia

Effective treatment of adductor type spasmodic dysphonia with botulinum toxin injection is presented. Patients showed objective and/or subjective improvement in phonation. The beneficial effect lasted for approximately 3 months. An immediate complication is temporary hoarseness or aphonia, mainly due to diffusion of BT into the adjacent muscles. This is avoided by limiting the injection to one vocal fold only and by keeping the dose at less than 5 units. Insertion technique of the needles, such as percutaneous and laryngoscopically controlled techniques, are discussed.

Involuntary expiratory phonation as a dose-related consequence of L-dopa therapy in a patient with Parkinson's disease.

We report a case of involuntary phonation caused by abnormal vocal cord movements during expiration in a patient with Parkinsons disease. A 60-year-old woman had been treated for parkinsonism at the outpatient clinic of the Department of Neurology since August 1999. She began to groan involuntarily in the daytime in September 2001. She could not eat well while groaning. Stridor was not noted during sleep at night. Endoscopic examination of the larynx revealed insufficient abduction of the bilateral vocal cords, although the glottis was not so small as to cause stridor during inspiration. During expiration, however, the vocal cords adducted, resulting in the involuntary production of voice. Electromyography showed an increase in the activity of the thyroarytenoid and lateral cricoarytenoid muscles. This muscle activity was further enhanced during inspiration. The involuntary phonation disappeared when the patients dose of l-dopa was decreased, although she had a decrease in her systemic mobility as well. When the dose of l-dopa was increased to the therapeutic level, involuntary phonation recurred, and her voluntary systemic activity improved. In the present case, it was considered that excessive dopaminergic denervation occurred in the nerve innervating the laryngeal adductors. Involuntary voice appeared to be produced by hypertonus of the laryngeal adductors because of a lowering in the threshold level for l-dopa, even though the drug was administered at the usual dose.

The syllable method: proportion of impaired syllables as an indicator of spasmodic dysphonia severity.

We have previously proposed the ‘mora method’ to evaluate the degree of impairment in spasmodic dysphonia (SD) in Japanese-speaking patients. With this method, impairment is judged as the proportion of impaired morae in a 25-mora sentence in a longer passage read aloud. As the mora is the phonologically isochronic unit in Japanese, the proportion of impaired morae in speech can be used to represent the temporal proportion of impaired Japanese speech. This proportional measure of impairment reflects the perceived severity of the impairment, and is a more reliable measure than a 4-point perceptual rating scale completed either by patients or by voice professionals. In this paper, we propose a ‘syllable method’ to characterize the severity of impairment in English-speaking SD patients. Instead of morae, the severity of SD was represented by the proportion of impaired syllables. It should be possible to characterize SD impairments more reliably and precisely with this method than using a 4-point rating scale completed by voice professionals. Ultimately, the syllable method should become a simple and effective method for evaluating the severity of SD. Furthermore, such methods can be applied to other languages, using the appropriate phonological unit (either mora or syllable).

Observation of the laryngeal movements for throat singing

Throat singing is a traditional singing style of people who live around the Altai Mountains. Khoomei in Tyva and Khoomij in Mongolia are representative styles of throat singing. The laryngeal voices of throat singing is classified into (i) a drone voice which is the basic laryngeal voice in throat singing and used as drone and (ii) a kargyraa voice which is very low pitched with the range outside the modal register. In throat singing, the special features of the laryngeal movements are observed by using simultaneous recording of high‐speed digital images, EGG, and sound wave forms. In the drone voice, the ventricular folds (VTFs) vibrate in the same frequency as the vocal folds (VFs) but in opposite phases. In the kargyraa voice, the VTFs can be assumed to close once for every two periods of closure of the VFs, and this closing blocks airflow and contributes to the generation of the subharmonic tone of kargyraa. Results show that in throat singing the VTFs vibrate and contribute to producing the laryngeal...

Quantitative analysis of vocal fold vibration during register change by high‐speed digital imaging system

The physiological study of prosody is indispensable in terms not only of the physiological interest but also of the evaluation and treatment for pathological cases of prosody. In free talk, the changes of vocal fold vibration are found frequently and these phenomena are very important prosodic events. To analyze quantitatively the vocal fold vibration at the register change as the model of prosodic event, our high‐speed digital imaging system was used at a rate of 4500 images of 256–256 pixels per second. Four healthy Japanese adults (2 males and 2 females) were served as subjects. Tasks were sustained phonation containing register changes. Two major categories (Category A and B) were found in the ways of changing of vocal fold vibrations at the register change. In Category A, changes were very smooth in terms of the vocal fold vibration. In Category B, changes were not so smooth with some additional events at the register change, such as the anterior–posterior phase difference of the vibration, the abduc...

Comparing materials for the evaluation of symptom severity in the read speech of spasmodic dysphonia patients

Reliability and validity of evaluation methods for assessing the degree of severity of spasmodic dysphonia (SD) symptoms have become a matter of concern for voice specialists. With the syllable method [M. Kumada et al. (1997)], overall degree of severity is represented by the proportion of impaired syllables. This method has shown promise for English, though it appears to work better for evaluating prose read aloud than for evaluating the recitation of sequences of cardinal numbers, because inappropriate pauses are more easily identified in prose. The present study aims to compare types of English prose according to their tendencies to reveal SD symptoms. Specifically, audio recordings of seven patients reading Fairbanks Rainbow Passage are evaluated by five voice professionals, as are audio recordings by the same patients of sentences in which tempo is expected to be highly predictable and thus, by hypothesis, potentially more stable for purposes of cross‐speaker comparison. These sentences are constructed entirely of stressed monosyllables. If the phonatory dysfunction observed correlates with disturbances to so‐called stress‐timing patterns [K. L. Pike, Intonation of American English (Ann Arbor, 1945)], sequences of stressed monosyllables would be expected to be especially useful in the evaluation of SD.

Functions of the muscles of the tongue during speech

To investigate the functions of tongue muscles during speech, three methods were combined: conventional MRI, to identify the musculature; tagging snapshot MRI, to visualize the displacement of tissues and measure contractions of muscles; and electromyography (EMG), to observe muscle activities. Five Tokyo‐dialect speakers produced sustained phonations of five Japanese vowels. (Sessions of five English speakers are also planned to observe English vowels and consonants.) Muscle contractions of four regions of genioglossus (GG1‐4, anterior to posterior), styloglossus (SG), vertical (V), superior and inferior longitudinal (SL, IL) were measured. The functional units of GG seemed to be overlapped with each other: GG3‐4 to make the highest point of the tongue higher, working against V; GG2‐4 to move the most posterior point anteriorly; and GG1‐3 to move the highest point anteriorly, working against SG. SL contributed to groove formation. IL contributed to ‘‘landslide’’ formation in /o/ by keeping the lower half...

Spasmodic dysphonia in Japan: 1486 Botulinum toxin injections for 260 spasmodic dysphonia patients

Botulinum toxin injection is a very effective treatment for spasmodic dysphonia. We experienced 1486 injections for 260 patients in past 15 years in Japan. Here we show statistics of these injections. We use type A toxin that is produced by Clostridium Botulinum. This toxin affects the neuro‐muscular junction as a blocker of release of Ach, which leads to inversible parasis of a muscle. Mainly, we inject the toxin paracutaneously on the neck to the vocalis muscle using a partly covered needle that works as an EMG electrode. Mainly we have four options: 2.5 i.u. unilaterally (38% of 256 patients), 2.5 i.u. for each laterality bilaterally (16%), 5.0 i.u. unilaterally (29%), and 5.0 i.u. for each laterality bilaterally (5%). Its effectiveness persisits for 17.3 weeks on average. The longest effectiveness we have ever experienced is more than 1 year. A small percentage of the injections are not effective; it can be thought that the injected toxin does not reach the neuromuscular junction even when the needle ...

Movie MRI at five frames a second for evaluation of speech and swallowing

Magnetic resonance imaging (MRI) is a noninvasive imaging method that is widely used in the medical field. One of the limitations of MRI is its low time‐resolution; images of MRI are usually obtained as still images. Here we introduced a newly developed method of ‘‘movie’’ MRI with high time‐resolution at five images a second. Its good application would include study and evaluation of speech and swallowing. Instrument: MRT‐2001 XG with Software ver.5.5. (Toshiba). Coil: head QD coil for the tongue; CTL ARRY coil (3ch) for the neck, Imaging condition: sagital FFE2D; TR=2.8 ms; TE=1.2 ms; FA=10 deg; Matrix=64×128; ST=10 mm; NAQ=1 AV; FOV=23×35 ; ROAFI; sequential acquisition. Maximum imaging length=51 s. A healthy Japanese male (Tokyo dialect speaker, 39 years). Task: Repetitive utterance of /tenten.../ and intentional swallowing of saliva. Results: In the task of /tenten..../, we could detect, in temporal order, velopharyngeal (VP) closure, opening of the tongue‐palate (TP) closure, VP opening, TP closure,...