Aki Taguchi

Japanese Version of Voice Handicap Index for Subjective Evaluation of Voice Disorder

Recently, the Voice Handicap Index (VHI), developed in the United States, has been highlighted as a means to assess a patients perceptions of the severity of his or her voice disorder. The VHI is based on a self-administered questionnaire that quantifies the degree of a patients disability related to his/her voice disorder. The questionnaire was translated into Japanese and applied to Japanese patients with various kinds of disordered voice or dysphonia. The results were analyzed and the usefulness discussed. In this study, 546 patients (281 males and 265 females) were included. Mean VHI scores were 36.2/120 in males and 44.1/120 in females. In the male patients, VHI scores were the highest among teens. However, VHI scores did not vary with age in the female patients. Patients with vocal fold paralysis, functional dysphonia, psychological dysphonia, and spasmodic dysphonia showed relatively high VHI scores, whereas those with laryngeal granuloma and laryngopharyngeal reflux disease showed low scores. In most diseases, functional and physiological scores were higher than emotional scores. In any treated patients, those with vocal nodule, vocal polyp, polypoid vocal fold, and recurrent laryngeal nerve paralysis, VHI scores decreased after therapeutic intervention. These findings suggest that the Japanese VHI is a useful tool for monitoring a patients psychological status, choosing appropriate treatment, and assessing the therapeutic outcome.

Age-related changes in rat intrinsic laryngeal muscles: analysis of muscle fibers, muscle fiber proteins, and subneural apparatuses

We compared age-related changes in the intrinsic laryngeal muscles of aged and young adult rats by determining the number and diameter of muscle fibers, contractile muscle protein (myosin heavy chain isoforms, MHC) composition, and the morphology of the subneural apparatuses. In aged rats, both the numbers and the diameters of muscle fibers decreased in the cricothyroid (CT) muscle. The number of fibers, but not diameter, decreased in the thyroarytenoid (TA) muscle. In the posterior cricoarytenoid (PCA) muscle, neither the number nor the diameter of fibers changed significantly. Aging was associated with a decrease in type IIB and an increase in type IIA MHC isoform levels in CT muscle, but no such changes were observed in the TA or PCA muscles. Morphological examination of primary synaptic clefts of the subneural apparatus revealed that aging resulted in decreased labyrinthine and increased depression types in only the CT muscle. In the aged group, morphologically immature subneural apparatuses were found infrequently in the CT muscle, indicating continued tissue remodeling. We suggest, therefore, that age-related changes in the intrinsic laryngeal muscles primarily involve the CT muscle, whereas the structures of the TA and PCA muscles may better resist aging processes and therefore are less vulnerable to functional impairment. This may reflect differences in their roles; the CT muscle controls the tone of the vocal folds, while the TA and PCA muscles play an essential role in vital activities such as respiration and swallowing.

Age-Related Remodeling of the Hypopharyngeal Constrictor Muscle and Its Subneural Apparatuses: A Scanning Electron Microscopical Study in Rats

Age-related remodeling of the hypopharyngeal constrictor muscle was studied by comparing the morphological features of the subneural apparatus (SNA) of the thyropharyngeal (TP) and cricopha ryngeal (CP) muscles in young and old rats. Scanning electron microscopy revealed that the TP and CP muscles had both gutter- and depression-type SNAs, although different proportions of the two types of apparatus were found in each muscle. In young-adult rats, the gutter-type SNA was predominant in the TP muscle, whereas in the CP muscle the depression type was predominant. By contrast, in old rats, the depression-type SNA was predominant in the TP muscle, while no such transformation of the dominant SNA was noted in the CP muscle. In addition, the number of type IIb and type I muscle fibers was lower and greater, respectively, in older animals compared with those of younger animals. Furthermore, there were more type IIc fibers in the TP muscle of old rats, but no difference in the CP muscle between young and old animals. These findings suggest that the transformation of SNAs and the muscle fibers of the hypopharyngeal constrictor muscle takes place during aging and that their remodeling processes differ in the TP and CP muscles.

Endoscopic Laryngeal Findings in Japanese Patients with Laryngopharyngeal Reflux Symptoms

Objective. To know the characteristics of endoscopic laryngeal and pharyngeal abnormalities in Japanese patients with laryngopharyngeal reflux symptoms (LPRS). Methods. A total of 146 endoscopic images of the larynx and pharynx (60 pairs for the rabeprazole group and 13 pairs for the control group) were presented to 15 otolaryngologists blinded to patient information and were scored according to several variables potentially associated with laryngopharyngeal reflux. The median value of the 15 scores for each item from each image was obtained. The mean pretreatment scores of each item and total score were assessed in both rabeprazole and control groups. In the rabeprazole group, the endoscopic findings before and after the 4-week treatment with rabeprazole were compared. Changes between corresponding duration in the control group were also evaluated. Results. The median and mean pretreatment total score was 3 and 3.02, respectively, from the 73 patients with LPRS. No significant differences were observed before and after treatment in either the rabeprazole or control groups for any item or total score. In 24 patients with a high pretreatment score (total score ≥ 4) from the rabeprazole group, significant decreases in scores for “thick endolaryngeal mucous” (0.54 to 0.17, P = 0.017) and total (4.77 to 3.58, P = 0.0003) were observed after the 4-week treatment.

A complex muscle fiber network in the cricothyroid muscle: a scanning electron microscopic study.

Objectives: To examine the three‐dimensional ultrastructure of cricothyroid (CT) muscle fibers to elucidate their morphologic characteristics with regard to the specific functions of the muscle.

Preventive effects of bortezomib on denervation-induced atrophy of the intrinsic laryngeal muscles: an experimental study in the rat

Abstract Conclusion: Bortezomib was effective in attenuating atrophy of the posterior cricoarytenoid (PCA) muscle, but not the thyroarytenoid (TA) muscle. This was probably due to differences in the fiber composition of the two muscles. The PCA muscle is composed of a combination of fast- and slow-twitch fibers, and therefore is more resistant to atrophy than the TA muscle, which is composed solely of fast-twitch fibers. Objectives: To investigate the preventive effects of bortezomib on denervation-induced atrophy of the TA and PCA muscles in the rat. Methods: Following transection of the left recurrent laryngeal nerve, bortezomib (100 μg/kg) was administered subcutaneously on post-denervation days 1 and 4, followed by a 10-day rest period every 14 days; each 2-week period constituted a single treatment cycle. In controls, saline was administered instead. Animals were killed for histological examination at 4 (n = 6), 8 (n = 7), and 12 (n = 7) weeks post-denervation. Muscle atrophy was assessed using three indices: wet muscle weight, muscle fiber cross-sectional area, and the number of muscle fibers/mm2. The effects of bortezomib were evaluated by comparing the left (L) and right (R) muscles, with sequential changes in the L/R ratio assessed. Results: In saline-administered animals, atrophy of the left-sided TA and PCA muscles progressed rapidly during the first 4 weeks post-denervation, following which progression slowed. Atrophy was greater in the TA compared with the PCA muscle, although this difference was not statistically significant. In bortezomib-administered animals, atrophy of the PCA muscle was attenuated significantly at post-denervation weeks 8 and 12; no such reduction in atrophy was observed for the TA muscle.

Scanning electron microscopic study of the muscle fiber arrangement in the rat cricopharyngeal muscle.

Conclusions. Myomyous junctions comprise a complex muscle fiber network, which is thought to synchronize the activity of the cricopharyngeal (CP) muscle fibers. Myomyous and myotendinous junctions explain the heterogeneity in muscle fiber length which contributes to the efficient behavior of the muscle. This scanning electron microscopy (SEM) study demonstrated the complex muscle fiber arrangement of the CP muscle and improved on the previous description of its morphological specificity. Objective. To examine the 3D ultrastructure of the inferior pharyngeal constrictor muscle fibers to obtain further knowledge of their morphological characteristics with regard to the specific functions of the muscle in deglutition. Material and methods. Six adult rats were used. Their CP and thyropharyngeal (TP) muscles were obtained and processed using the HCl hydrolysis method to remove i.m. connective tissue. The fine muscle fiber structure was observed by means of SEM. Results. Multifaceted muscle fiber interconnections (myomyous junctions) were identified in the CP muscle. The myomyous junctions were characterized by the tight connection of many finger-like processes at the ends of a lateral branch or bifurcating trunk of the muscle fibers. In addition, muscle fibers occasionally tapered and ended within the muscle belly, forming myotendinous junctions. The TP muscle lacked these structures.

Comparison of the Laryngopharyngeal/Esophageal Symptoms Between High and Low Endoscopic Laryngeal Findings in Japanese Patients With Laryngopharyngeal Reflux Symptoms

Dental erosions are loss of tooth enamel caused by prolonged and/or repeated acid exposure, occurring in 2 to 5% of the general population. Acid in the mouth may occur from ingestions of soft drinks or fruit juices. Acid in the mouth may also occur from gastroesophageal reflux disease (GERD), although this relationship is not well established in children. The aims of this study were to assess correlations between dental erosions and GERD in pediatric subjects, and correlate the stage and number of teeth involved with dental erosions to the presence of GERD. We did a retrospective chart review from July 2009 to June 2010, which included 14 subjects (12 male), 5 to 12 yr old (mean 9 yr), referred by pediatric dentists for GERD evaluation because of dental erosions. A GERD diagnosis was confirmed by positive results of esophagoscopy, esophageal biopsies, impedance and/or pHmetry. We assessed symptoms associated with GERD, including recurrent or chronic heartburn, chest pain, coughing, nausea, abdominal pain, spitting up, vomiting, anorexia, and sour taste in the mouth. Of the 14 subjects 3 had GERD (21%), diagnosed based on abnormal pHmetry in 2 (1 with abnormal impedance) and on abnormal histology in 1. Two of 14 subjects met symptombased (Rome) criteria for rumination syndrome. Nine of 13 subjects had symptoms. Of the symptomatic subjects, 1 had GERD. Of 4 asymptomatic subjects, 2 had GERD. Symptoms were not associated with the presence or absence of GERD. We had staging data for 12 subjects: 1 with stage 1, 3 with stage 2, 7 with stage 3, and 1 with stage 4 dental erosions. There was no correlation between the stage of dental erosions or number of affected teeth and GERD. Conclusion: GERD may not be the major cause for dental erosions in children. Because rumination syndrome is thought to be uncommon, it appeared that the risk of dental erosions may be increased by co-morbid rumination syndrome.

Age-Related Morphological Changes of the Neuromuscular Junction of the Hypopharyngeal Constrictor Muscles in Rats; A Scanning Electron Microscopic Study

Age-related functional deterioration of deglutition is a serious problem in the elderly population since it increases the risk of aspiration pneumonia. In the present study, aging effects in the subneural apparatus (SNA) were histologically investigated in the inferior pharyngeal muscle of a rat using scanning electron microscopy. In young-adult group, the primary synaptic clefts (PSCs) of the SNAs in the thyropharyngeal muscle (TP) were predominantly labyrinthine type, whereas, those in the cricopharyngeal muscle (CP) were mostly depression type. The ratio of length to width (L/W ratio) of the secondary synaptic clefts (SSCs) and the ratio of areas of SSCs to those of PSCs (ASC/APC ratio) were larger in the TP than in the CP.In the TP, the labyrinthine type of PSC decreased in percentage with age, while the depression type increased instead. However, the CP showed no significant change of PSC typing. The L/W ratio and ASC/APC ratio of the SSC decreased in the TP with age, and those in the CP increased. In the aged group, thin muscle fibers which contained immature SNA were occasionally identified in both muscles. These fibers were considered to be undergoing a regenerating process. Myosin ATPase staining showed age-related decrease of type II muscle fiber and increase of type I fiber in the TP. Similar findings were noted in the CP, although the change was not as great as in the TP.These age-related changes of the TP might suggest weakening and slowing of the muscle contraction, and therefore cause a disturbance of food transport into the esophagus during deglutition. In contrast, the CP is less affected by aging. Disturbed function of the TP together with maintained tonic contraction of the CP may work disadvantageously for deglutition, thereby resulting in increased risk of aspiration.

Laryngeal Paralysis in Children

Masamitsu Hyodo, Takahiko Yamagata, Kazumi Motoyoshi and Aki Taguchi Recurrent laryngeal nerve paralysis in children is a relatively rare disease. Its clinical features in children are considered dissimilar to those in adults. Here we present 11 cases of children with recurrent laryngeal nerve paralysis and discuss the manner of treatment for this disease. Clinical features compared and found to differ with those in adults are summarized as follows: 1) congenital paralysis is the most common cause, 2) bilateral paralysis is frequent, 3) congenital systemic abnormalities are frequently combined, 4) respiratory disorder is the most critical symptom especially in infants, 5) vocal cord movement ordinarily recovers in a few years especially in patients with congenital paralysis. Management strategies should be focused on the maintenance of a safe and stable airway and the acquisition of intelligible speech. Less traumatic laterofixation of the vocal cord by Ejnells procedure is a preferable surgical treatment for prolonged respiratory disorder due to bilateral laryngeal paralysis.