著者

青柳 優 鈴木 豊

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.89, no.6, pp.653-667, 1996-06-01 (Released:2011-11-04)

参考文献数

53

被引用文献数

1

---

The ultimate goal of objective audiometry is to draw an audiogram in a frequency specific manner with no response from the subject. Auditory evoked brainstem response (ABR) is now most commonly used for objective audiometry. However, the frequency specificity of ABR elicited with tone pips is not enough to predict accurate hearing on a frequency-specific basis across the audiometric range. Amplitude-modulation following response (AMFR), which is an auditory steady-state response elicited with sinusoidally amplitude-modulated tone, is expected to be an ideal tool for objective audiometry, because of the frequency specificity of the stimulus tone.When detected by phase coherence, the threshold pattern of 40-Hz AMFR, which is elicited with tone amplitude modulated at 40 Hz, resembles very closely the corresponding audiogram patterns in all types of hearing impairment in adults while awake. However, 40-Hz AMFR is not sufficiently reliable for determining the hearing threshold in young children during sleep.On the other hand, 80-Hz AMFR is clearly detected in young children during sleep with the use of phase coherence. The threshold pattern of 80-Hz AMFR also resembles closely the corresponding audiogram pattern. An 80-Hz AMFR thus appears to be potentially useful for objective audiometry in young children during sleep.In this paper, our present knowledge about objective audiometry and AMFR is reviewed, and techniques for detecting AMFR and sources of AMFR are discussed.

著者

岡崎 儀四郎

出版者

The Society of Practical Otolaryngology

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.21, no.4, pp.840-853, 1928

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上來諸實驗ノ結果ニ基キ結論スレバ次ノ如シ.<br>1. 正常家兎ノ皷室腔内ニ注入セル色素ハ一定時間中ニ皷室腔内ヨリ吸收セラル.<br>2. 皷室腔ニ於ケル色素ノ吸收經路トシテハ血管, 淋巴管共ニ之ニ參與ス.<br>3. 皷室腔内ニ於ケル色素吸收ノ時間的經過ハ血液ニアリテハ注入後10分淋巴ニアリテハ30分ニシテ始メテ之ヲ證明シ此等液中ニ於ケル含有色素濃度ノ最高ニ達スル所要時間ハ血液ニ於テハ注入後2-3時間, 淋巴ニアリテハ3-4時間ナリ.<br>4. 色素吸收ノ時間的經過ニ於ケル血液及淋巴中ノ含有色素濃度ハ皷室腔内ニ注入セル色素ノ種類ニヨリテ差異アリ. 一般ニ擴散度大ナル色素 (Trypanblu, Trypanrot 及 Fuchsin S) 注入ノ場合ハ吸收ノ初期及中期ニ於テ血液中ノ色素濃度ハ淋巴ノ夫レニ比シ著シク大ナリ. 然ルニ吸收後期ニ至レバ血液及淋巴中ノ色素濃度ハ互ニ接近スルノミナラズ擴散度小ナル色素 (Neutralrt, Mlethylenblue) ノ場合ハ淋巴中ノ色素濃度ハ血液中ノ色素濃度ヲ凌駕スルニ至ル.<br>5. 皷室腔内ニ注入セル色素溶液ノ濃度ノ大小ニヨリテ色素吸收ノ時間的經過ニ多少ノ差異アリ. 一般ニ色素溶液ル濃度大ナルモノハ小ナルモノニ比シテ色素吸收ノ時間的經過ハ少シク延長ス.<br>6. 尿中ニ排泄セラル色素濃度ハ色素ノ種類ニヨリテ血液中ノ色素濃度ニ比シテ稍々大ナルモノ (Trypanblaue 及 Trypanrot) 及却テ小ナルモノ (Neutralrot, Mechylenblue, Fuchsin. S. etc) アリ.

著者

山口 宗一 鴫原 俊太郎 池田 稔

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.97, no.4, pp.291-297, 2004-04-01 (Released:2011-10-07)

参考文献数

16

被引用文献数

1 1

---

The etiology of sudden sensorineural hearing loss is unknown, but viral infection is suspected as one possible cause. We retrospectively studied 102 sudden sensorineural hearing loss patients to evaluate the efficacy of acyclovir therapy. Acyclovir had been administered to 25 patients as single therapy or in combination with corticosteroid or batroxobin. They were given 750mg of acyclovir per day intravenously. These patients were compared with the other 77 patients treated without acyclovir. Hearing recovery was assessed by the criteria of the Sudden Deafness Research Group of the Japanese Ministry of Health and Welfare. In the patients treated with acyclovir, the rate of complete recovery was 56.0%, the rate of recovery was 80.0%, and the rate of efficiency was 88.0%. We found significantly better recovery in the group therapy by acyclovir than in the group without acyclovir.

著者

久米 淳子 小川 恭生 萩原 晃 市村 彰英 鈴木 衞

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.99, no.8, pp.623-633, 2006-08-01 (Released:2011-10-07)

参考文献数

11

被引用文献数

2 4

---

Cerebral infarction occurs predominantly in the elderly, but may occur in young adults, especially when complicated with collagen disease, heart disease, and dissecting aneurysm. Four patients (range: 31-47 years old) complaining of a sudden onset of vertigo and nausea without a history of trauma are presented. Emergency computed tomography was initially interpreted as normal, but subsequent magnetic resonance imaging and a magnetic resonance angiogram disclosed vertebral artery (VA) dissection. Arterial dissection resulting in embolic stroke in the area of the ipsilateral posterior inferior cerebellar artery was suspected. All patients were treated conservatively without sequelae. Spontaneous VA dissection should be suspected in young patients presenting with ischemic stroke but without predisposing risk factors or associated trauma.

著者

古川 雅史 梶川 泰 松代 直樹 北村 貴裕 大畠 和也 北原 糺 鎌倉 武史

出版者

The Society of Practical Otolaryngology

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.105, no.10, pp.913-918, 2012 (Released:2012-10-01)

参考文献数

12

被引用文献数

2

---

We studied 804 patients with idiopathic sudden sensorineural hearing loss (ISSNHL) regarding the correlation between the duration from the onset to the start of treatment and hearing outcome. An analysis of the 804 yielded the following results: 1) The overall cure rate was 30.0%. 2) The cure rate was better in patients with a shorter duration (within about 10 days) between the onset and the start of treatment. 3) In patients with mild hearing loss (Grade 1, 2), the cure rate was better in patients with a shorter duration. 4) In patients with severe hearing loss (Grade 3, 4), the cure rate of over 8-10 days was clearly worse, and it is very important to start treatment within 8-10 days.

著者

大山 勝 山際 幹和 荘司 邦夫 橋本 真実 古田 茂 小幡 悦朗 三吉 康郎

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.75, no.8, pp.1681-1689, 1982-08-01 (Released:2011-11-04)

参考文献数

18

被引用文献数

1

---

By means of laryngofiberscopy, pneumatography and photoelectric glottography, the closure reflex activity of the larynx which was evoked by trasnasal stimulation with various concentrations of isovaleric acid and ammonia during inspiration was determined in 24 normal subjects and 53 patients with chronic sinusitis, anosmia, nasal allergy and chronic obstructive pulmonary diseases (COPD).The reflex activity was characterized by a remarkable tendency to decrease in the majority of normal older subjects and most of the patients with conditions other than nasal allergy.It was assumed that this reflex might be of great importance in preventing hazardous materials from going into the lung and that depression or absence of the reflex sensitivity in the upper respiratory tract might lead to a higher incidence of pulmonary diseases.The results which were obtained here will help clarify the laryngeal clossure reflex. This methodology may be employed practically to serve as objective olfactometry.

著者

時田 喬 宮田 英雄 牧 達夫 浅井 徳光 橋本 正彦 前田 正徳 棚橋 聰子

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.73, no.6special, pp.1124-1130, 1980-06-25 (Released:2011-11-04)

参考文献数

4

---

We report herein the examinations required for evaluation of the effects of treatment of Meniere's disease. Prior to the discussion, it is indispensable to clarify the design of the treatment. In the treatment, the authors take into consideration the following three subjects: (1) treatment of vertigo, (2) treatment of damage to the inner ear, and (3) treatment of recurrence of attacks of vertigo.(1) For evaluation of effects of treatment of vertigo in attacks and dizziness in the chronic stage of the disease, complaints of vertigo and spontaneous nystagmus as objective evidence of vertigo should be investigated. Furthermore, righting reflex and deviation test should be performed in order to demonstrate the mechanism of improvement of the vertigo. Despite the improvement obtained by inhibitory effects of drugs on the vertigo, the righting function and deviation phenomenon remain unchanged. On the contrary, when the pathological condition of the inner ear is healed there is an improvement of these signs.(2) Effects of the treatment for damage of the inner ear are evaluated by hearing and caloric tests. In cases where the labyrinthine excitability is not reversible, compensatory process of balancing activity of the body should be examined using the standing test, tests for spontaneous nystagmus, deviation and caloric tests and tests for postrotatory nystagmus. Disappearance of spontaneous nystagmus and deviation phenomenon reveal a recovery of static balance of the vestibular system. Disappearance of asymmetry of postrotatory nystagmus indicates a restoration of balance in the kinetic labyrinthine reflexes.(3) Recurrences of attacks of vertigo are treated on the basis of the results of examination of etiologic factors of Meniere's disease in each patient. Effects of this treatment should be evaluated by long-term follow-up of the vertiginous attacks.

著者

時田 喬 宮田 英雄 加藤 加藤 鈴木 省吾 小林 武

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.64, no.1, pp.3-15, 1971 (Released:2011-10-14)

参考文献数

22

著者

清水 啓成 高橋 明洋 小口 直彦 石戸谷 淳一

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.90, no.12, pp.1409-1414, 1997-12-01 (Released:2011-11-04)

参考文献数

23

被引用文献数

1

---

Chronic paranasal sinusitis encompasses a variety of pathologies, and eosinophil infiltration of nasal polyps is characteristic of chronic sinusitis in which allergy is a strong etiologic factor (allergic paranasal sinusitis). Suplatast tosilate is an anti-allergy agent that suppresses production of IgE antibody and inhibits tissue infiltration by eosinophils. In the present study we assessed the efficacy of suplatast tosilate immunohistochemically in surgical specimens of nasal polyps before and after drug therapy to evaluate its efficacy in allergic sinusitis.The subjects were 8 patients with allergic sinusitis associated with nasal polyps. These patients were treated with suplatast tosilate for about three months. Nasal polyps were collected before and after treatment, and 5-μm frozen serial sections were prepared and stained with HE and by immunochemical methods. The number of eosinophils and eosinophil activation were assessed by using EG2 antibody, which recognizes secretory type eosinophilic cationic protein (ECP) alone, as the primary antibody, to investigate eosinophil activation.Infiltration by numerous eosinophils, predominantly in the superficial layer of the lamina propria, was observed in the nasal polyps of allergic rhinitis patients. Significant decreases in the number of eosinophils and the number of EG2-positive cells were observed in the nasal polyps after treatment with suplatast tosilate, and a significant decrease was also observed in the ratio of the number of EG2-positive cells to the number of eosinophils. Thus, suplatast tosilate was shown to have eosinophil tissue infiltration suppressing activity in human nasal polyps, and to also possess inhibitory activity against eosinophil degranulation. Based on these findings, suplatast tosilate suppresses allergic inflammation, which is predominantly manifested by eosinophil infiltration, and was found to be effective in the treatment of allergic paranasal sinusitis.

著者

兵 行義 雑賀 太郎 濵本 真一 原田 保 原 浩貴

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.111, no.4, pp.227-234, 2018 (Released:2018-04-01)

参考文献数

16

被引用文献数

1

---

The number of patients suffering from cedar pollinosis is increasing. It would be no exaggeration to say that it is the unique cause of allergic rhinitis in Japan. Allergen immunotherapy has recently attracted attention as a radical treatment for cedar pollinosis, just as for allergic rhinitis. We examined cedar pollinosis was more marked in the cypress season than in the cedar season. The present study included 27 patients who had received allergen immunotherapy for cedar pollinosis for more than a year. A questionnaire survey was also conducted on drug usage according to the Japanese Allergic Conjunctival Disease QOL Questionnaire (JACQLQ), a modified version of the Japanese Allergic Rhinitis Standard QOL Questionnaire.In 2015, the amount of scattered pollen was 1660.7/cm2, being lower than the average of the past 20 years. In patients who had received immunotherapy against cedar pollinosis regardless of the duration of the therapy, the nasal and eye symptoms, medication score, and face scale were worse in the cypress season. In addition, tests for allergn-specific IgE antibodies before and after the cedar/cypress seasons demonstrated that while the cedar-specific IgE levels did not increase, the cypress-specific IgE levels significantly increased in subjects who had received immunotherapy for shorter periods. Cypress-specific IgG4 levels tended to increase in patients who had received cedar-pollen immunotherpy for longer periods, however, to a lesser degree than the cedar-specific IgG4 levels.Thus, the allergen-speccific antibody titers demonstrated the ineffectiveness of cedar allergen immunotherapy against cypress pollen allergy in 2015, in which year, the average amounts of airborne pollen was lower than the average in the last 20 years, suggesting that cypress extracts should also be developed to treat cypress pollen allergy.

著者

田中 信三

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.99, no.7, pp.513-518, 2006-07-01 (Released:2011-10-07)

参考文献数

19

被引用文献数

2

---

Change and its significance in the treatment of the hypopharyngeal carcinoma (HPC) are discussed, chiefly based on the author's experiences. In the nineteen-seventies and eighties, the prognosis of HPC was poor, and the 5-year over-all survival was only 24% in 173 patients. Locoregional recurrence was the most serious problem. To improve locoregional control, we introduced extended surgery with reconstruction using a free jejunal graft, in which a safety margin of 3cm or more was secured at the primary site while bilateral retropharyngeal and paratracheal dissections were added to bilateral radical neck dissections. This treatment achieved a disease-specific 3-year survival of 64% for patients with advanced (stage III, IV) HPC, which was significantly better than that of patients treated by previous methods. Furthermore, postoperative radiotherapy was introduced for advanced HPC treatment, in which a 50Gy dose was basically used to irradiate the bilateral neck and a 10Gy dose was locally added when a retropharyngeal lymphnode metastasis was histopathologically identified or the number of lymphnode metastasis was three or more. In the recent five years, the disease-specific 3-year survival reached 81% in 39 advanced HPC patients. During this period, we endeavored to conserve in laryngeal functions for patients with early (stage I, II) HPC by performing a radiotherapy or partial pharyngectomy. In 14 early HPC patients, there was no recurrence and the larynx was well conserved in eleven. We also developed a new method of reconstruction after partial laryngopharyngectomy, in which aspiration was well prevented by reconsfructing the supraglottis and hypopharynx using hyoid bone attached to sternohyoid muscle and free forearm flap. Progress in surgical reconstruction techniques and radiotherapy changed the treatment of HPC, providing a better prognosis for advanced HPC patients and a better life quality for early HPC patients.

著者

朝日 淳仁 浅野目 充 原渕 保明

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.100, no.10, pp.813-816, 2007-10-01 (Released:2011-10-07)

参考文献数

23

被引用文献数

3 3

---

Pyogenic granuloma is a benign rapidly growing hemorrhagic lesion that involves the skin and mucosa. As pyogenic granulomas often occur on the oral mucosa during pregnancy, they are called pregnancy tumors. The author encountered a case of pyogenic granuloma involving the right nasal septum.A 29-year-old woman, 6 weeks after delivery of a baby, presented with spontaneous right-sided epistaxis that had started in the 32th week of pregnancy. Physical examination demonstrated a dark-red mass that bleed easily at the front of the right side nasal septum.Since the mass did not show any decrease in size, excision of the lesion under local anesthesia was performed about 8 weeks postpartum. Histologic examination demonstrated pyogenic granuloma. There has not been any recurrence for 7 months postoperatively.

著者

佐藤 文彦 竹之内 智 鈴木 由一 矢野原 邦生 日向 誠 田中 康夫

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.74, no.1, pp.109-116, 1981 (Released:2011-11-04)

参考文献数

7

被引用文献数

4

---

A series of 120 unselected radiographs of the larynx without organic laryngeal disorders was analysed from the standpoint of laryngeal calcification or ossification. The special patterns of laryngeal ossification were described in the lateral X-ray using low kilovoltage technique of the larynx.1) Normal “figure 8” configuration of the ossified thyroid cartilage angle was characterized in men (37/45, 82%) but rare in women (10/75, 13%).2) A horn-like shadow of the ossified arytenoid cartilage was characteristic in women (43/75, 57%) as compared with men (7/45, 16%).3) A crescent-shaped shadow of the ossified top of the cricoid cartilage was observed in 42% of the total cases.These special configurations of the laryngeal ossification were also discussed from the viewpoint of laryngeal functional surgery.

著者

関谷 透

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.82, no.12, pp.1822-1823, 1989-12-01 (Released:2011-11-04)

著者

久保 伸夫 川村 繁樹 福武 知重 山下 敏夫

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.89, no.5, pp.533-536, 1996-05-01 (Released:2011-11-04)

参考文献数

9

被引用文献数

1 1

著者

柴田 敏之 坂下 哲史

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.98, no.6, pp.438-439, 2005-06-01 (Released:2011-10-07)

被引用文献数

1 1

著者

稲木 勝英 設楽 哲也 岡本 牧人 徳増 厚二 藤野 明人 石井 豊太 鎌田 利彦

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.82, no.4, pp.537-541, 1989-04-01 (Released:2011-11-04)

参考文献数

12

被引用文献数

2 2

---

Aortitis syndrome is known to be an autoimmune disease, which has many symptoms of occulusive thromboaortopathy. It has recently been reported that the patients with systemic autoimmune diseases may have sensorineural hearing loss and that steroid therapy should be effective not only for the original disorder but also for the associated hearing disturbance.Eleven patients (3 males and 8 females) with aortitis syndrome and sensorineural hearing loss have been treated in Kitasato University Hospital during the 16 years since the opening of the hospital.The onset of hearing impairment was at 32 to 48 years of age, 10 years older than the mean age of onset of the aortitis syndrome reported in the literatures.Various types of hearing impairment were noted : slight hearing loss, total deafness of sudden onset and fluctuating type. Tinnitus was associated with hearing loss in many cases.Several patients also had vertigo and dysequilibrium, and in some of them the diagnosis was peripheral vestibular hearing loss, although in the cases of aortitis syndrome with hearing loss reported in the literature neither vertigo nor dizziness was mentioned.The usual treatment for acute stage sudden deafness was not effective in most of our patients. However, one female patient treated with long-term steroid therapy for systemic arteritis showed marked improvement of both her hearing and her general condition.We cannot conclude that the origin of sensorineural hearing loss is arteritis in the inner ear in all cases of aortitis syndrome with hearing loss. However, our cases of aortitis syndrome with steroid-dependant hearing loss indicate that the possibility remains of hearing loss due to arteritis of the labyrinthine artery in aortitis syndrome.

著者

山本 佳史 北原 糺 久保 武

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.99, no.5, pp.397-401, 2006-05-01 (Released:2011-10-07)

参考文献数

18

---

Cervical lymph node swelling and high fever are common in patients presenting to the Department of Otolaryngology. Kikuchi's disease is an idiopathic necrotizing histiocyte lymphadenitis with the main clinical feature being adenopathy, generally in a cervical location. The disease is relatively rare and often misdiagnosed as lymphoma or lupus and inappropriately treated, potentially causing numerous medical consultations without relief of symptoms. The case described is that of a 28-year-old female with persistent cervical lymphadenitis and fever who presented to our department without an appropriate diagnosis at previous hospitals. All symptoms were quite resistant to antibiotics or NSAIDs. Laboratory results showed WBC decrease and AST/ALT increase, although common viral infectious diseases were denied. Finally, left cervical lymph node biopsy was performed under local anesthesia and the patient was diagnosed as having histiocytic necrotizing lymphadenitis or Kikuchi's disease. Since Kikuchi's disease is sometimes recurrent and coupled with collagen disease, long-term follow-up should be required.

著者

田中 明子 土師 知行 新正 由起子 前田 秀明 竹林 慎治 八木 伸也

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.93, no.11, pp.939-943, 2000-11-01 (Released:2011-11-04)

参考文献数

15

被引用文献数

1

---

We report 2 adult cases of inspiratory dyspnea caused by an epiglottal prolapse.The first case was a 61-year-old man who was suffering from inspiratory dyspnea, especially while sleeping. A laryngofiberscopic examination revealed that the epiglottis was contacting the posterior pharyngeal wall during inspiration, causing airway obstruction. A partial epiglottectomy with a Holmium: YAG laser improved respiratory dystress during sleep.The second case was a 60-year-old man who also suffered from dyspnea while sleeping. The laryngofiberscopic findings were the same as in the first case, and a partial epiglottectomy was also effectve for the dyspnea during sleep. A pathological examination revealed degeneration of the epiglottic cartilageThe Holmiun: YAG laser was useful in resecting the epiglottic cartilage in both cases.

著者

進 武幹 梅崎 俊郎

出版者

耳鼻咽喉科臨床学会

雑誌

耳鼻咽喉科臨床 (ISSN:00326313)

巻号頁・発行日

vol.88, no.5, pp.553-559, 1995-05-01 (Released:2011-11-04)

参考文献数

14

被引用文献数

2 3

---

In general, esophagography with a VTR system, electromyography and measurement of the pressure of the digestive tract are used for evaluation of the swallowing function. In previous reports a time lag in movement of the bolus was pointed out in many patients with dysphagia. However, a standardized time reference for this lag was not clarified in most cases.A new concept evaluating dysphagia is introduced in this study to clarify the pathophysiology of swallowing disorders. The movement of the bolus is referred to as a phase, and the time progress of the patterned output from the medullary swallowing center is referred to as a stage. It can, therefore, be considered that dysphagia occurs when the time lag between the phase and stage exceeds the physiologically permissible limits.The standard point of the phase and stage were determined separately from an analysis of the esophagogram with a VTR system in normal volunteers, and the time lag between the two points was measured in patients with dysphagia. We devised a new instrument to evaluate the swallowing function, which can record simultaneously the pressure of the oral cavity and pharynx and the air flow rate. These methods were useful for detecting the delay of the initiation of pharyngeal swallowing which is observed in patients with dysphagia caused by lesions of the corticobulbar tract.