＜Purpose＞ Velopharyngeal closure is observed not only in swallowing but also in pneumatic actions including speech and blowing．Clinically，velopharyngeal closure in pneumatic action is not distinguished from that in swallowing． However，pneumatic closure，which is acquired，prevents expiratory air from passing into the nasal cavity． While during swallowing，velopharyngeal closure is achieved innately；it keeps the bolus from regurgitating into the nasal cavity．This suggests that velopharyngeal closure during pneumatic action is operated by a different mechanism from that during swallowing． The purpose of this study is to clarify the differences in activity of the levator veli palatini muscle (LVP)，which is the primary muscle for velopharyngeal movement，during velopharyngeal closure for swallowing，speech and blowing，using power spectra analysis．＜Methods＞ Four normal adults were used as subjects in this study．Each subject was instructed to perform the three experimental tasks which were speech，blowing and swallowing．Electromyograms were recorded and analyzed for each task to calculate the mean power frequency (MPF)．＜Results＞ There was no significant difference in MPF between speech and blowing activities for all subjects．MPF was significantly greater during swallowing than during pneumatic action for all subjects．The MPF value reflects the composition of active motor units during muscle contraction．Therefore，it was clarified that the motor units which participated in contraction during swallowing were different from those used during respiration in LVP．＜Conclusion＞ The results of this study indicate that movement of the LVP in swallowing is operated by a different mechanism from that used in pneumatic action．

A tapping test with a flexible laryngoscope (we use a fiberscope) was carried out for one hundred dysphagia patients．We evaluated the view of the remaining jelly，salivous collection in the pyriform fossa，salivous inflow into the larynx and sensation of tapping of the larynx．Laryngeal sensation was tested by tapping the center of the epiglottic inside (superior laryngeal nerve area) by the tip of the fiberscope．The results heard from patients (laryngeal sensation) were classified into two groups，the bad group，“recognizing nothing or only a little,” and the good group，“recognizing clearly， and exhibiting a swallowing reflex or escaping reaction.” We carried out examinations of the relationship between the position while eating，the view from the laryngoscopy (remaining jelly， salivous collection in the pyriform fossa， salivous inflow into the larynx)，the view from video-fluoroscopy (VF：remaining jelly， aspiration)， the grade of dysphagia (Fujishima) indicating ingestion，the incidence of pneumonia and laryngeal sensation．From these data，①Laryngeal sensation showed significant differences in aspiration， grade of dysphagia and incidence of pneumonia．②We could not determine a consistent relationship between the view from the laryngoscopy (the remaining jelly，salivous collection in the pyriform fossa，salivous inflow into the larynx)，the view of VF (the remaining jelly， aspiration) and the grade of dysphagia and incidence of pneumonia．Laryngeal sensation was most closely related with the grade of dysphagia and the incidence of pneumonia．③It was suggested that evaluation of laryngeal sensation would be a new standard of dysphagia which can be used to predict the possibility of ingestion and risk of aspiration pneumonia．

Swallowing function was investigated in 12 tongue cancer patients who underwent secondary unilateral neck dissection after partial glossectomy or glossectomy and reconstruction． We studied the relation between resection of suprahyoid muscles， the reconstruction method and swallowing function．We also examined postoperative changes over time compared to the preoperative swallowing function．

1） Tongue movement and tongue function in transporting test foods to the oropharynx had already become retarded preoperatively in cases requiring subtotal resection of the moving element of the tongue and in cases requiring subtotal glossectomy and reconstruction．

2） With time， there was postoperative recovery of tongue function in transporting test foods to the oropharynx after partial glossectomy and reconstruction and after hemiglossectomy and reconstruction．It was difficult to transport hard-sticky test food to the oropharynx using the tongue after subtotal glossectomy of the moving element and reconstruction， and after subtotal glossectomy and reconstruction．

3） After unilateral resection of the anterior and posterior bellies of the digastricus，mylohyoideus，geniohyoideus and hyoglossus muscles，the forward movement of the hyoid bone was impeded．After bilateral resection of the anterior and posterior bellies of digastricus and mylohyoideus and geniohyoideus and hyoglossus muscles，the forward and upward movements of the hyoid bone were impeded．In these cases，penetration of liquid test food into the larynx was observed．

4）With regard to the reconstructive method of the defect after subtotal resection of the moving element of the tongue， we reconstructed the defect by using a large flap to facilitate contact between hard and soft palates． As a result，residual test foods in the oral cavity were reduced．

5）With regard to the reconstructive method of the defect after subtotal glossectomy，we reconstructed the oropharynx as narrow as possible and reconstructed the defect by using a large flap to facilitate contact between hard and soft palates． As a result，liquid test food could be held in the oral cavity and residual liquid in the oral cavity was decreased．

6） Postoperative patients receiving 50 Gy radiation showed aspiration of the liquid test food one month later because of a delayed swallowing reflex．However，aspiration had disappeared six months postoperatively．

Objectives ： When normal subjects eat solid food，the bolus is formed in the oropharynx prior to swallowing．When subjects chew liquid or a mixture of solid and liquid before swallowing，liquid frequently enters the hypopharynx before swallow onset．The purpose of this study was to determine whether transport to the hypopharynx is due to muscle activity (active transport) or gravity (passive transport)．

Methods ： Ten healthy volunteers were imaged with videofluorography in the lateral projection while consuming foods with barium (10 ml 50％ liquid barium，8 g corned beef hash [CBH]，and a mixture of 5 ml liquid barium with 4 g CBH [MIX]．With each food (including liquid) the subject was instructed to chew and then swallow．Recordings were made in upright and facedown postures．Videotapes were reviewed in slow motion and swallow onset defined as the onset of rapid hyoid elevation．The location of the leading edge of the barium was classified as follows： Oral cavity (OC)； Upper oropharynx (UOP，from the fauces to the inferior border of mandible) ； Valleculae (VAL) ； or Hypopharynx (HYP)．Swallows were divided into three groups based on position of the leading edge at swallow onset： UOP or more (UOP-om；in the UOP，VAL ，or HYP) ； Valleculae or more (VAL-om；in the VAL or HYP)； or Hypopharynx (HYP)．

Results： 1．Upright Posture：The “VAL-om” position was significantly more frequent for MIX (100％) than other foods (Liquid 65％，CBH 55％) and more frequent for Liquid than CBH．Frequency of HYP position differed significantly among all three test foods（Liquid 35％，CBH 0％，MIX 71％)．2． Facedown Posture：Position of the leading edge did not vary significantly among foods．3．Comparison of Upright and Facedown Postures： With MIX，the VAL-om and HYP positions were each significantly more frequent for upright than facedown swallows (VAL-om position： 100％ upright and 60％ facedown； Hypopharynx position： 71％ upright and 5% facedown)． With CBH and Liquid，position was not significantly affected by position．

Discussion ： The leading edge often reached the oropharynx before swallow onset in either posture，but commonly reached the hypopharynx before swallow in upright posture only．This suggests that pre-swallow food transport to the oropharynx is active，but transport to the hypopharynx due to gravity．Food in the hypopharynx before swallowing may increase aspiration risk because the larynx is open．Testing patients with mixed consistency foods may be useful in evaluation of swallow safety for dysphagic individuals．

In order to establish a non-invasive method for the bedside evaluation of swallowing function of patients with dysphagia，the authors developed a computerized system capable of simultaneously recording and analyzing larynx movement，electromyograms of suprahyoid musculature，and swallowing sound．The system was applied to a quantitative analysis of rice-gruel swallowing，a typical food for patients with dysphagia．

Clinics dealing with dysphagia require methods for assessing how easily patients can swallow rice gruel．Conventional methods for such assessment are as follows：(1) food-texture measurement；(2) sensory testing； and (3) measurement of physiological data． The authors have already employed methods (1) and (2) for evaluating two different types of rice gruel，an ordinary “Zengayu” and less adhesive “Fukkuraokayu^R” (Kameda Seika Co.) developed for patients with dysphagia．In this study，method (3) was used to perform a physiological evaluation of swallowing these types of rice gruel．Seven male subjects without symptoms of dysphagia were used for the experiment．The amount and temperature of rice gruel were standardized into 5 [g] and 60 [deg]，respectively．The results were as follows： when swallowing Fukkuraokayu^R，(A) the larynx motion was faster particularly in the early phase； and (B) the suprahyoid musculature was less active compared to when swallowing Zengayu．Results (A) and (B) were both statistically significant at the 5％ and 1％ levels，respectively．These results demonstrated that Fukkuraokayu^R can be swallowed more easily and effectively than ordinary Zengayu．Our measurement system was verified to be effective for the non-invasive，quantitative assessment of swallowing motion．

Videofluorography (VF) is considered to be the gold standard for evaluating dysphagia because of its usefulness in clarifying both morphological and functional swallowing problems．Although dysphagic persons are evaluated routinely with VF in well-equipped hospitals，in poorly-equipped institutes many patients are subjected to tube feeding without adequate evaluation and treatment of swallowing disorders．The development of clinical systems for assessing dysphagia without using VF has therefore been desired．

Three clinical tests (Modified Water Swallowing Test，Food Test，and Pre- and Post-Swallowing X-P)，a non-VF assessment flowchart that is composed of these three clinical tests，and a dysphagia severity scale were developed in Integrated Research on the Treatment of Dysphagia project，funded by the Comprehensive Research on Aging and Health program in 1999．We used the flowchart system for 63 dysphagic patients，and examined whether it could accurately identify those patients who have sufficient ability to swallow some foods with training．The results suggested that the cu-off line of the three clinical tests was appropriate．The sensitivity，the specificity，the predictive negative value test，and the concordance of the flowchart for distinguishing patients who can start direct therapy with food were sufficiently high．It was therefore concluded that the non-VF assessment flowchart is useful and safe for clinical use，especially in poorly-equipped institutions．

A palatal augmentation prosthesis (PAP) is essential in assisting dysphagic patients with lingual function including swallowing． The purpose of this study was to establish a method of evaluating lingual function and to clarify the effect of palate plate thickness on lingual movement during swallowing．The subjects were 10 healthy adult men (mean age: 26.5 years)．Experimental PAPs of two thicknesses (1mm (thin PAP) and 5 mm (thick PAP)) were fabricated for each subject．Pressure sensors were secured in cavities prepared on the anterior，lateral，central and posterior portions of the experimental PAPs，and linguopalatal pressure during the swallowing of test food (3g mashed pumpkin) was measured with a computerized manometric system fitted with an ultrasound device developed by ourselves．The following were our findings．

1．This system made possible the recording and analysis of linguopalatal pressures and of the order of appearance of linguopalatal pressure at the sensor sites during the processes of food intake，mastication and swallowing．

2．The maximum linguopalatal pressure on the anterior portion during swallowing was less with the 5 mm experimental PAP than with the thin one，whereas that on the posterior region was greater with the thick PAP．

3．The duration of the anterior linguopalatal contact (LPCD) during swallowing with the thick PAP was shorter than that with the thin PAP，while the posterior LPCD was less with the latter．

4．The pressure integral of the anterior portion during swallowing with the thick PAP tended to be less than with the thin PAP，but that of the posterior portion of the thick PAP was the greater．

5．The first portion of the palate where linguopalatal pressure was detected during swallowing was the anterior portion in 6 of the 10 subjects with thin PAPs，and in 7 of the 10 with the thick PAPs．In all cases，linguopalatal pressure appeared initially on the anterior or lateral portion，and the order of appearance in each individual was not affected by PAP thickness．

6． The maximum linguopalatal pressure during swallowing showed no consistent order，differing considerably between individuals．Moreover，the order of the pressures at the sensor sites did not vary with PAP thickness．

In this article，we examine the effects of neck protrusion on the pharyngeal swallowing． We performed videofluoroscopy，in which 20 healthy males swallowed 15cc liquid barium in two head positions： a neutral position and neck protrusion．

The following results were obtained:

1．Among the measures of pharyngeal swallowing，the extent of laryngeal elevation，and the diameter and duration of upper esophageal opening increased significantly in subjects with neck protrusion (p＜ 0.05)．There was no significant difference between the two positions in pharyngeal transit time or the extent of hyoid bone movement．

2． The shape of the pyriform sinus changed in subjects with neck protrusion．The size of the pyriform sinus increased in width and depth in 11 subjects， and depth increased in 7 subjects．

3． Aspiration was not observed in either position．Penetration，however，occurred in 5 subjects with a neutral position，and in 7 subjects with neck protrusion． Residue in the pyriform sinus was observed in 4 subjects in a neutral position，but not in subjects with neck protrusion．

In conclusion，swallowing with neck protrusion might be beneficial for patients with dysphagia，as the diameter and duration of the upper esophageal opening as well as the size of the pyriform sinus increased．On the other hand，the risk of aspiration might increase with neck protrusion．