Interrater and intrarrater reliability of the exeter dysphagia assessment technique applied to healthy elderly adults

The purpose of this study was to evaluate the inter- and intrarater reliabilities of the Exeter Dysphagia Assessment Technique in a sample of elderly adults. This procedure uses noninvasive methods to record aspects of oral motor efficiency and synchronization of respiration during swallowing with the aid of specially developed equipment. Changes in the direction of nasal air flow, time of lip or tongue/spoon contact, and the time/frequency of swallow sounds are monitored and analyzed. Seventy records were evaluated independently by three trained assessors on three consecutive occasions. Interrater reliability was found to be good to very good for five of the respiratory variables assessed and moderate for the sixth. Interrater agreement was also very good for three of the timed oropharyngeal events assessed and moderate for the fourth. Intrarater reliability was very good for the same five respiratory variables and moderate for the sixth. Intrarater agreement was also very good for three of the timed oropharyngeal events and moderate for the fourth. Repeat evaluations of these records showed that agreement between and within raters concerning the sixth respiratory variable was improved substantially when the charts were examined in an enlarged form that provided improved resolution. We conclude that the majority of variables monitored by the Exeter Dysphagia Assessment Technique can be evaluated very reliably.

Pathophysiological mechanisms of oropharyngeal dysphagia in amyotrophic lateral sclerosis

We investigated the pathophysiological mechanisms of dysphagia in amyotrophic lateral sclerosis. Forty-three patients with sporadic amyotrophic lateral sclerosis were examined by clinical and electrophysiological methods that objectively measured the oropharyngeal phase of voluntarily initiated swallowing, and these results were compared with those obtained from 50 age-matched control subjects. Laryngeal movements were detected by a piezoelectric sensor and EMG of submental muscles, and needle EMG of the cricopharyngeal muscle of the upper oesophageal sphincter of both the amyotrophic lateral sclerosis and control groups was recorded during swallowing. Amyotrophic lateral sclerosis patients with dysphagia displayed the following abnormal findings. (i) Submental muscle activity of the laryngeal elevators, which produce reflex upward deflection of the larynx during wet swallowing, was significantly prolonged whereas the laryngeal relocation time of the swallowing reflex remained within normal limits. (ii) The cricopharyngeal sphincter muscle EMG demonstrated severe abnormalities during voluntarily initiated swallows. The opening of the sphincter was delayed and/or the closure occurred prematurely, the total duration of opening was shortened and, at times, unexpected motor unit bursts appeared during this period. (iii) During voluntarily initiated swallows there was significant lack of co-ordination between the laryngeal elevator muscles and the cricopharyngeal sphincter muscle. These results point to two pathophysiological mechanisms that operate to cause dysphagia in amyotrophic lateral sclerosis patients. (i) The triggering of the swallowing reflex for the voluntarily initiated swallow is delayed and eventually abolished, whereas the spontaneous reflexive swallows are preserved until the preterminal stage of amyotrophic lateral sclerosis. (ii) The cricopharyngeal sphincter muscle of the upper oesophageal sphincter becomes hyper-reflexic and hypertonic. As a result, the laryngeal protective system and the bolus transport system of deglutition lose their co-ordination during voluntarily initiated swallowing. We conclude that these pathophysiological changes are related mainly to the progressive degeneration of the excitatory and inhibitory corticobulbar pyramidal fibres.

Effects of tongue electrical stimulation on pharyngeal mechanics in anaesthetized patients with obstructive sleep apnoea

The tongue plays a significant role in the maintenance of a patent airway. The purpose of this study was to examine the effects of tongue musculature contraction on the static mechanical properties of the pharynx in patients with obstructive sleep apnoea (OSA). During hyperventilation-induced apnoea in seven OSA patients anaesthetized with sevoflurane, the static pressure/area relationships of the oropharynx were obtained by means of step changes in airway pressure while endoscopically measuring cross-sectional area. At each airway pressure, the tongue was electrically stimulated via electrodes placed bilaterally. Tongue electrical stimulation (TES) did not further dilate the oropharyngeal area at higher airway pressure (3.2+/-1.9 versus 3.0+/-2.1 cm2), although the narrowed oropharyngeal area at lower airway pressures increased during TES (0.8+/-9.0) versus 1.7+/-1.8 cm2, p<0.05). Accordingly, the slope of the pressure/area relationship decreased during TES (0.24+/-0.20 versus 0.12+/-0.09 cm2 x cm H2O(-1), p<0.05). In conclusion, electrical stimulation of the tongue stiffens the retroglossal airway wall in patients with obstructive sleep apnoea.

A comparison of the reinforced and standard laryngeal mask airway: ease of insertion and the influence of head and neck position on oropharyngeal leak pressure and intracuff pressure

We conducted a randomized, crossover study of 60 paralysed anaesthetized adult patients to compare ease of insertion for the reinforced (RLMA) and standard laryngeal mask airway (LMA). We also test the hypothesis that oropharyngeal leak pressure (OLP) and intracuff pressure (ICP) vary with head and neck position for the two devices. OLP and ICP were documented in four head and neck positions (neutral first, then flexion, extension and rotation in random order) for each device. The size 5 was used for all patients and the ICP was set at 60 cm H2O in the neutral position. The first time insertion success rates were similar (LMA: 60/60 v RLMA; 59/60), but insertion time was slightly less for the LMA (6 v 8 s, P = 0.004). Compared with the neutral position, OLP for the LMA was higher in flexion (21 v 28 cm H2O, P < 0.0001) and rotation (21 v 23 cm H2O, P < 0.0001), but lower in extension (21 v 14 cm H2O, P < 0.0001). Compared with the neutral position, OLP for the RLMA was higher in flexion (19 v 27 cm H2O, P < 0.0001), similar in rotation (20 v 19 cm H2O), but lower in extension (27 v 14 cm H2O, P < 0.0001). The difference in OLP between flexion and extension was 13 and 14 cm H2O for the RLMA and LMA respectively. OLP was slightly higher for the LMA compared with the RLMA when the head was in neutral (P < 0.0001) and rotation (P < 0.0001), but was similar during flexion and extension. There was a significant positive correlation between ICP and OLP for the LMA (P < 0.0001) and RLMA (P < 0.0001). We conclude that ease of insertion is similar for the RLMA and LMA. OLP is higher with head/neck flexion and lower with extension for both devices and is associated with a similar change in ICP. We recommend assessing the efficacy of seal for all head and neck positions likely to be encountered prior to the start of surgery.

Relationship of the functional oropharynx to craniofacial morphology

The association between the functional oropharyngeal airway (defined as the minimal sagittal dimension at right angles to the airstream) and craniofacial morphology was investigated using 16 craniofacial variables taken from lateral cephalometric radiographs. The sample consisted of 70 subjects (31 males and 39 females) 10 to 13 years of age. There was no difference in ages between males and females, and no correlation with age except upper face height. Oropharyngeal airway was positively correlated with length of the mandible (Gon-Men), the distance between the third cervical vertebra and the hyoid bone (C3-Hy), and cranial base angle (NSBa). Although short mandibular length is a characteristic finding in patients with obstructive sleep apnea, none of the subjects in this study had this diagnosis.

Interobserver agreement on normal swallowing physiology as viewed by videoendoscopy

This study examines the agreement of 2 observers in identifying selected normal oropharyngeal swallow events in the 1- and 5-ml swallows of 3 normal young adult males as identified by videoendoscopy at each of two endoscopic positions: (1) with the tip of the endoscope just at or below the tip of the uvula (high position), and (2) with the tip of the endoscope just below the tip of the epiglottis (low position), and thereby defines the needed focus for observer training in endoscopic assessment of swallowing. Overall, the more and less experienced examiners agreed on seeing or not seeing the onsets and terminations of the 12 events 83% of the time. Scope position affected observer agreement on several events while bolus volume did not.

[Efficacy of the cuffed oropharyngeal airway in spontaneously breathing patients]

A cuffed oropharyngeal airway (COPA) was used in 20 adult patients for airway management under epidural and brachial plexus block supplemented with light general anesthesia. Insertion of a COPA was successful at first attempt in 17 of 20 patients (85%). Sore throat developed in one patient (5%). Aspiration regurgitation, or laryngospasm was not observed. We conclude that a COPA can be an efficient airway device is spontaneously breathing patients under anesthesia.

Comparison of the flexible and standard laryngeal mask airways

PURPOSE

To determine mucosal pressures, ease of insertion, mask position and oropharyngeal leak pressures for the flexible (FLMA) and standard laryngeal mask airway (LMA).

METHODS

Forty anesthetized, paralysed adult patients were randomly allocated to receive either the FLMA or LMA. Microchip sensors were attached to the LMA or FLMA at identical locations corresponding to the base of tongue, hypopharynx, lateral pharynx, oropharynx, posterior pharynx and pyriform fossa. Mucosal pressure, oropharyngeal leak pressure (OLP) and mask position (assessed fibreoptically) were recorded during inflation of the cuff from 0-40 ml in 10 ml increments.

RESULTS

Ease of insertion and mask position were similar between devices. Mean OLP was higher for the LMA (22 vs 19 cm H2O), but the maximum OLP was similar (25 vs 24 cm H2O). Mean mucosal pressures were generally low (< 12 cm H2O) for both devices, but were higher for the LMA in the lateral pharynx (4 vs 1 cm H2O) and oropharynx (13 vs 3 cm H2O) and higher in the posterior pharynx for the FLMA (4 vs 2 cm H2O). The OLP for both devices increased with increasing intracuff volume from 0-10 ml and 10-20 ml, and from 20-30 ml for the FLMA.

CONCLUSIONS

We conclude that the LMA and FLMA perform similarly in terms of ease of insertion and mask position, but OLP and mucosal pressures are slightly higher for the LMA. Pharyngeal mucosal pressures for both devices are lower than those considered safe for the tracheal mucosa. The overall clinical performance between the two devices is similar.

Effects of physostigmine on swallowing and oral motor functions in patients with progressive supranuclear palsy: A pilot study

The purpose of this pilot study was to investigate whether cholinergic stimulation reduces swallowing and oral motor disturbances in patients with progressive supranuclear palsy (PSP). A controlled, double-blind crossover trial of physostigmine, a centrally active cholinesterase inhibitor, and placebo was conducted. Patients were randomized to a 10-day crossover placebo-controlled double-blind trial of physostigmine at their previously determined best dose administered orally every 2 hr, six times per day. Patients were evaluated with ultrasound imaging of the oropharynx and an oral motor examination at baseline and during the third or fourth days of each study phase (placebo and drug). Under the double-blind placebo-controlled conditions, patients showed no statistically significant improvement in oral motor functions or swallow durations. Because patients with PSP have increased sensitivity to cholinergic blockade compared with control subjects, studies with newer, more potent cholinergic stimulating agents need further exploration. Suggestions for future research include the evaluation of newer direct cholinergic agonists in the treatment of the less-impaired PSP patients who may have a greater number of cholinergic neurons preserved and the evaluation of combined therapies.

Laryngeal mask airway size selection in males and females: ease of insertion, oropharyngeal leak pressure, pharyngeal mucosal pressures and anatomical position

We have compared ease of insertion, oropharyngeal leak pressure, directly measured pharyngeal mucosal pressure and anatomical position (assessed fibreoptically) for the size 4 and size 5 laryngeal mask airway (LMA) in 20 male and 20 female patients. Microchip pressure sensors were attached to the LMA at locations corresponding to the piriform fossa, hypopharynx, base of the tongue, lateral and posterior pharynx, and the oropharynx. Oropharyngeal leak pressure, mucosal pressure and fibreoptic position were recorded during inflation of the cuff from 0 to 30 ml in 10-ml increments. In males, oropharyngeal leak pressure over the inflation range was higher for size 5 (21 vs 17 cm H2O; P = 0.01); mucosal pressure over the inflation range was higher in the posterior pharynx for size 4 (7 vs 2 cm H2O; P = 0.007), and higher in the piriform fossa (8 vs 5 cm H2O; P = 0.003) and hypopharynx (9 vs 5 cm H2O; P = 0.003) for size 5. In females, oropharyngeal leak pressure over the inflation range was the same (21 vs 21 cm H2O), but mucosal pressure over the inflation range was higher in the piriform fossa (21 vs 8 cm H2O; P = 0.003) and posterior pharynx (4 vs 2 cm H2O; P = 0.004) for size 4, and higher in the lateral pharynx (5 vs 1 cm H2O; P = 0.01) and oropharynx (11 vs 5 cm H2O; P = 0.009) for size 5. The distribution of mucosal pressure was different for size 4 between males and females, but not for size 5. For both males and females, fibreoptic position was similar. We conclude that the size 5 LMA is optimal in males, but either size is suitable for females. The shape of the pharynx may be different between males and females.

The target plasma concentration of propofol required to place laryngeal mask versus cuffed oropharyngeal airway

To determine the target plasma concentration of propofol required to place either a laryngeal mask airway (LMA) or a cuffed oropharyngeal airway (COPA), we started a continuous target-controlled infusion of propofol in 60 ASA physical status I or II unpremedicated patients scheduled for minor orthopedic surgery with peripheral nerve block. The target plasma concentration of propofol was initially set at 2 microg/mL. When the effect-site calculated concentration of propofol was equal to the plasma concentration according to the computer simulation, the target plasma concentration was increased by 0.5-microg/mL steps until successful placement of either the LMA (n = 30) or the COPA (n = 30). The mean target plasma concentration of propofol required to place a LMA was 4.3 +/- 0.8 microg/mL compared with 3.2 +/- 0.6 microg/mL to place a COPA (P < 0.001). To successfully place the airways in 95% of patients, the target plasma concentration of propofol had to be increased up to 4 microg/mL for the COPA and 6 microg/mL for the LMA. We conclude that placing a LMA in healthy, unpremedicated patients requires target plasma concentrations of propofol higher than those required for placing a COPA.

IMPLICATIONS

We evaluated the use of target-controlled infusion of propofol to place extratracheal airways in this prospective, randomized study and demonstrated that the target plasma concentration of propofol required to successfully place a laryngeal mask in >95% of healthy, unpremedicated patients is 6 microg/mL, compared with 4 microg/mL to place a cuffed oropharyngeal airway.

The influence of head and neck position on oropharyngeal leak pressure and cuff position with the flexible and the standard laryngeal mask airway

We conducted a randomized, cross-over study of 20 paralyzed anesthetized adult patients to test the hypothesis that oropharyngeal leak pressure and cuff position (assessed fiberoptically) vary with head and neck position for the flexible (FLMA) and standard laryngeal mask airway (LMA). Both devices were inserted into each patient in random order. Oropharyngeal leak pressure and fiberoptic position (including degree of rotation) were documented in four head and neck positions (neutral first, then flexion, then extension and rotation in random order) for each device. The size 5 was used for all patients, and the intracuff pressure was set at 60 cm H2O in the neutral position. All airway devices were inserted at the first attempt. Oropharyngeal leak pressure was similar for the FLMA and LMA in the neutral (22 vs 21 cm H2O), flexed (26 vs 26 cm H2O), and extended positions (19 vs 18 cm H2O) but was slightly higher for the LMA when the head was rotated (19 vs 22 cm H2O; P = 0.04). Compared with the neutral position, oropharyngeal leak pressure for the LMA was higher with flexion (26 vs 21 cm H2O; P = 0.0004) and lower with extension (18 vs 21 cm H2O; P = 0.03) but similar with rotation. Compared with the neutral position, oropharyngeal leak pressure for the FLMA was higher with flexion (26 vs 22 cm H2O; P = 0.0001) and lower with extension (19 vs 22 cm H2O; P = 0.03) and rotation (19 vs 22 cm H2O; P = 0.03). The difference in oropharyngeal leak pressure between flexion and extension was 7 and 8 cm H2O for the FLMA and LMA, respectively. Fiberoptic position was similar between devices and was unchanged by head and neck position. Rotation was not detected fiberoptically. We conclude that there are small changes in oropharyngeal leak pressure but no changes in cuff position in different head and neck positions for the FLMA and LMA. Oropharyngeal leak pressure may be improved by head and neck flexion and by avoiding extension.

IMPLICATIONS

There are small changes in oropharyngeal leak pressure but no changes in cuff position in different head and neck positions for the flexible and standard laryngeal mask airways. Oropharyngeal leak pressure may be improved by head and neck flexion and by avoiding extension.

Some new developments in the understanding of oropharyngeal and postingestional controls of meal size

This review focuses on new developments in the understanding of how oropharyngeal and postingestional stimulation control the ingestive behavior of the rat ingesting liquids. With the development of the computer-controlled lickometer it is now possible to measure and analyze in fine detail the impact these two variables have on the rat's licking behavior. Because variations in this behavior are responsible for variations in intake this methodology is beginning to provide a clearer picture of how oropharyngeal and postingestional stimulation control ingestive behavior and interact to control meal size. These developments should in turn ultimately provide the basis for better understanding of how the motor systems of the brain control the behavior that supplies the body with its nutrients.

Preliminary evaluation of a new prototype laryngeal mask in children

We have assessed a prototype laryngeal mask airway (pLMA) in 50 anaesthetized children for ease of insertion, oropharyngeal leak pressures, gastric insufflation and fibreoptic position. The pLMA has a second smaller mask, which rests against the upper oesophageal sphincter, and a second cuff to increase the seal pressure of the glottic mask. All insertions were graded as easy and an effective airway was achieved in all patients. Oropharyngeal leak pressure was > 40 cm H2O in 49 of 50 patients. Gastric insufflation was not detected by epigastric auscultation. In 46 of 50 patients, the vocal cords were seen via a fibreoptic laryngoscope. One patient regurgitated clear fluid, but aspiration did not occur. On removal, blood staining was detected in three of 50 children. We conclude that the pLMA was easy to insert, facilitated high airway pressure ventilation and may provide some protection against gastric insufflation.

Food transport and bolus formation during complete feeding sequences on foods of different initial consistency

Food movements during complete feeding sequences on soft and hard foods (8 g of chicken spread, banana, and hard cookie) were investigated in 10 normal subjects; 6 of these subjects also ate 8 g peanuts. Foods were coated with barium sulfate. Lateral projection videofluorographic tapes were analyzed, and jaw and hyoid movements were established after digitization of records for 6 subjects. Sequences were divided into phases, each involving different food management behaviors. After ingestion, the bite was moved to the postcanines by a pull-back tongue movement (Stage I transport) and processed for different times depending on initial consistency. Stage II transport of chewed food through the fauces to the oropharyngeal surface of the tongue occurred intermittently during jaw motion cycles. This movement, squeeze-back, depended on tongue-palate contact. The bolus accumulated on the oropharyngeal surface of the tongue distal to the fauces, below the soft palate, but was cycled upward and forward on the tongue surface, returning through the fauces into the oral cavity. The accumulating bolus spread into the valleculae. The total oropharyngeal accumulation time differed with initial food consistency but could be as long as 8-10 sec for the hard foods. There was no predictable tongue-palate contact at any time in the sequence. A new model for bolus formation and deglutition is proposed.

Saline as an alternative to air for filling the laryngeal mask airway cuff

We have assessed a new method to evacuate saline completely from the laryngeal mask airway (LMA) cuff and tested the hypothesis that intracuff pressures, fibreoptic position and oropharyngeal leak pressures are similar for saline compared with air during nitrous oxide-oxygen anaesthesia. Eight size 4 LMA were inflated with saline 30 ml. After syringe evacuation, median residual weight was 0.56 (range 0.24-0.98) g; after additional manual cuff squeezing it was 0.26 (0.21-0.35) g; and after drying for 12 h at 60 degrees C with the valve open it was -0.02 (-0.05-0.04) g. Pressure-volume curves of four size 3-5 LMA showed that compliance was lower for the saline-filled cuff. A clinical study of 20 patients allocated randomly to have saline or air in the cuff showed a significant increase in intracuff pressure with air, but not saline, during nitrous oxide-oxygen anaesthesia. The fibreoptic position of the LMA changed more frequently in the air, compared with the saline-filled group (four of 10 vs none of 10; P = 0.04). Oropharyngeal leak pressures were similar between groups. We conclude that the saline-inflated LMA cuff was reliably emptied and more stable in terms of intracuff pressures and possibly fibreoptic position. Filling the LMA cuff with saline is a viable option during laser surgery to the airway.

Dentistry's role in the recognition and treatment of sleep-breathing disorders: the need for cooperation with the medical community

While oral appliance therapy for the treatment of sleep-disordered breathing can be an exciting and rewarding adjunct to the practice of dentistry, it is essential that dentists realize that snoring and obstructive sleep apnea are medical and not dental problems. Sleep-disordered breathing and its sequelae are diseases that should remain in the purview of the medical community. While the dentist can identify patients with sleep-breathing disorders and participate in their treatment, it is essential to emphasize that sleep-breathing disorders are potentially life-threatening diseases whose diagnosis and treatment are the domain of the medical profession. Accepting dentistry's position as part of a treatment team, ongoing review of scientific literature, cooperation with medical colleagues, and attendance at educational meetings dedicated to the study of sleep-related disorders are essential to proper and ethical dental participation in the treatment of sleep-disordered breathing.

Neurorespiratory pattern of gill and lung ventilation in the decerebrate spontaneously breathing tadpole

A decerebrate, spontaneously breathing tadpole preparation (Taylor-Kollros stages 16-19) was used to test the general hypothesis that the efferent bursting activities of cranial nerves (CN) V, VII and spinal nerve (SN) II are respiratory in nature, and, in particular, to identify separate and specific neural correlates of gill and lung ventilation. Oropharyngeal pressure (POP), intrapulmonary pressure (PIP), electromyogram (EMG) of the buccal levator muscle (interhyoideus), and efferent neural activities of CN V, CN VII and SN II were recorded while the animal was exposed to hyperoxia (100% inspired O2), normoxia (21% inspired O2), and hypoxia (10, 5 and 0% inspired O2). Gill ventilation, indicated by fluctuations in POP at constant PIP, was characterized by high-frequency, low-amplitude bursts of action potentials in CN V and VII and interhyoideus EMG without phasic activity in SN II. Lung breaths, indicated by oscillations in POP and PIP were characterized by large bursts in EMG, CN V and VII together with a large burst in SN II. The amplitude of the moving average of nerve activities associated with lung ventilation was significantly larger than those associated with gill ventilation. During gill ventilation, the burst in CN V led that in CN VII, and both preceded the rise in POP. By contrast, a more synchronous neural burst onset pattern was observed during lung ventilation. The results document the neural, muscular, and mechanical characteristics of gill and lung ventilation in the tadpole, and establish bursting activity in SN II as a specific marker for lung ventilation in the metamorphic tadpole.

[The course of the oropharyngeal stage of deglutition in physiological condition. Computer topokinetic analysis of videofluoroscopic images]

The performed analysis covers the physiology of the pharyngeal phase of deglutition in 11 patients aged 45-65 years. The studies were carried out with the aid of roentgenocinematographic examinations (RTGC) and after preparing an adequate computer program, a computer topokinetic analysis was accomplished (CTA). The measurement of parameters established in CTA make it possible to obtain the image of the pathway passed by the anatomical structures, the dynamics, the shape and the relative distances of two anatomical structures, with the duration of the deglutition act being taken into consideration. The use of RTGC images in CTA allows for better understanding of the mechanism acting in the pharyngeal phase of deglutition act in physiological conditions.

A significant proportion of exhaled nitric oxide arises in large airways in normal subjects

Nitric oxide (NO) of endogenous origin is present in exhaled breath. An increase in exhaled NO concentration (ENO) has been described in bronchial asthma and ENO falls after inhaled steroid therapy. The sources of ENO may include pulmonary blood, the gas exchange region, conducting airways and the nasal cavity. In four healthy volunteers, a catheter was placed in a main bronchus after topical anesthesia in order to sample airway NO (CNO). Exhaled nitric oxide of bronchopulmonary and oropharyngeal origin (ENO(b/o)) was measured while excluding nasal NO and was controlled for expiratory flow. During the same exhalation, ENO(b/o) was compared to CNO at multiple sites in the airway as the catheter was progressively withdrawn. Mean CNO concentration in a position corresponding to a main bronchus was 51.4 +/- 10.8% of ENO(b/o). As the catheter was withdrawn, mean CNO concentration progressively increased both in absolute values and as a proportion of ENO(b/o), until in the oropharynx, it was 96.1 +/- 5.2% ENO(b/o). We conclude that a significant proportion of ENO(b/o) arises in the large airways and trachea in normal subjects and contains a minor oropharyngeal component.

Reflexogenic areas for velopharyngeal closure in rabbits

Responsive areas for velopharyngeal closure were examined by recording diaphragmatic and superior pharyngeal constrictor activities of anesthetized rabbits. Pressure stimulation was applied with a cotton applicator to the mucosae of three pharyngeal areas: the anterior (palatal) and posterior walls of the nasopharynx and the posterior wall of the oropharynx. The intensity and duration of the stimulation were around 9.0 gf and 0.43 sec, respectively. Velopharyngeal closure was elicited more frequently from the posterior wall of the nasopharynx than the other two areas tested. The higher responsiveness of the posterior wall of the nasopharynx for velopharyngeal closure is suggested to be attributed to higher density and/or lower threshold of pressure receptors in this area than those in the other two areas tested. Possible physiological implications of the present results are discussed.

Recovery after exercise in the heat--factors influencing fluid intake

The restoration of body fluid balance following dehydration induced by exercise will occur through regulatory responses which stimulate ingestion of water and sodium ions. A number of different afferent signalling systems are necessary to generate appropriate thirst or sodium appetite. The primary sensory information of naturally occurring thirst is derived from receptors sensing cell volume and the volume of the extracellular fluid compartment. Sensory information from the oropharyngeal region is also an important determinant of thirst. The interaction of these various afferent signalling systems within the central nervous system determines the extent of fluid replacement following dehydration.