Eating and Breathing: Interactions Between Respiration and Feeding on Solid Food

Chewed solid food accumulates in the oropharynx prior to swallowing. The mechanism for preventing aspiration during this interval is unknown, but may be related to respiration. The purpose of this study was to determine how eating, especially bolus formation in the pharynx, affects respiration. We examined nasal air pressures, masseter electromyography (EMG), and videofluorography (VFG) of four normal young adults eating 8 g each of banana and cookie (two trials each food). Resting respiration was recorded for 30 s before eating. Respiratory cycles (RCs) were classified as prefeeding, feeding (excluding cycles with included swallows), and swallowing cycles. RC duration was greater for swallowing than for feeding and prefeeding RCs (P < 0.001). There were up to three swallows in a single RC, but the increase in swallowing RC duration was greater than swallow duration. Swallow apnea began before bolus transport through the hypopharynx and ended as the bolus tail entered the esophagus. There were semirhythmic perturbations in nasal air pressure associated with masseter activity during chewing, suggesting that there was oronasal airflow during jaw closing via the velopharyngeal isthmus. The most important finding was that bolus aggregation in the valleculae usually occurred during an extended plateau in nasal air pressure following active expiration. This suggests that aspiration during eating is prevented by inhibiting respiration during bolus formation in the oropharynx. Supported in part by award #R01-DC02123 from the National Institute on Deafness and other Communication Disorders of the National Institutes of Health.     

Hyoid motion during swallowing: factors affecting forward and upward displacement

During swallowing, the hyoid bone is described as moving first upward, then forward, then returning to the starting position. This study examined hyoid motion during swallowing of chewed solids and liquids. Barium videofluorography (VFG) was performed on 12 healthy volunteers eating 8-cc portions of various solid foods and drinking liquid. Hyoid position was measured frame-by-frame for 88 swallows relative to the occlusal plane of the upper teeth. The hyoid bone moved both upward and forward during swallowing, but upward displacement was sometimes very small. There was no correlation between the amplitudes of hyoid upward and forward displacements. The amplitude of upward displacement was highly variable, smaller for liquids than for solid foods (p <0.001), and, for solid foods, larger for the first swallow than for the second swallow (p = 0.02). The amplitude of forward displacement did not differ significantly between liquids and solids or between first and second swallows. We conclude that upward displacement of the hyoid bone in swallowing is related primarily to events in the oral cavity, while its forward displacement is related to pharyngeal processes, especially the opening of the upper esophageal sphincter.     

健康老年妇女吞咽功能的研究

目的　通过电视X线透视吞咽功能的研究 ,评价健康老年妇女液体吞咽运动 ,并对液体吞咽运动的影响因素进行分析。　方法　 4 0例健康老年妇女 ,老年前期组 (5 0～ 5 9岁 ) 2 0例 ;老年组 2 0例 ,年龄 6 0～ 79岁。进行电视X线透视液体吞咽功能检查 ,分别对口咽部相关结构进行运动学分析 ,比较不同液体食团体及年龄对健康老年妇女吞咽的影响。　结果　 (1 )老年组较老年前期组渗透、口咽部滞留发生率增高 ,两组渗透发生率分别为 :7 5 %、3 8% ;口腔滞留发生率分别为 :1 2 5 %、6 3% ;咽腔滞留发生率分别为 :2 6 5 %、1 7 5 % ;口咽传递时间、腭咽部关闭时间及环咽部开放时间延长 (均为P <0 0 5 ) ;喉、舌骨向上运动距离增大 (P <0 0 5 )。 (2 ) 1 0ml食团较 1ml渗透、口咽部滞留发生率增高 ,两组渗透发生率分别为 :8 8%、2 5 % ;口腔滞留发生率分别为 :1 3 8%、5 0 % ;咽腔滞留发生率分别为 :31 3%、1 3 8% ;口传递时间缩短而环咽部开放时间延长 (均为P <0 0 5 ) ;喉向上、前运动 ,舌骨向前、向上运动的距离增大 (P <0 0 5 )。　结论　临床应用电视X线透视吞咽功能检查并对口咽期吞咽功能进行运动学分析是可行的 ;年龄及食团体积均影响健康老年妇女的液体吞咽功能     

Chewing and Food Consistency: Effects on Bolus Transport and Swallow Initiation

Preswallow bolus formation usually occurs in the mouth for liquids and in the oropharynx for solid foods. We examined the effect of chewing on the relationship between bolus transport and swallow initiation. Fifteen healthy subjects were imaged with lateral projection videofluorography while eating liquids, solid foods, and a mixture of liquid and solid foods in upright and facedown postures. Videotapes were reviewed to measure the location of the leading edge of the barium at swallow initiation. Chewing and initial consistency each altered the relationship between food transport and swallow initiation. In particular, when chewing liquid (or consuming foods with both liquid and solid phases), a portion of the food commonly reached the hypopharynx well before swallow onset. This transport to the hypopharynx was highly dependent on gravity, but transport to the valleculae for chewed solid food was active, depending primarily on tongue-palate contact. Chewing appeared to reduce the effectiveness of the posterior tongue-palate seal, allowing oral contents to spill into the pharynx. Consuming two-phase foods with both solid and liquid phases may increase the risk of aspiration in dysphagic individuals with impaired airway protective reflexes.     

Bolus Location at the Initiation of the Pharyngeal Stage of Swallowing in Healthy Older Adults

This study characterized the vertical position of the bolus head at the onset of the pharyngeal swallow in healthy older adults. Lateral-view videofluoroscopic (VF) images were obtained from ten healthy volunteers (age-71.6 ± 7.5 years, mean± SD) as they swallowed 5-cc thin liquid barium aliquots. For each swallow, the bolus head and several anatomic landmarks were digitally recorded from the image in which pharyngeal swallow-related hyoid bone elevation began. Vertical distance between the bolus head and the intersection of the tongue base and mandibular ramus (TMI) was computed. Bolus head position at swallow onset ranged from 47.4-mm above to 34.9-mm below the TMI (2.2 ± 14.4-mm, mean ± SD). Although the bolus head was below the level of the TMI for the majority of swallows, neither penetration nor aspiration occurred. For individual subjects, mean bolus head position ranged from 25.8 ± 5.0-mm above to 15.5 ± 6.5-mm below the TMI. Whereas five of ten subjects initiated the pharyngeal swallow with the bolus head consistently above or consistently below the TMI, five subjects initiated swallowing with the bolus head either above or below the TMI across trials. Older adults commonly initiate thin-liquid swallows with the bolus head well below the TMI without associated penetration or aspiration. Thus, bolus position alone does not differentiate between normal and pathologic swallowing within the healthy elderly. Bolus position at pharyngeal swallow onset can vary substantially from trial to trial within an individual, suggesting that the triggering of swallowing depends on multiple influences. This research was supported by NSERC grant No. 0GPO171208 and an Ontario Ministry of Health Career Scientist Award to REM.     

Videomanometric Analysis of Supraglottic Swallow, Effortful Swallow, and Chin Tuck in Healthy Volunteers

Simultaneous videoradiography and solid-state manometry (videomanometry) was applied in eight healthy volunteers (four women, four men; age range 25–64 years, mean age 41 years) without swallowing problems. Three different swallowing techniques were tested; supraglottic swallow, effortful swallow, and chin tuck. Seven videoradiographic variables and six manometric variables were analyzed. The supraglottic swallowing technique did not differ significantly from that of the control swallows. The effortful swallow had a significantly (p= 0.0001) reduced hyoid–mandibular distance preswallow due to an elevation of the hyoid and the larynx, which caused a significantly (p= 0.007) reduced maximal hyoid movement and a significantly (p= 0.009) reduced laryngeal elevation during swallow. The chin tuck swallow had a significantly (p= 0.001) reduced laryngohyoid distance and also a significantly (p= 0.004) reduced hyoid–mandibular distance. The chin tuck swallow also displayed significantly (p= 0.003) weaker pharyngeal contractions. Videomanometry allows for analysis of bolus transport, movement of anatomical structures, and measurement of intraluminal pressures. These variables are important when evaluating swallowing techniques. In the present study, we made a few observations that never have been reported before. When healthy volunteers performed supraglottic swallow, they performed the technique somewhat differently. Therefore, we assume dysphagic patients would need a substantial period of training to perform a technique efficiently. Chin tuck could impair protection of the airways in dysphagic patients with weak pharyngeal constrictor muscles.     

Volume accommodation during swallowing

Bolus volume is an important modifier of the biomechanical events of the oropharyngeal swallow. The biomechanical events comprising a swallow can be divided into events associated with the reconfiguration of the pharynx into a swallow pathway and events associated with bolus transport from the oropharynx into the esophagus. Volume modification is achieved differently for the events of reconfiguration and propulsion. In the case of reconfiguration, a longer time is allocated to the process, as exemplified by sustained laryngeal elevation and hyoid excursion during larger volume swallows. On the other hand, in the case of bolus expulsion, volume accommodation is accomplished within the same period of time by utilizing increased vigor of expulsion. The result of deglutitive volume accommodation is a remarkably different fluoroscopic appearance of a small vs. a large volume swallow. The larger volume swallow seemingly takes longer and results in much more vigorous bolus expulsion than a small volume. However, this is more related to the bolus than the swallow.     

Timing Differences Between Cued and Noncued Swallows in Healthy Young Adults

Temporal parameters such as stage transition duration, bolus location at swallow onset, and pharyngeal transit time are often measured during videofluoroscopy, but these parameters may vary depending on assessment instructions. Specifically, “command” (cued) swallows have been observed to alter timing compared to spontaneous (noncued) situations in healthy older adults. The aim of our study was to confirm whether healthy young people show timing differences for thin liquid swallows between cued and noncued conditions. Twenty healthy young adults swallowed 10-cc boluses of ultrathin barium in videofluoroscopy. The cued condition was to hold the bolus in the mouth for 5 s before swallowing. Three noncued swallows were also recorded. In the cued condition, bolus advancement to the pyriform sinuses prior to swallow initiation was seen significantly less frequently. Stage transition durations showed a nonsignificant trend toward being shorter. Pharyngeal transit times and pharyngeal response time (a measure capturing the interval between hyoid movement onset and bolus clearance through the upper esophageal sphincter) were both significantly longer in the cued condition. Our study in healthy young adults confirms findings previously observed in older adults, namely, that swallow onset patterns and timing differ between cued and noncued conditions. In particular, bolus advancement to more distal locations in the pharynx at the time of swallow onset is seen more frequently in noncued conditions. This pattern should not be mistaken for impairment in swallow onset timing during swallowing assessment.     

Timing of videofluoroscopic,manometric events,and bolus transit during the oral and pharyngeal phases of swallowing

The aims of this study were to evaluate and quantify the timing of events associated with the oral and pharyngeal phases of liquid swallows. For this purpose, we recorded 0–20 ml barium swallows in three groups of volunteers using videoradiographic, electromyographic, and manometric methods. The study findings indicated that a leading complex of tongue tip and tongue base movement as well as onset of superior hyoid movement and mylohyoid myoelectric activity occurred in a tight temporal relationship at the inception of swallowing. Two distinct general types of normal swallows were observed. The common “incisor-type” swallow began with the bolus positioned on the tongue with the tongue tip pressed against the upper incisors and maxillary alveolar ridge. At the onset of the “dipper-type” swallow the bolus was located beneath the anterior tongue and the tongue tip scooped the bolus to a supralingual location. Beginning with tongue-tip peristaltic movement at the upper incisors, the two swallow types were identical. Swallow events that occurred after lingual peristaltic movement at the maxillary incisors showed a volume-dependent forward migration in time that led to earlier movement of the hyoid and larynx as well as earlier opening of the upper esophageal sphincter in order to receive the large boluses that arrived sooner in the pharynx during the swallow sequence than did smaller boluses. The study findings indicated that timing of swallow events should be considered in reference to both swallow type and bolus volume. The findings also indicated an important distinction between peristaltic transit and bolus clearance.     

Effect of Viscosity on Food Transport and Swallow Initiation During Eating of Two-Phase Food in Normal Young Adults: A Pilot Study

When eating food containing both liquid and solid phases (two-phase food), the liquid component frequently enters the hypopharynx before swallowing, which may increase the risk of aspiration. We therefore tested whether preswallow bolus transport and swallow initiation would change as the viscosity of two-phase food was increased. Fiberoptic endoscopy was recorded while 18 adult subjects ate 5 g of steamed rice with 3 ml of blue-dye water. Liquid viscosity was set at four levels by adding a thickening agent (0, 1, 2, and 4 wt%, respectively). We measured the timing of the leading edge of the food reaching the base of the epiglottis, as well as the location of the leading edge at swallow initiation. As viscosity increased, the leading edge of the food reached the epiglottis significantly later during chewing and was higher in the pharynx at swallow onset. The time after the leading edge reached the epiglottis did not vary among the viscosities of the two-phase food. This study found that the initial viscosity of two-phase food significantly altered oropharyngeal bolus flow and the timing of swallow initiation. Accordingly, increased two-phase food viscosity may delay food entry into the pharynx and be of use in dysphagic diets.     

Swallowing Physiology of Sequential Straw Drinking

The goal of this study was to examine deglutitive physiology during sequential straw drinking in healthy young adults (n = 15) to learn how sequential swallowing differs from single swallows. The physiology of single swallows has been studied extensively in healthy adults and in adults with a variety of debilitating conditions, but the physiology of sequential swallows has not been studied adequately. Videofluoroscopic analysis revealed three distinct patterns of hyolaryngeal complex (HLC) movement during sequential straw swallows: opening of the laryngeal vestibule after each swallow (Type I, 53%), continued vestibule closure after each swallow (Type II, 27%), and interchangeable vestibule opening and closing during the swallow sequence (Mixed, 20%). Unlike discrete swallowing, the onset of the pharyngeal swallow occurred when the bolus was inferior to the valleculae in the majority of subjects and was significantly associated with HLC movement pattern. The leading bolus edge was inferior to the valleculae at swallow onset for Type II movement patterns. For Type I movement patterns, bolus position at swallow onset was randomly distributed between three anatomical positions: superior to the valleculae, at the level of the valleculae, and inferior to the valleculae. Preswallow pharyngeal bolus accumulation, which is common during mastication, was evident and significantly associated with the HLC pattern of opened laryngeal vestibule after each swallow. These data suggest that in healthy young adults, sequential swallows differ physiologically from discrete swallows and indicate substantial variability in deglutitive biomechanics.     

A Randomized Study Comparing the Shaker Exercise with Traditional Therapy: A Preliminary Study

Seven institutions participated in this small clinical trial that included 19 patients who exhibited oropharyngeal dysphagia on videofluorography (VFG) involving the upper esophageal sphincter (UES) and who had a 3-month history of aspiration. All patients were randomized to either traditional swallowing therapy or the Shaker exercise for 6 weeks. Each patient received a modified barium swallow pre- and post-therapy, including two swallows each of 3 ml and 5 ml liquid barium and 3 ml barium pudding. Each videofluorographic study was sent to a central laboratory and digitized in order to measure hyoid and larynx movement as well as UES opening. Fourteen patients received both pre-and post-therapy VFG studies. There was significantly less aspiration post-therapy in patients in the Shaker group. Residue in the various oral and pharyngeal locations did not differ between the groups. With traditional therapy, there were several significant increases from pre- to post-therapy, including superior laryngeal movement and superior hyoid movement on 3-ml pudding swallows and anterior laryngeal movement on 3-ml liquid boluses, indicating significant improvement in swallowing physiology. After both types of therapy there is a significant increase in UES opening width on 3-ml paste swallows.     

The Effects of Cervical Bracing Upon Swallowing in Young,Normal, Healthy Volunteers

Abstract The purpose of this study was to evaluate radiographically the effects of cervical bracing upon swallowing thin liquids and solid food in normal adults under three cervical bracing conditions. This was a prospective, repeated measures design study. Seventeen healthy adult volunteers between the ages of 30 and 50 were recruited from hospital staff. All subjects reported no previous history of swallowing difficulty or diseases that might affect swallowing. Subjects were radiographically observed swallowing thin liquids and solid food without cervical bracing and with three common cervical orthoses (Philadelphia collar, SOMI, and halo-vest brace). Order of bracing and type of bolus were randomized. Changes in swallowing function (point of initiation of swallow response, presence of pharyngeal residue, airway penetration, hyoid bone movement, diameter of oropharyngeal airway, and durational measurements) were analyzed by two independent raters. Eighty-two percent (14/17) of the subjects demonstrated radiographic changes under one or more of the bracing conditions. Forty-seven percent (8/17) of subjects demonstrated changes with point of initiation of the swallow response, 59% (10/17) demonstrated increased pharyngeal residue, and 23.5% (4/17) demonstrated changes with bolus flow with laryngeal penetration present. Aspiration did not occur under any of the bracing conditions. Changes noted in durational measurements for oral containment and total pharyngeal transit under the bracing conditions were not considered statistically significant. This study shows that cervical bracing does change swallowing physiology in normal healthy adults.     

Effects of systematic bolus viscosity and volume changes on hyoid movement kinematics

Using ultrasonography with head and transducer stabilization, this study examined the effects of maximally controlled, systematic changes in bolus viscosity (thin juice-like, 7 cP; nectar-like, 243–260 cP; honey-like, 724–759 cP; spoon-thick, 2760–2819 cP) and volume (5, 10, 20, 30 cc) on hyoid kinematics in 31 healthy subjects (16 male, 15 female) in three age groups (20–39, 40–59, 60–79 years). Frame-by-frame hyoid displacements were tracked from digitized images of 612 swallows. Measures of movement durations, maximal amplitudes, total distances, and peak velocities were subjected to repeated measures multivariate analyses of variance with viscosity, volume, age, and gender as factors. Results showed that (1) spoon-thick swallows had the greatest preswallow gesture and total movement durations; (2) larger-volume swallows had significantly greater maximal amplitudes, forward peak velocity, and total vertical distance; (3) older subjects had longer start-to-max duration (though shorter preswallow gesture and total movement durations), greater maximal vertical amplitude, longer total vertical distance, and greater backward peak velocity than younger subjects; (4) males had greater values for all kinematic parameters except preswallow gesture, hyoid-at-max, and max-to-end durations. The results illustrate the importance of examining the interrelations among kinematic variables to better understand task accommodation and motor control strategies. The evidence also supports the concept of suprahyoid–infrahyoid functional adaptation and compensation in the healthy elderly.     

Volume and Rate of Milk Delivery as Determinants of Swallowing in an Infant Model Animal (<Emphasis Type="BoldItalic">Sus scrofia</Emphasis>)

The volume transported into the valleculae by the rhythmic tongue movements of suckling is considered the prime factor for initiating pharyngeal swallowing (the movement of milk out of the valleculae and through the pharynx to the esophagus). This study addressed the impact of variation in two factors on sucking (oral phase) and on swallowing (pharyngeal phase) in infant pigs, as a model for mammalian function: (1) the delivery of different-volume aliquots of milk and (2) the delivery of equal-sized aliquots at different frequencies. The number of sucks per second remained constant with change in both aliquot volume and change in the frequency of milk delivery. However, while the number of swallows per second remained constant as delivery volume increased, it increased as delivery frequency increased. Conversely, swallow volume increased with both increase in aliquot volume and in the frequency of delivery. Piglets consequently initiated pharyngeal swallows with a highly variable amount of milk in the valleculae. We conclude that volume is only one factor initiating the pharyngeal swallow. The sensory stimulation of milk delivery to the anterior oral cavity is also a factor in determining the frequency of swallows and the volume of milk per swallow.     

Upper esophageal sphincter opening and modulation during swallowing

Studies were done on 8 normal subjects with synchronized videofluoroscopy and manometry to facilitate a biomechanical analysis of upper esophageal sphincter opening and volume-dependent modulation during swallowing. Movements of the hyoid and larynx, dimensions of sphincter opening, and intraluminal sphincter pressure were determined at 1/30th-s intervals during swallows of 1, 5, 10, and 20 ml of liquid barium. Our analysis subdivided upper esophageal sphincter activity during swallowing into five phases: (a) relaxation, (b) opening, (c) distention, (d) collapse, and (e) closure. Sphincter relaxation occurred during laryngeal elevation and preceded opening by a mean period of 0.1 s. Opening occurred as the sphincter was pulled apart via muscular attachments to the hyoid such that the hyoid coordinates at which sphincter opening and closing occurred were constant among bolus volumes. Sphincter distention after opening was modulated by intrabolus pressures rather than graded hyoid movement. The generation of intrabolus pressure coincided with the posterior thrust of the tongue that culminated in pharyngeal wall contact and the initiation of pharyngeal peristalsis. Larger volume swallows were associated with greater intrabolus pressure and increased bolus head velocity. The duration of sphincter opening increased in conjunction with a prolongation of the anterior-superior excursion of the hyoid and a delay in the onset of pharyngeal peristalsis (the event that determined the timing of sphincter closure). We conclude that transsphincteric transport of increasing swallow bolus volumes is accomplished by modulating sphincter diameter, opening interval, and flow rate (reflected by bolus head velocity). Furthermore, upper esophageal sphincter opening is an active mechanical event rather than simply a consequence of cricopharyngeal relaxation.     

Swallowing problems after excision of tumors of the skull base: Diagnosis and management in 12 patients

Acute-onset dysphagia can be a debilitating complication of operative intervention in skull base surgery. A retrospective study performed at Baptist Hospital in vestigated the oropharyngeal deficits, compensatory swallow techniques, and diet modifications of 12 patients who had undergone excision of skull base tumors. Oropharyngeal dysfunction, reduced laryngeal elevation, and copious pharyngeal retention were the most prominent swallowing deficits. Aspiration occurred in 75% of the patients studied. The most frequently employed compensatory swallow techniques were head turns to the affected side, supraglottic swallow, double swallows, alternating liquids and solids, carbonated beverage swallows, and small bolus size. Approximately 2 weeks following skull base surgery, 58% of the patients were able to tolerate oral intake with the aid of compensatory swallow techniques and diet modifications. Only 1 patient in this group remained unable to tolerate food by mouth. This paper focuses on identification of the disordered components of the swallow and the therapeutic management techniques characteristic of the patient who has undergone excision of a skull base tumor.     

Effects of Bolus Volume on Pharyngeal Contact Pressure During Normal Swallowing

This cross-sectional study investigated the effect of bolus volume on contact pressure within the pharynx and upper esophageal sphincter (UES). Three solid-state manometric pressure sensors were placed transnasally into the pharynx and the proximal esophagus of 40 participants (gender equally represented and between the ages of 20 and 45 years). Participants completed five repetitions each of three swallowing conditions: 5-, 10-, and 20-ml water bolus swallows. Repeated-measures ANOVA revealed no significant differences in the amplitude of pharyngeal contact pressure between the three swallowing conditions (sensor 1: p = 0.627, sensor 2: p = 0.764). Similarly, for durational measures nonsignificant main effects were found at both sensor 1 (p = 0.436) and sensor 2 (p = 0.350). Significant differences were found in UES pressure between the three conditions of bolus swallows (p = 0.000), with negative pressure in the UES inversely proportionate to bolus volume. However, durational measures of UES relaxation pressure were not significantly different between all conditions (p = 0.473). This study demonstrates no significant pressure differences of amplitude and duration between swallowing conditions in the pharynx. At the level of the UES, smaller boluses generated greater negative pressure.     

Structural Displacements Affecting Pharyngeal Constriction in Nondysphagic Elderly and Nonelderly Adults

This study investigated spatial displacement variables important to pharyngeal constriction and clearing in nondysphagic elderly subjects and a control group of nondysphagic younger adults. Height, weight, and body mass index (BMI) characteristics were determined for all subjects, who then underwent videofluoroscopic swallow studies. Measures obtained during swallow of a 20-cc bolus included hyoid and laryngeal displacement, unobliterated pharyngeal space at the point of maximum pharyngeal constriction, and pharyngeal width when maximally expanded during the swallow. Data were first examined to determine if elderly subjects with medical conditions common to an aged population differed from elderly subjects with no medical condition. No differences were identified and data for all elderly subjects were subsequently pooled for comparison to data for the nonelderly control group. Findings revealed no differences in maximum hyoid displacement between the groups. Significant differences were identified for larynx-to-hyoid approximation and for the measure representing unobliterated pharyngeal space at the point of maximum pharyngeal constriction. Elderly subjects did not elevate the larynx to the same extent, or clear the pharynx, as well as the younger control subjects. In addition, data suggested that the larynx was positioned lower and that the width of the pharynx maximally expanded was greater in elderly subjects. Implications of the data for swallowing function in the elderly are discussed.     

Scintigraphic quantification of pharyngeal retention following deglutition

A procedure is described for quantifying the amount of bolus material retained in the pharynx after completion of a swallow, using radionuclide swallow techniques. Data are derived from scintigraphic time-activity curves. The procedure takes into consideration the differential attenuation of radioactivity through various regions in the body, and expresses the result as a percentage of the total radioactivity in the ingested bolus. Illustrative examples are provided for swallows by normal individuals and patients with head and neck cancer.