Improving care for intensive care survivors and their families requires collaboration between practitioners and researchers in both the inpatient and outpatient settings. Strategies were developed to address the major themes arising from the conference to improve outcomes for survivors and families.
SYNOPSISEating and swallowing are complex behaviors involving volitional and reflexive activities of more than 30 nerves and muscles. They have two crucial biological features: food passage from the oral cavity to stomach and airway protection. The swallowing process is commonly divided into oral, pharyngeal, and esophageal stages according to the location of the bolus. The movement of the food in the oral cavity and to the oropharynx differs between eating solid food and drinking liquid. Dysphagia can result from a wide variety of functional or structural deficits of the oral cavity, pharynx, larynx or esophagus. The goal of dysphagia rehabilitation is to identify and treat abnormalities of feeding and swallowing while maintaining safe and efficient alimentation and hydration.
The coordination of mastication, oral transport, and swallowing was examined during intake of solids and liquids in four normal subjects. Videofluorography (VFG) and electromyography (EMG) were recorded simultaneously while subjects consumed barium-impregnated foods. Intramuscular electrodes were inserted in the masseter, suprahyoid, and infrahyoid muscles. Ninety-four swallows were analyzed frame-by-frame for timing of bolus transport, swallowing, and phases of the masticatory gape cycle. Barium entered the pharynx a mean of 1.1 s (range -0.3 to 6.4 s) before swallow onset. This interval varied significantly among foods and was shortest for liquids. A bolus of food reached the valleculae prior to swallow onset in 37% of sequences, but most of the food was in the oral cavity at the onset of swallowing. Nearly all swallows started during the intercuspal (minimum gape) phase of the masticatory cycle. Selected sequences were analyzed further by computer, using an analog-to-digital convertor (for EMG) and frame grabber (for VFG). When subjects chewed solid food, there were loosley linked cycles of jaw and hyoid motion. A preswallow bolus of chewed food was transported from the oral cavity to the oropharynx by protraction (movement forward and upward) of the tongue and hyoid bone. The tongue compressed the food against the palate and squeezed a portion into the pharynx one or more cycles prior to swallowing. This protraction was produced by contraction of the geniohyoid and anterior digastric muscles, and occurred during the intercuspal (minimum gape) and opening phases of the masticatory cycle. The mechanism of preswallow transport was highly similar to the oral phase of swallowing. Alternation of jaw adductor and abductor activity during mastication provided a framework for integration of chewing, transport, and swallowing.
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.
The videofluorographic swallowing study (VFSS) is the definitive test to identify aspiration and other abnormalities of swallowing. When a VFSS is not feasible, nonvideofluorographic (non-VFG) clinical assessment of swallowing is essential. We studied the accuracy of three non-VFG tests for assessing risk of aspiration: (1) the water swallowing test (3 ml of water are placed under the tongue and the patient is asked to swallow); (2) the food test (4 g of pudding are placed on the dorsum of the tongue and the patient asked to swallow); and (3) the X-ray test (static radiographs of the pharynx are taken before and after swallowing liquid barium). Sixty-three individuals with dysphagia were each evaluated with the three non-VFG tests and a VFSS; 29 patients aspirated on the VFSS. The summed scores of all three non-VFG tests had a sensitivity of 90% for predicting aspiration and specificity of 71% for predicting its absence. The summed scores of the water and food tests (without X-ray) had a sensitivity of 90% and specificity of 56%. These non-VFG tests have limitations but may be useful for assessing patients when VFSS is not feasible. They may also be useful as screening procedures to determine which dysphagia patients need a VFSS.
ABSTRACT:The position of the tongue relative to the upper and lower jaws is regulated in part by the position of the hyoid bone, which, with the anterior and posterior suprahyoid muscles, controls the angulation and length of the floor of the mouth on which the tongue body 'rides'. The instantaneous shape of the tongue is controlled by the 'extrinsic muscles' acting in concert with the 'intrinsic' muscles. Recent anatomical research in non-human mammals has shown that the intrinsic muscles can best be regarded as a 'laminated segmental system' with tightly packed layers of the 'transverse', 'longitudinal', and 'vertical' muscle fibers. Each segment receives separate innervation from branches of the hypoglosssal nerve. These new anatomical findings are contributing to the development of functional models of the tongue, many based on increasingly refined finite element modeling techniques. They also begin to explain the observed behavior of the jaw-hyoid-tongue complex, or the hyomandibular 'kinetic chain', in feeding and consecutive speech. Similarly, major efforts, involving many imaging techniques (cinefluorography, ultrasound, electro-palatography, NMRI, and others), have examined the spatial and temporal relationships of the tongue surface in sound production. The feeding literature shows localized tongue-surface change as the process progresses. The speech literature shows extensive change in tongue shape between classes of vowels and consonants. Although there is a fundamental dichotomy between the referential framework and the methodological approach to studies of the orofacial complex in feeding and speech, it is clear that many of the shapes adopted by the tongue in speaking are seen in feeding. It is suggested that the range of shapes used in feeding is the matrix for both behaviors.
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