Biomedical subjects

Jeffrey B Palmer

Publications and source records attributed to Jeffrey B Palmer.

7 recordsLinked to original sources

PubMed2003

Three tests for predicting aspiration without videofluorography.

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.

Adolescent↗

PubMed2003

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.

Adult↗

PubMed2003

Tongue movements in feeding and speech.

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.

Animals↗

PubMed2003

[Dysphagia severity scale].

A simple, broadly applicable, standardized dysphagia severity scale would be useful to standardize dysphagia evaluations, to monitor recovery and efficacy of treatment and to study the consequences of dysphagia. We developed a global Dysphagia Severity Scale (DSS) from videofluorographic swallowing studies which included subjective clinical ratings of functional swallowing. We rated laryngeal penetration/aspiration (P/A) and pharyngeal retention (PR), and then assessed methods for scoring severity of P/A and PR and for combining them in a global scale. Each method was tested by correlation with overall clinical severity ratings. The highest correlations were found by: 1) scoring P/A based on which foods were aspirated (no aspiration or penetration; penetration only; thin liquid aspiration; thick liquid, pudding, or chewed solid food aspiration; 2) scoring PR based on how much food was retained (none; minimal; moderate; severe); and 3) combining P/A and PR by taking the higher of the two scores as the final DSS rating. The final global DSS score and the clinical severity rating correlated well (r = 0.71). This proposed scale shows promise for rating global dysphagia severity.

Adult↗

PubMed2002

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.

Adult↗

PubMed2002

Hyoid and tongue surface movements in speaking and eating.

The human hyoid moves continuously in feeding, facilitating movements of the tongue surface and the processing and transport of food. The hypothesis that similar hyoid movements support tongue movements in speech was tested in 10 normal young adults of both sexes, who were recorded with lateral-projection videofluorography when feeding on hard and soft foods and when reading the 'Grandfather Passage', which includes the major vowel-consonant combinations in English. Recordings were made with and without tongue-markers. Images were analysed with a digital frame grabber and computer. Each participant served as his/her own control. The hyoid moved continuously during speech and feeding. In speech, hyoid motions were irregular and not linked to jaw movement, as they were for feeding. The centroids and variances of the domains for all reference points were compared for speech and feeding; the centroid represents the average position of a structure and variance its amount of motion. Gape and hyoid centroids were significantly different for feeding and speech (P<0.001), but differences for gape averaged <1mm while the difference for the hyoid centroid was >7mm. There were no significant differences in gape attributable to sex. Consistent with the known differences in hyolaryngeal position there were significant sex differences in hyoid centroid (P=0.031) but not variance. In speech, tongue-markers had a smaller spatial domain (P=0.001) condensed within the larger feeding domain. The small shift in the gape centroid does not explain the larger forward shift of the hyoid during speech. These findings raise questions about the neuromotor control of hyoid position in the two behaviours and the biomechanics of the supralaryngeal vocal tract.

Adult↗

PubMed2002

A postero-anterior videofluorographic study of the intra-oral management of food in man.

Recent studies of the manipulation and reduction of food in the human mouth have used lateral-projection videofluorography (VFG) and so have concerned antero-posterior food movement. To determine the degree to which (a) food was chewed bilaterally as opposed to unilaterally, (b) the frequency of side changes, (c) the contribution of tongue and cheek activity to food manipulation, and (d) the effect of food consistency on these activities, nine young adults were recorded eating 7g cubes of four foods (banana, biscuit [cookie] and two types of meat: "tender" and "tough") in the postero-anterior projection. Videotapes recorded at 30 frames/s were acquired to disk; data were analysed as single frames and in slow-motion. As expected, the meat samples, being fibrous, required more chewing and manipulation, allowing details of the process to be established. Food was ingested in the midline; the tongue then positioned the cube on the occlusal plane of one side by a combination of pushing, tilting and twisting movements before any occlusal contact (stage I transport). During processing, food was kept on the occlusal surface by a combination of rhythmic tongue-pushing moving the food buccally (41% of cycles), and cheek-pushing (28% of cycles) returning it in the lingual direction. This reciprocating movement ensured that different parts of the food were subjected to occlusal force in successive cycles. Bilateral chewing was common and associated with either: (a) a near-symmetrical closing movement with tooth-food-tooth contact occurring almost simultaneously on both sides, or (b) an identifiable "active side" but a jaw movement extended medially to carry the lower molars through a power stroke on the "balancing" side. During the sequence, food requiring further chewing might be moved to the erstwhile balancing-side (balancing-side shift); or across the mouth to the tooth row or vestibule on the other side and "stored" for later reduction (segregation shift). Towards the end of the sequence, triturated material was moved to the midline (aggregation shift) for bolus formation and deglutition. While distinct patterns of mediolateral and vertical jaw movements seem to be associated with shift and transport cycles, these connections have not yet been established with sufficient robustness to support predictions of intra-oral events from jaw movement profiles alone.

Adult↗