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PubMed1983

Connections between the ventral medullary swallowing area and the trigeminal motor nucleus of the sheep studied by tracing techniques.

The anatomical connections between two regions involved in swallowing, the medullary reticular formation around the nucleus ambiguous (ventral group of swallowing interneurons) and the trigeminal motor nucleus (NMV) were studied in sheep using anterograde and retrograde tracing techniques. [3H]leucine and HRP were injected into the ventral medulla and the NMV respectively. These injections were performed according to stereotaxic coordinates previously established by electrophysiological recording tests. The results show bilateral connections between the ventral medulla, 2-4 mm rostral to the obex, and the trigeminal motor nucleus. In addition, the same area of the ventral medulla is connected with the homologous contralateral region and with the facial, vagal and hypoglossal nuclei that are also involved in swallowing. Some connections between the ventral medulla and the NMV must be monosynaptic since aggregates of silver grains typical of axon terminals were observed on the cell bodies of trigeminal motoneurons. Obviously, the various connections shown to exist in this study may serve other functions than swallowing. Nevertheless, most of the results are consistent with the view that the ventral group of medullary swallowing interneurons are switching neurons that distribute the programmed swallowing excitation to the various motoneuron pools involved in deglutition.

Animals↗
PubMed1990

Swallowing patterns in human subjects with and without temporomandibular dysfunction.

Recent clinical impressions have suggested that tongue-thrust swallowing may often occur in patients with internal derangement of the temporomandibular joint(s) and may represent an unconscious effort to avoid temporomandibular joint (TMJ) dysfunction by minimizing noxious stimuli from the joints. The purpose of this study, therefore, was to determine the swallowing patterns in human subjects with and without TMJ dysfunction. The swallowing patterns of 25 adult orthodontic patients already known to have TMJ dysfunction and 25 adult control subjects without such dysfunction were examined with the aid of kinesiographic and electromyographic recordings taken while the subjects were sipping water. Analysis of the data revealed that 19 patients with TMJ dysfunction used a tongue-thrust open-jaw swallowing pattern, while only nine control subjects used such a swallowing pattern. Furthermore, six of the patients with TMJ dysfunction had an anterior open bite, while none of the control subjects had an anterior open bite. The results suggest that patients with aberrant swallowing patterns should be examined for temporomandibular joint dysfunction.

Adolescent↗
PubMed2006

The effect of nasogastric tubes on swallowing function in persons with dysphagia following stroke.

OBJECTIVE: To determine whether the use of a nasogastric tube influences swallowing function in stroke patients with dysphagia. DESIGN: Before-after trial. SETTING: Primary care center. PARTICIPANTS: A total of 22 patients with stroke (12 men, 10 women; mean age, 69.7 y; range, 19-85 y) participated in the study. Time from onset of stroke to time of assessment averaged 20.3 days (range, 14-38 d). All participants continued to use a nasogastric tube for nutrition supply and had either minor or no aspiration of barium on videofluoroscopic examination of swallowing (VFES). INTERVENTION: The swallowing function was evaluated by VFES with thin and thick bariums (5 mL each) as a contrast medium. MAIN OUTCOME MEASURES: The oral transit, swallowing trigger, and pharyngeal transit times were measured and compared before and after the removal of the nasogastric tube. The patients were also observed for changes in velopharyngeal closure, pharyngeal contraction, epiglottic tilt, valleculae stasis, pyriform sinus stasis, penetration, and aspiration. RESULTS: Transit times were reduced by 0.2 to 0.6 seconds after removal of the nasogastric tube, but the reduction was not statistically significant. These transit times were slightly longer with thick barium than with thin barium, but were without statistical significance. Similarly, most of the patients had no change in nontemporal assessment of swallowing function after the tube was removed. CONCLUSIONS: The placement of a nasogastric tube did not affect temporal and nontemporal measurement of swallowing in stroke patients with dysphagia with or without minor aspiration.

Adult↗
PubMed2004

Differential activation of medullary vagal nuclei during different phases of swallowing in the cat.

The aim of this study was to identify the medullary vagal nuclei involved in the different phases of swallowing activated physiologically in a species with an esophagus similar to human. In decerebrate cats, the pharyngeal (0.5-1.0 ml water in pharynx (N=6)) or esophageal (1-3 ml air in esophagus (N=5)) phases of swallowing were stimulated separately once per minute for 3 h, and we compared the resulting c-fos immunoreactivity within neuronal cell nuclei of the dorsal motor nucleus (DMN), nucleus tractus solitarius (NTS) and nucleus ambiguus (NA) with a sham control group (N=5). We found that the pharyngeal phase was associated with an elevated number of c-fos positive neurons in the intermediate (NTSim), interstitial (NTSis), ventromedial (NTSvm) subnuclei of the NTS, caudal DMN, and dorsal NA; and the esophageal phase was associated with an elevated number of c-fos positive neurons in the central (NTSce), ventral, dorsolateral, ventrolateral subnuclei of the NTS, rostral DMN, and ventral NA. We concluded that the pharyngeal and esophageal phases of swallowing are associated with different sets of NTS subnuculei; and the DMN and NA may contain functionally different populations of motor neurons situated rostrocaudally and dorsoventrally associated with the different phases of swallowing. The central pattern generator (CPG) for swallowing probably receives significant peripheral feedback, and the NTSvm may participate in the transition of the pharyngeal to the esophageal phase of swallowing.

Animals↗
PubMed2005

Voice and swallowing outcomes of an organ-preservation trial for advanced laryngeal cancer.

INTRODUCTION: Organ-preservation treatment approaches for advanced laryngeal cancer patients that use combination chemoradiotherapy result in cure rates similar to primary laryngectomy with postoperative radiotherapy. In the national VA Larynx Cancer Trial, successful organ preservation was associated with an overall improvement in quality of life but not in subjective speech compared with long-term laryngectomy survivors. As part of a Phase II clinical trial, a prospective study of speech and swallowing results was conducted to determine if larynx preservation is associated with improved voice and swallowing compared with results in patients who require salvage laryngectomy. SUBJECTS: A total of 97 patients with advanced laryngeal cancer (46 Stage III, 51 Stage IV) were given a single course of induction chemotherapy (cisplatin 100 mg/m2 on Day 1 and 5-FU 1,000 mg/m2/day x 5 days), followed by assessment of response. Patients with less than 50% response underwent early salvage laryngectomy, and patients with 50% or better response underwent concurrent chemoradiation (72 Gy and cisplatin 100 mg/m2 on Days 1, 22, and 43), followed by two cycles of adjuvant chemotherapy (DDP/5-FU). Direct laryngoscopy and biopsy were performed 8 weeks after radiation therapy to determine final tumor response. Late salvage surgery was performed on patients with persistent or recurrent disease. METHODS: Completed survey data on voice and swallowing utilizing the Voice-Related Quality of Life Measure (V-RQOL) and the List Performance Status Scale for Head and Neck Cancer Patients (PSS-HN) were obtained from 56 patients who were alive and free of disease at the time of survey, with a minimum follow-up of 8 months. Comparisons were made between patients with an intact larynx (n = 37) vs. laryngectomy (n = 19), as well as early (n = 12) vs. late salvage laryngectomy (n = 7). Multivariate analysis was performed to determine factors predictive of voice and swallowing outcomes. Overall 3-year determinant survival was 87%, with median follow-up of 40 months. RESULTS: Patients with an intact larynx demonstrated significantly higher (p = 0.02) mean V-RQOL scores (80.3) than did laryngectomy patients (65.4). This finding was consistent in the social-emotional (p = 0.007) and physical functioning domains (p = 0.03). No differences in V-RQOL scores were found in comparisons between early and late salvage laryngectomy. Multiple linear regression revealed that predictors of higher total V-RQOL scores include lower T stage (p = 0.03), organ preservation (p = 0.0007), and longer duration since treatment (p = 0.01). Understandability of speech was better in patients with an intact larynx (p = 0.001). Overall swallowing function was comparable between groups. Multiple logistic regression revealed that longer duration since treatment (p = 0.03, odds ratio = 1.1) and lower maximal mucositis grade (p = 0.03, odds ratio = 0.3) were predictive of higher likelihood of eating in public. Nutritional mode consisting of oral intake alone without nutritional supplements was achieved in 88.9% of patients with an intact larynx compared with 64.3% of laryngectomees (p = 0.09). CONCLUSIONS: Voice-related quality of life is better in patients after chemoradiation therapy compared with salvage laryngectomy. Earlier salvage, although known to be associated with fewer surgical complications, did not result in improved voice; however, the number of patients analyzed is small. Overall swallowing function is good in all patients; however, patients with an intact larynx are more likely to obtain nutrition with oral intake alone without supplements. Such measures of function and quality of life are important endpoints to help judge overall effectiveness as newer, more aggressive treatment protocols with added toxicities are developed and evaluated.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Aspirin absorption rates and platelet inhibition times with 325-mg buffered aspirin tablets (chewed or swallowed intact) and with buffered aspirin solution.

Large clinical trials such as the second International Study of Infarct Survival routinely gave patients with myocardial infarction a chewed aspirin, yet there are no data to show whether chewing of aspirin is better, or worse, than swallowing a whole tablet. We performed a randomized, placebo-controlled study to determine whether chewing aspirin or administering it in solution accelerates its absorption and antiplatelet activity. On separate days, 12 fasting volunteers ingested 325 mg of buffered aspirin, either by chewing a tablet for 30 seconds before swallowing it with 4 ounces of water, swallowing a whole tablet with 4 ounces of water, or drinking 4 ounces of Alka Seltzer. Frequent blood samples were obtained for serum aspirin, salicylate, and thromboxane B2 (TxB2) concentrations. With all formulations of aspirin, serum TxB2 decreased 50% when the plasma aspirin concentration reached approximately 1,000 ng/ml. A 50% and 90% decrease in serum TxB2 occurred more quickly after chewing a tablet than after a tablet was swallowed whole. For example, the t 50% for serum TxB2 inhibition was 5.0 +/- 0.6 minutes with the chewed tablet versus 12.0 +/- 2.3 minutes when the tablet was swallowed (p = 0.01). A 50% decrease in serum TxB2 occurred 7.6 +/- 1.2 minutes after Alka Seltzer solution (p = 0.04 vs chewing a tablet; p = 0.13 vs swallowing a whole tablet). Chewing an aspirin tablet is the most effective way of accelerating absorption of aspirin into the blood and shortening the time required for an antiplatelet effect.

Absorption↗
PubMed1995

Swallow management in patients on an acute stroke pathway: quality is cost effective.

OBJECTIVE: To assess the effects of swallowing management in patients with acute nonhemorrhagic stroke placed on a clinical pathway, and to evaluate whether swallow function on admission can be used as a predictor of length of stay (LOS) and outcome disposition. DESIGN: Intervention study to reduce complications of dysphagia in patients with acute stroke. SETTING: Urban community hospital. PATIENTS: Data were collected on 124 patients with acute nonhemorrhagic stroke admitted from January to December 1993. INTERVENTIONS: A swallow screen was completed within one day of admission and before any oral intake. MAIN OUTCOME MEASURES: Dysphagia and functional independence measure (FIM) scores on admission, occurrence of aspiration pneumonia, LOS, outcome disposition and cost effectiveness analysis. RESULTS: Thirty-nine percent of all patients (p < .05) failed the initial swallow screen and required altered dietary texture and intervention. No patients developed aspiration pneumonia. Of those with dysphagia, 21% recovered intact swallowing by discharge; 19% required gastrostomy tube placement. Patients with dysphagia had lower admission FIM scores than nondysphagia patients. The LOS was longer for the dysphagia group (8.4 +/- 0.9 days) compared with patients without dysphagia (6.4 +/- 0.6 days, p < .05). Patients with dysphagia were less likely to be discharged to home (27%) than were nondysphagia patients (55%), and twice as likely to be discharged to a nursing home (p < .05). CONCLUSIONS: This study demonstrates that early swallow screening and dysphagia management in patients with acute stroke reduces the risk of aspiration pneumonia, is cost effective, and assures quality care with optimal outcome.

Cerebrovascular Disorders↗
PubMed2002

Intracellular activity of superior laryngeal nerve motoneurons during fictive swallowing in decerebrate rats.

We examined the swallowing-related intracellular activity of motoneurons of the superior laryngeal nerve (SLN) in decerebrate, paralyzed and artificially-ventilated rats, to elucidate the neuronal mechanism of the pharyngo-esophageal and laryngo-esophageal coordination during swallowing. The majority of the SLN motoneurons exhibited respiratory rhythm (n=16; 13 inspiratory, one expiratory and two non-respiratory neurons). During fictive swallowing evoked by electrical stimulation of the SLN, all these motoneurons showed a hyperpolarization-depolarization sequence in their membrane potentials. The hyperpolarization, which was shown to consist of inhibitory postsynaptic potentials, started at the onset of the hypoglossal swallowing burst, lasted during the burst, and was followed by a depolarization at the end of the burst. This hyperpolarization-depolarization pattern implies that the SLN motoneurons may be involved in the 'inhibitory chain' within the swallowing pattern generator, which may be cardinal in the sequential activation of different populations of motoneurons innervating the swallowing-related muscles.

Action Potentials↗
PubMed1998

Upper airway motor outputs during vomiting versus swallowing in the decerebrate cat.

Swallowing and vomiting are antagonistic motor acts; nevertheless, vomiting can be immediately followed by swallowing. The purpose of this study was to clarify the interrelationship between these two behaviors, particularly in regard to comparing the upper airway motor patterns at the end of the expulsion phase with those during subsequent swallowing. Experiments were conducted using both paralyzed and non-paralyzed decerebrate cats, in which recordings were obtained either from upper airway muscles, the diaphragm and abdominal muscles or from the nerves that innervate those muscles. The activity patterns of most nerves recorded in paralyzed animals were consistent with the behavior recorded in non-paralyzed animals from the muscles innervated by those nerves, with the exception of the cricothyroid and stylopharyngeus muscles. Vomiting can be divided into a series of retches followed by expulsion, which itself can be further subdivided into three phases. The final stage of expulsion, characterized by burst-like exaggerated activity of the laryngeal elevator thyrohyoid and the pharyngeal constrictors, proved to be different from pharyngeal swallowing, as judged from differences in the spatio-temporal patterns of the upper airway motor outputs. However, post-vomiting swallowing activity was still observed even after total deafferentation of the laryngeal and pharyngeal areas in paralyzed animals. It is therefore likely that the central processes for vomiting and swallowing closely relate in generating these two behaviors.

Afferent Pathways↗
PubMed1991

The development of normal feeding and swallowing.

The development of feeding skills is an extremely complex process influenced by multiple anatomic, neurophysiologic, environmental, social, and cultural factors. Most children negotiate the necessary developmental sequence without significant difficulties. An understanding of the development of normal feeding abilities aids the pediatrician in monitoring this remarkable process in his or her normal patients. This understanding also helps equip the pediatrician who is challenged by a child with complex feeding problems. The following statements summarize the major elements of feeding development. 1. Structural integrity is essential to the development of normal feeding and swallowing skills. Infant anatomy differs from adult anatomy. Anatomic changes associated with growth affect feeding function. 2. Normal infant feeding is reflexive, under brainstem control, and does not require suprabulbar input. As feeding development progresses, basic brainstem-mediated responses come under voluntary control through the process of encephalization. 3. The mature swallow consists of a voluntary oral-preparatory phase, a voluntary oral phase, and involuntary pharyngeal and esophageal phases. The infant swallow does not have a voluntary oral-preparatory and oral phase but is otherwise similar. 4. The neurophysiologic control of feeding and swallowing is complex and involves sensory afferent nerve fibers, motor efferent fibers, paired brainstem swallowing centers, and suprabulbar neural input. Close integration of sensory and motor functions is essential to the development of normal feeding skills. 5. Feeding development, although dependent on structural integrity and neurologic maturation, is a learned progression of behaviors. This learning is heavily influenced by oral sensation, fine and gross motor development, and experiential opportunities. 6. The basic physiologic complexity of feeding is compounded by individual temperament, interpersonal relationships, environmental influences, and culture. 7. The main goal of feeding is the acquisition of sufficient nutrients for optimal growth and development. Malnutrition may result directly from feeding problems and may also help perpetuate them. 8. Protection of the airway during swallow is a reflexive, multileveled function consisting of the apposition of the epiglottis and aryepiglottic folds and the adduction of both false and true vocal folds.

Deglutition↗
PubMed1998

Crossing inputs of the superior laryngeal nerve afferents to medullary swallowing-related neurons in the cat.

To understand the neural mechanism for generation of synchronous activity on both sides during swallowing, we examined the convergence of inputs from the bilateral superior laryngeal nerves (SLNs) in the urethane-anesthetized cat medulla and we also examined the changes in swallowing outputs after a longitudinal brain-stem split in decerebrate cats. Twenty-six (31%) of 84 swallowing-related neurons (SRNs) that were oligosynaptically activated by ipsilateral SLN stimulation and recorded mostly in the reticular formation received contralateral inputs, which were confirmed by orthodromic spike responses (n = 16) or were detected as subliminal facilitatory or inhibitory inputs (n = 10) using conditioning-test stimuli. The rate of convergence of inputs from bilateral SLNs in these SRNs was significantly higher than that (4%) in the SRNs that were regarded as sensory-relay neurons in the nucleus tractus solitarius (NTS). The SRNs receiving signals from the contralateral SLN were located diffusely from the NTS and the adjacent reticular formation to the nucleus ambiguus (NA) and the reticular formation dorso-medial to the NA. A midsagittal split from 3 mm caudal to 6 mm rostral to the obex could change symmetrical swallowing to unilateral swallowing. Thus the crossing projections to the contralateral SRNs appear to contribute to symmetrical swallowing.

Afferent Pathways↗
PubMed2001

Hybrid fuzzy logic committee neural networks for recognition of swallow acceleration signals.

Biological signals are complex and often require intelligent systems for recognition of characteristic signals. In order to improve the reliability of the recognition or automated diagnostic systems, hybrid fuzzy logic committee neural networks were developed and the system was used for recognition of swallow acceleration signals from artifacts. Two sets of fuzzy logic-committee networks (FCN) each consisting of seven member networks were developed, trained and evaluated. The FCN-I was used to recognize dysphagic swallow from artifacts, and the second committee FCN-II was used to recognize normal swallow from artifacts. Several networks were trained and the best seven were recruited into each committee. Acceleration signals from the throat were bandpass filtered, and several parameters were extracted and fed to the fuzzy logic block of either FCN-I or FCN-II. The fuzzified membership values were fed to the committee of neural networks which provided the signal classification. A majority opinion of the member networks was used to arrive at the final decision. Evaluation results revealed that FCN correctly identified 16 out of 16 artifacts and 31 out of 33 dysphagic swallows. In two cases, the decision was ambiguous due to the lack of a majority opinion. FCN-II correctly identified 24 out of 24 normal swallows, and 28 out of 29 artifacts. In one case, the decision was ambiguous due to the lack of a majority opinion. The present hybrid intelligent system consisting of fuzzy logic and committee networks provides a reliable tool for recognition and classification of acceleration signals due to swallowing.

Acceleration↗
PubMedDate not supplied

Swallowing difficulties for cerebellar stroke may recover beyond three years.

Swallowing disorders after stroke or skull base surgery can be life threatening. Although late recovery can occur, it remains poorly documented. We report a case of a 54-year-old woman with dysphagia resulting from a cerebellar stroke with hemorrhage that was evacuated through craniotomy. Swallowing difficulties were assessed by a videoendoscopic swallowing study. She presented with disruption of swallow initiation and impairment of the pharyngeal stage, resulting in hypopharyngeal stasis and penetration with aspiration. Supportive swallowing therapy was conducted with careful reeducation to assist initiation of the pharyngeal stage as well as development of compensatory postural technique. Initial improvement was very slow but became rapidly progressive from the 31st month after the stroke. By the 34th month, oral feeding was possible without aspiration. This case demonstrates that improvement in swallowing function can be expected even 3 years after stroke or skull base surgery. Determination of predictive factors for late functional recovery is of great importance and should be the focus of further investigation.

Cerebellar Diseases↗
PubMed1997

Swallowing difficulty in Parkinson's disease.

Dysphagia is a frequent and potentially serious complication of Parkinson's disease (PD). We examined the oropharyngeal swallowing ability in 19 PD patients (15 men and 4 women, mean age 68.42 years, mean Hoehn and Yahr stage 1.8) using modified barium swallow before and after administering oral levodopa (in combination with benserazide). Twelve (63.2%) patients demonstrated objective evidence of swallowing abnormalities; although only six patients (31.6%) had subjective complaints. Vallecula sinus and pyriform sinus residues were the most frequent abnormalities (47.4% and 42.1%); followed by delayed swallowing reflex (26.3%). Three patients demonstrated silent aspiration. In the 12 patients with abnormal swallowing, six (50%) showed objective improvement after levodopa treatment, while the remaining six showed no change. Of the former group of six, one patient showed improvement in the oral phase, but deterioration in the pharyngeal phase. We concluded that PD patients had a high percentage of objective swallowing abnormalities which could be reduced in half of the patients through the administration of levodopa treatment.

Adult↗
PubMed1999

The traditional Chinese medicine banxia houpo tang improves swallowing reflex.

A marked depression of swallowing reflex has been found in patients with aspiration pneumonia. We have examined the effects of Banxia Houpo Tang (BHT, Hange Koboku-To in Japanese), on swallowing reflex among the elderly. Thirty-two patients, mean age 74.2 +/- 1.7 years who had at least one episode of aspiration pneumonia, were divided into two groups. Twenty patients took BHT extracts of 7.5 g per day for four weeks, and the other 12 patients took a placebo. The swallowing reflex was measured by a bolus injection of 1 ml of distilled water into the pharynx through a nasal catheter. The reflex was evaluated by the latency time of response, which was the time from the injection to the onset of swallowing. The latency of response decreased significantly from 11.6 +/- 3.0 sec to 2.6 +/- 0.4 sec in the group treated with BHT (p < 0.01), while in the other group with placebo it was from 11.0 +/- 4.0 to 10.8 +/- 3.6 (p > 0.5). Depletion of substance P in the pharynx causes impairments of the swallowing reflex. Substance P in the saliva of treated patients increased from 9.2 +/- 2.5 fmol/ml to 15.0 +/- 2.2 fmol/ml after BHT treatment (p < 0.01), while levels were 8.0 +/- 4.0 fmol/ml before and 7.1 +/- 3.1 fmol/ml after among the placebo group (no significant difference). We suggest that BHT improves the impaired swallowing reflex and may help to prevent aspiration pneumonia in the elderly.

Aged↗
PubMed2002

Non-invasive monitoring of functionally distinct muscle activations during swallowing.

OBJECTIVES: Dysphagia is an important consequence of many diseases. As some of the muscles of deglutition tend to be deep to the surface, needle electrodes are typically used, but this limits the number of muscles that can be simultaneously recorded. Since control of swallowing involves central pattern generators (CPGs) which distribute commands to several muscles, monitoring several muscles simultaneously is desirable. Here we describe a novel method, based on computing the independent components (ICs) of the simultaneous sEMG recordings (Muscle Nerve Suppl 9 (2000) 9) to detect the underlying functional muscle activations during swallowing using only surface EMG (sEMG) electrodes. METHODS: Seven normal subjects repeatedly swallowed liquids of varying consistency while sEMG was recorded from 15 electrodes from the face and throat. Active areas of EMG were excised from the recordings and the ICs of the sEMG were calculated. RESULTS: The ICs demonstrated less swallow-to-swallow variability than the raw sEMG. The ICs, each consisting of a unique temporal waveform and a spatial distribution, provided a means to segregate the complex sequence of muscle activation into rigorously defined separate functional units. The temporal profiles of the ICs and their spatial distribution were consistent with prior needle EMG studies of the cricopharyngeal, superior pharyngeal constrictor, submental and possibly arytenoid muscles. Other components appeared to correspond to EKG artifact contaminating the EMG recordings, laryngeal excursion, tongue movement and activation of the buccal and/or masseter musculature At least two of the components were affected by the consistency of the liquids swallowed. Re-testing one subject a week later demonstrated good intertrial reliability. CONCLUSIONS: We propose that the ICs of the sEMG provide a non-invasive means to assess the complex muscle sequence activation of deglutition.

Adult↗
PubMed2001

Developmental patterns of rhythmic suck and swallow in preterm infants.

Twenty healthy preterm infants (gestational age 26 to 33 weeks, postmenstrual age [PMA] 32.1 to 39.6 weeks, postnatal age [PNA] 2.0 to 11.6 weeks) were studied weekly from initiation of bottle feeding until discharge, with simultaneous digital recordings of pharyngeal and nipple (teat) pressure and nasal thermistor and thoracic strain gauge readings. The percentage of sucks aggregated into 'runs' (defined as > or = 3 sucks with < or = 2 seconds between suck peaks) increased over time and correlated significantly with PMA (r=0.601, p<0.001). The length of the sucking-runs also correlated significantly with PMA (r=0.613, p<0.001). The stability of sucking rhythm, defined as a function of the mean/SD of the suck interval, was also directly correlated with increasing PMA (r=0.503, p=0.002), as was increasing suck rate (r=0.379, p<0.03). None of these measures was correlated with PNA. Similarly, increasing PMA, but not PNA, correlated with a higher percentage of swallows in runs (r=0.364, p<0.03). Stability of swallow rhythm did not change significantly from 32 to 40 weeks' PMA. In low-risk preterm infants, increasing PMA is correlated with a faster and more stable sucking rhythm and with increasing organization into longer suck and swallow runs. Stable swallow rhythm appears to be established earlier than suck rhythm. The fact that PMA is a better predictor than PNA of these patterns lends support to the concept that these patterns are innate rather than learned behaviors. Quantitative assessment of the stability of suck and swallow rhythms in preterm infants may allow prediction of subsequent feeding dysfunction as well as more general underlying neurological impairment. Knowledge of the normal ontogeny of the rhythms of suck and swallow may also enable us to differentiate immature (but normal) feeding patterns in preterm infants from dysmature (abnormal) patterns, allowing more appropriate intervention measures.

Child Development↗
PubMed2005

Mapping metabolic brain activation during human volitional swallowing: a positron emission tomography study using [18F]fluorodeoxyglucose.

We have previously shown that labelled water positron emission tomography (H2(15)O PET) can be used to identify regional cerebral blood flow (rCBF) changes in the human brain during volitional swallowing. (18F) fluorodeoxyglucose (FDG PET), by comparison, uses a glucose analogue to quantitatively measure regional cerebral glucose metabolism (rCMRglc) rather than rCBF. The main advantage of FDG PET is improved spatial resolution, and because of its pharmacodynamic properties, activation can be performed external to the scanner, allowing subjects to assume more physiologic positions. We therefore conducted a study of the brain's metabolic response while swallowing in the erect seated position, using FDG PET. Eight healthy male volunteers were studied with a randomised 2 scan paradigm of rest or water swallowing at 20-second intervals for 30 minutes. Data were analysed with SPM99 using multisubject conditions and covariates design. During swallowing, analysis identified increased rCMRglc (P<0.01) in the following areas: left sensorimotor cortex, cerebellum, thalamus, precuneus, anterior insula, left and right lateral postcentral gyrus, and left and right occipital cortex. Decreased rCMRglc were also seen in the right premotor cortex, right and left sensory and motor association cortices, left posterior insula and left cerebellum. Thus, FDG PET can be applied to measure the brain metabolic activity associated with volitional swallowing and has the advantage of normal task engagement. This has implications for future activation studies in patients, especially those suffering swallowing problems after brain injury.

Adult↗