Assessment of impaired coordination between respiration and deglutition in children and young adults with ataxia telangiectasia.

AIM: This cross-sectional investigation aimed to assess the value of non-invasive measures of temporal respiratory-swallow coupling in individuals with ataxic swallowing. METHOD: Twenty participants (11 males, 9 females; range 9-21y) with ataxia telangiectasia were presented with water and pudding boluses. Their 193 swallows were compared with 2200 swallows from 82 age-matched healthy controls. The two components of airway protection during swallowing that were analyzed were: direction of peri-deglutitive airflow and duration of deglutitive inhibition of respiratory airflow (DIORA). RESULTS: Safe expiratory patterns of peri-deglutitive airflow occurred significantly less often in participants with ataxia telangiectasia than in age-matched control participants (younger p<0.015 and older p<0.001). The frequency of an expiratory pattern of peri-deglutitive airflow increased with age in participants in the comparison group (p=0.006), but not in those with ataxia telangiectasia (p=0.234). With age, mean duration of DIORA decreased in controls (p<0.001) but was unchanged in participants with ataxia telangiectasia (p=0.164). INTERPRETATION: Non-invasive quantitative measures of respiratory-swallow coupling capture temporal relationships that plausibly contribute to airway compromise from dysphagia. Changes in respiratory-swallow coupling observed with advancing age in control participants were not seen in participants with ataxia telangiectasia. Measures of perturbations may herald swallowing problems prior to development of pulmonary and nutritional sequelae.

Reduced somatosensory activations in swallowing with age.

Understanding the neural functional organization of swallowing in healthy elders is essential in diagnosing and treating older adults with swallowing difficulties. The primary aims of this investigation were to identify the neural activation sites of different components of deglutition in healthy elders using functional Magnetic Resonance Imaging (fMRI) and to investigate age differences in the neural control of swallowing. Ten young (age range 19-25 years of age) and nine older (age range 66-77 years of age) right-handed healthy individuals were scanned in a 3-Tesla MRI scanner. Subjects were visually cued for both a "Swallow" task and for component/control tasks ("Prepare to swallow," "Tap your tongue," and "Clear your throat"). Behavioral interleaved gradient (BIG) methodology was used to address movement related artifacts. Between-group comparisons revealed statistically stronger activations in the primary somatosensory cortex of young adults during the motor tasks examined. Both groups showed activations in the major motor areas involved in the initiation and execution of movement; however, areas involved in sensory processing, sensorimotor integration and/or motor coordination and control, showed reduced or limited activity in the elderly. Potential implications of these findings for clinical practice are discussed.

Age-related differences in laterality of cortical activations in swallowing.

The present study examined age differences in neural lateralization patterns during swallowing and three related tasks, using functional magnetic resonance imaging (fMRI). Ten healthy right-handed young adults (mean age = 21.7 years, SD = 2.1 years) and nine healthy elders (mean age = 70.2 years, SD = 3.9 years) were scanned in a 3-T MRI head scanner. Participants were visually cued to "prepare to swallow," "swallow," "tap your tongue," and "clear your throat" in randomized order. Laterality preference for each task was examined within and between groups using region-of-interest (ROI) analyses in seven areas of the left and right primary sensorimotor and premotor cortices. Results of the within-group comparisons verified a more active role of the left premotor cortex in motor-cognitive planning of deglutition in both young and older adults and a more active role of selected areas of the right hemisphere during swallowing in young adults. Greater variability was seen during tongue tapping and throat clearing in both groups. Finally, as people age the cortical hemispheric control of swallowing seems to start becoming more symmetrical/bilateral, which may indicate neural compensatory mechanisms of the aging brain commonly seen for other motor and cognitive functions.

Neural activation of swallowing and swallowing-related tasks in healthy young adults: an attempt to separate the components of deglutition.

Understanding the underlying neural pathways that govern the highly complex neuromuscular action of swallowing is considered crucial in the process of correctly identifying and treating swallowing disorders. The aim of the present investigation was to identify the neural activations of the different components of deglutition in healthy young adults using functional magnetic resonance imaging (fMRI). Ten right-handed young healthy individuals were scanned in a 3-Tesla Siemens Allegra MRI scanner. Participants were visually cued for both a "Swallow" task and for component/control tasks ("Prepare to swallow", "Tap your tongue", and "Clear your throat") in a randomized order (event-related design). Behavioral interleaved gradient (BIG) methodology was used to address movement-related artifacts. Areas activated during each of the three component tasks enabled a partial differentiation of the neural localization for various components of the swallow. Areas that were more activated during throat clearing than other components included the posterior insula and small portions of the post- and pre-central gyri bilaterally. Tongue tapping showed higher activation in portions of the primary sensorimotor and premotor cortices and the parietal lobules. Planning did not show any areas that were more activated than in the other component tasks. When swallowing was compared with all other tasks, there was significantly more activation in the cerebellum, thalamus, cingulate gyrus, and all areas of the primary sensorimotor cortex bilaterally.

Bolus location associated with videofluoroscopic and respirodeglutometric events.

The purpose of the present investigation was to determine the relation between specific events observed with simultaneous videofluoroscopy and respirodeglutometry. The order of occurrence was determined for each of 31 events (18 videofluoroscopic, 13 respirodeglutometric). Using 1 video frame (33.3 ms) as the maximum distance allowed between the average times of 2 events in the same cluster, 8 potential clusters were identified, 3 of which were statistically confirmed based on 90% confidence intervals on the mean time distances between events. Confirmed clusters included the time of (a) complete velar descent and the onset of the small noninspiratory flow (SNIF), (b) full separation of the base of the tongue from the pharyngeal wall and SNIF nadir, complete upper esophageal sphincter closure, and SNIF nadir, and (c) onset of epiglottic return and apnea offset. The onset of respiratory flow occurred within 13 ms after the onset of epiglottic return. Additionally, the percentage of swallows during which the bolus head or tail was located at each of 6 locations was determined for 20 of these events (10 videofluoroscopic, 10 respirodeglutometric). The 6 locations of interest included the oral cavity, base of tongue, valleculae, pyriform sinuses, upper esophageal sphincter, and the esophagus. Lastly, of the 72 swallows performed by these healthy, young adults, 65 (90.3%) were preceded by expiration, and all (100%) were followed by expiration.

Hyoid displacement in post-treatment cancer patients: preliminary findings.

PURPOSE: Dysphagia after head and neck cancer treatment is a health care issue; in some cases, the cause of death is not cancer but, rather, the passage of food or liquid into the lungs. Hyoid displacement is known to be important to safe swallowing function. The purpose of this study was to evaluate hyoid displacement after cancer treatment. METHOD: Hyoid displacement was measured in healthy persons with normal swallowing function, head and neck cancer patients postradiation only, and head and neck cancer patients postsurgery only. Three bolus conditions (5 ml and 10 ml liquid and 5 ml paste) were examined. The influence of 2 different measurement algorithms on the extent of hyoid movement was also explored. RESULTS: Radiation-therapy patients in this study had greater hyoid displacement than did surgery patients. Bolus viscosity and measurement method significantly influenced displacement results, whereas bolus volume did not. However, more multiple swallows occurred with 10 ml liquid; this may account for the apparent insignificance of bolus volume. CONCLUSIONS: These findings can be used to assist head and neck cancer treatment planning and counseling. Because hyoid measurement methods influence research conclusions, this aspect of design should be considered when interpreting research findings.

Teledynamic evaluation of oropharyngeal swallowing.

PURPOSE: The objective of the present investigation was to test the feasibility and clinical utility of a real-time Internet-based protocol for remote, telefluoroscopic evaluation of oropharyngeal swallowing. METHOD: In this prospective cohort study, the authors evaluated 32 patients with a primary diagnosis of stroke or head/neck cancer. All patients participated in 2 separate fluoroscopic swallowing evaluations--one traditional on site and one telefluoroscopic off site--through the use of a telemedicine system. Agreement between sites was tested for 3 categories of variables: (a) overall severity of swallowing difficulty, (b) presence and extent of laryngeal penetration and aspiration as rated by the 8-point Penetration-Aspiration scale, and (c) treatment recommendations. RESULTS: Results showed overall good agreement in subjective severity ratings (κ = 0.636) and in Penetration-Aspiration scale ratings (mean absolute difference = 1.1 points) between the onsite and offsite clinicians. Agreement in treatment recommendations was moderate to high, ranging from 69.3% to 100%. CONCLUSIONS: The present study supports the feasibility and clinical utility of a telemedicine system for evaluating oropharyngeal swallowing. Given the difficulty and expertise needed to complete such evaluations, this study offers promising clinical avenues for patients in rural, remote, and underserved communities and countries where expert swallowing specialists are not available.

Neuroanatomy and Neurophysiology: Implications for Swallowing.

Deglutition is a complicated neuromuscular process that requires a complex level of communication between the central and peripheral nervous systems, and which results in highly coordinated actions from the muscles of mouth, pharynx, larynx, and esophagus. The actions of the individual muscles involved in deglutition and their cranial nerve innervation for the oral and pharyngeal stages of the swallow are presented. This is followed by a discussion of the research relating to potential areas of breakdown, and the corresponding symptomology, associated with the oral and pharyngeal stages of swallowing following a stroke.

Real-time remote telefluoroscopic assessment of patients with dysphagia.

Dysphagia is a serious health problem that affects persons of all ages, from the neonate to those of advanced age. Many smaller communities and areas with sparse populations do not have regular access to professionals with expertise in the area of oral/pharyngeal dysphagia. Telemedicine is one method by which people in these areas can receive quality of service. The intent of this work was to develop an Internet system that permits real-time, remote, interactive evaluation of oral/pharyngeal swallowing function. The system consists of two major components. The first is a PC that is located in the fluoroscopy suite of a hospital. The computer is connected to the fluoroscope output and is responsible for (1) capturing video signals, (2) converting the analog video data into digitized video formats of both full resolution and transmission-optimized resolution, (3) simultaneously transmitting the transmission-optimized video stream over the network while the examination is being performed, and (4) storing the full-resolution data as a file in local storage for later retrieval. The second component is the controller computer which is located at a site some distance from the hospital. That controller computer manages the video capture process at the remote hospital site, manages the transmission of the stored images, and is then used for video analysis. The delay between the image as it was captured at the remote hospital site and viewed on the controller computer in the Principal Investigator's (PI's) laboratory ranged from 3 to 5 s. Video transmission occurred over a standard T1 line.

Magnetic resonance imaging of the levator veli palatini muscle during speech.

OBJECTIVE: To obtain detailed anatomic information on the levator veli palatini (LVP) muscle from magnetic resonance imaging (MRI). Quantitative measures of the configuration of the LVP muscle at rest and during speech activities were obtained. DESIGN: Prospective study using MRI of adult subjects with normal velopharyngeal mechanisms to determine anatomic and physiologic parameters of the levator muscle. The levator veli palatini muscle was imaged at rest and during speech activities consisting of nasal and non-nasal sounds mixed with vowels, consonants, or both (e.g., /ansa, asna, amfa, afma/). PARTICIPANTS: Ten normal healthy adults (five men, five women) between 21 and 53 years of age and free of oropharyngeal abnormalities. MAIN OUTCOME MEASURES: Two-dimensional spin echo static images and dynamic fast gradient echo images of the levator muscle in both the sagittal and oblique/coronal planes. RESULTS: On average across female (F) and male (M) subjects: distance between LVP muscle origin points, 52.6 mm (F), 54.6 mm (M); angle of levator muscle origin at rest, 64.5 degrees (F), 60.4 degrees (M); length of the levator muscle at rest, 44.1 mm (F), 46.4 mm (M); width of levator muscle at lateral margin of velum, 5.5 mm (F), 6.6 mm (M). Both the levator muscle angle of origin and length became progressively smaller from rest, nasal consonants, low vowels, high vowels, and fricatives for both female and male subjects. Across all subjects, there was a 19% reduction in length of the LVP muscle from rest position to fricative production. CONCLUSIONS: MRI is an effective method of imaging and measuring the LVP muscle and related structures in living subjects. Understanding the normal tissue distribution and quantification of the LVP muscle provides important information for development of a functional biomechanical model of the velopharynx and for improved surgical treatment.