[151] THE EFFECT OF EXERCISE ON HEMOGLOBIN A1CS IN TYPE-2 DIABETES IN SUPERVISED VS. HOME EXERCISE PROGRAMS
Carol J. Leach, MHA, PT; Charles F. Kunkel, MD, MS;
Thomas G. Cagle, PhD; Janette Carter, MD; Clifford Qualls,
PhD
Albuquerque VA Medical Center (117), Albuquerque, NM
87108; email: Leach.Carol@albuquerque.va.gov
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #A2154-RA)
PURPOSE--Exercise has been shown to increase glucose utilization and improve insulin sensitivity in patients with type-2 diabetes, even after adjusting for weight loss. An inverse relationship has been noted between level of physical activity and level of hemoglobin A1c. In the clinical setting, however, prescribing exercise for type-2 diabetes may be complicated by poor adherence and lower limb problems. This study attempts to measure the value of exercise prescription in the treatment of type-2 diabetes. A home exercise program is being tested as a clinically practical alternative to the traditional supervised model. Components of fitness are being compared to weight loss for their relative contributions to change in hemoglobin A1c levels.
METHODOLOGY--Working with primary care providers, a research assistant conducts ongoing recruitment of 150 veterans with type-2 diabetes, not currently using insulin. After demonstrating stable hemoglobin A1cs for 3 mo, recruits are screened by ECG during an exercise tolerance test on a treadmill. Subjects are then randomly assigned to one of three groups for the 3-mo intervention phase: a Home Exercise Group monitored by weekly phone consultations, a Supervised Exercise Group attending the Fitness Center three times a week, and a Control Group receiving the usual care. Measurements of hemoglobin A1c, estimated VO;i2max, percent body fat, body mass index, and waist-to-hip ratio, are taken before and after the 3-mo intervention and again 6 mo later. Both exercise groups are given an exercise prescription based on the results of the treadmill test. The prescription tapers up to walking at 70 percent of heart rate reserve for 45 min, 5 days a week. Heart rate monitors, exercise logs, and patient education encourage adherence to the prescription. Subjects are compensated $20 at each of the three measurement sessions.
PROGRESS--Smooth ramp protocols have been designed for the treadmill tests using 30-s ramp increments. A preliminary reliability study of the skinfold method of body fat estimation was conducted. Twenty-eight subjects have now been randomized into the intervention phase. Baseline characteristics of these participants are: 26 males, mean age 60 years, mean age at diagnosis 51 years, 19 taking oral agents, mean hemoglobin A1c of 7.62 percent, estimated VO2max of 21.85 ml/kg·min-1 ("poor" fitness classification), mean body fat of 26.26 percent, mean body mass index of 30.75, and mean waist-to-hip ratio of 0.99.
PRELIMINARY RESULTS--The between-rater study of skin fold body fat estimates revealed a 2 to 5 percent absolute error of measurement with a positive correlation to body mass index, suggesting that the method may be less reliable in obese subjects. Within-rater repeat measurement contributed 0 percent to the variability in skin-fold measurements in a variance component analysis using a restricted maximum likelihood estimation. The 0 percent is an estimate on a boundary and indicates that within-rater variability is less important than the variability between raters.
[152] EFFECTS OF AGING ON MOTOR UNIT FIRING BEHAVIOR
Zeynep Erim, PhD; Carlo J. De Luca, PhD; Joseph F.
Jabre, MD
NeuroMuscular Research Center, Boston University,
Boston, MA 02215; Physical Medicine and Rehabilitation
Service, Boston VA Medical Center, Boston, MA 02130; email:
erim@bu.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #B829-RA)
PURPOSE--It is hypothesized that the control of motor units is altered as a result of, or in accommodation to, the mechanical and physiological properties of muscle fibers altered by aging. The knowledge of age-related alterations in the control of motor units will provide insight into the observed decline in neuromuscular performance in the elderly.
METHODOLOGY--The first dorsal interosseous muscle was studied in male subjects during voluntary abduction of the index finger. Electromyographic signals detected via the quadrifilar needle electrode and the surface bipolar electrodes were recorded along with the force generated by the muscle. The Precision Decomposition Technique was used to identify firing times of motor units.
PROGRESS--Data from 10 young subjects between the ages of 20 and 37, and 10 elderly subjects between the ages of 65 and 88 have been analyzed and the results compiled.
RESULTS--Observations on data analyzed reveal three main findings: 1) The common fluctuations in the firing rates of concurrently active motor units, highly correlated in the young, are not as correlated in the elderly; 2) The phenomenon of onion skin observed in the young, whereby motor units recruited earlier during increasing force have a higher average firing rate than motor units recruited later, is not observed in the elderly in whom the firing rate plots of motor units "cross over"; 3) Motor unit firing rates which show decreases in the young during constant-force contractions as a result of the potentiation in twitch forces, do not display any decreases in the elderly, suggesting a decrease in the capacity of aged muscle fibers to potentiate.
In addition to these novel findings, our results provided support for some previous observations: 1) Depression of the firing rate of motor units in the elderly was observed as compared to the young; 2) There was a shift in the recruitment thresholds toward lower values suggesting a fiber type change toward Type I fibers; 3) There are polyphasic and satellite motor unit action potentials observed in the elderly; 4) Although there is wide intersubject variability, maximal force levels were decreased in the elderly. On the other hand, synchronization analysis did not reveal any significant differences among the two age groups in the percentage of motor unit pairs that exhibited synchronized firing behavior, or the extent of synchronization among the firings of motor unit pairs.
FUTURE PLANS--Future plans include investigating the effects of exercise on motor control in the elderly and studying the potential of exercise to reverse some of the age-related alterations in the control of motor units.
[153] SWEAT RESPONSE IN MS PATIENTS DURING EXERCISE: A PILOT STUDY
Janet A. Mulcare, PhD; Thomas Mathews, MD
Research and Neurology Services, Dayton VA Medical
Center, Dayton, OH 45428; email: jmulcare@wright.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #A2126-PA)
PURPOSE--Many individuals with multiple sclerosis (MS) experience a subtle intolerance to increases in body or climatic temperatures. As such, many self-impose limitations to physical exertion to prevent increases in body temperature. This assumption of a relatively sedentary lifestyle may be associated with the high prevalence of secondary medical problems (e.g., CAD, hypertension, type II diabetes, obesity) that often accompany MS following diagnosis. Physical activity and exercise can play a key role in preventing or reducing the debilitating effects of these medical conditions. In performing aerobic exercise the body's primary mechanism for eliminating metabolic heat generated from contracting muscle is through sweating. This response is initiated when skin temperature (Tsk) reaches approximately 35 °C. Sudomotor (sweat) response in persons with MS has been reported to be abnormal in a high percentage of patients (42-60 percent). It is unknown whether decreased sweating in some patients with MS is from central lesions or is a matter of these patients not exerting sufficiently to elicit a sweat response. Earlier studies of sudomotor response in this population have used inappropriate measurement techniques, have neglected to record Tsk, or have only examined the phenomenon under resting conditions. Based upon our current understanding of the relationship among the metabolic/thermal load associated with physical activity, the sudomotor response, and core temperature, prescribing activity (e.g., exercise) to this population may be incorrect using published guidelines for the general population. Therefore, the overall goal of this research will be to document the relationship between metabolic and thermoregulatory responses of patients with MS during moderate aerobic exercise. This will be accomplished through fulfillment of the following objectives: 1) characterize baseline neurological status of patients; 2) document metabolic, cardiorespiratory, thermoregulatory, and central hemodynamic responses during aerobic bicycle exercise; and 3) utilize the acquired data to develop rehabilitation guidelines for physical activity and exercise for this population.
METHODOLOGY--Twenty persons with MS and 10 control subjects will be recruited. All individuals with MS would be evaluated to determine baseline neurological status. The subjects would also have their body composition measured (height, weight, and body fat by the use of skinfold calipers) and a short medical history taken. After subjects were cleared for exercise, they would perform a test of maximal aerobic power and a 30-min aerobic endurance exercise test. During the endurance test, subjects will have warm water circulated over their bodies via a full-body water garment. Metabolic, cardiorespiratory, and thermoregulatory data will be collected continuously during each test. Tsk will be measured at nine anatomical locations and a starch/iodine technique used to identify the exact location of sweating at a given Tsk.
PROGRESS--Collaboration with the local Chapter of the National MS Society resulted in 800 brochures being sent to persons on their mailing list. While awaiting their response, a computer program for measuring skin and rectal temperatures was written and the heating/cooling system tested. The body suits were modified in order to allow easier access to measurement areas.
To date, 20 subjects have had their neurological test, resting EKG, body composition, and medical history evaluated. Twenty MS subjects have performed their max tests and another 14 have finished their endurance tests. We are now in the process of matching individuals by gender, age, and similar body characteristics to the MS group in order to establish a control group. We have matched two persons so far.
[154] SENSITIVITY AND SPECIFICITY OF A CLINICAL EXAMINATION OF SWALLOWING
Robert T. Wertz, PhD; Gary H. McCullough, PhD; John C.
Rosenbek, PhD
Audiology and Speech Pathology, VA Medical Center,
Nashville, TN 37212; Department of Speech Pathology and
Audiology, University of Tennessee, Knoxville, TN 37996;
Audiology and Speech Pathology, VA Medical Center, Madison,
WI 53705; email: wertz.robert_t.@nashville.va.gov
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #C2113-RA)
PURPOSE--The objective of this investigation is to develop a sensitive and specific clinical/bedside swallowing examination by testing the sensitivity and specificity of clinical/bedside appraisal procedures for dysphagia. We seek answers to two primary research questions: What is the sensitivity of a clinical/bedside examination for detecting dysphagia? What is the specificity of a clinical/bedside examination in the evaluation of dysphagia? We define dysphagia as the presence of bolus penetration/aspiration into the laryngeal vestibule during swallowing and/or the presence of a delayed initiation of swallowing.
METHODOLOGY--Subjects will be 180 clients in the VA Medical Centers in Nashville and Madison who have suffered a recent stroke. Each subject receives a clinical/bedside swallowing examination and is rated for the presence of penetration/aspiration and/or delayed swallowing. A videofluoroscopic examination (VFE) of swallowing is conducted on each subject, and the presence of penetration/aspiration and/or delayed swallowing is rated. Using the VFE results as the gold standard for detecting the presence of dysphagia, signal detection analysis will be conducted to determine the sensitivity and specificity of the clinical/bedside swallowing examination.
PROGRESS--Since the investigation's launch in October 1997, we have entered and evaluated 90 stroke patients. We continue to recruit and evaluate additional subjects to meet the prescribed sample size.
[155] BIOMECHANICS AND SENSORY INPUT OF SWALLOW AFTER HEAD AND NECK CANCER
Jerilyn A. Logemann, PhD
Northwestern University, Communication Sciences and
Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health National Cancer Institute Bethesda, MD 20892
PURPOSE--The purpose of this work is to define the underlying neuromuscular mechanisms causing the swallow dysfunction in the treated head and neck cancer patient and to identify sensory enhancements and swallow maneuvers that facilitate improved safety and efficiency in swallowing. At the same time, analyses of the procedures in control subjects increases our understanding of neuromuscular control of the normal swallow. And the biomechanical analysis of the changes in swallow over time posttreatment in selected groups of head and neck cancer patients promises to improve our understanding of those neuromuscular components most critical to swallowing recovery in specific groups of patients and any spontaneous compensations used by them. This project examines the biomechanical effects of head and neck treatment on swallowing function and on the patient's ability to exert voluntary control over specific aspects of the swallow as well as the impact of varying bolus flavor. A biomechanical analysis will enable us to define the changes in muscle pull created by head and neck surgical procedures and to develop more effective swallow interventions, including surgical reconstruction.
METHODOLOGY--Videofluoroscopic swallowing studies of treated head and neck cancer patients, collected at three points in time posttreatment, will be quantified temporally and biomechanically to identify the ways in which voluntary maneuvers and postures, as well as heightened sensory input from bolus flavors, impact the swallow, as compared to nonimpaired age- and gender-matched subjects.
PROGRESS--Over the last 12 months we have worked at the establishment and maintenance of approval for use of human subjects at participating institutions and at the establishment and maintenance of contractual arrangement between the grantee institution and the participating institutions. During the same time, we have been involved in the training of clinicians at participating institutions in the proper instruction, administration, and assessment of adequacy of postures and maneuvers, as well as in the accrual of head and neck cancer patients and age and gender-matched control subjects.
FUTURE PLANS--We shall complete a study of the effect of a sour flavored bolus in head and neck cancer patients and continue accrual of head and neck cancer patients and age and gender-matched controls.
[156] LONG-TERM SURVIVORS OF HEAD AND NECK CANCER
Jerilyn A. Logemann, PhD
Northwestern University, Communication Sciences and
Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health, National Cancer Institute, Bethesda, MD 20892
PURPOSE--Our first hypothesis, based on pilot data, is that treated head and neck cancer patients continue to suffer significant functional deficits long after treatment has been completed, and that the exact nature of these deficits will vary, based on the original tumor site and stage, and nature of treatment (surgery and/or radiotherapy). A second objective of this project is to evaluate the effects of a specific intervention strategy on patient function. A third is to determine whether the gains are maintained long term. A fourth is to define the cost of the intervention proposed, and the cost impact of the intervention such as a reduction of the need for expensive prepared feedings, decreased incidence of hospitalization for pneumonias that may be aspiration-related or for depression-related disorders due to speech and swallowing problems, and changes in other health care needs. A fifth objective is to determine whether it is possible to predict from baseline measures, and disease stage and treatment variables, which patients will benefit most from the intervention.
METHODOLOGY--Data collection begins with a baseline collection period on each of the 300 head and neck cancer subjects at least 1 yr posttreatment, after which any subject not eating a full range of diet consistencies (liquid, paste, and masticated materials) because of a swallowing disorder, or whose oropharyngeal swallow efficiency is 30 or less on any food consistency, will be entered into the intervention stage of the protocol and randomized to early intervention (group A) or delayed intervention (group B). At the end of the 4-mo intervention for Group A, all patients will be retested and any change measured. After retesting of function, patients in Group B will begin their 4-mo intervention protocol, while Group A will receive no intervention. At the end of the second 4-mo period, all will again be retested to identify the effects in Group B and the carry-over in Group A.
PROGRESS--The focus of work in the last 12 mo has been the continued recruitment of treated head and neck cancer patients who are at least 1 yr posttreatment and free of disease. We have added the University of Tennessee to this project to increase patient accruals.
FUTURE PLANS--We seek to accrue head and neck cancer patients, follow them for a year, and complete data reduction on a total of 150 patients.
[157] THE EFFECTS OF RADIOTHERAPY/CHEMOTHERAPY ON VOICE, SPEECH, AND SWALLOWING FUNCTION
Bharat B. Mittal, MD; Jerilyn A. Logemann, PhD; Merrill
Kies, MD
Department of Radiology/Oncology and the Department of
Medicine, Northwestern Memorial Hospital, Chicago, IL 60611;
Northwestern University, Communication Sciences and
Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health National Cancer Institute Bethesda, MD 20892
PURPOSE--This project proposes to define the effects of organ preservation protocols involving high dose radiotherapy (>5,000 cGy) with or without chemotherapy in 300 oral, laryngeal, and pharyngeal cancer patients with previously untreated Stages II to IV disease, and to measure the effectiveness of swallow maneuvers in improving the swallow. Each subject's response to swallow maneuvers will be defined.
METHODOLOGY--Each subject will be followed for 12 mo after treatment completion; all will be studied pretreatment, and at 1, 3, 6, and 12 mo postcompletion of chemoradiotherapy. At each of these data collection points, each will receive a videofluoroscopic assessment of swallowing, a voice recording for acoustic analysis, and a speech analysis for understandability and articulatory production.
PROGRESS--Over the last 12 mo we have worked at the establishment and maintenance of approval for use of human subjects at participating institutions and at the establishment and maintenance of contractual arrangement between the grantee institution and the participating institutions. During the same time, we have been involved in the training of clinicians at participating institutions in the study protocol, as well as in the accrual of head and neck cancer patients.
RESULTS--We continue to see a severe effect of combined high dose radiation and chemotherapy to the functions of laryngeal elevation and tongue-base/pharyngeal wall contraction. The combination of high-dose radio- and chemotherapy appears to have a more devastating effect on swallowing than radiotherapy alone. However, these are very early results and must be corroborated with larger numbers of subjects.
FUTURE PLANS--We seek to accrue 75 patients, follow them for a year, and complete data reduction on them.
[158] THE EFFECTS OF SURGICAL INTERVENTION ON SPEECH AND SWALLOWING FUNCTION IN PATIENTS WITH RECURRENT/RESIDUAL DISEASE
Barbara Roa Pauloski, PhD; Jerilyn A. Logemann,
PhD
Northwestern University, Communication Sciences and
Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health, National Cancer Institute, Bethesda, MD 20892
PURPOSE--Changes in patterns of care over the past 5 yrs have resulted in the treatment with radiation only or with radiation and chemotherapy combined of oral and oropharyngeal cancer patients who would previously have received surgical intervention. It is expected that a number of these persons will present with residual or recurrent disease for which surgery will be required for cancer control, and they may face significant functional impairment in the areas of speech and swallowing after salvage surgery. This study will examine the functional impairments and recovery of function experienced by this group over a 12-mo period after surgery.
METHODOLOGY--Each subject will be followed for 12 mo postoperatively; all will be studied preoperatively, and at 1, 3, 6, and 12 mo posttreatment. At each of these data collection points, each subject will receive a videofluoroscopic assessment of swallowing and speech, an articulation test, and recording of conversational speech for later intelligibility rating.
PROGRESS--Over the last 12 mo we have worked at the establishment and maintenance of approval for use of human subjects at participating institutions and at the establishment and maintenance of contractual arrangement between the grantee institution and the participating institutions. During the same time, we have been involved in the training of clinicians at participating institutions in the study protocol, as well as in the accrual of head and neck cancer patients. We have surveyed participants concerning changes in the pattern of care for recurrent episodes and modified the study protocol to include four groups of subjects according to the combinations of primary and salvage treatment (either of which may be radiotherapy/chemotherapy or surgery).
FUTURE PLANS--We seek to accrue 50 patients, follow them for a year, and complete data reduction on them.
[159] HEAD AND NECK CANCER: QUALITY OF LIFE, PERFORMANCE AND PATIENTS' PRIORITIES
Marcy List, PhD; Jerilyn A. Logemann, PhD
University of Chicago, Cancer Research Center, Chicago,
IL 60637; Northwestern University, Communication Sciences
and Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health, National Cancer Institute, Bethesda, MD 20892
PURPOSE--The specific aims of the project are to determine rate and degree of recovery of function, mood, and overall quality of life by group (site, treatment) and time since treatment; to identify times of greatest difficulty for patients; to evaluate patients' priorities with respect to potential disease and treatment sequelae; to determine whether these rankings change over time as patients experience effects of disease and treatment; and to determine the relationship between priority rankings and actual function; to compare the priorities of patients with head and neck cancer to nonimpaired controls.
METHODOLOGY--A total of 500 head and neck cancer patients, representing four treatment types, will be assessed at four points in time: pretreatment, and at 3, 6, and 12 mo posttreatment. The assessment will consist of the PSS-HN (Performance Status Scale for Head and Neck Cancer), the FACT-HN (Functional Assessment of Cancer Therapy Scale-Head and Neck), the Patient's Priorities Ranking Scale, as well as the collection of relevant medical, personal, and social demographic data.
PROGRESS--Over the last 12 mo we have worked at the establishment and maintenance of approval for use of human subjects at participating institutions and at the establishment and maintenance of contractual arrangement between the grantee institution and the participating institutions. During the same time, we have been involved in the training of clinicians at participating institutions in the study protocol, as well as in the accrual of head and neck cancer patients.
FUTURE PLANS--We shall focus on continued accrual of both patients and control subjects and follow-up of patients already on study, monitoring all incoming data and maintaining close contact with speech language pathologists to identify and resolve any issues that interfere with timely, accurate collection. Patient demographics will be summarized and recruitment of controls will continue.
[160] THE EFFECTS OF SURGICAL RECONSTRUCTION ON SPEECH AND SWALLOWING
Fred McConnel, MD; Jerilyn A. Logemann, PhD
Southern Ear, Nose, and Throat, Lawrenceville, GA 30245;
Northwestern University, Communication Sciences and
Disorders, Evanston, IL 60208-3540
Sponsor: National Institutes of Health, National Cancer Institute, Bethesda, MD 20892
PURPOSE--This study examines the effects of surgical reconstruction for oropharyngeal cancer as a first-line rehabilitation strategy in oral cancer patients. It is our hypothesis that particular surgical reconstruction can facilitate speech and swallowing or cause a further decrement in function. This project will follow 8 groups of surgically treated subjects to examine the effects of surgical reconstruction on early and late functional outcomes of speech and swallowing.
METHODOLOGY--Each subject will be followed for 3 mo postoperatively; all will be studied preoperatively, and at 1 and 3 mo posthealing. Those reconstructed with flaps designated as sensate will receive an additional assessment at 12 mo posthealing. At each of these data collection points, each will receive a videofluoroscopic assessment of swallowing and speech, an articulation test, and recording of conversational speech for later intelligibility rating.
PROGRESS--Over the last 12 mo we have worked at the establishment and maintenance of approval for use of human subjects at participating institutions and at the establishment and maintenance of contractual arrangement between the grantee institution and the participating institutions. During the same time, we have been involved in the training of clinicians at participating institutions in the study protocol, as well as in the accrual of head and neck cancer patients.
FUTURE PLANS--We plan to accrue 14 patients, follow them for 3 mo, and complete data reduction on them.
[161] IN SEARCH FOR PROPER BOUNDARY CONDITION AT THE GLOSSO-PALATAL JUNCTION FOR PHARYNGEAL BOLUS MODELING: A STUDY USING NEURAL NETWORK INVERSION
Eugene Lin, MS; Jenq-Neng Hwang, PhD; Michael W. Chang,
MD, PhD
Department of Electrical Engineering, College of
Engineering, and the Department of Rehabilitation Medicine,
School of Medicine, University of Washington, Seattle,
WA 98195; email: mwc@u.washington.edu
Sponsor: The Whitaker Foundation, Rosslyn, VA 22209
PURPOSE--Dysphagia is a common clinical symptom that can cause life-threatening pulmonary complications, such as choking and aspiration pneumonia. Pharyngeal bolus modeling using computational fluid dynamics (CFD) enables analysis of relationship between forces applied to the bolus and bolus movement. This analysis can be used to supplement clinical tests to develop guidelines for safe swallowing. However, the model requires specification of velocity boundary condition at the inlet of the oro-pharynx or glosso-palatal junction (GPJ). The velocity boundary condition at the GPJ thought to be related to the tongue driving force, which pushes the bolus into the pharynx. This velocity is difficult to estimate using a standard videofluorographic (VFG) swallowing study. In this work, a neural network inversion technique is successfully used to help specify the velocity boundary condition at the GPJ.
METHODOLOGY--VFG was performed on a control subject using a 10-mL barium-mixed bolus (standard EZ-HD barium sulfate suspension, 250%w/v). Bolus viscosity and density were measured to be 185 centi-poise and 2.84 g/mL, respectively. FIDAP (Fluent Inc., Lebanon, NH), a computational fluid dynamic software using finite element method (FEM) was used to solve equations representing bolus transport. Initial and boundary conditions are required to obtain the solution for the pharyngeal bolus transport. A feed-forward neural network is used for modeling computational fluid dynamics using FEM. Inputs contain the boundary condition and the coordinates of the bolus front for different locations at a certain time instant. Outputs contain the coordinates of the bolus front for a different location at the next time instant. The forward network is trained first by repeatedly presenting input-output training pairs and performing the back-propagation learning algorithm. After this training, the forward network is inverted by presenting a desired output (i.e., bolus front) to the network and by using inversion to minimize the error between the actual output and the desired output through a gradient descent search. Forward propagation of the forward network provides the coordinates of the bolus front for a particular boundary condition, while the forward network inversion provides a valid boundary condition corresponding to a set of bolus front coordinates, giving us a means of inference from effect to causes.
RESULTS--Based on the two-dimensional (2-D) CFD model of the pharyngeal bolus movement using lateral view of VFG study, 150 input-output training data pairs were created using FIDAP. Inputs were the boundary condition and the coordinates of the bolus front at time instant t-1. Outputs were the coordinates of the bolus front at time instant t. All these input/output values were normalized to a range between 0 and 1. Using this information, we trained a forward network which had 11 inputs, 10 outputs, and 1 hidden layer with 30 neurons. This trained forward network approximates the 2-D model of pharyngeal bolus movement. After the network was trained, we identify the coordinates of the bolus front (directly from the lateral VFG study) for inversion. Iterative inversion was used to find the inverted boundary condition parameter corresponding to the coordinates of the bolus front. To validate the results, we modeled the pharyngeal bolus transport using the inverted boundary condition at the GPJ to calculate the bolus front, which was in favorable comparison with the VFG data.
IMPLICATIONS--We employed neural network inversion to estimate the velocity boundary condition at the GPJ using bolus front location. We demonstrated that the inversion of a trained forward model is a promising method for providing the velocity boundary condition at the GPJ. This boundary condition is required for pharyngeal bolus modeling.
FUTURE PLANS--Velocity boundary condition at the GPJ for a 3-D pharyngeal bolus model is currently under investigation using neural network inversion.
[162] POLESTRIDING EXERCISE AND VITAMIN E FOR MANAGEMENT OF CLAUDICATION PAIN
W. Edwin Langbein, PhD; Eileen G. Collins, PhD, RN;
Cynthia Orebaugh, BSN, RN; Fred N. Littooy, MD; Lonnie
Edwards, MD; Domenic Reda, MS
Rehabilitation R&D Center, Nursing, Medical and Surgical
Services, Hines Cooperative Studies Program Coordinating
Center, VA Hines, Hines, IL 60141; email:
elangbei@wwa.com
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #B2095-RA)
PURPOSE--Patients with atherosclerotic peripheral arterial disease (PAD) of the lower limbs are subject to periods of intermittent claudication caused by the formation of atherosclerotic plaques that narrow or occlude arteries. This condition results in an inadequate blood flow causing ischemic muscle pain. If unchecked, progressive atherosclerotic disease in the leg arteries will result in tissue damage, ulceration, gangrene, and ultimately amputation. The purpose of this project is to determine the efficacy of utilizing polestriding (a form of walking that uses muscles of the upper and lower body in a continuous movement similar to cross country skiing) with and without vitamin E supplements for increasing exercise tolerance and management (delaying the onset) of intermittent claudication pain in patients with PAD.
METHODOLOGY--This clinical trial utilizes a prospective, randomized, two-by-two factorial design. Subjects are randomized into four groups after baseline testing is completed: polestriding with vitamin E, polestriding with placebo, vitamin E, or placebo. A sample of 84 subjects with a current diagnosis of PAD, a history of intermittent claudication, and an ankle to brachial index (ABI) <0.85 at rest, and/or <0.60 after exercise are being recruited. Intermittent claudication pain must be the primary limiting factor to maximal exercise during the treadmill test.
Initially, all subjects complete a symptom-limited maximal wheelchair exercise test to screen for coronary artery disease, at least two symptom-limited ramp treadmill tests to establish a stable baseline, a constant-load treadmill test, a segmental arterial examination, ABIs determined immediately before and after treadmill walking, Borg's ratio scale to determine subjects' perception of effort and severity of exercise-induced claudication pain, a quality of life battery, and daily physical activity recall. Subjects are then randomized.
Those randomized into the polestriding group receive polestriding instruction and training. Polestriding training sessions include a 3-5 min warm-up, interval training, and cool down. Each training program is individualized and based on the results of the baseline exercise tests. Individuals in the vitamin E and Placebo groups come to the laboratory weekly for ABI measurements, and physical activity recall. The walking endurance treadmill test, constant load treadmill test, segmental arterial exams, quality of life testing, and physical activity recall interviews are repeated on all subjects at specified intervals.
PROGRESS--To date, 35 subjects have been randomized. They are older (non-Polestriders age=65±8 yrs; polestriders age 65±7 yrs), educated (13 yrs school completed), moderately obese (non-polestriders body mass index = 30.1±5.8; polestriders 29.4±5.3) and primarily men (97 percent). Prevalent co-morbidities and risk factors include arthritis, hypertension, and smoking. Subjects report that they are able to walk one to two blocks before the onset of claudication pain.
At baseline, subjects were able to walk 632±314 (non-polestriders) and 644±266 (polestriders) seconds on a specially designed ramp protocol treadmill test. Resting ABIs were diminished in both groups (non-polestriders = 0.71±0.18; polestriders = 0.67±0.22).
FUTURE PLANS--Our principles of interventional prevention and vascular rehabilitation may be applied nationally to create VA special clinics dedicated to enhancement of health via the proposed polestriding exercise program. The reduction in the need for expensive, and labor intensive hospitalizations would also be cost-effective.
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