RESEARCH IN PHYSICAL DISABILITIES
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Steven J. Stanhope, PhD, Head, Physical Disabilities Branch Barbara C. Sonies, PhD, Chief, Oral Motor Function Section Gloria Chi-Fishman, PhD, Staff Scientist Jeri L. Miller, PhD, Staff Scientist Barbara Myklebust, PhD, Staff Scientist Frances Sheehan, PhD, Staff Scientist Thomas M. Kepple, MA, Senior Research Assistant Tracy Rausch, BS, Research Assistant Kelly Nelson, MS, Motion Lab Engineer Susan Bender, BS, Protocol Coordinator Timothy Brindle, PhD, Postdoctoral Fellow Zohara Cohen, PhD, Postdoctoral Fellow Lauro Halstead, MD, MPH, Guest Researchera Robert Jaeger, PhD, Guest Researcherb Claudia Mazzà, MS, Guest Researcherc |
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| The Physical Disabilities Branch (PDB) was established in part to accelerate the formation of a highly collaborative, multidisciplinary, technology and rehabilitation research network. We develop and apply advanced technologies that create new directions for our basic, translational, and clinical rehabilitation research in support of the transrehabilitation research domain model, which postulates that our ability to understand disablement rests on linking knowledge of the impairment, functional limitation, and physical disability rehabilitation research. These advanced technologies encompass a broad range that includes theoretical concepts, numeric models, computational methods, and instrumentation development. We use the technologies to conduct translational and clinical research in the following patient diagnostic categories: post-polio syndrome; stroke, rheumatoid arthritis/osteoarthritis; neuropathy; myositis; cerebral palsy; cancer and spinal cord injuries; cystinosis; Sjögren's syndrome; multiple sclerosis; and dysphagia symptoms. Induced acceleration analysis for rehabilitation Kepple, Lohmann Siegel, Selbie, Stanhope; in collaboration with Neptune By studying the contribution of net joint moments and individual muscle forces to the control of human movement and the performance of activities of daily living, we intend to link a physically challenged person's capabilities to his or her ability to perform activities of daily living. Measuring these contributions is critical for defining adaptive movement control strategies and understanding the process whereby the strategy of movement control is selected and implemented. Earlier efforts to determine the contribution of net muscular joint moments and individual muscle forces to human movement control have been limited by the assumption that the relative contribution of muscular effort to the control of movement is proportional to the magnitude of the effort and independent of the position of body segments. A generalized coordinate formulation of the equations of motion shows that the assumption is incorrect and can lead to errors in interpreting human movement analysis data. We have extended existing gait analysis methodology by developing a mechanical linkage model that provides direct estimates of the influence a given joint moment or muscle force on the movement of all joints, body segments, and overall task performance. Our research revealed that the generation of forward velocity during normal gait arises primarily from ankle joint plantar flexor push-off rather than through a controlled fall. We found that the ankle joint plantar flexor muscle group produces forward acceleration of the upper body during periods in which the same muscle group acts eccentrically. The literature suggests that deceleration of the lower extremity swing limb is an additional source of forward velocity generation during gait. However, our results indicate that the swing limb moments do not make a significant contribution to the forward acceleration of the upper body during normal walking. We examined the relative contribution of the lower extremity joint moments to the maintenance of upright posture (support) and found that, during the single limb support phase, ankle moments make the greatest contribution to support. During double limb support, the knee and hip moments of the forward positioned leg increase their contributions to support. We also examined the relative sensitivity of the joint accelerations to the joint moments during at-foot and found that the ankle, knee, and hip joint accelerations are almost twice as sensitive to moments generated at the knee than to the moments at any other lower extremity joint. During the heel-off phase of gait, the acceleration sensitivities at both the ankle and hip joints increase in response to moments at their own joint. It is clear from the data that there is significant redundancy in controlling the motion of the stance limb. Our findings explain, in part, the ability of persons with muscle weakness to compensate by using alternative movement control strategies. We further extended the model to estimate the source of mechanical energy exchange between segments and used it to determine the muscle groups responsible for the intersegment transfer of mechanical energy during gait, showing that the energy transfer depends on the sign of the joint moment rather than on the sign of the joint power and that pairs of net joint moments function in combination to balance energy flow through the leg and trunk segments during normal gait. We have further enhanced the induced acceleration analysis models to track the deformations in ankle-foot-orthosis (AFO). By first measuring the visco-elastic properties of the AFO and then applying our latest models, we are now able to track which muscle groups are working to bend the AFO and thus store energy in the device. We are then able to determine how much energy is released by the device during the later part of stance phase and where the released energy goes. Future research will develop a seamless integration of the induced acceleration techniques with the C-Motion, Visual3D software. We have also started to develop a clinical biomechanical model to determine the capacity and, ultimately, the actual contribution of individual muscles to controlling motion during a functional task. We also intend to expand our analysis to evaluate the utility of other assistive technologies (e.g., instrumented walkers) in the control of human movement and performance of activities of daily living. Proceedings of the IV World Congress of Biomechanics, 2002; published on CD. Siegel KL, Kepple T, Stanhope SJ. Joint moment control of mechanical energy flow during normal gait. Gait Posture; in press. Siegel KL, Kepple T, Stanhope SJ. Joint moment control of mechanical energy Dow during normal gait. Proceedings of the IV World Congress of Biomechanics, 2002; published on CD. Siegel KL, Kepple T, Stanhope SJ. Muscular control of mechanical energy during normal walking. Proceedings of the 2002 Public Health Professional Conference; published on CD.
Ankle foot orthosis contributions to net ankle moments in gait Nelson, Lohmann Siegel, Kepple , Halstead , Stanhope A variety of disorders and diseases affecting muscle and nerve function can cause sufficient lower extremity weakness to affect gait. Some individuals may be unable to ambulate while others have limited ability to walk. Frequently, these individuals are prescribed orthotic devices to assist their ambulation. The nancial impact is substantial, as Medicare expenditures for related prosthetics and orthotics reached $900 million in 2002. Yet, little is known of the assistance that advanced brace designs provide during functional tasks. Conventional AFOs are made of polypropylene and can deform in variable and unpredictable ways, hindering studies of the mechanical properties of the orthoses and the functional assistance they provide during walking. A new AFO design (Advanced Prosthetics and Orthotics Inc., Encinitas, CA) is made from continuous carbon fiber and consists of semirigid tibial cuff and footplate components connected by two deformable posterior longitudinal struts (see Figure 22.1). The materials and design of the new brace are much better suited to mechanical testing and modeling than older polypropylene devices.
By developing testing procedures to determine the mechanical properties of the brace and models that allow the brace's contribution to gait to be quantified, our goal is to evaluate the mechanical properties of the dynamic AFO, quantify the assistance it provides during gait, and evaluate the effect of the brace on lower extremity function during gait. We used a force platform and three-dimensional motion capture system in bench testing and to record kinetic and kinematic data from braced and unbraced walking trials for two subjects with post-polio syndrome. Bench testing established different spring stiffness relationships for each of the two subjects' AFOs. Using the spring model, we isolated the moment contributions from the AFO and the subjects' muscles during the walking trials for comparison with unbraced ankle moments. In braced and unbraced walking trials, we noted minimal differences in walking speed and stride length for subject 1. In late stance, the peak subject ankle moment was reduced by 20 percent in the braced condition compared with the unbraced condition despite a 29 percent larger net ankle moment (see Figure 22.2).
Therefore, the advanced AFO may benefit this particular subject by reducing the level of ankle joint muscle activity needed to maintain the same walking speed. In contrast, as compared with unbraced trials, subject 2 experienced increased speed and stride length when wearing the dynamic AFO. At the same time, subject 2 was able to generate a net ankle moment that was 100 percent greater than that without the brace while maintaining an identical subject-generated moment (see Figure 22.3).
The results indicate that the increases in speed and stride length observed for the subject are solely attributable to increased moment generation capabilities from the AFO. This measurement capability is a first step toward quantifying the contributions from, and ultimately improving on, advanced assistive technologies.
Nelson KM, Kepple TM, Siegel KL, Halstead LS, Stanhope SJ. Ankle foot orthosis contribution to net ankle moments in gait. American Society of Biomechanics, Toledo, OH, September 2003; in press. Movement visualization and analysis for rehabilitation Kepple, Lohmann Siegel, Nelson, Bender, Selbie, Sheehan, Stanhope An ongoing challenge for the Biomechanics and Biomedical Engineering (BBE) section is the continued development, enhancement, and maintenance of our powerful set of human movement analysis tools. Since 1988, the BBE section (formally part of the Biomechanics Laboratory) has been developing, with a rehabilitation focus, generalized computational tools for the analysis of human movement disorders. Historically, command line versions of the NIH software package have resided in the public domain and have been licensed to numerous facilities throughout the world under the material transfer agreement mechanism.
The objective of the ongoing project is to create a powerful yet cost-effective software environment that provides clinicians, scientists, and engineers with access to existing PDB biomechanical modeling and human movement analysis methodologies and a software development infrastructure to support our new and emerging biomechanical modeling and analysis techniques. Figure 22.4 contains single-frame examples of the segment tracking, anthropometric modeling, and musculoskeletal reconstruction and analysis capabilities of algorithms. To accomplish our goal, the PDB teamed with C-motion, Inc., and the Catholic University of America to convert the original NIH biomechanics software from a library of Fortran routines with a command line interface to an extensive collection of powerful routines based on Visual C++. The new library brings together several new computer programs (Visual3D, CALtester, and FPloc) that are analytically powerful, low-cost, and visually oriented and that can run on personal computers. Under this Small Business Innovation Research (SBIR) collaboration, the PDB retains unrestricted access to the extensive (source code) library of data management, analysis, and display routines. Such access provides an advanced platform on which to build future biomechanical modeling and human movement analysis capabilities (e.g., the Induced Acceleration Analysis Initiative) and to launch several technology development initiatives (e.g., the Virtual Functional Anatomy Initiative and instrumented walker technologies). Our past accomplishments include conversion of all primitive utilities associated with the preparation of data for biomechanical analyses to Visual C++ with significant enhancements to the automated event-determination algorithms, creation of the events storage structure, the development of a range class, and the design of a metrics data class. Furthermore, we have designed and implemented a universal viewer utility, an interactive graph utility, an enhanced data (C3D) file format, a method for the automated processing of motion data, a visual biomechanical model-building utility, and a report generation utility. We plan to continue to merge advancing modeling and human movement analysis technologies developed in the PDB with the Visual3D library, including induced acceleration analysis methods, dynamic MRI imaging data, instrumented walkers, and motion data derived from a proposed new three-dimensional universal movement assessment device. The execution of this highly collaborative, multidisciplinary, multiyear initiative has brought the most powerful human movement analysis techniques to scientists, clinicians, educators, and students worldwide on a cost-effective basis. Stanhope SJ. Advanced methods in computer based movement analysis in education and clinical practice. Theoretical Issues in Ergonomics Science; in press. Accuracy and reliability of movement analysis techniques Stanhope, Nelson, Kepple, Lohmann Siegel, Selbie; in collaboration with Holden, Manal The general purpose of this ongoing series of projects is to evaluate continually and improve the accuracy and reliability of biomechanical modeling and human movement analysis techniques so that the methods and findings will support the field's emerging quality assurance needs. Our past accomplishments include the development of a device and procedure for the automatic and accurate determination of the position and orientation of multiple force plate systems, a method developed by the BBE Section and implemented by C-motion, Inc., in the program FPLoc. The percutaneous skeletal tracker (PST) is a device designed by Steven Stanhope to achieve minimally invasive skeletal fixation of kinematic targets to human limbs. The PST enables us to measure actual bone movement and compare it directly with motion measured simultaneously using surface-mounted targets. Recently, we used the method to determine the optimal method for attaching surface-mounted markers. We also found that optimal surface-mounted target attachment techniques are incapable of locating proximal tibial position with sufficient accuracy to measure strain on joint structures such as the anterior cruciate ligament. We have developed a powerful technique for simultaneously evaluating the performance of all components of a clinical movement analysis laboratory. The Commission for Motion Laboratory, Inc., recently endorsed use of the technique by clinical movement analysis laboratories seeking accreditation. C-Motion, Inc., has implemented the method in the program CALtester, and Motion Lab Systems, Inc., is currently distributing the testing device. Holden J, Selbie S, Stanhope SJ. A proposed test to support the clinical movement analysis laboratory creditation process. Gait Posture 2003;17:205-213. Manal K, McClay Davis I, Galinat B, Stanhope S. Efficacy of proximal tibial translation estimates during natural cadence walking: bone vs. skin mounted targets. Clin Biomech; in press. Manal K, McClay I, Richards J, Galinat B, Stanhope S. Knee moment profiles during walking: errors due to soft tissue movement of the shank and the influence of the reference coordinate system. Gait Posture 2002;15:10-17. Manal K, McClay I, Stanhope S, Richards J, Galinat B. Comparison of surface mounted markers and attachment methods in estimating tibial rotations during walking: an in vivo study. Gait Posture 2000;11:38-45. Virtual functional anatomy Sheehan, Cohen, Rausch, Brant, Graham, Hunt, Li, Stanhope; in collaboration with Boden, Lu, Luo, Mohammed, Rebmann, Weston, Wirick, Yao The Virtual Functional Anatomy (VFA) project is designed to fill the important knowledge gap that exists between the relationship of normal or impaired joint structure/function and the functional movement limitations associated with performing activities of daily living. Our current focus is on developing and ultimately validating a combined set of tools that will enable the accurate and precise measurement, analysis, and visualization of three-dimensional static and dynamic musculoskeletal anatomy (i.e., bone shape, skeletal kinematics, tendon and ligament strain, muscle force, and joint space). We plan to combine MRI imaging and analysis capabilities with a highly accurate, imaging-based measurement and analysis technique for the noninvasive quantification of complete joint anatomy and tissue dynamics during functional movements. Our effort will require the development of a method for creating 3-D digital images of loaded and moving joint tissues (bone, cartilage, and connective tissues) to reveal joint contact patterns and tissue loads. We plan to evaluate the variability of bone shape and the sensitivity of defined joint posture (translation and rotation of one bone relative to another) to osteo-based coordinate system definition. We intend to use these capabilities to document and evaluate the function of normal and impaired joint structures (e.g., ACL rupture and patellar tracking syndrome) under simulated conditions experienced during activities of daily living. We have demonstrated the feasibility of studying musculoskeletal kinematics with cine-phase contrast (PC) and fast-PC MRI (the primary component of VFA) and determined the accuracy of Cine-PC MRI and, by extension, fast-PC MRI in the measurement of skeletal kinematics, in particular, the precision of Cine-PC and fast-PC MRI in the measurement of knee joint kinematics and patellar tendon strain during a leg extension task, under load. Work is ongoing to define static and dynamic measures of patellar tracking abnormalities as a potential source of patellofemoral (PF) pain and to determine which 3-D imaging sequence is the most accurate and precise in defining skeletal landmarks, cartilage thickness, and joint space proles. We are developing a technique to define skeletal-based coordinate systems based on skeletal landmarks and to determine their sensitivity to small variations in landmark definition. Our work involves three major areas of interest. First, we quantify healthy knee joint dynamics during loaded tasks that mimic functional activities of daily living. We then compare the resultant data with the knee joint dynamics of impaired subjects (e.g., patellar maltracking problems and anterior cruciate ligament loss). The second area is similar in that we are quantifying the 3-D kinematics of the bones of the ankle joint during loaded tasks mimicking functional activities of daily living. Third, we continue to make improvements in imaging time and data accuracy through algorithm and image sequence development. 2003;17:2:206-213. Shibanuma N, Sheehan FT, Lipsky P, Stanhope S. Osteoalignment is critical for quantifying patel- lofemoral alignment. Clin Orthop; in press. Shibanuma N, Sheehan FT, Lipsky P, Stanhope S. Sensitivity of femoral attitude estimates to mr image plane location relative to condylar surface. Clin Biomech; in press. Association between subject functional status, seat height, and movement strategy in sit-to-stand performance Mazzà, Stanhope; in collaboration with Benvenuti, Bimbi Understanding the process and governing principles that link impairment to functional movement limitations and, ultimately, to disability is a fundamental goal of the rehabilitation and geriatric research fields. Impairments may cause the inability to perform specific body functions and result in disability when physiological reserve is markedly reduced and an individual cannot devise successful compensatory strategies. To assess the association between a subject's functional status and the role and effectiveness of compensatory movement strategies, we investigated an experimental sit-to-stand (STS) paradigm. The difficulty in performing the STS task is inversely related to the height of the chair seat. When the chair is lowered, the biomechanical demands increase and can reach levels that require compensatory movement strategies to complete the task successfully. We speculated that, when the demands become too great for any compensation to overcome, the individual will lose the ability to stand successfully. Several strategies exist to assist an individual with the execution of an STS task: foot positioning, speed of execution, and trunk movements can be changed, and the use of the arms can be introduced. Subjects with impairments of the neuromusculoskeletal system create an overall compensatory movement strategy by simultaneously implementing a set of basic compensations. The effectiveness of the resulting effort is a function of the subject's level of impairment, the effectiveness of the compensatory movement strategy, and the overall difficulty of the movement task. We think it is important to understand the interaction between the different determinants of the STS task and therefore focused on the analysis of the association among the individual's functional status, the difficulty of the movement task, and the effectiveness of compensatory movement strategies. Our study involved a sample (n=131) of the elderly population referred to a geriatric hospital. We divided the subjects into five groups based on their general functional status level as determined by performance-based repeated chair standing (RCS) test. According to standard test protocol, we performed the test with a standard chair (seat height 0.45 m). We asked the subjects to stand and sit five times consecutively "as fast as possible" with their upper extremities folded on their chest and recorded the time needed by the subjects to perform the task. We then assigned each subject into one of the groups, according to either the time each individual needed to complete the task or the subject's inability to perform it. Each subject then performed a series of single sit-to-stand (SSTS) trials in which we used the seat height to control the task difficulty. We controlled the strategy-related determinant by observing the use of the upper limbs and used three different strategies (no use of the arms, swinging of the arms, and pushing with the hands) and the inability to stand to describe the subject's performance. Subjects within the two highest functional groups could complete the SSTS task at all seat heights with a slightly increased use of the swinging arms upper extremity strategy at the lowest seat height. When the difficulty of the task increased, the more functionally limited subjects were more affected and were forced to adopt compensatory movement strategies to perform the task successfully. The subject's functional status and task difficulty strongly influenced the effectiveness of the compensatory strategies. As seat height decreased, the compensatory movement strategies were less effective at maintaining sit-to-stand ability across the three lowest functional groups. Results of our study clearly show the existence of a hierarchy of compensatory movement strategies in which the effectiveness of each strategy to maintain standing ability is strongly influenced by both the individual's general functional status and the difficulty of the sit-to-stand task. Some methodological considerations surfaced from our study. Subjects with an intermediate functional level and with shorter legs could complete the RCS test but were not able to stand when the seat was lowered at their shank heights. The results indicate that, to evaluate the relative status of all subjects properly when using instrumental performance-based tests, the seat should be height-adjustable and no single height should be fixed a priori. Sit-to-stand and balance control motor strategies investigated in elderly stroke subjects Mazzà, Lohmann Siegel, Brindle, Stanhope; in collaboration with Cappozzo For the execution of a certain motor task, an individual selects a strategy among those that are consistent with the structural and functional constraints of his/her locomotor system and that tends to maximize the effectiveness of the motor act. The identification of the strategy allows for the assessment of the individual's functional status. Our study of a sample of hemiparetic stroke patients aims to identify the motor strategies adopted for execution of a sit-to-stand motor task followed by maintenance of the upright posture. Asymmetric dynamic posture and movement is the most prevalent locomotor deficit of stroke-related hemiparesis. Weight bearing during dynamic tasks, such as rising from a chair, is usually compromised after a stroke. To understand the compensatory maneuvers that a person may use following a stroke, it is also important to understand the complex biomechanics underlying the performance of sit-to-stand transfer. To continuously measure weight-bearing ability and whole-body postural stability with minimum inconvenience for the patients, we decided to use only a force plate as a measuring instrument. We have already applied a similar approach to the problem of functional evaluation for the description of motor strategies used by young and elderly people to rise from a chair. Beginning by recording external forces only and using a musculoskeletal system model that is based on a telescopic inverted-pendulum (TIP) moved by a linear and two rotational muscle-equivalent actuators, we extracted parameters describing the kinematics and dynamics of the actuators. We identified different motor strategies in the two age groups and associated with both a different initial posture (ankle dorsiflexion angle) and speed of execution of the motor task. The proposed motor act, involving both dynamic and static balance control and the use of the TIP model to interpret the ground reactions data, shows potential to identify and evaluate movement alterations and the consequent functional limitations and level of disability in stroke patients. Our study involves hemiplegic stroke patients, 55 to 65 years old, who suffered a stroke more than a year ago and who are medically stable and do not present movement disorders attributable to other neuropathies. Subjects are able to ambulate, at least at home, without aids, to rise from a chair with folded arms, and to stand for 60 seconds. Each study begins with the evaluation of strength, range of motion, and alignment of the joints. We then administer the NIH Stroke Scale questionnaire followed by a battery of performance tests (standing balance, repeated chair standing, walking speed) to assess the subject's functional ability level. According to the test results, we divide the subjects into three functional level groups. We performed the sit-to-stand test protocol after the screening. We collected anthropometric measurements (mass, height, thigh, shank, and foot length) for each subject. We then asked the subject to sit over a height-adjustable seat set at knee height and to choose the most comfortable foot position. We recorded knee and ankle angles and foot positioning and kept them constant for each subject among different trials. We next asked the subjects to rise from the chair while keeping their feet on the ground and their arms folded onto their chest and to perform the sit-to-stand motor task five times at a self-selected natural speed and five times at a self-selected high speed. Once the subjects were standing, we asked them to remain in the upright position for 60 seconds, facing a visual target. We will feed the recorded ground reaction forces and anthropometric measures to the model and use its outputs to describe the motor strategies used by the subjects both before (in terms of trunk flexions and relevant velocity and momentum) and after (in terms of rotations and elevation of the whole body and both global muscular effort and coordination effort associated with the achievement of balance and raising) the "seat-off." We will then analyze the displacement of the center of pressure with respect to the affected side and make statistical comparisons between the different functional groups and investigate correlations with clinical evaluations. Ultrasound examination of swallowing, oropharyngeal, and laryngeal activity in the fetus Sonies, Miller; in collaboration with Macedonia At birth, the normal-term neonate is able to suck and swallow for nutritional intake. The integrity of feeding skills is dependent on the prenatal development of orofacial, pharyngeal, and laryngeal anatomy that supports the emergence of respiratory and gastrointestinal tract functions that serve both the fetus and neonate. It is known that fetal swallowing contributes to homeostatic regulation of amniotic fluid volume, the acquisition and recirculation of intrauterine solutes, and overall fetal growth, which are influenced by a variety of maternal-fetal conditions that may also alter intrauterine aerodigestive function and potentially affect behaviors needed for postnatal feeding, swallowing, and respiration. Research has not yet investigated how these functions develop and when they become integrated. With advances in real-time noninvasive ultrasound imaging, we can examine these activities in the living human fetus. In a collaboration with the National Naval Medical Center Prenatal Assessment Center aimed at investigating prenatal development of the upper aerodigestive anatomy and the association of emerging functions as predictors of postnatal feeding skills, we studied postnatal feeding and swallowing dysfunction in 62 randomly selected mothers with healthy fetuses 15 to 38 weeks gestational age and seven at-risk cases. We performed a standard clinical examination, collected biophysical measurements of fetal development , and performed a sonogram of upper aerodigestive structures observed during suckling, swallowing, and fetal breathing. All movements of the lips, jaw, tongue, larynx, and pharynx were video-recorded and observed for rate and periodicity. Four sonographic scan planes were used as well as power Doppler imaging to examine pulsations of the vascular anatomy and fluid flow. We distinguished fetal breathing patterns (nasal and oral) from swallowing and visualized respiration patterns of amniotic fluid flow through the nares and/or oral cavity. We developed behavioral classification criteria for observations of fetal behaviors, including tongue cupping, licking, suckling, mouthing, glottic utter, swallowing, cough, and snort. We found significant linear regressions in pharyngeal and lingual growth across gestation while ingestive behaviors such as suckling emerged in a sequence of basic to complex movement patterns. Our data suggest that several ingestive behaviors emerge in a succession of basic to complex movement patterns and that the progression forms the basis for postnatal suckling and swallowing skills. For example, jaw and lip movements appeared first as simple opening and later progressed to repetitive open-close movements similar to excursion patterns found in infant suckling. Lingual movements increased in complexity from simple forward thrusting and cupping to anterior-posterior motions observed in suckling at term. Laryngeal movements varied from shallow utter focused at the lumen to more complete abduction-adduction of the entire region. Our observations substantiate the premise that suckling, swallowing, and prephonatory movements are developing in preparation for extra-uterine survival. In the abnormal cases, we demonstrated delays in pharyngeal growth and a lack of pharyngeal movement during fetal swallowing and postnatal feeding complications. We postulate that prenatal developmental indices of emerging aerodigestive skills may guide postnatal decisions for feeding readiness and, ultimately, advance the care of the premature medically fragile neonate. Miller JL, Sonies BC, Macedonia C. Emergence of oropharyngeal, laryngeal and swallowing activity in the developing fetal upper aerodigestive tract: an ultrasound evaluation. Early Hum Dev 2003:2371:1-27. COLLABORATORS Francesco Benvenuti, MD, Istituto Nazionale Riposo e Cura Anziani (INRCA), Florence, Italy Carlo Bimbi, MS, Istituto Nazionale Riposo e Cura Anziani (INRCA), Florence, Italy Barry Boden, MD, The Orthopaedic Center, Rockville MD Aurelio Cappozzo, PhD, Istituto Universitario di Scienze Motorie, Rome, Italy Joseph M. Hidler, PhD, Catholic University of America and National Rehabilitation Hospital, Washington DC John P. Holden, PhD, Center for Devices & Radiological Health, FDA, Rockville MD Hong Lu, MS, Catholic University of America, Washington DC Weidong Luo, MS, Catholic University of America, Washington DC Christian Macedonia, MD, National Naval Medical Center, Bethesda MD Kurt Manal, PhD, University of Delaware, Newark DE Nizamuddin Mohammed, BS, Catholic University of America, Washington DC Richard R. Neptune, PhD, University of Texas, Austin TX Andrea Rebmann, MS, Diagnostic Radiology Department, Warren Grant Magnuson Clinical Center, Bethesda MD Neil Weston, MS, National Oceanic & Atmospheric Administration, Silver Spring MD Beth Wirick, BS, Catholic University of America, Washington DC Larry Yao, MD, Diagnostic Radiology Department, Warren Grant Magnuson Clinical Center, Bethesda MD
aNational Rehabilitation Hospital, Washington DC bU.S. Department of Education/OSERS/NIDRR, Washington DC cUniversitario di Scienze Motorie, Rome, Italy dC-Motion, Inc., Rockville MD eVanderbilt University, Nashville TN fCatholic University of America, Washington DC gLeTourneau University, Longview TX hStanford University, Palo Alto CA For further information, contact sstanhope@mail.cc.nih.gov
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