Robert S. Kistenberg

Developing Core Sets for persons following amputation based on the International Classification of Functioning, Disability and Health as a way to specify functioning

Amputation is a common late stage sequel of peripheral vascular disease and diabetes or a sequel of accidental trauma, civil unrest and landmines. The functional impairments affect many facets of life including but not limited to: Mobility; activities of daily living; body image and sexuality. Classification, measurement and comparison of the consequences of amputations has been impeded by the limited availability of internationally, multiculturally standardized instruments in the amputee setting. The introduction of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in May 2001 provides a globally accepted framework and classification system to describe, assess and compare function and disability. In order to facilitate the use of the ICF in everyday clinical practice and research, ICF core sets have been developed that focus on specific aspects of function typically associated with a particular disability. The objective of this paper is to outline the development process for the ICF core sets for persons following amputation. The ICF core sets are designed to translate the benefits of the ICF into clinical routine. The ICF core sets will be defined at a Consensus conference which will integrate evidence from preparatory studies, namely: (a) a systematic literature review regarding the outcome measures of clinical trails and observational studies, (b) semi-structured patient interviews, (c) international experts participating in an internet-based survey, and (d) cross-sectional, multi-center studies for clinical applicability. To validate the ICF core sets field-testing will follow. Invitation for participation: The development of ICF Core Sets is an inclusive and open process. Anyone who wishes to actively participate in this process is invited to do so.

The Biomechanics of Cycling with a Transtibial Amputation: Recommendations for Prosthetic Design and Direction for Future Research

People with amputations may find cycling advantageous for exercise, transportation and rehabilitation. The reciprocal nature of stationary cycling also makes it a viable model for research in motor control because the body is supported by the saddle allowing the researcher to focus on the cyclic movement of the legs without the confounding variable of balance. The purpose of this article is to provide an overview of the cycling task in intact cyclists and relate this information to understanding the challenges faced by cyclists with transtibial amputations (CTA). Ongoing research into the biomechanics of CTAs will be summarized to expose the differences between intact and CTA cycling mechanics, asymmetries between limbs of CTAs as well as neuromuscular adaptation following amputation. The article will include recommendations for prosthetic design and modification of the bicycle to improve cycling performance for CTA at all experience levels.

Mathematical modeling and mechanical and histopathological testing of porous prosthetic pylon for direct skeletal attachment

This article presents recent results in the development of the skin and bone integrated pylon (SBIP) intended for direct skeletal attachment of limb prostheses. In our previous studies of the porous SBIP-1 and SBIP-2 prototypes, the bond site between the porous pylons and residuum bone and skin did not show the inflammation characteristically observed when solid pylons are used. At the same time, porosity diminished the strength of the pylon. To find a reasonable balance between the biological conductivity and the strength of the porous pylon, we developed a mathematical model of the composite permeable structure. A novel manufacturing process was implemented, and the new SBIP-3 prototype was tested mechanically. The minimal strength requirements established earlier for the SBIP were exceeded threefold. The first histopathological analysis of skin, bone, and the implanted SBIP-2 pylons was conducted on two rats and one cat. The histopathological analysis provided new evidence of inflammation-free, deep ingrowth of skin and bone cells throughout the SBIP structure.

Neural activation differences in amputees during imitation of intact versus amputee movements

The mirror neuron system (MNS) has been attributed with increased activation in motor-related cortical areas upon viewing of anothers actions. Recent work suggests that limb movements that are similar and dissimilar in appearance to that of the viewer equivalently activate the MNS. It is unclear if this result can be observed in the action encoding areas in amputees who use prosthetic devices. Intact subjects and upper extremity amputee prosthesis users were recruited to view video demonstrations of tools being used by an intact actor and a prosthetic device user. All subjects pantomimed the movements seen in the video while recording electroencephalography (EEG). Intact subjects showed equivalent left parietofrontal activity during imitation planning after watching the intact or prosthetic arm. Likewise, when prosthesis users imitated prosthesis demonstrations, typical left parietofrontal activation was observed. When prosthesis users imitated intact actors, an additional pattern was revealed which showed greater activity in right parietal and occipital regions that are associated with the mentalizing system. This change may be required for prosthesis users to plan imitation movements in which the limb states between the observed and the observer do not match. The finding that prosthesis users imitating other prosthesis users showed typical left parietofrontal activation suggests that these subjects engage normal planning related activity when they are able to imitate a limb matching their own. This result has significant implications on rehabilitation, as standard therapy involves training with an intact occupational therapist, which could necessitate atypical planning mechanisms in amputees when learning to use their prosthesis.

Motor performance benefits of matched limb imitation in prosthesis users

Our previous work demonstrated that the action encoding parietofrontal network, which is crucial in planning and executing motor tasks, is less active in prosthesis users who imitate movements of intact actors (mismatched limb) versus prosthesis users (matched limb). Such activation could have behavioral consequences in prosthesis users rehabilitating with intact therapists. The goal was to identify behavioral effects of matched versus mismatched limb action imitation in naïve users of prostheses. Intact subjects donned a specially adapted prosthetic device to simulate the wrist and forearm movement that transradial amputees experience. While electrogoniometry was recorded, non-amputated prosthesis users (NAPUs) observed and imitated demonstrations of a skillful motor task performed by either an intact actor or NAPU. We hypothesized that NAPUs would elicit less motion variability when performing matched versus mismatched imitation. Matched imitation resulted in a significant decrease in shoulder motion variability compared with mismatched imitation. The matched group also developed elbow motion patterns similar to the NAPU demonstrator, while the mismatched group attempted patterns similar to the intact demonstrator. This suggests a behavioral advantage to matched imitation when adapting to a prosthetic device, as it yielded more consistent movements and facilitated development of new motor patterns. Further, these results suggest that when prosthesis users are faced with the impossible task of imitating movements of an intact hand, they perform this action with greater variability and poorer technique. This work has implications on how prosthetic device operation is conveyed to persons with amputation as their clinical interactions often involve mismatched limb imitation.

An animal model to evaluate skin-implant-bone integration and gait with a prosthesis directly attached to the residual limb.

BACKGROUND Despite the number of advantages of bone-anchored prostheses, their use in patients is limited due to the lack of complete skin-implant integration. The objective of the present study was to develop an animal model that would permit both detailed investigations of gait with a bone-anchored limb prosthesis and histological analysis of the skin-implant-bone interface after physiological loading of the implant during standing and walking. METHODS Full-body mechanics of walking in two cats were recorded and analyzed before and after implantation of a percutaneous porous titanium pylon into the right tibia and attachment of a prosthesis. The rehabilitation procedures included initial limb casting, progressively increasing loading on the implant, and standing and locomotor training. Detailed histological analysis of bone and skin ingrowth into implant was performed at the end of the study. FINDINGS The two animals adopted the bone-anchored prosthesis for standing and locomotion, although loads on the prosthetic limb during walking decreased by 22% and 62%, respectively, 4months after implantation. The animals shifted body weight to the contralateral side and increased propulsion forces by the contralateral hindlimb. Histological analysis of the limb implants demonstrated bone and skin ingrowth. INTERPRETATION The developed animal model to study prosthetic gait and tissue integration with the implant demonstrated that porous titanium implants may permit bone and skin integration and prosthetic gait with a bone-anchored prosthesis. Future studies with this model will help optimize the implant and prosthesis properties.

Prosthetic Choices for People with Leg and Arm Amputations

New technology and materials have advanced prosthetic designs to enable people who rely on artificial limbs to achieve feats never dreamed before. However, the latest and the greatest technology is not appropriate for everyone. The aim of this article is to present contemporary options that are available for people who rely on artificial limbs to enhance their quality of life for mobility and independence.

Á priori alignment of transtibial prostheses: a comparison and evaluation of three methods

Purpose: The objectives of this study were to compare three á priori alignment methods and evaluate them based on initial gait quality and further alignment changes required to optimize gait. Á priori alignment is requisite for monolimbs, transtibial prostheses in which the socket and pylon are made from one piece of plastic, because monolimbs have no alignment adjustability. Method: The three methods investigated were traditional bench alignment (TRAD), vertical alignment axis (VAA) and anatomical based alignment (ABA). Endoskeletal components were utilized for the study, rather than monolimbs, so that alignment could be experimentally manipulated. Three endoskeletal prostheses were aligned, one according to each á priori method, for each of seven subjects. Gait and alignment data were captured, dynamic alignment was performed to optimize gait, and data were captured again. Results: VAA and TRAD methods required less change compared to ABA in socket flexion angle. Looking at subjects individually, VAA produced a better alignment and better gait for the greatest number of subjects. Conclusions: A new refined method of á priori alignment is proposed based on the results of this study, and is applicable for á priori alignment of monolimbs or any type of transtibial prosthesis. Implications for Rehabilitation This study shows that there is a wide range of acceptable alignments for a transtibial prosthesis. Using the best possible alignment for a monolimb could produce a high-quality transtibial prosthesis at a great cost savings.

Enhanced Neurobehavioral Outcomes of Action Observation Prosthesis Training

Background. Previous studies have demonstrated improved neurobehavioral outcomes when prosthesis users learn task-specific behaviors by imitating movements of prosthesis users (matched limb) compared with intact limbs (mismatched limb). Objective. This study is the first to use a unique combination of neurophysiological and task performance methods to investigate prosthetic device training strategies from a cognitive motor control perspective. Intact nonamputated prosthesis users (NAPUs) donned specially adapted prosthetic devices to simulate the wrist and forearm movement that persons with transradial limb loss experience. The hypothesis is that NAPUs trained with matched limb imitation would show greater engagement of parietofrontal regions and reduced movement variability compared with their counterparts trained with a mismatched limb. Methods. Training elapsed over 3 days comprised alternating periods of video demonstration observation followed by action imitation. At the beginning and end of the training protocol, participants performed a cued movement paradigm while electroencephalography and electrogoniometry data were collected to track changes in cortical activity and movement variability, respectively. Results. Matched limb participants showed greater engagement of motor-related areas while mismatched limb participants showed greater engagement of the parietooccipital system. Matched limb participants also showed lower movement variability. Conclusions. These results indicate that the type of limb imitated influences neural and behavioral strategies for novel prosthetic device usage. This finding is important, as customary prosthetic rehabilitation with intact therapists involves mismatched limb imitation that may exacerbate challenges in adapting to new motor patterns demanded by prosthesis use.

Influence of Perspective of Action Observation Training on Residual Limb Control in Naïve Prosthesis Usage

ABSTRACT Prior work in amputees and partial limb immobilization have shown improved neural and behavioral outcomes in using their residual limb with prosthesis when undergoing observation-based training with a prosthesis-using actor compared to an intact limb. It was posited that these improvements are due to an alignment of user with the actor. It may be affected by visual angles that allow emphasis of critical joint actions which may promote behavioral changes. The purpose of this study was to examine how viewing perspective of observation-based training effects prosthesis adaptation in naïve device users. Twenty nonamputated prosthesis users learned how to use an upper extremity prosthetic device while viewing a training video from either a sagittal or coronal perspective. These views were chosen as they place visual emphasis on different aspects of task performance to the device. The authors found that perspective of actions has a significant role in adaptation of the residual limb while using upper limb prostheses. Perspectives that demonstrate elbow adaptations to prosthesis usage may enhance the functional motor outcomes of action observation therapy. This work has potential implications on how prosthetic device operation is conveyed to persons adapting to prostheses through action observation based therapy.