Residual Arm Research Articles

Investigating the International Classification of Functioning, Disability, and Health (ICF) Framework to Capture User Needs in the Concept Stage of Rehabilitation Technology Development

This study evaluates whether the International Classification of Functioning, Disability, and Health (ICF) framework provides a useful basis to ensure that key user needs are identified in the development of a home-based arm rehabilitation system for stroke patients. Using a qualitative approach, nine people with residual arm weakness after stroke and six healthcare professionals with expertise in stroke rehabilitation were enrolled in the user-centered design process. They were asked, through semi-structured interviews, to define the needs and specification for a potential home-based rehabilitation device to facilitate self-managed arm exercise. The topic list for the interviews was derived by brainstorming ideas within the clinical and engineering multidisciplinary research team based on previous experience and existing literature in user-centered design. Meaningful concepts were extracted from questions and responses of these interviews. These concepts obtained were matched to the categories within the ICF comprehensive core set for stroke using ICF linking rules. Most of the concepts extracted from the interviews matched to the existing ICF Core Set categories. Person factors like gender, age, interest, compliance, motivation, choice, and convenience that might determine device usability are yet to be categorized within the ICF comprehensive core set. The results suggest that the categories of the comprehensive ICF Core Set for stroke provide a useful basis for structuring interviews to identify most users needs. However some personal factors (related to end users and healthcare professionals) need to be considered in addition to the ICF categories.

Deprivation-related and use-dependent plasticity go hand in hand

Arm-amputation involves two powerful drivers for brain plasticity-sensory deprivation and altered use. However, research has largely focused on sensory deprivation and maladaptive change. Here we show that adaptive patterns of limb usage after amputation drive cortical plasticity. We report that individuals with congenital or acquired limb-absence vary in whether they preferentially use their intact hand or residual arm in daily activities. Using fMRI, we show that the deprived sensorimotor cortex is employed by whichever limb individuals are over-using. Individuals from either group that rely more on their intact hands (and report less frequent residual arm usage) showed increased intact hand representation in the deprived cortex, and increased white matter fractional anisotropy underlying the deprived cortex, irrespective of the age at which deprivation occurred. Our results demonstrate how experience-driven plasticity in the human brain can transcend boundaries that have been thought to limit reorganisation after sensory deprivation in adults. DOI: http://dx.doi.org/10.7554/eLife.01273.001.

Subcutaneous fat of extremities independent of abdominal fat does not promote insulin resistance and cardiovascular risk in Japanese type 2 diabetic patients

Thigh subcutaneous fat has recently been advocated to have a favorable association with insulin resistance or cardiovascular disease (CVD) risk, in contrast to abdominal and visceral fat. However, because individual regional fat components are strongly correlated with each other, multiple regression analysis of these independent variables in the same model is not valid due to multicollinearity, even though most previous reports regarding this issue have applied this invalid statistical analysis. In the present study, we applied another statistical analysis instead of this widely applied multiple regression analysis. In 570 type 2 diabetic patients, we measured the amount of fat in each region using bioelectrical impedance analysis (INBODY720) and drew a regression line between trunk fat percentage (F%) on the x-axis and logarithm of leg or arm F% on the y-axis. Thereafter, the residual from this line on the y-axis was calculated and defined as the trunk fat-adjusted leg or arm F% (residual leg or arm F%), from which the effect of abdominal adiposity had been eliminated. Total and regional F% values were all positively correlated to a log-transformed homeostasis model assessment of insulin resistance (HOMA-IR) and triglyceride (TG)/HDL-cholesterol (HDL-C). However, residual leg or arm F% was not related to log(HOMA-IR) or log(TG/HDL-C) in either male or female patients, with the exception of a negative correlation between residual leg F% and log(TG/HDL-C) in male patients. On the other hand, while trunk F% showed a strong positive relation to the number of CVD risk factors, residual arm or leg F% did not show any relationship to this parameter in either gender. These results confirmed that subcutaneous fat in extremities does not promote insulin resistance or CVD risk per se, in contrast to abdominal visceral fat. Furthermore, leg subcutaneous fat may exert a beneficial effect on insulin resistance in male diabetic patients. This is the first report to have investigated the effects of leg or arm fat independent of abdominal fat using a unique residual method.

Small but Consequential: A Case of Deep Intracerebral Hemorrhage (ICH) Caused by Distal Lenticulostriate Artery Aneurysm (P05.218)

Objective: To report a rare case of hemorrhage stroke caused by a lenticulostriate aneurysmal rupture missed initially by both multidetector cerebral CT angiography and digital subtraction angiography. Background Intracerebral hemorrhage is the deadliest form of stroke. Cerebral angiography is not routinely performed in typical deep intracranial hemorrhage which is often associated with hypertension. In as many as a third of cases of deep ICH, however, there is a treatable underlying structural lesion. We report a case of lenticulostriate artery aneurysmal rupture-a rare subtype of vascular abnormality-which led to a diagnostically challenging but ultimately treatable case of ICH. Design/Methods: Case report. Results: A 41 year-old female presented with headache, diaphoresis, agitation, and left-sided visual-spatial and limb asomatognosia, and hemiparesis. Cerebral CT scan showed an acute intracerebral hemorrhage approximately 28cc in volume centered near the right superior temporal lobe and centrum semiovale. Multidetector CT angiography performed did not reveal definitive evidence of any vascular abnormality. Cerebral catheter-based angiography was also initially negative. On hospital day 4, the patient had increased headache and somnolence with expansion of her intracerebral hemorrhage. Repeat angiogram demonstrated a 3mm distal lenticulostriate aneurysm which was then surgically clipped. The patient underwent extensive physical rehabilitation and was left with residual left arm greater than leg weakness with otherwise good neurological recovery. Repeat cerebral angiogram 3 months later showed resolution of the aneurysm. Conclusions: This is a rare case of intracerebral hemorrhage caused by rupture of a distal lenticulostriate artery aneurysm. After extensive neuroimaging, an underlying aneurysm was discovered. Patients without history of hypertension, who are under the age of 45, and who have atypical hematoma patterns or expansion of ICH after presentation should undergo neuroimaging for underlying structural lesion. Disclosure: Dr. Cai has nothing to disclose. Dr. Han has received personal compensation for activities with Harvard/MIT Health Sciences and Technology-Beth Israel Deaconess Medical Center in collaboration with Pfizer Inc and Merck & Co. Dr. Chou has nothing to disclose.

Surgical Strategy for Aortic Coarctation Repair Resulting in Physiologic Arm and Leg Blood Pressures

The goal of aortic coarctation repair is laminar aortic blood flow resulting in a negative or absent arm:leg blood pressure (BP) gradient. Despite satisfactory relief of coarctation, associated arch hypoplasia can result in residual obstruction and postoperative upper body hypertension. We devised a surgical strategy to create a tension-free anastomosis with a diameter as large as both the adjacent proximal and distal aorta using a radically extended end-to-end anastomosis via sternotomy and/or thoracotomy. Sternotomy is chosen when there is significant transverse arch hypoplasia defined as a distal transverse arch ≤ diameter of the left carotid artery, presence of a common brachiocephalic trunk, or coexisting intracardiac lesion requiring repair. Thoracotomy is used in all other cases. From 2000 to 2008, 95 consecutive patients were repaired using this approach, 35 with sternotomy and 60 with thoracotomy. At a mean follow-up of 50 ± 23 months, mean systolic BP was 94 ± 10 mm Hg, and 84% of patients had no residual arm:leg BP gradient. Mean arm:leg BP gradient was not statistically different between groups (-8.5 ± 15 sternotomy and -7.0 ± 10 mm Hg thoracotomy, P= .7). With Doppler echocardiography, 96% of patients demonstrated normal early diastolic reversal of blood flow in the descending thoracic aorta. For aortic coarctation repair in infancy, a strategy designed to directly address aortic arch hypoplasia results in excellent intermediate-term results with normal BP, physiologic arm:leg BP relationship, and near normal descending aortic blood flow velocities by Doppler.

A Novel Approach and Design of Embedded Controlled Prosthetic Upper Limb to Assist the above Elbow Amputees

The existing prosthetic upper limb design and control is divided into two broad categories. One is the myoelectric prosthesis where electromechanical active joints actuate the arm segments and is directly activated by acquiring Electromyogram (EMG) signals from the amputee which is sensed by myoelectric electrodes. Acquiring of the EMG signals is a tedious process as it involves adequate amplification and proper filtering. Also isolation of noise from EMG signals poses difficulty. The other category falls under intelligent prosthetic hand where neural networks (NN) are involved. It requires adequate training for NN operation that leads to the complexity in implementing electronic circuits. The major disadvantage of the above mentioned technologies is lack of proprioceptive feedback from the amputee. The drawbacks of the existing technologies motivates us to design a prototype with proprioceptive feedback to control the Above Elbow (AE) prosthesis with a permanent magnet implanted at the distal end of the residual humerus of the amputee. The proprioception remains intact to the residual limb skeletal structure. In this work, the proposed approach involves in processing the magnetic field variation due to residual arm bone movement which is sensed by magnetic field sensors. The embedded controller controls the movements of the prosthetic hand by processing the signals received from the sensors to assist the AE amputee.

Assessment of vascular phenotype using a novel very-high-resolution ultrasound technique in adolescents after aortic coarctation repair and/or stent implantation: relationship to central haemodynamics and left ventricular mass

ObjectivesCoarctation of the aorta (CoA) has been associated with abnormal vascular function, increased blood pressure (BP) and premature cardiovascular disease even after a successful intervention. The objective was to determine...

Targeted Muscle Reinnervation for Real-time Myoelectric Control of Multifunction Artificial Arms

Improving the function of prosthetic arms remains a challenge, because access to the neural-control information for the arm is lost during amputation. A surgical technique called targeted muscle reinnervation (TMR) transfers residual arm nerves to alternative muscle sites. After reinnervation, these target muscles produce electromyogram (EMG) signals on the surface of the skin that can be measured and used to control prosthetic arms. To assess the performance of patients with upper-limb amputation who had undergone TMR surgery, using a pattern-recognition algorithm to decode EMG signals and control prosthetic-arm motions. Study conducted between January 2007 and January 2008 at the Rehabilitation Institute of Chicago among 5 patients with shoulder-disarticulation or transhumeral amputations who underwent TMR surgery between February 2002 and October 2006 and 5 control participants without amputation. Surface EMG signals were recorded from all participants and decoded using a pattern-recognition algorithm. The decoding program controlled the movement of a virtual prosthetic arm. All participants were instructed to perform various arm movements, and their abilities to control the virtual prosthetic arm were measured. In addition, TMR patients used the same control system to operate advanced arm prosthesis prototypes. Performance metrics measured during virtual arm movements included motion selection time, motion completion time, and motion completion ("success") rate. The TMR patients were able to repeatedly perform 10 different elbow, wrist, and hand motions with the virtual prosthetic arm. For these patients, the mean motion selection and motion completion times for elbow and wrist movements were 0.22 seconds (SD, 0.06) and 1.29 seconds (SD, 0.15), respectively. These times were 0.06 seconds and 0.21 seconds longer than the mean times for control participants. For TMR patients, the mean motion selection and motion completion times for hand-grasp patterns were 0.38 seconds (SD, 0.12) and 1.54 seconds (SD, 0.27), respectively. These patients successfully completed a mean of 96.3% (SD, 3.8) of elbow and wrist movements and 86.9% (SD, 13.9) of hand movements within 5 seconds, compared with 100% (SD, 0) and 96.7% (SD, 4.7) completed by controls. Three of the patients were able to demonstrate the use of this control system in advanced prostheses, including motorized shoulders, elbows, wrists, and hands. These results suggest that reinnervated muscles can produce sufficient EMG information for real-time control of advanced artificial arms.

Modeling of Prosthetic Limb Rotation Control by Sensing Rotation of Residual Arm Bone

We proposed a new approach to improve the control of prosthetic arm rotation in amputees. Arm rotation is sensed by implanting a small permanent magnet into the distal end of the residual bone, which produces a magnetic field. The position of the bone rotation can be derived from magnetic field distribution detected with magnetic sensors on the arm surface, and then conveyed to the prosthesis controller to manipulate the rotation of the prosthesis. Proprioception remains intact for residual limb skeletal structures; thus, this control system should be natural and easy-to-use. In this study, simulations have been conducted in an upper arm model to assess the feasibility and performance of sensing the voluntary rotation of residual humerus with an implanted magnet. A sensitivity analysis of the magnet size and arm size was presented. The influence of relative position of the magnet to the magnetic sensors, orientation of the magnet relative to the limb axis, and displacement of the magnetic sensors on the magnetic field was evaluated. The performance of shielding external magnetostatic interference was also investigated. The simulation results suggest that the direction and angle of rotation of residual humerus could be obtained by decoding the magnetic field signals with magnetic sensors built into a prosthetic socket. This pilot study provides important guidelines for developing a practical interface between the residual bone rotation and the prosthesis for control of prosthetic rotation.

An observer-based piezoelectric control of flexible Cartesian robot arms: theory and experiment

An observer-based control strategy is proposed for regulating problem of a Cartesian robot arm, which is modeled as a flexible cantilever beam with a translational base support. The base motion is controlled utilizing an electrodynamic shaker, while a piezoelectric (PZT) patch actuator is bonded on the surface of the flexible beam for suppressing residual arm vibrations. Taking into account both electrical and mechanical fields for the PZT patch actuator, a full-order model is developed using assumed mode model expansion and the Lagrangian approach. Utilizing three measurable quantities (i.e., the base displacement, arm tip deflection and the strain at the root end of the arm), a reduced-order observer is designed to estimate the velocity related variables, which are not directly measurable for the truncated model. A simple PD controller is selected for the moving base regulation, while a Lyapunov-based controller is utilized for the PZT input voltage to make the closed-loop system energy dissipative and hence stable. The PZT input voltage control uses the velocity related signals estimated by the reduced-order observer, which simplifies the control implementation in practice. The feasibility of the controller is validated through both numerical simulations and experimental testing. Significant matching between experimental results and numerical simulation is observed.

Alterations in reaching after stroke and their relation to movement direction and impairment severity

Kamper DG, McKenna-Cole AN, Kahn LE, Reinkensmeyer DJ. Alterations in reaching after stroke and their relation to movement direction and impairment severity. Arch Phys Med Rehabil 2002;83:702-7. Objectives: To examine the effects of stroke severity and target location on reaching (1) to identify regions in space that are difficult to reach, (2) to determine whether specific alterations in reaching are associated with particular clinical impairment levels, and (3) to characterize relationships between reaching alterations. Design: Participants reached toward a screen of 75 targets spanning an approximate range from ±90° side to side and from waist to head. Setting: Rehabilitation research center. Participants: Sixteen chronic stroke patients with a wide range in residual arm function and 4 control subjects. Interventions: Not applicable. Main Outcome Measures: Chedoke-McMaster Stroke Arm Assessment, distance, velocity, smoothness, straightness, and direction of the hand path during each reach. Hand position trajectories were recorded with an electromagnetic sensor. Results: Reaches performed with the impaired arms showed significant degradation in all performance measures. Although only modestly dependent on the target location, these features correlated strongly with impairment level, as well as with each other. Reaching distance showed the strongest correlations with the other parameters. Conclusions: Stroke alters a broad array of features of reaching, yet largely the same degree of movement control is preserved across a range of target locations. The only consistently problematic task is to reach far out from the torso, independent of the movement direction. Thus, active range of motion (AROM), rather than control over a specific subset of movement directions, is a logical focus for therapy. In addition, measuring AROM is a simple clinical measure that yields much information. © 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

Skull Base Resection with Cervical-To-Petrous Carotid Artery Bypass to Facilitate Repair of Distal Internal Carotid Artery Lesions

Purpose: To demonstrate a direct operative approach to vascular lesions of the internal carotid artery (1CA) at the level of the skull base. Methods: Between January 1993 and October 1999, five patients underwent lateral skull base resection with cervical-to-petrous carotid artery saphenous vein bypass for repair of distal 1CA lesions. This report describes operative methods, morbidity, graft patency, and long-term outcome with this experience. Results: Of the five patients with skull base ICA lesions, all had aneurysmal disease. Three were atherosclerotic and two were dysplastic. Preoperative neurologic symptoms including transient ischemic attacks (2) and Horner's syndrome with vascular headaches (1) were completely resolved after operation. Preoperative dysphagia (2) was resolved in one patient and clinically improved in the other. Postoperative complications included transient paresis in the cranial nerve (CN) VII distribution, as well as permanent loss of the eustachian tube and chorda tympani nerve in all five patients. One patient had lasting paresis in the CN XI distribution as well as a mild stroke resulting in arm weakness. No residual arm weakness was detected at one year. There were no graft occlusions by duplex ultrasound at 45.8 months mean objective follow-up, and no ipsilateral stroke or mortality at 51.2 months mean clinical follow-up. Conclusions: Saphenous vein bypass from the cervical-to-petrous ICA is technically feasible and provides a valuable reconstruction option for patients with skull base ICA lesions.

Skull base resection with cervical-to-petrous carotid artery bypass to facilitate repair of distal internal carotid artery lesions

Purpose: To demonstrate a direct operative approach to vascular lesions of the internal carotid artery (ICA) at the level of the skull base. Methods: Between January 1993 and October 1999, five patients underwent lateral skull base resection with cervical-to-petrous carotid artery saphenous vein bypass for repair of distal ICA lesions. This report describes operative methods, morbidity, graft patency, and long-term outcome with this experience. Results: Of the five patients with skull base ICA lesions, all had aneurysmal disease. Three were atherosclerotic and two were dysplastic. Preoperative neurologic symptoms including transient ischemic attacks (2) and Horner's syndrome with vascular headaches (1) were completely resolved after operation. Preoperative dysphagia (2) was resolved in one patient and clinically improved in the other. Postoperative complications included transient paresis in the cranial nerve (CN) VII distribution, as well as permanent loss of the eustachian tube and chorda tympani nerve in all five patients. One patient had lasting paresis in the CN XI distribution as well as a mild stroke resulting in arm weakness. No residual arm weakness was detected at one year. There were no graft occlusions by duplex ultrasound at 45.8 months mean objective follow-up, and no ipsilateral stroke or mortality at 51.2 months mean clinical follow-up. Conclusions: Saphenous vein bypass from the cervical-to-petrous ICA is technically feasible and provides a valuable reconstruction option for patients with skull base ICA lesions.

Effect of reaction conditions on synthesis and properties of multiarm star-branched polyisobutylenes

A series of multiarm star-branched polyisobutylenes was synthesized from narrow polydispersity arms with molecular weights ranging from 12,000 to 60,000 g/mol, via living carbocationic polymerization using the cumyl chloride/TiCl4/pyridine initiating system and divinylbenzene (DVB) as core-forming comonomer. The effect on star development of arm molecular weight, temperature, solvent composition, and DVB concentration was studied. The rate of star formation and the weight-average number of arms per star polymer, Nw, were found to scale inversely with arm molecular weight; Nw = 60 was attained for 13,100 g/mol arms, but Nw = 2.5 for 60,000 g/mol arms. It was established that star formation was much faster at −80°C compared to 23°C, regardless of solvent composition. For hexane : methyl chloride (MeCl) solvent compositions containing from 40 to 60 vol % MeCl, star–star coupling was observed at −80°C, but not at 23°C, even after 312 h; for the most polar 40 : 60 hexane : MeCl composition, star–star coupling was so extensive at −80°C that gelation was observed after only 44 h. The rate of star formation was found to be substantially higher in 60 : 40 hexane : MeCl compared to 60 : 40 hexane : methylene chloride (MeCl2). Some reactions containing MeCl were immediately warmed to 23°C after DVB addition, and the MeCl thus volatilized was replaced with either MeCl2 or hexane for the duration of the star-forming reaction. Slightly higher rates were consistently observed when MeCl2 was the replacement solvent. The strong influence of initial MeCl content on rate of star formation was found to persist throughout the star-forming reaction, even when the solvent was immediately converted to 100% hexane. The fraction of arms that remained unlinked into stars was found to be higher at the higher temperature and at lower solvent polarity. Regardless of solvent or temperature, the residual arm fraction was approximately the same at a given stage of star development as measured by the average number of arms per star. One star sample was produced with the UV-transparent 2-chloro-2,4,4-trimethylpentane initiator; analysis showed that the residual arm fraction had approximately the same UV absorbance as the star fraction, indicating efficient crossover to DVB and the potential for approximately quantitative arm incorporation given sufficient time. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 471–483, 1998

Rupture of the Tendon of the Long Head of the Biceps Brachii

Twenty-seven shoulders (in 26 patients) that had surgical repair of a rupture of the long head of the biceps tendon between 1962 and 1981 were evaluated at three to 22 years after injury (mean, 13 years). Thirty similar patients had been treated nonsurgically and were evaluated two to 15 years (mean, 4.6 years) after tendon rupture. Biomechanical testing was performed on ten patients in the surgical group and 13 in the nonsurgical group. Residual arm pain was infrequent in both surgically and nonsurgically treated groups. Residual subjective weakness at the elbow was reported in four of the surgical group and in 20 of the nonsurgical group. Surgically treated patients returned to work later than nonsurgical patients; however, 11 in the nonsurgical group were not able to return to full work capacity, versus only two in the surgical group. On biomechanical testing, the nonsurgical group had lost a mean of 21% of supination strength and 8% of elbow flexion strength but had no weakness in grip, pronation, or elbow extension. The surgical group had lost no strength in any of these testing modes.

Automated measurement and CAD analysis technique for accurate determination of UHF acoustic resonator equivalent circuit parameters

Many measurement techniques have been reported for accurate determination of equivalent electrical circuit parameters of HF and VHF acoustic resonators. Recent technological advances in the fabrication and processing of conventional bulk- and surface-wave resonators, and in the development of monolithic sputtered film resonators, have extended device operating frequencies into the UHF range. At UHF, resonator package and bond-wire parasitic reactances are nonnegligible and can significantly mask the impedance characteristics of the resonator itself and result in inaccurate determination of device equivalent circuit. This paper describes an automated resonator measurement and data analysis technique that has been developed for accurate determination of UHF acoustic resonator equivalent circuit parameters. The procedure consists of computer-controlled measurement of resonator input reflection coefficient using an HP4191 RF impedance analyzer. Subsequent automatic data transfer, in the form of a circuit analysis file, is used in conjunction with the Super Compact1 RF analysis/optimization software for determination and “removal” of effects of packaged resonator parasitic reactances from the measured data, based on device out-of-band impedance characteristics. The residual resonator motional arm impedance characteristic is calculated from which equivalent circuit element values are readily determined. The HP4191 RF analyzer control software enables determination and identification of individual resonator desired and spurious (anharmonic) resonances in specified search bands. This is extremely helpful when the resonator exact operating frequency is unknown as is often the case for sputtered, thin-film, monolithic devices. Examples will be given showing the results of measurement of UHF resonators including conventional surface acoustic wave (SAW), bulk-wave quartz and lithium niobate resonators, and monolithic sputtered aluminum nitride and zinc oxide and ZnO film resonators.