Arm Research Papers - Academia.edu (original) (raw)

A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a... more

A new procedure for the calibration of an articulated arm coordinate measuring machine (AACMM) is presented in this paper. First, a self-calibration algorithm of four laser trackers (LTs) is developed. The spatial localization of a retroreflector target, placed in different positions within the workspace, is determined by means of a geometric multilateration system constructed from the four LTs. Next, a nonlinear optimization algorithm for the identification procedure of the AACMM is explained. An objective function based on Euclidean distances and standard deviations is developed. This function is obtained from the captured nominal data (given by the LTs used as a gauge instrument) and the data obtained by the AACMM and compares the measured and calculated coordinates of the target to obtain the identified model parameters that minimize this difference. Finally, results show that the procedure presented, using the measurements of the LTs as a gauge instrument, is very effective by ...

A randomization method is developed for the calculation of covariation between multiple variables that are linked nonlinearly to a dependent variable. Covariation is a phenomenon often invoked in the study of movement coordination to... more

A randomization method is developed for the calculation of covariation between multiple variables that are linked nonlinearly to a dependent variable. Covariation is a phenomenon often invoked in the study of movement coordination to capture the fact that in coordinated movement the outcome shows greater than expected consistency from the variability in the component processes. However, in most cases, the problem is that more than two variables covary in a nonlinear fashion, which makes quantification with the bivariate linear covariation and correlation coefficient inapplicable. This paper presents a generalization of the calculation of linear bivariate covariance using a variant of a randomization method that is based on the comparison between the empirically measured variability in the outcome and a covariation-free variability. The latter can be estimated by permuting data sets. A generalized correlation coefficient is derived, and it is shown how errors of estimation can be qua...

Retrospective analysis. To evaluate the efficacy of intrathecal baclofen (ITB) for upper extremity spastic hypertonia in tetraplegia of spinal origin. University of Alabama at Birmingham hospital. The medical records of 14 individuals... more

Retrospective analysis. To evaluate the efficacy of intrathecal baclofen (ITB) for upper extremity spastic hypertonia in tetraplegia of spinal origin. University of Alabama at Birmingham hospital. The medical records of 14 individuals with tetraplegia of spinal origin who underwent intrathecal baclofen pump placement were reviewed. The effects of intrathecal baclofen on spasm frequency, deep tendon reflexes, and tone (Ashworth scale) were assessed for the upper and lower extremities for a 1-year follow-up period. There were statistically significant declines in upper extremity spasm scores (1.8 points, P=0.012), reflex scores (1.4 points, P<0.0001) and Ashworth scores (0.6 points, P<0.0001) for the 1-year follow-up period. For the lower extremities, all decreases were significant (P<0.0001). There was also a statistically significant (P<0.0001) increase in intrathecal baclofen dosage requirements during the 1-year follow-up period to maintain the reductions in spasm freq...

We compared a unilateral robot-assisted training protocol (URTP) and a bilateral robot-assisted training protocol (BRTP) to study their differential effects. We recruited 21 patients with stroke who received 90–105 min of therapy 5... more

We compared a unilateral robot-assisted training protocol (URTP) and a bilateral robot-assisted training protocol (BRTP) to study their differential effects. We recruited 21 patients with stroke who received 90–105 min of therapy 5 days/wk for 4 wk. Participants in the URTP and BRTP groups practiced forearm pronation and supination and wrist flexion and extension in a simultaneous manner with the Bi-Manu-Track. The control group received standard rehabilitation. Clinical measures included the Fugl-Meyer Assessment, the Medical Research Council instrument, grip strength, and the Modified Ashworth Scale to assess motor impairment, muscle power, muscle strength, and spasticity, respectively. The pilot study indicated that the URTP and BRTP might have differential benefits for movement improvement. URTP might be a more compelling approach to improving upper-limb motor impairment, muscle power, and strength at the distal joints than BRTP, whereas BRTP could be an optimal approach to impr...

Previous research has shown that changes to the body can influence the perception of distances in near space (Witt et al 2005). In this paper, we question whether changes to the body can also influence the perception of extents in... more

Previous research has shown that changes to the body can influence the perception of distances in near space (Witt et al 2005). In this paper, we question whether changes to the body can also influence the perception of extents in extrapersonal space, namely the perception of aperture widths. In experiment 1, broad-shouldered participants visually estimated the size of apertures to be smaller than narrow-shouldered participants. In experiment 2, we questioned whether changes to the body, which included holding a ...

Handball is a sport with high anaerobic demands in lower body as has been indicated by Wingate test (WT) performed with the legs, but there are no data available concerning power production during a WT performed with the arms in handball... more

Handball is a sport with high anaerobic demands in lower body as has been indicated by Wingate test (WT) performed with the legs, but there are no data available concerning power production during a WT performed with the arms in handball players (HndP). Therefore, the purpose of this study was to explore the arm anaerobic profile of HndP during a WT. Twenty-one elite HndP and 9 physical education students (CON), performed a 30-s arm WT. Power production and muscle oxygenation were recorded. Peak power (PP) as well as mean power (MP) was higher (P = .017 and 0.03, and ES = 1.00 and 0.86, respectively) for HndP (HndP PP: 7.6 +/- 0.8 W x kg(-1); CON PP: 6.7 +/- 1.1 W x kg(-1); HndP MP 5.3 +/- 0.6 W x kg(-1); CON MP 4.7 +/- 0.9 W x kg(-1)) with no significant difference in fatigue index between the two groups. Muscle oxygen saturation (StO2) declined approximately 30% with exercise with no differences between groups. During recovery the HndP group had higher StO2 (P = .01, ES= 3.04), to...

Use of rehabilitation technology, such as (electro)mechanical devices or robotics, could partly relieve the increasing strain on stroke rehabilitation caused by an increasing prevalence of stroke. Arm support (AS) training showed... more

Use of rehabilitation technology, such as (electro)mechanical devices or robotics, could partly relieve the increasing strain on stroke rehabilitation caused by an increasing prevalence of stroke. Arm support (AS) training showed improvement of unsupported arm function in chronic stroke. To examine the effect of weight-supported arm training combined with computerized exercises on arm function and capacity, compared with dose-matched conventional reach training in subacute stroke patients. In a single-blind, multicenter, randomized controlled trial, 70 subacute stroke patients received 6 weeks of training with either an AS device combined with computerized exercises or dose-matched conventional training (CON). Arm function was evaluated pretraining and posttraining by Fugl-Meyer assessment (FM), maximal reach distance, Stroke Upper Limb Capacity Scale (SULCS), and arm pain via Visual Analogue Scale, in addition to perceived motivation by Intrinsic Motivation Inventory posttraining. ...

The capability of performing functional radiosurgery lesions in the brain using a dedicated linear accelerator (LINAC) have not yet been demonstrated. This study evaluates modern LINAC technology for the creation of a sharp, small and... more

The capability of performing functional radiosurgery lesions in the brain using a dedicated linear accelerator (LINAC) have not yet been demonstrated. This study evaluates modern LINAC technology for the creation of a sharp, small and functionally eloquent lesion in the thalamus. Three patients underwent thalamotomy using a dedicated linear accelerator to radiosurgery, 2 females and 1 male, ages were 52, 53, and 73 years. Two patients presented with unilateral poststroke central pain and 1 with unilateral upper extremity pain secondary to metastatic infiltration of the brachial plexus. Maximal doses varied from 150 to 200 Gy, delivered by a 5-mm diameter collimator and 5 to 8 noncoplanar arcs evenly distributed. All patients gained substantial relief of their pain. They were able to reduce their medications and improve their activity levels. The patient with end-stage metastatic disease died of his malignancy 2 weeks after the treatment. One patient presented with recurrence of the pain 4 months after the treatment. No clinical complications were noticed. A dedicated linear accelerator is able to perform a precise and circumscribed lesion in the thalamus for pain control. Moreover, it proved to be safe, because no complications were observed. For patients using chronic anticoagulant therapy or with severe disabilities caused by cardiac, pulmonary or malignant diseases, this technique represents an alternative of treatment to radiofrequency thalamotomy.

The role of arm swing in running has been minimally described, and the contributions of arm motion to lower extremity joint kinematics and external force generation are unknown. These contributions may have implications in the design of... more

The role of arm swing in running has been minimally described, and the contributions of arm motion to lower extremity joint kinematics and external force generation are unknown. These contributions may have implications in the design of musculoskeletal models for computer simulations of running, since previous models have usually not included articulating arm segments. 3D stance phase lower extremity joint angles and ground reaction forces (GRFs) were determined for seven subjects running normally, and running under two conditions of arm restraint. When arm swing was suppressed, the peak vertical GRF decreased by 10–13% bodyweight, and the peak lateral GRF increased by 4–6% bodyweight. Changes in peak joint angles on the order of 1–5 deg were observed for hip flexion, hip adduction, knee flexion, knee adduction, and ankle abduction. The effect sizes (ES) were small to moderate (ES<0.8) for most of the peak GRF differences, but large (ES>0.8) for most of the peak joint angle di...