Joseph W. Klaesner

In-shoe multisensory data acquisition system

Patients with diabetes and peripheral neuropathy are susceptible to unnoticed trauma on the foot that can cause skin breakdown. The authors have designed an electronic system in a shoe that monitors temperature, pressure, and humidity, storing the data in a battery-powered device for later uploading to a host computer for data analysis. The pressure sensors are located at the heel, and under three metatarsal heads. Temperature sensors are located under the medial metatarsal head and under the heel. The humidity sensor is located in the toe of the shoe. Correlations of data from pressure sensors with known values were high (r>0.85), even after extended use. Although data currently are being collected for descriptive purposes, the design potentially can be used to provide feedback to patients.

Quantifying Real-World Upper-Limb Activity in Nondisabled Adults and Adults With Chronic Stroke

Background. Motor capability is commonly assessed inside the clinic, but motor performance in real-world settings (ie, outside of the clinic) is seldom assessed because measurement tools are lacking. Objective. To quantify real-world bilateral upper-limb (UL) activity in nondisabled adults and adults with stroke using a recently developed accelerometry-based methodology. Methods. Nondisabled adults (n = 74) and adults with chronic stroke (n = 48) wore accelerometers on both wrists for 25 to 26 hours. Motor capability was assessed using the Action Research Arm Test (ARAT). Accelerometry-derived variables were calculated to quantify intensity of bilateral UL activity (ie, bilateral magnitude) and the contribution of both ULs to activity (magnitude ratio) for each second of activity. Density plots were used to examine each second of bilateral UL activity throughout the day. Results. Nondisabled adults demonstrated equivalent use of dominant and nondominant ULs, indicated by symmetrical density plots and a median magnitude ratio of −0.1 (interquartile range [IQR] = 0.3), where a value of 0 indicates equal activity between ULs. Bilateral UL activity intensity was lower (P < .001) and more lateralized in adults with stroke, as indicated by asymmetrical density plots and a lower median magnitude ratio (−2.2; IQR = 6.2, P < .001). Density plots were similar between many stroke participants who had different ARAT scores, indicating that real-world bilateral UL activity was similar despite different motor capabilities. Conclusions. Quantification and visualization of real-world bilateral UL activity can be accomplished using this novel accelerometry-based methodology and complements results obtained from clinical tests of function when assessing recovery of UL activity following neurological injury.

Accuracy and reliability testing of a portable soft tissue indentor

We have designed, built, and tested a portable indentor device that allows us to determine force/displacement (F/D) measurements on soft tissue in a clinical or research setting. The indentor system consists of a load cell mounted on a three-dimensional measurement device (Metrecom). The output of the load cell and the Metrecom are recorded and analyzed by software running on a notebook computer. The displacement calibration of the Metrecom gave an average error=0.005 mm [standard deviation (SD)=0.062)]. The force calibration of the load cell resulted in an average error=0.022 N (SD=0.049) and a linearity of 1.0062(R/sup 2/=0.9998). The indentor device was tested on six different human soft tissues by two different investigators. The interreliabilities and intrareliabilities were 0.99 [interclass correlation (ICC)] indicating that the results were repeatable by more than one investigator. F/D measurements from indentor testing on two materials were comparable to values measured using an Instron device (5.34 versus, 5.52 N/mm, and 0.98 versus 1.04 N/mm). The device was used to measure the soft tissue characteristics on the plantar surface of the foot of one subject. These data were used to calculate the effective Youngs modulus for the tissue using equations derived by Zheng et al. [1999] and indicated a wide range of values dependent upon the portion of the F/D curve used. All results indicate data from this portable indentor device are reliable, accurate, and sensitive enough to identify mechanical properties of human tissues.

An accelerometry-based methodology for assessment of real-world bilateral upper extremity activity.

Background The use of both upper extremities (UE) is necessary for the completion of many everyday tasks. Few clinical assessments measure the abilities of the UEs to work together; rather, they assess unilateral function and compare it between affected and unaffected UEs. Furthermore, clinical assessments are unable to measure function that occurs in the real-world, outside the clinic. This study examines the validity of an innovative approach to assess real-world bilateral UE activity using accelerometry. Methods Seventy-four neurologically intact adults completed ten tasks (donning/doffing shoes, grooming, stacking boxes, cutting playdough, folding towels, writing, unilateral sorting, bilateral sorting, unilateral typing, and bilateral typing) while wearing accelerometers on both wrists. Two variables, the Bilateral Magnitude and Magnitude Ratio, were derived from accelerometry data to distinguish between high- and low-intensity tasks, and between bilateral and unilateral tasks. Estimated energy expenditure and time spent in simultaneous UE activity for each task were also calculated. Results The Bilateral Magnitude distinguished between high- and low-intensity tasks, and the Magnitude Ratio distinguished between unilateral and bilateral UE tasks. The Bilateral Magnitude was strongly correlated with estimated energy expenditure (ρ = 0.74, p<0.02), and the Magnitude Ratio was strongly correlated with time spent in simultaneous UE activity (ρ = 0.93, p<0.01) across tasks. Conclusions These results demonstrate face validity and construct validity of this methodology to quantify bilateral UE activity during the performance of everyday tasks performed in a laboratory setting, and can now be used to assess bilateral UE activity in real-world environments.

Effect of metatarsal phalangeal joint extension on plantar soft tissue stiffness and thickness

BACKGROUND Plantar soft tissue stiffness and thickness are important biomechanical variables to understand stress concentrations that may contribute to tissue injury. OBJECTIVE The purpose of this study was to determine the effects of passive metatarsal phalangeal joint (MPJ) extension on plantar soft tissue stiffness and thickness. METHODS Seventeen healthy participants (7 male, 10 female, mean age 25.3 years, S.D. 4.4 years, mean BMI 24.7 kg/m(2), S.D. 3.2 kg/m(2)) were tested. Plantar soft tissue stiffness and thickness were measured at the metatarsal heads, midfoot and heel using a custom-built indentor device and an ultrasound machine. RESULTS Indicators of soft tissue stiffness (K1 values) at the metatarsal heads and midfoot showed increases in stiffness of 81-88% (S.D.20-33%) in the MPJ extension position compared with the MPJ neutral position. Soft tissue thickness measures at the metatarsal heads with the MPJ in neutral ranged from a mean of 8.9 to 13.5mm and decreased, on average, by 8.8% (S.D. 2.9%) with MPJ extension. CONCLUSIONS MPJ extension has a profound effect on increasing forefoot plantar soft tissue stiffness and a consistent but minimal effect on reducing soft tissue thickness. These changes may help transform the foot into a rigid lever at push-off consistent with the theory of the windlass mechanism.

Does Task-Specific Training Improve Upper Limb Performance in Daily Life Poststroke?

Background. A common assumption is that changes in upper limb (UL) capacity, or what an individual is capable of doing, translates to improved UL performance in daily life, or what an individual actually does. This assumption should be explicitly tested for individuals with UL paresis poststroke. Objective. To examine changes in UL performance after an intensive, individualized, progressive, task-specific UL intervention for individuals at least 6 months poststroke. Methods. Secondary analysis on 78 individuals with UL paresis who participated in a phase II, single-blind, randomized parallel dose-response trial. Participants were enrolled in a task-specific intervention for 8 weeks. Participants were randomized into 1 of 4 treatment groups with each group completing different amounts of UL movement practice. UL performance was assessed with bilateral, wrist-worn accelerometers once a week for 24 hours throughout the duration of the study. The 6 accelerometer variables were tested for change and the influence of potential modifiers using hierarchical linear modeling. Results. No changes in UL performance were found on any of the 6 accelerometer variables used to quantify UL performance. Neither changes in UL capacity nor the overall amount of movement practice influenced changes in UL performance. Stroke chronicity, baseline UL capacity, concordance, and ADL status significantly increased the baseline starting points but did not influence the rate of change (slopes) for participants. Conclusions. Improved motor capacity resulting from an intensive outpatient UL intervention does not appear to translate to increased UL performance outside the clinic.

A motor learning approach to training wheelchair propulsion biomechanics for new manual wheelchair users: A pilot study

Context/Objective: Developing an evidence-based approach to teaching wheelchair skills and proper propulsion for everyday wheelchair users with a spinal cord injury (SCI) is important to their rehabilitation. The purpose of this project was to pilot test manual wheelchair training based on motor learning and repetition-based approaches for new manual wheelchair users with an SCI. Design: A repeated measures within-subject design was used with participants acting as their own controls. Methods: Six persons with an SCI requiring the use of a manual wheelchair participated in wheelchair training. The training included nine 90-minute sessions. The primary focus was on wheelchair propulsion biomechanics with a secondary focus on wheelchair skills. Outcome Measures: During Pretest 1, Pretest 2, and Posttest, wheelchair propulsion biomechanics were measured using the Wheelchair Propulsion Test and a Video Motion Capture system. During Pretest 2 and Posttest, propulsion forces using the WheelMill System and wheelchair skills using the Wheelchair Skills Test were measured. Results: Significant changes in area of the push loop, hand-to-axle relationship, and slope of push forces were found. Changes in propulsion patterns were identified post-training. No significant differences were found in peak and average push forces and wheelchair skills pre- and post-training. Conclusions: This project identified trends in change related to a repetition-based motor learning approach for propelling a manual wheelchair. The changes found were related to the propulsion patterns used by participants. Despite some challenges associated with implementing interventions for new manual wheelchair users, such as recruitment, the results of this study show that repetition-based training can improve biomechanics and propulsion patterns for new manual wheelchair users.

In-shoe multisensory data acquisition

Patients with diabetes and peripheral neuropathy are susceptible to unnoticed trauma on the foot that can cause skin breakdown. The authors have designed an electronic system in a shoe that monitors temperature, pressure, and humidity, storing the data in a battery-powered device for later uploading to a host computer for data analysis. The pressure sensors are located at the heel, and under three metatarsal heads. Temperature sensors are located under three metatarsal heads and two are under the heel with the humidity sensor. Correlations of data from pressure and temperature sensors with known values were high (r>0.93). Although data currently are being collected for descriptive purposes, the design potentially can be used to provide feedback to patients.

Exercise testing protocol using a roller system for manual wheelchair users with spinal cord injury

Objective: Determine the validity and reliability of an exercise testing protocol to evaluate cardiorespiratory measures in manual wheelchair users (MWUs) with spinal cord injury (SCI) using a roller-based (RS) wheelchair system. Design: Repeated measures within-subject design. Setting: Community-based research laboratory. Participants: Ten adults with SCI requiring the use of a manual wheelchair. Interventions: Not applicable. Outcome measures: Cardiorespiratory measures (peak oxygen consumption [VO2peak], respiratory exchange ratio [RER], pulmonary ventilation [VE], energy expenditure [EE], heart rate [HR], accumulated kilocalories [AcKcal]) and perceived exertion (RPE) were measured during three separate maximal exercise tests using an arm crank ergometer (ACE) and an RS. Results: At maximal exertion, there were no significant differences in variables between groups, with moderate-to-strong correlations (P < 0.05, r = 0.79–0.90) for VO2, HR, RPE, AcKcal, and rate of EE between RS and ACE trials. Significant moderate-to-strong correlations existed between RS trials for VO2, AcKcal, rate of EE, and peak power output (P < 0.01, r = 0.77–0.97). Conclusions: VO2peak was highly correlated between ACE and RS trials and between the two RS trials, indicating the RS protocol to be reliable and valid for MWUs with SCI. Differences in perceived exertion and efficiency at submaximal workloads and maximal pulmonary ventilation at peak workloads indicated potential advantages to using the RS.

rehabilitation engineers, technologists, and technicians: vital members of the assistive technology team

The rehabilitation engineering professions include rehabilitation engineers, rehabilitation technologists / assistive technologists and rehabilitation technicians. The purpose of this white paper is to define the rehabilitation engineering professions, describe educational pathways for the field of rehabilitation engineering, and describe the role of the rehabilitation engineering professions in a multitude of professional settings. An ad-hoc committee was convened by the Rehabilitation Engineering and Technologists (RE&T) Professional Standards Group (PSG) at the 2013 annual meeting, RESNA Conference in Seattle, Washington. The ad-hoc committee reviewed over 80 different sources in preparing the white paper, which included peer reviewed journal articles, conference proceedings, professional organization websites. Based on this review, in addition to expert opinion and stakeholder feedback, the committee developed the following definitions. Rehabilitation Engineer (RE) uses the innovative and methodical application of scientific knowledge and technology to design and develop a device, system or process, which is intended to satisfy the human needs of an individual with a disability. Rehabilitation Technologist / Assistive Technologist (RT/AT) combines scientific and engineering knowledge and methods with technical skills to complement engineering activities for an individual with a disability. Rehabilitation Technician (RTn) works with equipment, primarily assembling and testing component parts of devices or systems that have been designed by others for individuals with disabilities; usually under direct supervision of a rehabilitation engineer or rehabilitation technologist / assistive technologist. Their preferences are given to assembly, repair, or evolutionary improvements to technical equipment by learning its characteristics, rather than by studying the scientific or engineering basis for its original design. This whitepaper provides a framework for future discussions on the advancement of the rehabilitation engineering professions with the goal of improving the quality of life of individuals with disabilities through the application of science and technology.