Upper limb kinetic analysis of three sitting pivot wheelchair transfer techniques

Kinematic analysis of preparation for transferring from wheelchair to bed

This study aimed to clarify the kinematics, particularly of the shoulder and hip joints, during preparation for manual wheelchair-to-bed transfer (i.e. when flipping up the arm and foot supports). This cross-sectional study included 32 able-bodied individuals. The kinematics of the shoulder and hip joints when the arm and foot supports were flipped up of manual wheelchair, were evaluated using a markerless inertial sensor-based motion capture system. We found that flipping the arm support upwards involved a large amount of abduction, internal and external rotation, flexion, and extension at the shoulder joint, whereas flipping the foot support upwards involved a large amount of flexion at the hip joint. The findings suggest that it is necessary to consider the range of motion required to flip up the arm and foot supports of manual wheelchairs, particularly in those with limited shoulder and hip range of motion such as older people, neuromuscular disorders, and orthopedic disorders.

Manual wheelchair use leads to a series of failed shoulder replacements: A case report and literature review

Manual wheelchair users place high stress on their shoulders. We describe a 69-year-old male who developed end-stage shoulder osteoarthritis from chronic manual wheelchair (MW) use. Three prosthetic total shoulder replacements failed, reflecting his refusal to transition to an electric wheelchair. MW use must be avoided in some of these patients.

Estimation of manual wheelchair-based activities in the free-living environment using a neural network model with inertial body-worn sensors

Shoulder pain is common in manual wheelchair (MWC) users. Overuse is thought to be a major cause, but little is known about exposure to activities of daily living (ADLs). The study goal was to develop a method to estimate three conditions in the field: (1) non-propulsion activity, (2) MWC propulsion, and (3) static time using an inertial measurement unit (IMU). Upper arm IMU data were collected as ten MWC users performed lab-based MWC-related ADLs. A neural network model was developed to classify data as non-propulsion activity, propulsion, or static, and validated for the lab-based data collection by video comparison. Six of the participants' free-living IMU data were collected and the lab-based model was applied to estimate daily non-propulsion activity, propulsion, and static time. The neural network model yielded lab-based validity measures ≥0.87 for differentiating non-propulsion activity, propulsion, and static time. A quasi-validation of one participant's field-based data yielded validity measures ≥0.66 for identifying propulsion. Participants' estimated mean daily non-propulsion activity, propulsion, and static time ranged from 158 to 409, 13 to 25, and 367 to 609 min, respectively. The preliminary results suggest the model may be able to accurately identify MWC users' field-based activities. The inclusion of field-based IMU data in the model could further improve field-based classification.

Effectiveness of a Web-Based Direct-to-User Transfer Training Program: A Randomized Controlled Trial

OBJECTIVE

To determine the effectiveness of a web-based, direct-to-user transfer training program in improving transfer quality and maintaining improvements for up to 1 month after training as compared with a control group.

DESIGN

Randomized controlled trial with participants randomized to an immediate intervention group (IIG) or waitlist control group (WLCG) that received the training after a 6-month delay.

SETTING

Wherever the participants accessed the web-based training, likely the home environment.

PARTICIPANTS

Convenience sample of full-time wheelchair users (N=72; IIG, n=34; WLCG, n=38 for between-group analysis, n=48 for combined within-group analysis) with spinal cord injury or disorder who were able to independently perform a lateral scoot transfer.

INTERVENTIONS

Self-paced, web-based transfer training module.

MAIN OUTCOME MEASURES

Transfer Assessment Instrument Questionnaire (TAI-Q) score at baseline, 1 month, and 6 months postbaseline (WLCG only), immediately posttraining, and 1 month posttraining. The TAI-Q is an 18-item self-assessment that covers several aspects of a quality transfer.

RESULTS

The IIG significantly increased particpants' baseline TAI-Q score from 6.91±0.98 to 7.79±1.12 (P<.001) by 1 month posttraining. The WLCG also increased from baseline to the 1-month postbaseline assessment (from 6.52±1.13 to 7.00±1.09; P=.014), potentially from learning effects secondary to self-assessment with the TAI-Q. The extent of change over time did not differ significantly between the IIG and WLCG from baseline to 1 month (P=.169). However, significant improvements in TAI-Q scores were still evident after the training for the WLCG (P<.001). Those with a lower pretraining TAI-Q score and more shoulder pain were most likely to benefit from the training.

CONCLUSIONS

Repeated TAI-Q self-assessments likely contributed to improved transfer quality, with web-based training having an additive effect. Wheelchair users are likely to benefit from transfer training and self-assessment of transfer quality in their home environments. This has the potential to decrease injury risk while avoiding barriers to in-person training.

Does the setting matter? Observing wheelchair transfers across different environmental conditions

The setting in which wheelchair transfers are performed can affect the difficulty and the risks associated with completion. This article presents results from an observational study involving 13 wheelchair users performing independent transfers across four settings. The aim is to understand how the environment affects how different types of independent transfers are performed. Descriptive analysis was performed alongside an objective assessment using the Transfer Assessment Instrument (TAI). The perceived difficulty reported after each transfer was also collected. Two participants exhibited radically different transferring techniques in different scenarios. Additionally, the transferring scenario was found to significantly affect the perceived difficulty of sitting transfers (toilet 2.17 ±.88; bed 1.47 ±.65, p =.001; car 1.63 ±.82, p =.012) and standing transfers (car 3.5 ±.71; bed 1 ± 0, p =.03; toilet 1 ± 0, p =.03), and the TAI score attributed to sitting pivot with use of a transfer board (couch 4.3 ±.88; bed 6.93 ± 1.29, p =.022; car 7.13 ± 1.32, p =.018). Overall, environmental constraints can lead to major technique changes and, more often, to different positioning of hands and feet which could impact the transfer's biomechanics.

BIOMECHANICAL COMPARISON OF MUSCLE USE PATTERNS OF YOUNG ADULTS AND OLDER ADULTS IN FLOOR AND BED TRANSFER MOVEMENTS

In this study, lift chair was developed to reduce safety accidents in the daily lives of elderly people with reduced muscle strength as the importance of health and well-being of the elderly was emphasized by the increase in the elderly population. In addition, muscle strength characteristics of the elderly and those in their 20s were compared and analyzed when using lift chair. The lift chair used are chairs that can be raised and lowered and designed to reach the floor in full descent. The EMG was measured to compare the near-term use of lift chair to those in their 20s. As a result, the elderly had higher use of lower limb muscles compared to young participants. It was judged that the upper and lower extremities were difficult to move due to the characteristics of the elderly with reduced muscle strength, and that the upper and lower limbs were used simultaneously to complete the movement. The results showed the characteristics of everyday motion of the elderly for the development of lift chair and can help improve design, function, etc. in later development of lift chair.

Novel lateral transfer assist robot decreases the difficulty of transfer in post-stroke hemiparesis patients: a pilot study

PURPOSE

The purpose of this study was to clarify whether the novel lateral transfer assist robot facilitates easier transfers compared with a wheelchair in post-stroke hemiparesis patients.

METHODS

This cross-sectional study enrolled 20 post-stroke hemiparesis patients, and the task difficulty of transfers was compared between a wheelchair and lateral transfer assist robot. All participants were asked to transfer from either wheelchair or lateral transfer assist robot to a platform table and back. The primary outcome was the transfer score of the Functional Independence Measure. The secondary outcome was the time required for transfer.

RESULTS

The transfer score of the Functional Independence Measure was significantly higher with lateral transfer assist robot than with wheelchair (p < .001). The transfer times from these devices to a platform table and back showed no significant differences (to device from platform table: 7.8 s, lateral transfer assist robot vs 7.6 s, wheelchair, p > .05: device to platform table: 7.1 s, lateral transfer assist robot vs 8.0 s, wheelchair, p > .05).

CONCLUSIONS

Transfer with a lateral transfer assist robot is easier than with wheelchair and facilitates independence in post-stroke hemiparesis patients.IMPLICATIONS FOR REHABILITATIONTransfer skill influences the functional independence and quality of life of a wheelchair userA novel structural mobility device-the lateral transfer assist robot (LTAR)-can facilitate transfersThe LTAR could improve the degree of independence for transfers than the wheelchair, without any time loss, in post-stroke hemiparesis patientsThe LTAR could potentially reduce the risk for falls in various medical and care facilities.

Design and evaluation of a simple and affordable transfer assistive device for wheelchair users in the context of developing country

PURPOSE

The present study aimed at designing a simple, affordable, yet safe transfer assistive device (TAD) for lower limb impaired individuals in the context of a developing country.

METHODS

The preliminary study carried out, comprising a pilot survey with the involvement of stakeholder's views to design and develop the proposed device that had a unique feature. To evaluate the present TAD in terms of user's comfort of use and level of physical strain, subjects including 19 healthy students serving as "patients" have participated in a laboratory-simulated setting. Data was collected based on user's physiologic effort and rate of perceived exertion using Heart rate monitoring device (Polar RS 400 heart taster) and Borg's scale, respectively.

RESULTS

The data were analysed statistically and revealed that the regression equation for predicting the RPE from HR showed 31.3% of the variance in RPE was predictable from the level of HR. The ANOVA significance also indicates the model is statistically significant with (p < 0.013). Similarly, the estimated strain level has computed in terms of %HRR, and the physical strain averaged over the subjects who performed the task (n = 19) was expressed in terms of (mean ± SD) %HRR were (16.21±7.64%) which was a relatively smaller strain level as compared to the previous research report.

CONCLUSION

The present device found a potentially affordable solution for reducing fatigue and strain level that might develop during unassisted transfer. Similarly, the unique feature of the armpit support has contributed to dynamic contact force reduction and as double safety support.Implications for rehabilitationThe use of transfer assistive device is associated with increased patient satisfaction and privacy of usersImproved patient adherence and cooperation with caregivers in rehabilitation center.Encourages the rehabilitation settings to use transfer assistive devices instead of manual handling there by increase the recovery period.

Upper-limb biomechanical analysis of wheelchair transfer techniques in two toilet configurations

BACKGROUND

Using proper technique is important for minimizing upper limb kinetics during wheelchair transfers. The objective of the study was to 1) evaluate the transfer techniques used during toilet transfers and 2) determine the impact of technique on upper limb joint loading for two different toilet configurations.

METHODS

Twenty-six manual wheelchair users (23 men and 3 women) performed transfers in a side and front wheelchair-toilet orientation while their habitual transfer techniques were evaluated using the Transfer Assessment Instrument. A motion analysis system and force sensors were used to record biomechanical data during the transfers.

FINDINGS

More than 20% of the participants failed to complete five transfer skills in the side setup compared to three skills in the front setup. Higher quality skills overall were associated with lower peak forces and moments in both toilet configurations (-0.68 < r < -0.40, p < 0.05). In the side setup, participants who properly placed their hands in a stable position and used proper leading handgrips had lower shoulder resultant joint forces and moments than participants who did not perform these skills correctly (p ≤ 0.04). In the front setup, positioning the wheelchair within three inches of the transfer target was associated with reduced peak trailing forces and moments across all three upper limb joints (p = 0.02).

INTERPRETATION

Transfer skills training, making toilet seats level with the wheelchair seat, positioning the wheelchair closer to the toilet and mounting grab bars in a more ideal location for persons who do sitting pivot transfers may facilitate better quality toilet transfers.

The Weight-Bearing Shoulder

The shoulder achieves a wide spectrum of motion, and in a subset of patients, including those who use manual wheelchairs and upper extremity walking aids, the shoulder also serves as the primary weight-bearing joint. Because the weight-bearing shoulder is subject to considerable joint reaction forces and overuse, a broad spectrum of pathology can affect the joint. The combination of muscle imbalance and repetitive trauma presents most commonly as subacromial impingement syndrome but can progress to other pathology. Patients with high-level spinal cord injury, leading to quadriplegia and motor deficits, have an increased incidence of shoulder pain. Understanding the needs of patients who use manual wheelchairs or walking aids can help the physician to better comprehend the pathology of and better manage the weight-bearing shoulder.

Short-term influence of transfer training among full time pediatric wheelchair users: A randomized trial

OBJECTIVE/BACKGROUND

To describe a structured, short-term, transfer training intervention for full-time pediatric wheelchair users, investigate the impact of training on transfer skills, and to examine similarities and differences in response to training compared to those seen in adult wheelchair users.

DESIGN

Randomized clinical trial.

METHODS

Participants were first randomized into an intervention (IG) or control group (CG). After completing surveys and demographic intake forms, all participants performed two sets of level transfers (from wheelchair to bench and back to wheelchair = one set) at three time points. Each time point composed of two transfer sets were scored using the Transfer Assessment Instrument (TAI) and averaged to produce a final transfer score per time point. No feedback or training were given to participants prior to time points one and two however the IG received structured training prior to transfer assessment # 3. TAI scores were compared at transfer assessment #3 using a Mann-Whitney test.

OUTCOME MEASURES

Transfer Assessment Instrument (TAI) and Self-Perception Profile for Children (SPPC).

RESULTS

Intervention group participants demonstrated significant improvements among TAI scores (9.06 ± 1.01) compared to the control group (7.15 ± 1.67), P = 0.030, d = 1.385. No significant differences were found among SPPC scores.

CONCLUSION

Pediatric wheelchair users transfer skills were found to improve immediately after training with TAI score changes similar to those seen in adult wheelchair users after training. Such improvements may be a factor in long-term upper extremity preservation. Further testing is needed to examine the long-term impact of improved transfer skills.

Stability analysis of electrical powered wheelchair-mounted robotic-assisted transfer device

The ability of people with disabilities to live in their homes and communities with maximal independence often hinges, at least in part, on their ability to transfer or be transferred by an assistant. Because of limited resources and the expense of personal care, robotic transfer assistance devices will likely be in great demand. An easy-to-use system for assisting with transfers, attachable to electrical powered wheelchairs (EPWs) and readily transportable, could have a significant positive effect on the quality of life of people with disabilities. We investigated the stability of our newly developed Strong Arm, which is attached and integrated with an EPW to assist with transfers. The stability of the system was analyzed and verified by experiments applying different loads and using different system configurations. The model predicted the distributions of the system's center of mass very well compared with the experimental results. When real transfers were conducted with 50 and 75 kg loads and an 83.25 kg dummy, the current Strong Arm could transfer all weights safely without tip-over. Our modeling accurately predicts the stability of the system and is suitable for developing better control algorithms to enhance the safety of the device.

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury

STUDY DESIGN

Repeated measures design.

OBJECTIVE

This study compared the upper extremity (UE) joint kinetics between three transfer techniques.

SETTING

Research laboratory.

METHODS

Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head-hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers.

RESULTS

Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique.

CONCLUSION

Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement.

Effect of different hand positions on trunk and shoulder kinematics and reaction forces in sitting pivot transfer

[Purpose] The purpose of this study was to compare the changes in trunk and shoulder angles, and reaction forces under the two hands elicited by different hand base of support positions during sitting pivot transfer. [Subjects and Methods] Eighteen unimpaired subjects performed independent sitting pivot transfer. Subjects performed sitting pivot transfer between an initial seat to a target seat by only using their hands positioned at the same height as and lower than the seat position. Trunk and shoulder kinematics, and reaction forces on the trailing and leading hands were calculated. Mean peak joint angles and forces were compared between the hand positions using the pared t-test for the lift phase of the transfer. [Results] There were significant increases in the trunk angles of forward and lateral flexion, even though rotation decreased while transferring in the lower hand position. Increased shoulder flexion, anterior/posterior forces and reduced lateral forces were also shown. [Conclusion] Placing the hands of the supporting arms lower than the seat position during sitting pivot transfer was identified as having biomechanical advantages. Therefore, the lower hand position can be recommended as an effective and safe method for sitting pivot transfer by patients with spinal cord injury and can be utilized as a reference data for considering the appropriate height of aids for a wheelchair.

The relationship between independent transfer skills and upper limb kinetics in wheelchair users

Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments (P < .02, model R(2) values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm was associated with lower average resultant moments and rates of rise of resultant moments at the trailing shoulder and/or elbow. Some skills involving the leading side had the effect of increasing the magnitude or rate loading on the leading side. Knowledge of the kinetic outcomes associated with each skill may help users to achieve the best load-relieving effects for their upper extremities.

Seat Adjustment Design of an Intelligent Robotic Wheelchair Based on the Stewart Platform

A wheelchair user makes direct contact with the wheelchair seat, which serves as the interface between the user and the wheelchair, for much of any given day. Seat adjustment design is of crucial importance in providing proper seating posture and comfort. This paper presents a multiple-DOF (degrees of freedom) seat adjustment mechanism, which is intended to increase the independence of the wheelchair user while maintaining a concise structure, light weight, and intuitive control interface. This four-axis Stewart platform is capable of heaving, pitching, and swaying to provide seat elevation, tilt-in-space, and sideways movement functions. The geometry and types of joints of this mechanism are carefully arranged so that only one actuator needs to be controlled, enabling the wheelchair user to adjust the seat by simply pressing a button. The seat is also equipped with soft pressure-sensing pads to provide pressure management by adjusting the seat mechanism once continuous and concentrated pressure is detected. Finally, by comparing with the manual wheelchair, the proposed mechanism demonstrated the easier and more convenient operation with less effort for transfer assistance.

Impact of Functional Electrical Stimulation of Lower Limbs during Sitting Pivot Transfer Motion for Paraplegic People

Individuals with Spinal Cord Injury (SCI), perform Sitting Pivot Transfer (SPT) motion around fifteen times a day using upper extremities. It can lead to upper limbs pain and often shoulder complications. In this paper, we investigate the influence of Functional Electrical Stimulation (FES) on SPT motion of a paraplegic person. First, we proposed to develop a dynamic optimization method in order to predict SPT motion of an able-bodied subject. This approach has been validated by comparing the computed SPT trajectories with the ones measured during the experiment with an able-bodied subject. Then, we used the optimization tool to analyze the influence of FES on the SPT maneuver of paraplegic persons. Our results suggest that FES can decrease arm participation during the transfer motion of a paraplegic person.

Effects of sensorimotor trunk impairments on trunk and upper limb joint kinematics and kinetics during sitting pivot transfers in individuals with a spinal cord injury

BACKGROUND

Depending on the level and severity of the sensorimotor impairment in individuals with a spinal cord injury, the subsequent reduced seated postural stability and strength generating-capacity at the upper limbs could affect performance during sitting pivot transfer. This study aimed to determine the effects of sensorimotor impairments on head, trunk and upper limb movement and efforts during sitting pivot transfers.

METHODS

Twenty-six individuals with a spinal cord injury participated and were stratified in two subgroups: with (N=15) and without voluntary motor control (N=11) of their lower back and abdominal muscles. Kinematics and kinetics of sitting pivot transfer were collected using a transfer assessment system. Mean joint angles and movement amplitudes and peak and average joint moments were compared between subgroups using independent Student t-tests (P<0.05) for the weight-bearing sitting pivot transfer phases.

FINDINGS

The subgroup without voluntary control of their lower back and abdominal muscles had significantly greater forward trunk flexion compared to the other subgroup resulting in higher wrist extension and elbow flexion at both upper limbs. No significant joint moment difference was found between the subgroups.

INTERPRETATION

Individuals with spinal cord injury who have no voluntary motor control of their abdominal and lower back muscles increase forward trunk flexion during sitting pivot transfers 1) to increase stiffness of their spine that may optimize the strength-generating ability of their thoracohumeral muscles and 2) to lower their center of mass that may facilitate lift-off and enhance the overall stability during sitting pivot transfers.

Development of an automated method to detect sitting pivot transfer phases using biomechanical variables: toward a standardized method

Background

Sitting pivot transfer (SPT) is one of the most important, but at the same time strenuous at the upper extremity, functional task for spinal cord injured individuals. In order to better teach this task to those individuals and to improve performance, a better biomechanical understanding during the different SPT phases is a prerequisite. However, no consensus has yet been reached on how to depict the different phases of the SPT. The definition of the phases of the SPT, along with the events characterizing these phases, will facilitate the interpretation of biomechanical outcome measures related to the performance of SPTs as well as strengthen the evidence generated across studies.

Methods

Thirty-five individuals with a spinal cord injury performed two SPTs between seats of similar height using their usual SPT technique. Kinematics and kinetics were recorded using an instrumented transfer assessment system. Based on kinetic and kinematic measurements, a relative threshold-based algorithm was developed to identify four distinct phases: pre-lift, upper arm loading, lift-pivot and post-lift phases. To determine the stability of the algorithm between the two SPTs, Student t-tests for dependent samples were performed on the absolute duration of each phase.

Results

The mean total duration of the SPT was 2.00 ± 0.49 s. The mean duration of the pre-lift, upper arm loading, lift-pivot and post-lift phases were 0.74 ± 0.29 s, 0.28 ± 0.13 s, 0.72 ± 0.24 s, 0.27 ± 0.14 s whereas their relative contributions represented approximately 35%, 15%, 35% and 15% of the overall SPT cycle, respectively. No significant differences were found between the trials (p = 0.480-0.891).

Conclusion

The relative threshold-based algorithm used to automatically detect the four distinct phases of the SPT, is rapid, accurate and repeatable. A quantitative and thorough description of the precise phases of the SPT is prerequisite to better interpret biomechanical findings and measure task performance. The algorithm could also become clinically useful to refine the assessment and training of SPTs.