Reviewing effectiveness of ankle assessment techniques for use in robot-assisted therapy

Reliability and Concurrent Validity of Mobile Health Technology for Patient Self-Monitoring in Physical Rehabilitation

Background

Forearm pronation and supination are important for everyday functional tasks and some recreational activities. Healthcare providers use reliable and valid tools during the physical rehabilitation process to measure joint range of motion (ROM), assess functional mobility, guide decisions for skilled interventions, and progress a plan of care. Since the onset of the COVID-19 pandemic, both healthcare providers and patients benefited from mobile health technologies that have emerged, which can be used by patients in the home to monitor ROM and assist the healthcare provider in guiding the rehabilitation process when utilizing telehealth.

Purpose

The goal of this study was to investigate the reliability and concurrent validity of a smartphone application for obtaining goniometric measurements of forearm pronation and supination.

Methods

This study consisted of 83 participants that were recruited on a voluntary basis from an academic institution. An iPhone with the application Clinometer and a standard goniometer (SG) were utilized to obtain goniometric measurements of forearm pronation and supination. The intraclass correlation coefficient (ICC) was used to analyze intrarater reliability, and the Pearson correlation coefficient was used to analyze concurrent validity. Scatterplots with regression lines were created to visually display the results.

Results

The smartphone demonstrated strong correlations for both pronation and supination (r = 0.71, P < .001; r = 0.73, P < .001). This study demonstrated overall good-excellent intrarater reliability and good concurrent validity for the smartphone application with a higher test-retest reliability in the measurement of forearm pronation compared to supination.

Conclusions

This study concludes that the reliability and concurrent validity of the smartphone was consistent with the SG for assessing forearm pronation and supination. It may be of value to further investigate interrater reliability between patient and healthcare practitioner, and report on the ease of use to assess ROM with a smartphone.

Identifying Instruments to Assess Care Quality for Individuals With Custom Ankle Foot Orthoses: A Scoping Review

OBJECTIVES

We conducted 2 complementary scoping reviews to identify instruments that assess the experience and outcomes of custom ankle-foot orthosis (AFO) care in individuals with neurologic and traumatic conditions and to determine to what extent they might be psychometrically sound for AFO users. A stakeholder advisory committee considered to what extent the identified and psychometrically sound instruments might be feasible for use in developing quality measures for custom AFO users.

DATA SOURCES

Both scoping reviews were conducted using PubMed, the Cumulative Index to Nursing and Allied Health Literature, Embase, and Cochrane Systematic Reviews. The following were used for the first scoping review only: Cochrane Central Register of Controlled Trials and the Physiotherapy Evidence Database.

STUDY SELECTION

The initial scoping review yielded 79 articles with 82 instruments, 16 of which were used in 4 or more studies. The second scoping review yielded 57 articles reporting psychometric properties.

DATA EXTRACTION

Psychometric properties for populations who use AFOs were summarized for 15 of the 16 instruments. The advisory committee eliminated 2 insrtruments, noted overlap between 4 instruments in terms of the constructs measured, and suggested 6 potential contemporary substitutes.

DATA SYNTHESIS

Most instruments assessed activity (specifically mobility) and pertained to the National Quality Forum domain of "Health-Related Quality of Life." The 10-meter walk test, 6-minute walk test, Berg Balance Scale, Timed Up and Go, and Rivermead Mobility Index were reported to have adequate reliability and validity, and were considered feasible for administration in a clinical setting.

CONCLUSIONS

Complementary scoping reviews demonstrated that some instruments with reasonable psychometric properties are available that are feasible to use in developing quality measures for custom AFO care. However, experience of care instruments suitable for this population were not identified but are needed for a comprehensive evaluation of care quality for AFO users.

Effects of antagonistic muscle contraction exercises on ankle joint range of motion

[Purpose] Antagonistic stretching is an important therapeutic program in rehabilitation. However, if pain occurs during stretching, other methods should be considered. This study aimed to investigate whether antagonistic muscle contraction exercises alone had an effect in expanding the joint range of motion. [Participants and Methods] Participants included 50 healthy males and females (aged 21.0 ± 3.1 years) who were each randomly assigned to one of four groups that performed either active, resistance, phasic, or isometric exercises or a control group that performed no exercise. Each exercise group performed five sets of 30-second ankle dorsiflexion exercises. Active and passive ranges of motion of ankle dorsiflexion were measured using a goniometer, with the participants in the knee extension and flexion positions. [Results] Ankle joint range of motion was increased in the knee extension position in the isometric exercise group. There were no other differences observed in any of the groups. [Conclusion] Our results indicated that isometric exercises had an immediate effect on increasing ankle joint range of motion. This is presumably attributed to the effects of Golgi tendon organ inhibition (Ib inhibition) or stretch tolerance of the gastrocnemius muscle.

Towards Optimal Platform-Based Robot Design for Ankle Rehabilitation: The State of the Art and Future Prospects

This review aims to compare existing robot-assisted ankle rehabilitation techniques in terms of robot design. Included studies mainly consist of selected papers in two published reviews involving a variety of robot-assisted ankle rehabilitation techniques. A free search was also made in Google Scholar and Scopus by using keywords “ankle^∗,” and “robot^∗,” and (“rehabilitat^∗” or “treat^∗”). The search is limited to English-language articles published between January 1980 and September 2016. Results show that existing robot-assisted ankle rehabilitation techniques can be classified into wearable exoskeleton and platform-based devices. Platform-based devices are mostly developed for the treatment of a variety of ankle musculoskeletal and neurological injuries, while wearable ones focus more on ankle-related gait training. In terms of robot design, comparative analysis indicates that an ideal ankle rehabilitation robot should have aligned rotation center as the ankle joint, appropriate workspace, and actuation torque, no matter how many degrees of freedom (DOFs) it has. Single-DOF ankle robots are mostly developed for specific applications, while multi-DOF devices are more suitable for comprehensive ankle rehabilitation exercises. Other factors including posture adjustability and sensing functions should also be considered to promote related clinical applications. An ankle rehabilitation robot with reconfigurability to maximize its functions will be a new research point towards optimal design, especially on parallel mechanisms.

Adaptive control of an actuated-ankle-foot-orthosis

This paper deals with the control of an active ankle foot orthosis (AAFO) to assist the gait of paretic patients. The AAFO system is driven by both, the residual human torque delivered by the muscles spanning the ankle joint and the AAFO's actuator's torque. A projection-based model reference adaptive control is proposed to assist dorsiflexion and plantar-flexion of the ankle joint during daily living walking activities. Unlike most classical model-based controllers, the proposed one does not require any prior estimation of the system's (foot-AAFO) parameters. The ankle reference trajectory was extracted from healthy subjects gait activities in a clinical environment. The input-to-state stability of the foot-AAFO system with respect to a bounded human muscular torque is proved in closed-loop based on a Lyapunov analysis. Preliminary experimental results with a healthy subject walking on a treadmill, show satisfactory results in terms of tracking performance and ankle assistance throughout the gait cycle.

Robot-aided assessment of lower extremity functions: a review

The assessment of sensorimotor functions is extremely important to understand the health status of a patient and its change over time. Assessments are necessary to plan and adjust the therapy in order to maximize the chances of individual recovery. Nowadays, however, assessments are seldom used in clinical practice due to administrative constraints or to inadequate validity, reliability and responsiveness. In clinical trials, more sensitive and reliable measurement scales could unmask changes in physiological variables that would not be visible with existing clinical scores.In the last decades robotic devices have become available for neurorehabilitation training in clinical centers. Besides training, robotic devices can overcome some of the limitations in traditional clinical assessments by providing more objective, sensitive, reliable and time-efficient measurements. However, it is necessary to understand the clinical needs to be able to develop novel robot-aided assessment methods that can be integrated in clinical practice.This paper aims at providing researchers and developers in the field of robotic neurorehabilitation with a comprehensive review of assessment methods for the lower extremities. Among the ICF domains, we included those related to lower extremities sensorimotor functions and walking; for each chapter we present and discuss existing assessments used in routine clinical practice and contrast those to state-of-the-art instrumented and robot-aided technologies. Based on the shortcomings of current assessments, on the identified clinical needs and on the opportunities offered by robotic devices, we propose future directions for research in rehabilitation robotics. The review and recommendations provided in this paper aim to guide the design of the next generation of robot-aided functional assessments, their validation and their translation to clinical practice.

Bilateral robots for upper-limb stroke rehabilitation: State of the art and future prospects

Robot-assisted bilateral upper-limb training grows abundantly for stroke rehabilitation in recent years and an increasing number of devices and robots have been developed. This paper aims to provide a systematic overview and evaluation of existing bilateral upper-limb rehabilitation devices and robots based on their mechanisms and clinical-outcomes. Most of the articles studied here were searched from nine online databases and the China National Knowledge Infrastructure (CNKI) from year 1993 to 2015. Devices and robots were categorized as end-effectors, exoskeletons and industrial robots. Totally ten end-effectors, one exoskeleton and one industrial robot were evaluated in terms of their mechanical characteristics, degrees of freedom (DOF), supported control modes, clinical applicability and outcomes. Preliminary clinical results of these studies showed that all participants could gain certain improvements in terms of range of motion, strength or physical function after training. Only four studies supported that bilateral training was better than unilateral training. However, most of clinical results cannot definitely verify the effectiveness of mechanisms and clinical protocols used in robotic therapies. To explore the actual value of these robots and devices, further research on ingenious mechanisms, dose-matched clinical protocols and universal evaluation criteria should be conducted in the future.

A novel assessment technique for measuring ankle orientation and stiffness

The measurement of ankle orientation and stiffness can provide insight into improvements and allows for effective monitoring during a rehabilitation program. Existing assessment techniques have a variety of limitations. Dynamometer based methods rely on manual manipulation. The use of torque meter is usually for single degree-of-freedom (DOF) devices. This study proposes a novel ankle assessment technique that can be used for multiple DOFs devices working in both manual and automatic modes using the position sensor and the multi-axis load cell. As a preliminary evaluation, an assessment device for ankle dorsiflexion and plantarflexion was constructed. Nine subjects participated to evaluate the effectiveness of the assessment device in determining ankle orientation and stiffness. The measured ankle orientation was consistent with that from the NDI Polaris optical tracking system. The measured ankle torque and stiffness compared well with published data. The test-retest reliability was high with intraclass correlation coefficient (ICC2, 1) values greater than 0.846 and standard error of measurement (SEM) less than 1.38.

A Robot-Driven Computational Model for Estimating Passive Ankle Torque With Subject-Specific Adaptation

BACKGROUND

Robot-assisted ankle assessment could potentially be conducted using sensor-based and model-based methods. Existing ankle rehabilitation robots usually use torquemeters and multiaxis load cells for measuring joint dynamics. These measurements are accurate, but the contribution as a result of muscles and ligaments is not taken into account. Some computational ankle models have been developed to evaluate ligament strain and joint torque. These models do not include muscles and, thus, are not suitable for an overall ankle assessment in robot-assisted therapy.

METHODS

This study proposed a computational ankle model for use in robot-assisted therapy with three rotational degrees of freedom, 12 muscles, and seven ligaments. This model is driven by robotics, uses three independent position variables as inputs, and outputs an overall ankle assessment. Subject-specific adaptations by geometric and strength scaling were also made to allow for a universal model.

RESULTS

This model was evaluated using published results and experimental data from 11 participants. Results show a high accuracy in the evaluation of ligament neutral length and passive joint torque. The subject-specific adaptation performance is high, with each normalized root-mean-square deviation value less than 10%.

CONCLUSION

This model could be used for ankle assessment, especially in evaluating passive ankle torque, for a specific individual. The characteristic that is unique to this model is the use of three independent position variables that can be measured in real time as inputs, which makes it advantageous over other models when combined with robot-assisted therapy.

A real-time computational model for estimating kinematics of ankle ligaments

BACKGROUND

An accurate assessment of ankle ligament kinematics is crucial in understanding the injury mechanisms and can help to improve the treatment of an injured ankle, especially when used in conjunction with robot-assisted therapy. A number of computational models have been developed and validated for assessing the kinematics of ankle ligaments. However, few of them can do real-time assessment to allow for an input into robotic rehabilitation programs.

METHOD

An ankle computational model was proposed and validated to quantify the kinematics of ankle ligaments as the foot moves in real-time. This model consists of three bone segments with three rotational degrees of freedom (DOFs) and 12 ankle ligaments. This model uses inputs for three position variables that can be measured from sensors in many ankle robotic devices that detect postures within the foot-ankle environment and outputs the kinematics of ankle ligaments. Validation of this model in terms of ligament length and strain was conducted by comparing it with published data on cadaver anatomy and magnetic resonance imaging.

RESULTS

The model based on ligament lengths and strains is in concurrence with those from the published studies but is sensitive to ligament attachment positions.

CONCLUSIONS

This ankle computational model has the potential to be used in robot-assisted therapy for real-time assessment of ligament kinematics. The results provide information regarding the quantification of kinematics associated with ankle ligaments related to the disability level and can be used for optimizing the robotic training trajectory.

An in-vivo lateral ankle ligament strain behavior assessment technique for potential use in robot-assisted therapy

Ankle sprains are very common, especially in sports activities. Accurate assessment of ankle ligament strain behavior is crucial in understanding ankle function and optimizing ankle rehabilitation programs. This study proposed an in-vivo lateral ankle ligament strain assessment technique for potential use in robot-assisted therapy. It consists of two phases: real-time identification of ankle joint and subtalar joint orientations and simulation of lateral ankle ligament strain behavior. A healthy participant conducted robot-assisted rehabilitation exercises and the results compared to a kinematic model. The model was found to be realistic, leading to the conclusion that this method may be appropriate for determining lateral ankle ligament strain in robot-assisted therapy.

Article Commentary: An Assistance-as-Needed Control Paradigm for Robot-Assisted Ankle Rehabilitation

Robots have been developed for treatment and rehabilitation of ankle injuries. Two reviews have been conducted involving the effectiveness of robot-assisted ankle rehabilitation and ankle assessment techniques respectively to investigate what the optimal therapy is. This study proposes an assistance-as-needed (AAN) control paradigm for potential use in robot-assisted ankle rehabilitation based on the review results. This AAN control strategy will consider real-time ankle assessment and make rehabilitation more effective.