A suite of automated tools to quantify hand and wrist motor function after cervical spinal cord injury

If we had any lick of sense in stroke leadership this would be immediately looked at for objective measurements of upper limb disability. With objective measurements we could finally get to mapping stroke rehab protocols that fix those disabilities.  But since we have NO stroke leadership nothing will get done and stroke survivors will have to muddle through forever with zero consequences for the doctors who have failed their patients.

A suite of automated tools to quantify hand and wrist motor function after cervical spinal cord injury

• Katelyn M. Grasse,
• Seth A. HaysEmail author,
• Kimiya C. Rahebi,
• Victoria S. Warren,
• Elizabeth A. Garcia,
• Jane G. Wigginton,
• Michael P. Kilgard and
• Robert L. RennakerII

Journal of NeuroEngineering and Rehabilitation201916:48

https://doi.org/10.1186/s12984-019-0518-8

©  The Author(s). 2019

• Received: 11 December 2018
• Accepted: 27 March 2019
• Published: 11 April 2019

Abstract

Background

Cervical spinal cord injury (cSCI) often causes chronic upper extremity disability. Reliable measurement of arm function is critical for development of therapies to improve recovery after cSCI. In this study, we report a suite of automated rehabilitative tools to allow simple, quantitative assessment of hand and wrist motor function.

Methods

We measured range of motion and force production using these devices in cSCI participants with a range of upper limb disability and in neurologically intact participants at two time points separated by approximately 4 months. Additionally, we determined whether measures collected with the rehabilitative tools correlated with standard upper limb assessments, including the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) and the Jebsen Hand Function Test (JHFT).

Results

We find that the rehabilitative devices are useful to provide assessment of upper limb function in physical units over time in SCI participants and are well-correlated with standard assessments.

Conclusions

These results indicate that these tools represent a reliable system for longitudinal evaluation of upper extremity function after cSCI and may provide a framework to assess the efficacy of strategies aimed at improving recovery of upper limb function.

Keywords

• Spinal cord injury
• Prehension
• Force
• Range of motion
• Hand
• Wrist
• Assessment

Introduction

Spinal cord injury is a common cause of disability, affecting more than 300,000 people in the US [1]. The majority of injuries occur at the cervical level, which often impairs function of upper extremities and can lead to chronic disability [2, 3, 4]. Accurate and sensitive measurement of upper limb function is a critical part of the development and assessment of new therapies to improve recovery after SCI.

The most common method of arm assessment after cSCI involves subjective ordinal scoring of motor function by a skilled examiner [5, 6, 7]. While this approach yields rapid and reliable results, ordinal assessment may not always be sensitive to small improvements that can be functionally meaningful [8, 9]. Objective measurement may provide improved measurement sensitivity, and as sensor technologies have become smaller and more accessible, numerous tools have been developed for assessing arm function after cSCI [10]. Dynamometers and myometers are widely used to measure isometric force of isolated arm functions in continuous physical units [11, 12]. Other assessment tools measure position and force during execution of simulated functional tasks [13, 14]. These systems indeed provide greater precision or a more direct characterization of functional ability than traditional measures, but the continued reliance upon ordinal assessment indicates an unmet clinical need for the development of measurement technologies.

To increase their utility and implementation, measurement systems should be simple to use, facilitate standardized administration, report sensitive, quantitative metrics, and provide reliable longitudinal testing [15]. We designed a suite of modular rehabilitative devices for objective assessment of various isolated hand and wrist motor functions to address these needs. In addition to the measurement modules, a table-mounted armrest with simple, interchangeable tasks facilitates standardized administration across a wide range of arm impairments [11]. The system records measurements in continuous physical units, providing unambiguous results across many aspects of function. Furthermore, the devices enable collection of multiple trials to increase sensitivity and reliability of measurements.

In this study, we tested whether these tools could quantify motor impairments in individuals with cSCI, determined measurement detection limits, and examined retest reliability by assessing the same participants 4 months later. We also established concurrent validity by correlating performance on the rehabilitative devices with two common metrics of upper limb function after cSCI, the Graded Refined Assessment of Strength, Sensibility, and Prehension (GRASSP) exam and the Jebsen Hand Function Test (JHFT) [5]. Our results demonstrate that the system provides reliable measurements over time and that performance correlates with established outcome measures. The results indicate that the novel system can deliver simple and reliable longitudinal evaluation of upper extremity function after cSCI and may provide a framework to assess the efficacy of strategies aimed at improving recovery of upper limb function.