Inter-rater reliability, sensitivity to change and responsiveness of the orthopaedic Wolf-Motor-Function-Test as functional capacity measure before and after rehabilitation in patients with proximal humeral fractures

Background: The incidence of proximal humeral fractures (PHF) increased by more than 30% over the last decade, which is accompanied by an increased number of operations. However, the evidence on operative vs. non-operative treatment and post-operative treatments is limited and mostly based on expert opinion. It is mandatory to objectively assess functional capacity to compare different treatments. Clinical tools should be valid, reliable and sensitive to change assessing functional capacity after PHFs. This study aimed to analyse inter-rater reliability of the videotaped Wolf-Motor-Function-Test-Orthopaedic (WMFT-O) and the association between the clinical WMFT-O and the Disability of the Arm, Shoulder and Hand (DASH) and to determine the sensitivity to change of the WMFT-O and the DASH to measure functional capacity before and after rehabilitation in PHF patients. Methods: Fifty-six patients (61.7 ± 14.7 years) after surgical treatment of PHF were assessed using the WMFT-O at two different time points. To determine inter-rater reliability, the videotaped WMFT-O was evaluated through three blinded raters. Inter-rater agreement was determined by Fleiss’ Kappa statistics. Pearson correlation coefficients were calculated to assess the association between the clinical WMFT-O and the video rating as well as the DASH. Sensitivity to change and responsiveness were analysed for the WMFT-O and the DASH in a subsample of forty patients (53.8 ± 1.4 years) who were assessed before and after a three week robotic-assisted training intervention. Results: Inter-rater agreement was indicated by Fleiss’ Kappa values ranging from 0.33–0.66 for functional capacity and from 0.27–0.54 for quality of movement. The correlation between the clinical WMFT-O and the video rating was higher than 0.77. The correlation between the clinical WMFT-O and the DASH was weak. Sensitivity to change was high for the WMFT-O and the DASH and responsiveness was given. In comparison to the DASH, the sensitivity to change of the WMFT-O was higher. Conclusion: The overall results indicate that the WMFT-O is a reliable, sensitive and responsive instrument to measure more objectively functional change over time in rehabilitation after PHF. Furthermore, it has been shown that video assessment is eligible for studies to ensure a full blinding of raters. Trial registration: Clinicaltrials.gov, NCT03100201. Registered on 28 March 2017. The trial was retrospectively registered

Robot-assisted arm assessments in spinal cord injured patients: a consideration of concept study

Robotic assistance is increasingly used in neurological rehabilitation for enhanced training. Furthermore, therapy robots have the potential for accurate assessment of motor function in order to diagnose the patient status, to measure therapy progress or to feedback the movement performance to the patient and therapist in real time. We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function. Twenty-four healthy subjects and five patients after spinal cord injury underwent robot-based assessments using the exoskeleton robot ARMin. Five different tasks were performed with aid of a visual display. Ten kinematic, kinetic and timing assessment parameters were extracted on joint- and end-effector level (active and passive range of motion, cubic reaching volume, movement time, distance-path ratio, precision, smoothness, reaction time, joint torques and joint stiffness). For cubic volume, joint torques and the range of motion for most joints, good inter- and intra-rater reliability were found whereas precision, movement time, distance-path ratio and smoothness showed weak to moderate reliability. A comparison with clinical scores revealed good correlations between robot-based joint torques and the Manual Muscle Test. Reaction time and distance-path ratio showed good correlation with the "Graded and Redefined Assessment of Strength, Sensibility and Prehension" (GRASSP) and the Van Lieshout Test (VLT) for movements towards a predefined position in the center of the frontal plane. In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe. The first results with spinal cord injured patients and healthy subjects suggest that the measurements are widely reliable and comparable to clinical scales for arm motor function. The methods applied and results can serve as a basis for the future development of end-effector and exoskeleton-based robotic assessments

Example RPM plot for elbow flexion (60°/s) of two patients (A and B).

<p>The black dotted line shows the torque progression measured during the assessment. The blue dash-dotted line is the data from the calibration routine without the patient. The cyan dashed line is the estimated torque progression of the patient’s joint. The red line is the linear least square fit for the patient’s joint torques. The movement in the left picture was rated a 2 on the Tardieu scale. The movement on the right example was rated a 0 on the Tardieu scale. The measured stiffness by the robot assigned 0.93 Nm/rad to the left and 0.84 Nm/rad to the right movement.</p

Plots of the patient <i>joint torques</i> from STRENGTH vs. MMT scores for all joints and in both directions.

<p>(x-axis = MMT score, y-axis = <i>joint torque</i> from STRENGTH).</p

Visualization of <i>joint stiffness</i> measurements within the RPM assessment for the non-dominant and dominant arms of healthy subjects and patients.

<p>The more a joint counteracted the robot movement over the angle, the higher and more intense in color (red) the value. The color gradient ranges from minimal (blue) to maximal values (red) and is different for the non-dominant (-2 to 4) and dominant arms (-1 to 2).</p

Characteristics of the patients.

<p>^aChronic (> 6 months) vs. subacute (≤ 6 months post SCI).</p><p>^bEvaluated with questionnaire of Chapman [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126948#pone.0126948.ref043" target="_blank">43</a>].</p><p>Characteristics of the patients.</p

Overview over implemented assessments and the measured parameters.

<p>Overview over implemented assessments and the measured parameters.</p

QOM: The hand paths of a patient moving to the 8 different targets.

<p>QOM: The hand paths of a patient moving to the 8 different targets.</p

Summary of the significant differences found from the Friedman test of the intra-rater reliability.

<p>^aAs healthy subjects almost exclusively reached the mechanical limits ROM values correspond in most cases to the mechanical end limit.</p><p>^bThe maximal <i>workspace levels</i> and therefore the maximal <i>cubic volume</i> were reached for the evaluated subjects for all the directions (p = 1.00).</p><p>Summary of the significant differences found from the Friedman test of the intra-rater reliability.</p

Example of an <i>aROM</i> Bland-Altman plot regarding wrist flexion for the nine patient arms.

<p>The limits of agreement (dashed lines for lower -4.3° and upper 5.4° limit) and the mean difference (solid line at 0.5°) are shown. The x-axis shows the mean values of the two measurements of tester 1 and 2 (negative values indicate flexion, positive values stand for extension), while the y-axis shows the measurement difference between tester 1 and 2.</p