Reliability, validity and discriminant ability of a robotic device for finger training in patients with subacute stroke

Marco Germanotta,Irene Aprile,Valerio Gower,Cristiano Pecchioli,Angelo Montesano,Francesca Cecchi,Arianna Cruciani,Rita Mosca,Dionysia Papadopoulou,Gabriele Speranza,Furio Gramatica,Federica Vannetti,Catuscia Falsini,Silvia Galeri

doi:10.1186/s12984-019-0634-5

Marco Germanotta, Irene Aprile + Show 12 more

Open Access

https://doi.org/10.1186/s12984-019-0634-5

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Abstract

BackgroundThe majority of stroke survivors experiences significant hand impairments, as weakness and spasticity, with a severe impact on the activity of daily living. To objectively evaluate hand deficits, quantitative measures are needed. The aim of this study is to assess the reliability, the validity and the discriminant ability of the instrumental measures provided by a robotic device for hand rehabilitation, in a sample of patients with subacute stroke.Material and methodsIn this study, 120 patients with stroke and 40 controls were enrolled. Clinical evaluation included finger flexion and extension strength (using the Medical Research Council, MRC), finger spasticity (using the Modified Ashworth Scale, MAS) and motor control and dexterity during ADL performance (by means of the Frenchay Arm Test, FAT). Robotic evaluations included finger flexion and extension strength, muscle tone at rest, and instrumented MAS and Modified Tardieu Scale. Subjects were evaluated twice, one day apart, to assess the test-retest reliability of the robotic measures, using the Intraclass Correlation Coefficient (ICC). To estimate the response stability, the standard errors of measurement and the minimum detectable change (MDC) were also calculated. Validity was assessed by analyzing the correlations between the robotic metrics and the clinical scales, using the Spearman’s Correlation Coefficient (r). Finally, we investigated the ability of the robotic measures to distinguish between patients with stroke and healthy subjects, by means of Mann-Whitney U tests.ResultsAll the investigated measures were able to discriminate patients with stroke from healthy subjects (p < 0.001). Test-retest reliability was found to be excellent for finger strength (in both flexion and extension) and muscle tone, with ICCs higher than 0.9. MDCs were equal to 10.6 N for finger flexion, 3.4 N for finger extension, and 14.3 N for muscle tone. Conversely, test-retest reliability of the spasticity measures was poor. Finally, finger strength (in both flexion and extension) was correlated with the clinical scales (r of about 0.7 with MRC, and about 0.5 with FAT).DiscussionFinger strength (in both flexion and extension) and muscle tone, as provided by a robotic device for hand rehabilitation, are reliable and sensitive measures. Moreover, finger strength is strongly correlated with clinical scales. Changes higher than the obtained MDC in these robotic measures could be considered as clinically relevant and used to assess the effect of a rehabilitation treatment in patients with subacute stroke.

Highlights

The majority of stroke survivors experiences significant hand impairments, as weakness and spasticity, with a severe impact on the activity of daily living
A growing interest has been addressed towards the use of robotic devices to treat the upper limb in patients suffering from neurological disease, especially stroke [8]
Exclusion criteria were: (1) upper extremity Fugl-Meyer score > 58; (2) behavioral and cognitive disorders and/or reduced compliance that would interfere with active therapy; (3) fixed contraction deformity in the affected limb that would interfere with active therapy; (4) inability to discriminate distinctly the images showed on a monitor placed at the eye level of each subject at a distance of about 50 cm, even with corrective glasses

Summary

Introduction

The majority of stroke survivors experiences significant hand impairments, as weakness and spasticity, with a severe impact on the activity of daily living. A growing interest has been addressed towards the use of robotic devices to treat the upper limb in patients suffering from neurological disease, especially stroke [8]. These devices allow to increase of the amount and intensity of the therapy, to standardize the treatment, providing a complex but controlled multisensory stimulation [9, 10] and helping the patient to complete the required task while preventing inappropriate movements [11]. Even if most of the robots focuses on the more proximal joints (shoulder and elbow) [12], some devices have been developed to target the hand, using either end-effector [13,14,15] or exoskeleton [16, 17] design, with encouraging results in terms of motor recovery [12, 18,19,20,21,22]

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