Validity and reliability of the assessment of hand flexors stiffness using a new electromechanical oscillatory device in people with stroke.

Hyper-resistance after a central nervous system injury has been largely referred to as spasticity, which is but one of its neural components. Assessment largely relies on clinical scales (Modified Ashworth scale - MAS and Modified Tardieu scale, MTS) which are unable to distinguish between the non-neural (tissue-related) and the neural (central nervous system-related) components. This study assessed criterion validity and reliability (reproducibility) of muscle stiffness measures, namely, maximum elastic stiffness (ELmax), viscous stiffness (VI), and path length (L-path) in the hand flexor muscles among people with stroke. Measurements were obtained with a wrist-electromechanical oscillatory device (w-EOD). Twenty-four people with arm impairment after stroke were evaluated with the w-EOD and clinical assessment (MAS and MTS), twice on the same day (short-term reliability) and once 10 days later (long-term reliability). For criterion validity, a Spearman coefficient ( r ) was calculated between stiffness values and the clinical scales. For reliability, intraclass correlation coefficients (ICCs), SEM, and MDC95 were calculated. Moderate correlations were observed between EL max and MAS ( r = 0.49) and MTS (V2, r = 0.43; V3, r = 0.49) of the wrist flexors, and finger flexors (MAS, r = 0.60; MTS V2, r = 0.56; MTS V3, r = 0.55). There was a poor correlation between the clinical scales and VI and L-path. Reliability was excellent for all stiffness measurements at short term (EL max : 0.95, VI: 0.94, L-path: 0.92) and good at long term (EL max : 0.87, VI: 0.76, L-path: 0.82). In conclusion, stiffness measurements are valid and reliable to evaluate hyper-resistance in people with stroke.

Variations in Patterns of Muscle Activity Observed in Participants Walking in Everyday Environments: Effect of Different Surfaces.

Purpose: The purpose of this study was to examine variations in lower limb surface electromyography (EMG) activity when individuals walked on different outdoor surfaces and to characterize the different potential motor strategies. Method: Forty healthy adult participants walked at a self-selected speed over asphalt, grass, and pavement. They then walked on an indoor treadmill at the same gait speed as observed for each outdoor condition. The EMG activity of the vastus lateralis (VL), tibialis anterior (TA), biceps femoris (BF), and gastrocnemius lateralis (GL) muscles was recorded, and the duration and intensity (root mean square) of EMG burst activity was calculated. Results: Walking on grass resulted in a longer TA burst duration than walking on other outdoor surfaces. Walking on pavement was associated with increased intensity of TA and VL activation compared with the indoor treadmill condition. The variability of EMG intensity for all muscle groups tested (TA, GL, BF, VL) was greatest on grass and lowest on asphalt. Conclusions: The muscle activity patterns of healthy adult participants vary in response to the different qualities of outdoor walking surfaces. Ongoing development of ambulatory EMG methods will be required to support gait retraining programmes that are tailored to the environment.

Objectif : examiner les variations de l'activité électromyographique (EMG) de surface des membres inférieurs lorsqu'une personne marche sur différentes surfaces extérieures et caractériser les diverses stratégies motrices potentielles. Méthodologie : au total, 40 participants adultes en bonne santé ont marché à vitesse spontanée sur de l'asphalte, du gazon et des pavés. Ils ont ensuite dû marcher sur un tapis roulant à la même vitesse que sur chaque surface extérieure. Les chercheurs ont enregistré l'activité EMG des muscles vaste latéral (VL), tibial antérieur (TA), biceps fémoral (BF) et gastrocnémien latéral (GL) durant la marche. Ils ont ensuite calculé la durée et l'intensité (moyenne quadratique) de la bouffée d'activité EMG. Résultats : la marche sur le gazon provoque principalement une bouffée d'activité du muscle TA plus longue que la marche sur les autres surfaces extérieures. La marche sur les pavés est liée à une augmentation de l'intensité d'activation des muscles TA et VL par rapport à celle sur le tapis roulant. La variabilité de l'intensité EMG de tous les muscles testés (TA, GL, BF, VL) était plus élevée sur le gazon et plus faible sur l'asphalte. Conclusion : les tracés d'activité musculaire des participants varient selon la nature des surfaces de marche extérieure. Les méthodes d'enregistrement de l'EMG devront être améliorées de façon à valider les programmes de rééducation de la marche adaptés à l'environnement.

Effect of Age and Body Size on the Wrist's Viscoelasticity in Healthy Participants From 3 to 90 Years Old and Reliability Assessment.

Excessive or insufficient levels of passive musculoarticular stiffness (PMAS) can lead to joint impairment or instability. Quantifying the PMAS may provide a better understanding of neurological or musculoskeletal disorders. The aims of the present study were multiple: first, to assess the reliability of quantifying PMAS and to collect normative data on the wrist in healthy participants, and second, to assess the effect of age and body size on PMAS. For this purpose, a total of 458 participants from 3 to 90 years old were analyzed with an electromechanical oscillation device (EOD). Passive sinusoidal movements were induced in a flexion/extension pattern in the participants' wrists, enabling an objective measurement of elastic stiffness (EL) and viscous stiffness (VI). Both the dominant and non-dominant wrists were assessed. Two-way repeated-measures ANOVA revealed a sex differentiation from puberty (12-18 years old) and an increase of EL and VI from childhood to adulthood and a decrease of stiffness at old age. EL and VI values were associated with body size characteristics and age. After body size normalization, EL was no longer influenced by the variables measured. On the other hand, VI remained moderately influenced by age and body size. The current study was able to provide normative data of PMAS in the wrist of healthy participants.

Biomechanical study of a low-cost external fixator for diaphyseal fractures of long bones.

BACKGROUND: External fixation improves open fracture management in emerging countries. However, sophisticated models are often expensive and unavailable. We assessed the biomechanical properties of a low-cost external fixation system in comparison with the Hoffmann® 3 system, as a reference. METHODS: Transversal, oblique, and comminuted fractures were created in the diaphysis of tibia sawbones. Six external fixators were tested in three modes of loading-axial compression, medio-lateral (ML) bending, and torsion-in order to determine construction stiffness. The fixator construct implies two uniplanar (UUEF1, UUEF2) depending the pin-rods fixation system and two biplanar (UBEF1, UBEF2) designs based on different bar to bar connections. The designed low-cost fixators were compared to a Hoffmann® 3 fixator single rod (H3-SR) and double rod (H3-DR). Twenty-seven constructs were stabilized with UUEF1, UUEF2, and H3-SR (nine constructs each). Nine constructs were stabilized with UBEF1, UBEF2, and H3-DR (three constructs each). RESULTS: UUEF2 was significantly stiffer than H3-SR (p < 0.001) in axial compression for oblique fractures and UUEF1 was significantly stiffer than H3-SR (p = 0.009) in ML bending for transversal fractures. Both UUEFs were significantly stiffer than H3-SR in axial compression and torsion (p < 0.05), and inferior to H3-SR in ML bending, for comminuted fractures. In the same fracture pattern, UBEFs were significantly stiffer than H3-DR (p = 0.001) in axial compression and torsion, while only UBEF1 was significantly stiffer than H3-DR in ML bending (p = 0.013). CONCLUSIONS: The results demonstrated that the stiffness of the UUEF and UBEF device compares to the reference fixator and may be helpful in maintaining fracture reduction. Fatigue testing and clinical assessment must be conducted to ensure that the objective of bone healing is achievable with such low-cost devices.

DYSKIMOT: An Ultra-Low-Cost Inertial Sensor to Assess Head's Rotational Kinematics in Adults during the Didren-Laser Test.

Various noninvasive measurement devices can be used to assess cervical motion. The size, complexity, and cost of gold-standard systems make them not suited to clinical practice, and actually difficult to use outside a dedicated laboratory. Nowadays, ultra-low-cost inertial measurement units are available, but without any packaging or a user-friendly interface. The so-called DYSKIMOT is a home-designed, small-sized, motion sensor based on the latter technology, aiming at being used by clinicians in "real-life situations". DYSKIMOT was compared with a gold-standard optoelectronic system (Elite). Our goal was to evaluate the DYSKIMOT accuracy in assessing fast head rotations kinematics. Kinematics was simultaneously recorded by systems during the execution of the DidRen Laser test and performed by 15 participants and nine patients. Kinematic variables were computed from the position, speed and acceleration time series. Two-way ANOVA, Passing-Bablok regressions, and dynamic time warping analysis showed good to excellent agreement between Elite and DYSKIMOT, both at the qualitative level of the time series shape and at the quantitative level of peculiar kinematical events' measured values. In conclusion, DYSKIMOT sensor is as relevant as a gold-standard system to assess kinematical features during fast head rotations in participants and patients, demonstrating its usefulness in both clinical practice and research environments.

Assessment of Resection Margins in Bone Tumor Surgery.

Limb salvage surgery is now the preferred procedure for bone tumor surgery. To decrease the risk of local recurrence, it is crucial to obtain adequate resection margins. The obtained margins must be evaluated postoperatively because they influence what treatment is given subsequently when margins are not adequate (e.g., surgical revision and radiotherapy). The study aims to evaluate margin assessment of tumor specimen by MRI compared to conventional histology (to establish the viability of using MRI) and assess the accuracy of a patient-specific instrument when narrow margins were aimed. The resection margins in 12 consecutive patients that were operated on for bone tumor resection were prospectively analyzed using three methods: MRI of the resection specimen, macroscopic evaluation of specimen slices, and microscopic pathological evaluation. The assessments were qualitative (R0, R1, and R2) and quantitative (distance in mm). MRI, macroscopic, and microscopic margins generated similar results for both the qualitative (all resections were R0) and quantitative assessments. The median error in safe margins was 2 mm with a surgical guide (PSI) and 5 mm without a surgical guide. Local recurrences were not detected after a mean follow-up period of 3.7 years (range, 2.1-5 years); however, four patients died during the study. In conclusion, MRI is a valuable tool for assessing safe margins. When specimens are not available for pathological assessment (e.g., extracorporeally irradiated autograft or autoclaved autograft), MRI could be used to evaluate margins. In particular, when tumor volume is high, MRI could also help to focus the pathological examination on areas of concern.

Validation of a robot serious game assessment protocol for upper limb motor impairment in children with cerebral palsy.

BACKGROUND: The ROBiGAME project aims to implement serious games on robots to rehabilitate upper limb (UL) motor function in children with cerebral palsy (CP). Serious game characteristics (target position, level of assistance/resistance, level of force) are typically adapted based on the child's assessment before and continuously during the game (measuring UL working area, kinematics and muscle strength). OBJECTIVE: This study developed an UL robotic motor assessment protocol to configure the serious game. METHODS: Forty-nine healthy children and 20 CP children participated in the study. The clinical assessment consisted of the child's UL length and isometric force. The robot assessment consisted of the child's UL working area (WA), the UL isometric and isokinetic force in three directions and the UL kinematics during a pointing task toward targets placed at different distances. RESULTS: Results showed that WA and UL isometric force were moderately to highly correlated with clinical measures. Ratios between the UL isokinetic force generated on three directions were established. The velocity and straightness indexes of all children increased when they had to reach to targets placed more distant. CONCLUSIONS: This protocol can be integrated into different serious games in order to continuously configure the game characteristics to a child's performance. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov (NCT02543424), 12 August 2015.

Development of a robotic upper limb assessment to configure a serious game.

BACKGROUNDROBiGAME project aims to implement serious games on robots to rehabilitate upper limb (UL) in stroke patients. The serious game characteristics (target position, level of assistance/resistance, level of force) are adapted based on the patient's assessment before and continuously during the game (measuring UL working area, kinematics and muscle strength).OBJECTIVETo develop an UL robotic motor assessment protocol to configure the serious game.METHODS32 healthy subjects and 20 stroke patients participated in the study. Subjects were clinically assessed (UL length and isometric force) and using a robot. The robot assessment consisted of the patient's UL working area (WA), the UL isometric and isokinetic force in three directions and the UL kinematics during a pointing task toward targets placed at different distances.RESULTSThe WA and the UL isometric force were moderately to highly correlated with clinical measures (respectively ρ= 0.52; p = 0.003, ρ= 0.68-0.73; p < 0.001). Ratios between the UL isokinetic force generated on three directions were established. The velocity and straightness indexes of all subjects increased when subjects had to reach to targets placed more distantly (r= 0.82-0.90; ρ= 0.86-0.90 respectively; p < 0.001).CONCLUSIONSThis protocol can be integrated into a serious game in order to continuously configure the game characteristics to patient's performance.

Assessment of upper limb spasticity in stroke patients using the robotic device REAplan.

OBJECTIVE:  To assess the capacity of the robotic device REAplan to measure overall upper limb peak resistance force, as a reflection of upper limb spasticity. METHODS:  Twelve patients with chronic stroke presenting upper limb spasticity were recruited to the study. Patients underwent musculocutaneous motor nerve block to reduce the spasticity of elbow flexor muscles. Each patient was assessed before and after the motor nerve block. Overall the REAplan measured upper limb resistance force. The robot passively mobilized the patient's upper limb at various velocities (10, 20, 30, 40 and 50 cm/s) in a back-and-forth trajectory (30 cm). The peak resistance force was analysed for each forward movement. Ten movements were performed and averaged at each velocity condition. RESULTS: The overall upper limb resistance force increased proportionally to the mobilization velocity (p< 0.001). Resistance force decreased after the motor nerve block at 40 and 50 cm/s (p < 0.05). Overall upper limb resistance force results showed excellent correlation with the Modified Ashworth Scale for elbow flexor muscles, for each velocity condition equal or higher than 30 cm/s (ρ >0.6). CONCLUSION:  This study proposes a new, valid, reliable and sensitive protocol to quantify upper limb resistance force using the REAplan, as a reflection of upper limb spasticity.

Reducing the energy cost of hemiparetic gait using center of mass feedback: a pilot study.

BACKGROUND: Hemiparetic gait following stroke requires substantial energy consumption, which would promote deconditioning and disability. Optimal modalities for decreasing this energy cost remain challenging. Excessive energy consumption, however, seems to be mainly due to extra positive muscle work to substantially lift the body's center of mass (CM) against gravity during the paretic limb swing. OBJECTIVE: The authors tested a new rehabilitation strategy in a pilot study to specifically reduce the energy cost in hemiparetic gait. METHODS: Six chronic hemiparetic patients underwent a 6-week gait training program on a treadmill with real-time feedback of their CM and were asked to reduce its increased vertical displacement. The authors assessed the walking energy cost, vertical CM displacement, kinematics, and electromyogram activity without feedback before and after treatment. RESULTS: After treatment, the vertical CM displacement decreased by 10% (P = .005), particularly when the CM vaulted over the nonparetic limb in stance, and the energy cost decreased markedly by 30% (P = .009). The paretic knee flexion in swing increased concomitantly by 45% and muscle co-contraction decreased significantly in both thigh muscles by 15%. CONCLUSIONS: The rehabilitation approach followed in this study seems remarkably effective in decreasing the walking energy cost. By treating the compensatory strategy (ie, the increased CM displacement), we also appear to treat primary deviations such as poststroke knee impairments, which is novel and complementary to current concepts in rehabilitation. This new approach is promising and merits further investigation.

Effect of speed on the energy cost of walking in unilateral traumatic lower limb amputees.

In this work, the effect of walking speed on the energy expenditure in traumatic lower-limb amputees was studied. The oxygen consumption was measured in 10 transfemoral amputees, 9 transtibial amputees and 13 control subjects, while they stood and walked at different speeds from 0.3 m s(-1) to near their maximum sustainable speed. Standing energy expenditure rate was the same in lower-limb amputees and in control subjects (approximately 1.85 W kg(-1)). On the contrary, during walking, the net energy expenditure rate was 30-60% greater in transfemoral amputees and 0-15% greater in transtibial amputees than in control subjects. The maximal sustainable speed was about 1.2 m s(-1) in transfemoral amputees and 1.6 m s(-1) in transtibial amputees, whereas it was above 2 m s(-1) in control subjects. Among these three groups, the cost of transport versus speed presented a U-shaped curve; the minimum cost increased with the level of amputation, and the speed at which this minimum occurred decreased.

Quantitative assessment of anaesthetic nerve block and neurotomy in spastic equinus foot: a review of two cases.

OBJECTIVE: To quantitatively evaluate the effect of motor nerve branch block and neurotomy of the soleus nerve on triceps surae spasticity, reviewing 2 cases. METHODS: Beside clinical assessment, we carried out a quantitative measurement of the stiffness of the ankle flexor muscles. The path length of the phase diagram between elastic and viscous stiffness quantifies the reflex response to movement and reflects the importance of the spasticity. The assessments were carried out before and 30 min after motor nerve branch block of the upper soleus nerve and more than 7 months after neurotomy. RESULTS: Both patients presented with pronounced ankle plantar flexor spasticity: their path lengths were more than 6 times greater than normal values at baseline (#1: 354 N m rad(-1); #2: 409 N m rad(-1)). Motor nerve branch block and neurotomy allowed a near-normalization of elastic and viscous stiffness of ankle plantar flexor muscles in the 2 patients. Their path length was almost similarly improved by motor nerve branch block (#1: 127 N m rad(-1); #2: 231 N m rad(-1)) and neurotomy (#1: 60 N m rad(-1); #2: 162 N m rad(-1)). CONCLUSION: These case reports highlight the fundamental role of the soleus muscle in triceps surae spasticity in our patients, the predictivity of motor nerve branch block in the preoperative assessment, and the effectiveness of soleus neurotomy in spastic equinus foot.

Mechanical work, energetic cost, and gait efficiency in children with cerebral palsy.

Many authors have reported increased energy expenditure during walking in children with hemiplegia. The origin of this increase is not well documented. The aim of our study was to understand better the origin of this increased energy expenditure of walking in children with cerebral palsy (CP) by simultaneously assessing the total mechanical work performed by the muscles and the efficiency of the work production.Twenty independently walking children with spastic, hemiplegic CP and a dynamic foot equinus deformity participated in the study. Instrumented gait analysis, including the analysis of kinematic, mechanical, and energetic variables, was performed. Despite excellent Gross Motor Function Measurement scores (range, 97-99), the energy cost was 1.3 times greater in children with CP than in healthy children. This increase in energy cost was related to an increase in the total positive mechanical work performed by the muscles and not related to a decrease in the efficiency of this work production. This study shows how segmental impairments (foot spastic equinus) increase the total mechanical work performed by the muscles and the energetic cost and how these segmental impairments contribute to the patient's disability. It is useful to associate the clinical examination, classic gait analysis, mechanical work, and energetic assessment to complete the evaluation of the condition of children with CP.

Relationship between energy cost, gait speed, vertical displacement of centre of body mass and efficiency of pendulum-like mechanism in unilateral amputee gait.

The energy cost of gait (C) is greater in amputee than in normal subjects. Our objective was to assess the influence of lower speed, inefficient pendulum mechanism and disturbed smoothness of centre of body mass (CM(b)) displacement on C in unilateral amputees and to have a better understanding the relationship between these variables. Twelve adult patients (six traumatic transfemoral and six vascular transtibial amputees) participated in the study. Lower limb kinematics, displacement of CM(b), mechanical work done by the muscles to move the CM(b) and the segments due to their movements relative to the CM(b), efficiency of the pendulum mechanism, and C were assessed simultaneously in the 12 amputees walking at their self-selected speed. Our results show that C depended on gait speed, and efficiency of pendulum-like mechanism of walking but did not depend on the smoothness of CM(b). The use of only a single variable to explain the extra cost in amputee gait could sometimes be misleading.

Outcome assessment in osteoarthritic patients undergoing total knee arthroplasty.

The purpose of this study was to better understand the relationship between knee pain, locomotor functional status, and health-related quality of life (HRQoL) outcomes in osteoarthritic (OA) patients undergoing primary total knee arthroplasty (TKA). Nine OA patients were recruited. Pain, locomotor function, and HRQoL were evaluated one day before and 6 months after TKA by means of a visual analogue scale (VAS) for knee pain, the function score of the Knee Society (KS), the metabolic cost of gait (C), the total mechanical work during gait (Wtot), and the Medical Outcomes Study Short Form-36 Health Survey (MOS SF-36). Our results showed a decrease in knee pain and metabolic cost of gait and an improvement in quality of life. Moreover we showed a relationship between: (1) the VAS score for knee pain, the function score of the KS, and MOS SF-36 Physical Functioning, Role-Physical, and Bodily Pain subscales; and (2) the C, the Wtot, and the MOS SF-36 Vitality subscale.