Combating sarcopenia in geriatric rehabilitation patients: study protocol of the EMPOWER-GR observational cohort, sarcopenia awareness survey and randomised controlled feasibility trial

INTRODUCTION

Sarcopenia is highly prevalent in geriatric rehabilitation patients. Resistance exercise training (RET) combined with protein supplementation is recommended to increase muscle mass and strength in older adults. However, sarcopenia awareness, feasibility to diagnose and treat sarcopenia, and efficacy of treatment in geriatric rehabilitation patients remain to be established.

METHODS AND ANALYSIS

Enhancing Muscle POWER in Geriatric Rehabilitation (EMPOWER-GR) encompasses four pillars: (1) an observational cohort study of 200 geriatric rehabilitation inpatients determining sarcopenia prevalence, functional and nutritional status at admission; (2) a survey among these 200 patients and 500 healthcare professionals and semistructured interviews in 30 patients and 15 carers determining sarcopenia awareness and barriers/enablers regarding diagnostics and treatment; (3) a feasibility, single-centre, randomised, controlled, open-label, two parallel-group trial in 80 geriatric rehabilitation patients with sarcopenia. The active group (n=40) receives three RET sessions per week and a leucine and vitamin D-enriched whey protein-based oral nutritional supplement two times per day in combination with usual care for 13 weeks. The control group (n=40) receives usual care. Primary outcomes are feasibility (adherence to the intervention, dropout rate, overall feasibility) and change from baseline in absolute muscle mass at discharge and week 13. Secondary outcomes are feasibility (participation rate) and change from baseline at discharge and week 13 in relative muscle mass, muscle strength, physical and functional performance, mobility, nutritional status, dietary intake, quality of life and length of stay; institutionalisation and hospitalisation at 6 months and mortality at 6 months and 2 years; (4) knowledge sharing on sarcopenia diagnosis and treatment.

ETHICS AND DISSEMINATION

Ethical exemption was received for the observational cohort study, ethics approval was received for the randomised controlled trial. Results will be disseminated through publications in scientific peer-reviewed journals, conferences and social media.

TRIAL REGISTRATION NUMBER

NL9444.

Computerised patient-specific prediction of the recovery profile of upper limb capacity within stroke services: the next step

INTRODUCTION

Predicting upper limb capacity recovery is important to set treatment goals, select therapies and plan discharge. We introduce a prediction model of the patient-specific profile of upper limb capacity recovery up to 6 months poststroke by incorporating all serially assessed clinical information from patients.

METHODS

Model input was recovery profile of 450 patients with a first-ever ischaemic hemispheric stroke measured using the Action Research Arm Test (ARAT). Subjects received at least three assessment sessions, starting within the first week until 6 months poststroke. We developed mixed-effects models that are able to deal with one or multiple measurements per subject, measured at non-fixed time points. The prediction accuracy of the different models was established by a fivefold cross-validation procedure.

RESULTS

A model with only ARAT time course, finger extension and shoulder abduction performed as good as models with more covariates. For the final model, cross-validation prediction errors at 6 months poststroke decreased as the number of measurements per subject increased, from a median error of 8.4 points on the ARAT (Q1-Q3:1.7-28.1) when one measurement early poststroke was used, to 2.3 (Q1-Q3:1-7.2) for seven measurements. An online version of the recovery model was developed that can be linked to data acquisition environments.

CONCLUSION

Our innovative dynamic model can predict real-time, patient-specific upper limb capacity recovery profiles up to 6 months poststroke. The model can use all available serially assessed data in a flexible way, creating a prediction at any desired moment poststroke, stand-alone or linked with an electronic health record system.

The effect of cerebellar transcranial direct current stimulation to improve standing balance performance early post-stroke, study protocol of a randomized controlled trial

Rationale

Restoration of adequate standing balance after stroke is of major importance for functional recovery. POstural feedback ThErapy combined with Non-invasive TranscranIAL direct current stimulation (tDCS) in patients with stroke (POTENTIAL) aims to establish if cerebellar tDCS has added value in improving standing balance performance early post-stroke.

Methods

Forty-six patients with a first-ever ischemic stroke will be enrolled in this double-blind controlled trial within five weeks post-stroke. All patients will receive 15 sessions of virtual reality-based postural feedback training (VR-PFT) in addition to usual care. VR-PFT will be given five days per week for 1 h, starting within five weeks post-stroke. During VR-PFT, 23 patients will receive 25 min of cerebellar anodal tDCS (cb_tDCS), and 23 patients will receive sham stimulation.

Study outcome

Clinical, posturographic, and neurophysiological measurements will be performed at baseline, directly post-intervention, two weeks post-intervention and at 15 weeks post-stroke. The primary outcome measure will be the Berg Balance Scale (BBS) for which a clinical meaningful difference of six points needs to be established between the intervention and control group at 15 weeks post-stroke.

Discussion

POTENTIAL will be the first proof-of-concept randomized controlled trial to assess the effects of VR-PFT combined with cerebellar tDCS in terms of standing balance performance in patients early post-stroke. Due to the combined clinical, posturographical and neurophysiological measurements, this trial may give more insights in underlying post-stroke recovery processes and whether these can be influenced by tDCS.

Comprehensive neuromechanical assessment in stroke patients: reliability and responsiveness of a protocol to measure neural and non-neural wrist properties

BACKGROUND

Understanding movement disorder after stroke and providing targeted treatment for post stroke patients requires valid and reliable identification of biomechanical (passive) and neural (active and reflexive) contributors. Aim of this study was to assess test-retest reliability of passive, active and reflexive parameters and to determine clinical responsiveness in a cohort of stroke patients with upper extremity impairments and healthy volunteers.

METHODS

Thirty-two community-residing chronic stroke patients with an impairment of an upper limb and fourteen healthy volunteers were assessed with a comprehensive neuromechanical assessment protocol consisting of active and passive tasks and different stretch reflex-eliciting measuring velocities, using a haptic manipulator and surface electromyography of wrist flexor and extensor muscles (Netherlands Trial Registry number NTR1424). Intraclass correlation coefficients (ICC) and Standard Error of Measurement were calculated to establish relative and absolute test-retest reliability of passive, active and reflexive parameters. Clinical responsiveness was tested with Kruskal Wallis test for differences between groups.

RESULTS

ICC of passive parameters were fair to excellent (0.45 to 0.91). ICC of active parameters were excellent (0.88-0.99). ICC of reflexive parameters were fair to good (0.50-0.74). Only the reflexive loop time of the extensor muscles performed poor (ICC 0.18). Significant differences between chronic stroke patients and healthy volunteers were found in ten out of fourteen parameters.

CONCLUSIONS

Passive, active and reflexive parameters can be assessed with high reliability in post-stroke patients. Parameters were responsive to clinical status. The next step is longitudinal measurement of passive, active and reflexive parameters to establish their predictive value for functional outcome after stroke.

Calibration of the "Flock of Birds" electromagnetic tracking device and its application in shoulder motion studies

In this paper the applicability in terms of measurement accuracy of the "Flock of Birds" six D.O.F. electromagnetic tracking device in shoulder research is investigated. Position measurements in a workspace of approximately 1 m3 were performed using a stylus. The andom error at the stylus tip appeared to be 1.86, 1.98 and 2.54 mm for x-, y- and z-coordinate, respectively. The error caused by distortion of the magnetic field by metal in the concrete of especially the floor was 20.8, 22.2 and 20.4 mm for the x-, y- and z-coordinate, respectively. Calibration and leaving out the measurements closest to the floor lowered this error to 2.07, 2.38 and 2.35 mm. Orientation errors of the shoulder bones evolving from the measurement inaccuracy were estimated from repeated measurements of shoulder bony landmarks of ten subjects by means of the stylus. These errors were generally below 2 degrees. This is lower than found for the same measurements using a spatial linkage digitizer. It is concluded that the "Flock of Birds" is a useful tool for shoulder kinematic studies.

Determination of the optimal elbow axis for evaluation of placement of prostheses

OBJECTIVE

To present a method to determine the position and orientation of the mean optimal flexion axis of the elbow in vivo to be used in clinical research.

DESIGN

Registering the movements of the forearm with respect to the upper arm during five cycles of flexion and extension of the elbow using a 6 degrees-of-freedom electromagnetic tracking device.

BACKGROUND

Loosening of elbow endoprostheses could be caused by not placing the prostheses in a biomechanically optimal way. To evaluate the placement of endoprostheses with regard to loosening, a method to determine the elbow axis is needed.

METHODS

The movements of the right forearm with respect to the upper arm during flexion and extension were registered with a 6 degrees-of-freedom electromagnetic tracking device. A mean optimal instantaneous helical axis of 10 elbows was calculated in a coordinate system related to the humerus.

RESULTS

The average position of the flexion/extension axis was 0.81 cm (SD 0.66 cm) cranially and 1.86 cm (SD 0.72 cm) ventrally of the epicondylus lateralis. The average angle with the frontal plane was 15.3 degrees (SD 2 degrees).

CONCLUSIONS

A useful estimation of the position and orientation of a mean optimal flexion axis can be obtained in vivo.

In vivo estimation of the glenohumeral joint rotation center from scapular bony landmarks by linear regression

In this paper, a method is described for in vivo prediction of the glenohumeral joint rotation center (GH-r), necessary for the construction of a humerus local coordinate system in shoulder kinematic studies. The three-dimensional positions of five scapula bony landmarks as well as a large number of data points on the surface of the glenoid and humeral head were collected at 36 sets of cadaver scapulae and adjacent humeri. The position of GH-r in each scapula was estimated by mathematically fitting spheres to the glenoid and humeral head. GH-r prediction from scapula geometry parameters by linear regression resulted in a RMSE between measured and predicted GH-r of 2.32 mm for the x-coordinate, 2.69 mm for the y-coordinate and 3.04 mm for the z-coordinate. Application in vivo revealed a random humerus orientation error due to measurement inaccuracies of 1.35, 0.29 and 1.26 degrees standard deviation per rotation angle. The estimated total humerus orientation error including the offset error due to the regression model inaccuracy was 2.86, 0.84 and 2.69 degrees standard deviation. As these errors were about 15 and 20% of, respectively, the intra- and inter-subject variability of the humerus orientations measured, it is concluded that the method described in this paper allows for an adequate construction of a humerus local coordinate system.

Estimation of instantaneous moment arms of lower-leg muscles

Muscle moment arms at the human knee and ankle were estimated from muscle length changes measured as a function of joint flexion angle in cadaver specimens. Nearly all lower-leg muscles were studied: extensor digitorum longus, extensor hallucis longus, flexor digitorum longus, flexor hallucis longus, gastrocnemius lateralis, gastrocnemius medialis, peroneus brevis, peroneus longus, peroneus tertius, plantaris, soleus, tibialis anterior, and tibialis posterior. Noise in measured muscle length was filtered by means of quintic splines. Moment arms of the mm. gastrocnemii appear to be much more dependent on joint flexion angles than was generally assumed by other investigators. Some consequences for earlier analyses are mentioned.