Gert Kwakkel

• Professor
• Chair at Amsterdam University Medical Center

Introduction: Upper limb (UL) rehabilitation is driven by intensive, task-specific training. In this article we further elaborate on the results of a systematic review and meta-analysis on the effectiveness of UL-robots (UL-RTs) to recovery of UL-motor impairment, UL-capacity, and basic-ADLs post-stroke when compared to any non-UL-RT. Our second ai...

Objective To assess the added value of caregiver-mediated exercises combined with telerehabilitation in addition to usual care compared to usual care alone on the self-reported mobility outcome after subacute stroke. Design Multicentre, observer-blinded, parallel randomised controlled trial. An off-site researcher allocated treatments using minimi...

Stroke is not only associated with muscle weakness, but also associated with reduced muscle fatigue resistance and reduced desaturation during exercise that may be caused by a reduced oxidative capacity and/or microvasculature. Therefore, the objective of the present study was to determine the effects of stroke on muscle mass, fiber size and shape,...

Background and objectives: Robot technology to support upper limb (UL) rehabilitation poststroke has rapidly developed over the past 3 decades. We aimed to assess the effects of UL-robots (UL-RTs) on recovery of UL motor functioning and capacity poststroke when compared with any non-UL-RT and to identify variables that are associated with the foun...

Stroke is a leading cause of disability worldwide which can cause significant and persistent upper limb (UL) impairment. It is difficult to predict UL motor recovery after stroke and to forecast the expected outcomes of rehabilitation interventions during the acute and subacute phases when using clinical data alone. Accurate prediction of response...

Introduction Center-of-pressure (COP) synchronization and symmetry can inform adaptations in balance control following one-sided sensorimotor impairments (e.g., stroke). As established force plates are impossible to transport, we aimed to criterion validate a portable pressure plate for obtaining reliable COP synchronization and symmetry measures,...

Background Mobility is a key priority for stroke survivors. Worldwide consensus of standardized outcome instruments for measuring mobility recovery after stroke is an essential milestone to optimize the quality of stroke rehabilitation and recovery studies and to enable data synthesis across trials. Methods Using a standardized methodology, which...

Background Mobility is a key priority for stroke survivors. Worldwide consensus of standardized outcome instruments for measuring mobility recovery after stroke is an essential milestone to optimize the quality of stroke rehabilitation and recovery studies and to enable data synthesis across trials. Methods Using a standardized methodology, which...

BACKGROUND Evidence of efficacy of repetitive transcranial magnetic stimulation (rTMS) for stroke recovery is hampered by an unexplained variability of reported effect sizes and an insufficient understanding of mechanisms of action. We aimed to (1) briefly summarize evidence of efficacy, (2) identify critical factors to explain the reported variati...

Background: Recovery of quiet standing balance early poststroke has been poorly investigated using repeated measurements. Objective: To investigate (1) the time course of steady-state balance in terms of postural stability and inter-limb symmetry, and (2) longitudinal associations with lower limb motor recovery in the first 3 months poststroke....

Purpose: To propose a consensus-based definition and framework for motor rehabilitation after stroke. Methods: An expert European working group reviewed the literature, attaining internal consensus after external feedback. Findings: Motor rehabilitation is defined as a process that engages people with stroke to benefit their motor function, ac...

Background Sixty percent of people have non-functional arms 6 months after stroke. More effective treatments are needed. Cochrane Reviews show low-quality evidence that task-specific training improves upper limb function. Our feasibility trial showed 56 h of task-specific training over 6 weeks resulted in an increase of a median 6 points on the Act...

Fatigue is a common complaint and a disabling symptom among patients following transient ischemic attack (TIA) or minor stroke. In patients with stroke, decreased cardiorespiratory fitness (CRF) is believed to be related to increased severity of post-stroke fatigue (PSF). However, this association between PSF and CRF in patients with TIA or minor s...

Dissociation between lower limb motor recovery and control of standing balance early poststroke – First results from a repeated-measurements cohort study Schröder J.1, Saeys W. 1, Embrechts E. 1, Hallemans A. 1, Yperzeele L. 2, Truijen S. 1, Kwakkel G. 3 1 University of Antwerp, Research group MOVANT, dep. Rehabilitation Sciences & Physiotherapy (...

The proportional recovery rule (PRR) posits that most stroke survivors can expect to reduce a fixed proportion of their motor impairment. As a statistical model, the PRR explicitly relates change scores to baseline values - an approach that arises in many scientific domains but has the potential to introduce artifacts and flawed conclusions. We des...

Background Patients with a transient ischemic attack (TIA) or ischemic stroke are at increased risk of developing cognitive impairment in the subacute phase. At present, the effects of exercise on cognitive functioning following a TIA or stroke are not fully known. The purpose of this trial was to investigate the effect of exercise on global cognit...

p>Some Western countries, such as England, the Netherlands, Canada, and Australia, have clinical guidelines that provide different time-based recommendations for rehabilitation after stroke. This review seeks to understand the effect of time spent in rehabilitation, to support service providers to optimize recovery for people following stroke. It d...

Transcranial direct current stimulation (tDCS) is a promising tool to improve and speed up motor rehabilitation after stroke, but inconsistent clinical effects refrain tDCS from clinical implementation. Therefore, this study aimed to assess the need for individualized tDCS configurations in stroke, considering interindividual variability in brain a...

Jonas Schröder¹, Ann Hallemans¹, Laetitia Yperzeele², Gert Kwakkel³, Wim Saeys¹, Steven Truijen¹ ¹University of Antwerp, ²University Hospital Antwerp, ³Amsterdam UMC, Vrije Universiteit Amsterdam BACKGROUND AND AIM: Posturography typically involves a single composite measure of the center-of-pressure (COP) under both feet. Such measures establi...

Introduction Although most stroke survivors show some spontaneous neurological recovery from motor impairments of the most-affected leg, the contribution of this leg to standing balance control remains often poor. Consequently, it is unclear how spontaneous processes of neurological recovery contributes to early improvements in standing balance. O...

Background: Disambiguation of behavioral restitution from compensation is important to better understand recovery of upper limb motor control post-stroke and subsequently design better interventions. Measuring quality of movement (QoM) during standardized performance assays and functional tasks using kinematic and kinetic metrics potentially allow...

Background The evidence for rehabilitation interventions poststroke lack sufficient robustness. However, variation in treatment effects across countries have been given little attention. Objective To compare two identically protocolized trials conducted in different western countries in order to identify factors that may have caused variation in s...

Secondary white matter degeneration is a common occurrence after ischemic stroke, as identified by Diffusion Tensor Imaging (DTI). However, despite recent advances, the time course of the process is not completely understood. The primary aim of this study was to assess secondary degeneration using an approach whereby we create a patient-specific mo...

Secondary white matter degeneration is a common occurrence after ischemic stroke, as identified by Diffusion Tensor Imaging (DTI). However, despite recent advances, the time course of the process is not completely understood. The primary aim of this study was to assess secondary degeneration using an approach whereby we create a patient-specific mo...

Background Recovery of walking ability is an important goal for patients poststroke, and a basic level of mobility is critical for an early discharge home. Caregiver-mediated exercises could be a resource-efficient strategy to augment exercise therapy and improve mobility in the first months poststroke. A combination of telerehabilitation and face-...

Objective – The present study aimed to create a shorter version of the Action Research Arm Test (ARAT) without compromising its measurement properties. Design – Secondary analysis of stroke recovery cohorts that used the ARAT to measure upper-limb impairment. Setting – Rehabilitation centers. Participants – Patients with stroke from five different...

This paper describes the design of the Armed4Stroke program. Patients after stroke and their caregivers are included as a couple. The caregiver is trained as a co-therapist by a physiotherapist experienced in providing caregiver-mediated exercises (CME) to support and motivate the patient. The program consists of 8 weeks of gait and gait-related ex...

Background Stroke survivors show deteriorated physical functioning and physical activity levels. Physical activity levels of stroke survivors are generally low. It is increasingly recognized that physical activity is a multidimensional construct that cannot be captured in a single outcome. In-depth insight into multidimensional physical activity pa...

Samenvatting Triage na een beroerte vindt landelijk niet op uniforme wijze plaats. Hierdoor kan het voorkomen dat bij dezelfde functionele prognose per zorgaanbieder en -locatie verschillende revalidatiebehandelingen gegeven worden. Met een ‘Leidraad voor meetinstrumenten ter ondersteuning van de triage na beroerte’ wordt de besluitvorming voor ver...

Background: Proprioception is important for regaining motor function in the paretic upper extremity after stroke. However, clinical assessments of proprioception are subjective and require verbal responses from the patient to applied proprioceptive stimuli. Cortical responses evoked by robotic wrist perturbations and measured by electroencephalogra...

Background Smoothness is commonly used for measuring movement quality of the upper paretic limb during reaching tasks after stroke. Many different smoothness metrics have been used in stroke research, but a ‘valid’ metric has not been identified. A systematic review and subsequent rigorous analysis of smoothness metrics used in stroke research, in...

Background: Stroke affects millions of people every year and is a leading cause of disability, resulting in significant financial cost and reduction in quality of life. Rehabilitation after stroke aims to reduce disability by facilitating recovery of impairment, activity, or participation. One aspect of stroke rehabilitation that may affect outcom...

Patients with poor upper limb motor recovery after stroke are likely to develop increased resistance to passive wrist extension, i.e., wrist hyper-resistance. Quantification of the underlying neural and non-neural elastic components is of clinical interest. This cross-sectional study compared two methods: a commercially available device (NeuroFlexo...

Background The cause of smoothness deficits as a proxy for quality of movement post stroke is currently unclear. Previous simulation analyses showed that spectral arc length (SPARC) is a valid metric for investigating smoothness during a multi-joint goal-directed reaching task. The goal of this observational study was to investigate how SPARC value...

Purpose The aim of this study was to assess the effects of experimentally induced photothrombotic stroke on structural and mechanical properties of rat m. flexor carpi ulnaris . Methods Two groups of Young-adult male Sprague–Dawley rats were measured: stroke ( n = 9) and control ( n = 7). Photothrombotic stroke was induced in the forelimb region o...

Introduction: Outcome measures are key to tailor rehabilitation goals to the stroke patient's individual needs and to monitor poststroke recovery. The large number of available outcome measures leads to high variability in clinical use. Currently, an internationally agreed core set of motor outcome measures for clinical application is lacking. Ther...

Background: Stroke affects the neuronal networks of the non-infarcted hemisphere. The central motor conduction time (CMCT) induced by transcranial magnetic stimulation (TMS) could be used to determine the conduction time of the corticospinal tract of the non-infarcted hemisphere after a stroke. Objectives: Our primary aim was to demonstrate the exi...

Background Flow is a subjective psychological state that people report when they are fully involved in an activity to the point of forgetting time and their surrounding except the activity itself. Being in flow during physical/cognitive rehabilitation may have a considerable impact on functional outcome, especially when patients with neurological d...

Introduction Botulinum toxin‐A (BoNT) is widely used to manage focal upper limb spasticity and is effective in reducing resistance to passive movement, as measured with the modified Ashworth scale. Discrimination and quantification of the underlying neural and non‐neural components of hyper‐resistance may further improve understanding of the effect...

Background Evidence from animal studies suggests that greater reductions in poststroke motor impairment can be attained with significantly higher doses and intensities of therapy focused on movement quality. These studies also indicate a dose-timing interaction, with more pronounced effects if high-intensity therapy is delivered in the acute/subacu...

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 r...

Objectives Investigate whether resting-state EEG parameters recorded early poststroke can predict upper extremity motor impairment reflected by the Fugl-Meyer motor score (FM-UE) after six months, and whether they have prognostic value in addition to FM-UE at baseline. Methods Quantitative EEG parameters delta/alpha ratio (DAR), brain symmetry ind...

Stroke is the second leading cause of death and a leading cause of disability worldwide. This invaluable reference provides clinicians caring for stroke patients with ready access to the optimal evidence for best practice in stroke prevention, acute stroke treatment, and stroke recovery. Now an edited volume, the editors and authors, many of whom a...

Introduction: Outcome measures are key to tailor rehabilitation goals to the stroke patient's individual needs and to monitor poststroke recovery. The large number of available outcome measures leads to high variability in clinical use. Currently, an internationally agreed core set of motor outcome measures for clinical application is lacking. Ther...

Background: Evidence from animal studies suggests that greater reductions in post-stroke motor impairment can be attained with significantly higher doses and intensities of therapy focused on movement quality. These studies also indicate a dose-timing interaction, with more pronounced effects if high-intensity therapy is delivered in the acute/suba...

This commentary is on the original article by Xu et al. on pages 1040–1046 of this issue.

Aim: We studied the longitudinal associations between freezing of gait (FoG), fear of falling (FoF) and anxiety, and how these associations are influenced by confounding factors. Materials & methods: We analyzed longitudinal motor and nonmotor measurements from 153 Parkinson’s disease patients. Possible confounding factors were divided into three s...

Background. Patients with an upper limb motor impairment are likely to develop wrist hyper-resistance during the first months post stroke. The time course of wrist hyper-resistance in terms of neural and biomechanical components, and their interaction with motor recovery, is poorly understood. Objective. To investigate the time course of neural and...

Background. Spontaneous recovery early after stroke is most evident during a time-sensitive window of heightened neuroplasticity, known as spontaneous neurobiological recovery. It is unknown whether poststroke upper-limb motor and somatosensory impairment both reflect spontaneous neurobiological recovery or if somatosensory impairment and/or recove...

Knowledge about the functional prognosis of stroke patients admitted to a stroke unit has increased substantially over the past years. Prospective cohort studies suggest that the return of some finger extension and voluntary activity in the shoulder abductors within days post-stroke onset predicts a favourable recovery of the upper extremity functi...

In the new edition of the Oxford Textbook of Neurorehabilitation all chapters have been updated to reflect advances in knowledge in the field of neurorehabilitation. It will be supplemented by additional chapters that reflect novel developments in the field of neurorehabilitation. During recent years there has been a strong evolution in the field o...

Background. The time course of cortical activation and its relation with clinical measures may elucidate mechanisms underlying spontaneous neurobiological recovery after stroke. Objective. We aimed to investigate (1) the time course of cortical activation as revealed by EEG-based spectral characteristics during awake rest and (2) the development of...

Exercise as a subset of physical activity is a cornerstone in the management of multiple sclerosis (MS) based on its pleotropic effects. There is an exponential increase in the quantity of research on exercise in MS, yet a number of barriers associated with study content and quality hamper rapid progress in the field. To address these barriers and...

Background. Addressing the role of somatosensory impairment, that is, afferent pathway integrity, in poststroke motor recovery may require neurophysiological assessment. Objective. We investigated the longitudinal construct validity of position-cortical coherence (PCC), that is, the agreement between mechanically evoked wrist perturbations and elec...

Objective: Recovery of the paretic arm post-stroke can be assessed using observational and self-reported measures. The aim of this study was to determine whether the correspondence (match) or non-correspondence (mismatch) between observational and self-reported improvements in upper limb capacity are significantly different at 0-3 months compared...

Primary Objective: To investigate the level of agreement and differences regarding the perception of family functioning between patients with acquired brain injury and their partners. Our hypothesis was that patients would report better family functioning than their partners. Research Design: Cross-sectional study Methods and Procedures: Baseline d...

Objective: Spontaneous recovery is an important determinant of upper extremity recovery after stroke, and has been described by the 70% proportional recovery rule for the Fugl-Meyer motor upper extremity (FM-UE) scale. However, this rule is criticized for overestimating the predictability of FM-UE recovery. Our objectives were to (1) develop a lon...

The second Stroke Recovery and Rehabilitation Roundtable “metrics” task force developed consensus around the recognized need to add kinematic and kinetic movement quantification to its core recommendations for standardized measurements of sensorimotor recovery in stroke trials. Specifically, we focused on measurement of the quality of upper limb mo...

The second Stroke Recovery and Rehabilitation Roundtable “metrics” task force developed consensus around the recognized need to add kinematic and kinetic movement quantification to its core recommendations for standardized measurements of sensorimotor recovery in stroke trials. Specifically, we focused on measurement of the quality of upper limb mo...

Background: Within the first 72 hours after stroke, active finger extension is a strong predictor of long-term dexterity. Transcranial magnetic stimulation may add prognostic value to clinical assessment, which is especially relevant for patients unable to follow instructions. Objective: The current prospective cohort study aims at determining w...

Bij de ziekte van Parkinson zijn evenwichtsproblemen niet ongewoon. Aanvullende visuele feedback over de zwaaibewegingen van het lichaam tijdens het staan kan de prestatie op een houdingstaak verbeteren en balanstraining ondersteunen. Tegelijkertijd lijken mensen met parkinson extra afhankelijk te zijn van visuele informatie. Ze zijn daarmee mogeli...

Introduction: Differentiating between the components of wrist hyper-resistance post stroke, i.e., pathological neuromuscular activation (“spasticity”) and non-neural biomechanical changes, is important for treatment decisions. This study aimed to assess the reliability and construct validity of an innovative measurement device that quantifies these...

Objective Peer support facilitates patients and caregivers in adjusting to long-term disabilities. This study aimed to determine which patient characteristics are related to need for peer support during rehabilitation after acquired brain injury (ABI) and investigate factors that explain whether peer support is perceived as meaningful or not. Desi...

Ambulatory sensing of gait kinematics using inertial measurement units (IMUs) usually uses sensor fusion filters. These algorithms require measurement updates to reduce drift between segments. A full body IMU suit can use biomechanical relations between body segments to solve this. However, when minimising the sensor set, we lose a lot of this info...

Objective: To classify patients with stroke into subgroups based on their characteristics at the moment of discharge from inpatient rehabilitation in order to predict community ambulation outcome 6 months later. Design: Prospective cohort study with a baseline measurement at discharge from inpatient care and final outcome determined after 6 mont...

Background and purpose We designed an 8-week caregiver-mediated exercise program with e-health support after stroke (CARE4STROKE) in addition to usual care with the aim to improve functional outcome and to facilitate early supported discharge by increasing the intensity of task specific training. Methods An observer-blinded randomized controlled t...

Absolute values of outcomes, reported as means and standard deviations (SD), Beta (SE = Standard error) and P-values of outcome measures. (DOCX)

Study protocol CARE4STROKE. (PDF)

Checklist physiotherapist intake exercise session. (DOCX)

CARE4STROKE database. (XLSX)

Self-reported exercise time over 8 weeks (in minutes), reported as medians and interquartile ranges (IQR). (DOCX)

The Stroke Recovery and Rehabilitation Roundtable (SRRR) meetings bring together an international group of preclinical and clinical researchers along with statisticians, methodologists, funders and consumers, working to accelerate the development of effective treatments for stroke recovery and to support best-evidence uptake in rehabilitation pract...

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...

Objective: We investigated the potential added value of high-density resting-state EEG by addressing differences with healthy individuals and associations with Fugl-Meyer motor assessment of the upper extremity (FM-UE) scores in chronic stroke. Methods: Twenty-one chronic stroke survivors with initial upper limb paresis and eleven matched contro...

Objective: To provide a comprehensive overview of reported effects and scientific robustness of botulinum toxin (BoNT) treatment regarding the main clinical goals related to poststroke upper limb spasticity, using the International Classification of Functioning, Disability and Health. Data sources: Embase, PubMed, Wiley/Cochrane Library, and Ebs...

Oefenen met een naaste (caregiver-mediated exercises, CME) in aanvulling op de reguliere therapie is een nieuwe vorm van oefenen voor patiënten met een beroerte. Deze exploratieve kwalitatieve studie, onderdeel van de CARE4STROKE trial, richt zich op de ervaring van het samen oefenen. De onderzoeksvragen waren: 1) Hoe oefenen patiënt en naaste same...

Purpose: Caregiver-mediated exercises are a novel way of delivering augmented exercise therapy for patients with stroke, in which patients do additional therapeutic exercises together with a caregiver. This explorative qualitative study is part of the CARE4STROKE trial and focused on how participants manage these exercises together. The research qu...

Transcranial direct current stimulation (tDCS) may serve as an adjunct approach in stroke rehabilitation. The cerebellum could be a target during standing balance training due to its role in motor adaptation. We tested whether cerebellar tDCS can lead to short-term effects on standing balance performance in patients with chronic stroke. Fifteen pat...

In hemiparetic stroke, functional recovery of paretic limb may occur with the reorganization of neural networks in the brain. Neuroimaging techniques, such as magnetic resonance imaging (MRI), have a high spatial resolution which can be used to reveal anatomical changes in the brain following a stroke. However, low temporal resolution of MRI provid...

Brain information flow for Control 1.

Brain information flow for Control 2.