Ann Hallemans

• PhD
• Professor (Associate) at University of Antwerp

Functional near-infrared spectroscopy (fNIRS) is particularly suitable for measuring brain activity during motor tasks, due to its portability and good motion tolerance. In such cases, the trials’ duration may vary depending on the experimental conditions or the participant’s response, therefore a comparison of hemodynamic responses across repetiti...

Background: Dravet Syndrome (DS), Helsmoortel-Van Der Aa Syndrome (HVDAS) and Tuberous Sclerosis Complex (TSC) are rare genetic syndromes, sharing intellectual disability (ID) and motor delay. In DS, two distinct gait patterns, crouch and non-crouch, have been described using instrumented 3D gait analysis (i3DGA). This cross-sectional study measur...

The joint position reproduction (JPR) approach is commonly used to assess joint position sense (JPS), but its psychometric properties in children remain unexplored. This study aimed to assess the reliability and precision of a multi‐joint JPR protocol for assessing lower‐limb JPS in typically developing (TD) children. Ankle, knee, and hip JPS were...

Background. Gait variability is increased in people with bilateral vestibulopathy (BVP). Since dedicated gait analysis can be resource-intensive, concurrent assessment with another vestibular function test, dynamic visual acuity (DVA), is worth consideration. Objective. To assess comparability of results from a combined gait and DVA assessment with...

Background: Balance deficits are one of the most common impairments in developmental coordination disorder (DCD) and cerebral palsy (CP), with shared characteristics between both groups. However, balance deficits in DCD are very heterogeneous, but unlike in CP, they are poorly understood. Aim: To unravel the heterogeneity of balance performance...

Background and Purpose In individuals with unilateral vestibulopathy (UVP), physical activity (PA) is recommended to stimulate central vestibular compensation. However, the presence of fear avoidance beliefs might negatively influence PA. The objectives of this study were to investigate the relationship between fear avoidance beliefs and PA and to...

Objective Chronic dizziness after acute unilateral vestibulopathy (AUVP) causes significant social and economic burdens. This study aims to identify predictors of chronic dizziness. Study Design Prospective, longitudinal cohort study. Setting ENT departments from secondary and tertiary hospitals. Methods Participants meeting the Barany Society's...

BACKGROUND: Gait variability is increased in people with bilateral vestibulopathy (BVP). Since dedicated gait analysis can be resource intensive, concurrent assessment with another vestibular function test, dynamic visual acuity (DVA), is worth consideration. OBJECTIVE: To assess comparability of results from a combined gait and DVA assessment with...

Background: The Joint Position Reproduction (JPR) approach has been commonly used to assess joint position sense (JPS), however, no prior study investigated its psychometric properties in children. This study aimed to assess the reliability and precision of a newly developed multi–joint JPR protocol for assessing lower limb JPS in school-aged typic...

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: DFNA9 is a genetic disease of the inner ear, causing progressive bilateral sensorineural deafness and bilateral vestibulopathy (BV). In this study, DizzyQuest, a mobile vestibular diary, and the MOX accelerometer were combined to assess the daily life functional limitations and physical activity of patients with DFNA9 suffering from BV....

This reference dataset contains biomechanical data of 138 able-bodied adults (21–86 years) and 50 stroke survivors walking bare-footed at their preferred speed. It is unique due to its size, and population, including adults across the life-span and over 70 years, as well as stroke survivors. Full-body kinematics (PiG-model), kinetics and muscle act...

Introduction Gait initiation is preceded by three anticipatory postural adjustment (APA) phases. In Parkinson's disease (PD) generated force, displacement and timing during APA differ from healthy controls. APA might be influenced by disease status, weight or emotion. It is unknown how motor severity, disease duration or presence of apathy influenc...

Trunk motion during walking acts as a biomarker for decreased mobility and can differ between sexes. Knowing how age and sex affect trunk motion and energy conservation can help clinicians decide when and in whom to intervene with physiotherapy to prolong functional mobility. A large sample of 138 able-bodied males and females in the age-categories...

Purpose In case of an acute unilateral vestibulopathy (UVP), compensatory strategies such as restoration and adaptation will lead to a decrease in intensity of the symptoms. Although measurements of compensatory strategies are available, currently, an overview taking the different strategies into account is lacking. The objectives of this study are...

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....

Objective To systematically evaluate the full spectrum of self-reported chronic symptoms in patients with unilateral vestibular hypofunction (UVH) and to investigate the effect of interventions on these symptoms. Methods A systematic review was conducted following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analy...

Background: Postural control deficits are one of the most common impairments treated in pediatric physiotherapeutic practice. Adequate evaluation of these deficits is imperative to identify postural control deficits, plan treatment and assess efficacy. Currently, there is no gold standard evaluation for postural control deficits. However, the numb...

Aim This cohort study aimed to describe functional mobility in Dravet syndrome, a developmental and epileptic encephalopathy. Method Functional mobility was assessed in individuals (aged 3–25 years), diagnosed with Dravet syndrome, using the Functional Mobility Scale (FMS), Mobility Questionnaire 28 (MobQues28), and estimated walking distance. Sec...

Objective To map the effect of motor-based interventions on motor skills in children with ADHD. Method A systematic literature search was performed in Pubmed, Web of Science, and the SCOPUS database (last search: October 30th 2022). Methodological quality was assessed using the PEDro-scale and the quality of evidence was determined with the GRADE-...

Two previous studies showed kinematic differences between novice and experienced performers during unchoreographed movements executed in standing position. However, no study explores if these kinematic differences holds during unchoreographed movements executed in quadrupedal position. The aim of this study is to compare the movement behaviour of e...

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 (...

Introduction Balance deficits are heterogeneous among children with Developmental Coordination Disorder (DCD). Balance performance depends on different balance domains, each associated with specific underlying neurological systems. In DCD, any of these domains can be affected, but the control mechanisms are poorly understood. The mirror neuron syst...

Introduction A vestibular schwannoma (VS) resection causes an acute unilateral vestibular deafferentation resulting in acute postoperative symptoms. Despite the expected resolution of most of the symptoms, due to central vestibular compensation, more than one out of four patients develop chronic dizziness. Several predictive factors, such as age an...

4 Rehabilitation Sciences and Physiotherapy, KU Leuven Campus Bruges, Brugge, Belgium Theme: Coordination of posture and gait, Aging, Falls and Fall prevention BACKGROUND AND AIM: The occurrence of balance and gait deficits increases with ageing and is associated with higher fall risk. While different aspects of gait balance have been studied in ol...

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...

Background: Patients with chronic health conditions risk aggravation of their health status due to reduced access to health services during the COVID-19 related lockdown. Objectives: To investigate the impact of Belgian COVID-19 measures on general health status (i.e. worse or stable/better) of patients, adult and pediatric, with chronic health...

Background Dravet Syndrome (DS) is a developmental and epileptic encephalopathy, characterized by drug resistant infantile onset seizures and cognitive and motor impairment. Walking problems progressively occur and crouch gait is frequently observed. Muscle weakness is hypothesized as contributing impairment. Yet, so far, no studies have performed...

Objectives: To assess the immediate and three days postintervention effect of one dry needling session compared to one sham needling session on pain, central pain processing, muscle co-contraction and spatiotemporal parameters during gait in knee osteoarthritis patients. Methods: A double-blind randomized controlled trial was conducted. Sixty-on...

Background Despite strong evidence that walking speed and forward propulsion decline with increasing age, their relationship is still poorly understood. While changes in the ankle and hip mechanics have been described, few studies have reported the effect of ageing on the whole leg’s contribution to propulsion. Research question The aim of this st...

Background Osteoarthritis (OA) is the leading cause of chronic disability in the elderly 1,2 . Abnormal central pain processing (CPP) is present in around 30% of the knee OA patients ³ and can be partly induced by peripheral nociception through long term potentiation ⁴ . An attempt to resolve abnormal CPP can be to eliminate this nociception ⁵ . My...

Objective: Describe the relationship between the Activities-Specific Balance Confidence (ABC) scale and Dizziness Handicap Inventory (DHI) with balance performance, as well as fall status in patients with peripheral vestibular disorders. Study design: Retrospective. Setting: Outpatient balance clinic, tertiary referral center. Patients: Data...

Walking is an activity you do every day without even thinking about it. But have you ever wondered how we walk or why some people walk a bit strangely? We all limp when we hit a toe against the table or when we sprain a foot. But some people seem to walk even more strangely. Having difficulties with walking is not always the result of weak legs or...

Integration of accurate vestibular, visual, and proprioceptive information is crucial in managing the centre of mass in relation to the base of support during gait. Therefore, bilateral loss of peripheral vestibular function can be highly debilitating when performing activities of daily life. To further investigate the influence of an impaired peri...

Patients with bilateral vestibulopathy (BVP) present with unsteadiness during standing and walking, limiting their activities of daily life and, more importantly, resulting in an increased risk of falling. In BVP patients, falls are considered as one of the major complications, with patients having a 31-fold increased risk of falling compared to he...

Dravet syndrome (DS) is a rare severe epilepsy syndrome associated with slowed psychomotor development and behavioral disorders from the second year onward in a previously seemingly normal child. Among cognitive impairments, visuospatial, sensorimotor integration, and expressive language deficits are consistently reported. There have been independe...

Background Dravet Syndrome (DS) is a developmental and epileptic encephalopathy characterized by severe drug-resistant seizures and associated with cognitive and motor impairments. Walking problems are frequently observed. As the foot plays a key role during walking, compromised foot function can be a feature of deviant gait. Aim To investigate fo...

Introduction Bilateral vestibulopathy (BVP) can affect visual acuity in dynamic conditions, like walking. This can be assessed by testing Dynamic Visual Acuity (DVA) on a treadmill at different walking speeds. Apart from BVP, age itself might influence DVA and the ability to complete the test. The objective of this study was to investigate whether...

Objectives: The objective of this study was two-fold: (1) To evaluate the impact of the physiological aging process on somatosensory, vestibular, and balance functions, and (2) To examine the extent to which age and somatosensory and vestibular functions can predict balance performance. Materials and methods: In this cross-sectional study, 141 asy...

Background Dravet Syndrome (DS) is a developmental and epileptic encephalopathy starting in infancy and characterised by treatment resistant epilepsy with cognitive impairment and progressive motor dysfunction. Walking becomes markedly impaired with age, but the mechanical nature of gait problems remains unclear. Research question What are the kin...

Aim To investigate the relation between cognitive and motor development in preschool aged children with Dravet syndrome, in particular between the age of independent walking and cognitive development. Method Results of cognitive and motor developmental assessments and the age of independent walking were retrieved retrospectively from the medical r...

Background: Trunk training after stroke is an effective method for improving trunk control, standing balance and mobility. The SWEAT² study attempts to discover the underlying mechanisms leading to the observed mobility carry-over effects after trunk training. Aim: A secondary analysis investigating the effect of trunk training on muscle activat...

The purpose of this study was to assess the interrater and test-retest reliability and the concurrent validity of the modified timed up and go test for preschoolers. As such, we aim to determine the most suited outcome of the modified timed up and go test: the best or the average performance. Thirty-two children (age 3–5) performed three timed up a...

Objective Patients with bilateral vestibulopathy (BVP) have severe balance deficits, but it is unclear which balance measures are best suited to quantify their deficits and approximate the diversity of their self-reports. The purpose of this study was to explore measures of balance control for quantifying the performance of patients with BVP relate...

Background Arm movements during gait are known to alter with increasing age during the slow maturation phase (>3years). It is unclear whether coordination between the arms and legs (i.e. interlimb coordination), which is a measure of gait quality, shows a similar pattern. Research Question to investigate age-related differences in interlimb coordi...

Objective: Trunk training after stroke is an effective method for improving mobility, yet underlying associations leading to the observed mobility carryover effects are unknown. The purposes of this study were to investigate the effectiveness of trunk training for gait and trunk kinematics and to find explanatory variables for the mobility carryov...

Age-related changes in the way of walking may induce changes in dynamic stability. Therefore, the relationship between age, spatio-temporal characteristics and margins of stability was examined. One hundred and five healthy adults aged between 20 and 89 years old were analysed on spatio-temporal characteristics and margins of stability using three-...

Background Trunk function and lower limb strength seem to be the primary predictors for functional independence in acute stroke patients. Gaining a better understanding of their relationship during walking aids in the identification of intrinsic trunk control deficits and underlying lower limb deficits resulting in compensatory trunk movements. Me...

Objectives To identify predictive factors for falls in patients with bilateral vestibulopathy (BV). Specific variables contributing to the general work-up of a vestibular patient were compared between BV patients experiencing falls and those who did not. Design Prospective multi-centric cohort study. Setting Department of Otorhinolaryngology & He...

Physics-based simulations of walking have the theoretical potential to support clinical decision-making by predicting the functional outcome of treatments in terms of walking performance. Yet before using such simulations in clinical practice, their ability to identify the main treatment targets in specific patients needs to be demonstrated. In thi...

Background: Crouch gait is a common gait impairment in children with cerebral palsy (CP). Growing up and gaining weight, lever arm dysfunctions further deteriorate and walking efficiency progressively worsens over time with risk of losing ambulant capacity in adolescent life. The purpose of this study is to evaluate whether walking in an innovative...

Background: Crouch gait is a common gait impairment in children with cerebral palsy (CP). Growing up and gaining weight, lever arm dysfunctions further deteriorate and walking efficiency progressively worsens over time with risk of losing ambulant capacity in adolescent life. The purpose of this study is to evaluate whether walking in an innovative...

Motor development includes the evolution from reflexive to voluntary and goal-directed motor actions. These motor actions are never performed in isolation but always in a varying physical environment, often requiring object and social interaction. For a child to function within this context, they require the ability to demonstrate skillful, efficie...

Immersive virtual reality (VR) might offer advantages for rehabilitation by answering to key requirements of motor learning, such as task specificity and variation. However, its usefulness for rehabilitation depends on its ability to elicit behavior that is comparable to that in real life. Before the clinical usage of VR can be encouraged, a thorou...

Objective: To quantify gait abnormalities in people with Dravet syndrome (DS). Methods: Individuals with a confirmed diagnosis of DS were enrolled, and stratified according to knee flexion at initial contact (IC) and range of motion (ROM) during stance (atypical crouch: knee flexion >20° at IC and knee ROM >15° during stance; straight: knee flex...

Model-based simulations of walking have the theoretical potential to support clinical decision making by predicting the functional outcome of treatments in terms of walking performance. Yet before using such simulations in clinical practice, their ability to identify the main treatment targets in specific patients needs to be demonstrated. In this...

Immersive virtual reality (IVR) might offer advantages for rehabilitation by answering to key requirements of motor learning, such as task-specificity, variability, feedback and repetition. However, its usefulness for rehabilitation depends on its ability to elicit behaviour that is comparable to that in real life. Before the clinical use of IVR ca...

Bilateral vestibulopathy (BVP) is characterized by (in)complete vestibular function loss in both inner ears. Patients with BVP primarily experience unsteadiness when walking or standing, worsening in darkness and/or on uneven ground. Thus, their balance mechanisms are disturbed, however, to which extent remains unclear. Therefore, the aim of this s...

Patients suffering from bilateral vestibulopathy (BVP) experience severe balance deficits due to the underlying partial or complete vestibular loss, which is linked to a greater risk of falling (RoF). Fall-related injuries and fear of falling can result in a decline of social interaction and quality of life. Therefore predicting the patient’s indiv...

Gait deficits in cerebral palsy (CP) are often treated with a single-event multi-level surgery (SEMLS). Selecting the treatment options (combination of bony and soft tissue corrections) for a specific patient is a complex endeavor and very often treatment outcome is not satisfying. A deterioration in 22.8% of the parameters describing gait performa...

In healthy adults, four different muscle synergies have been described compared to three after stroke, as a result of merging of synergies. The presence of merged synergies was related to impaired motor function which makes muscle synergies a powerful tool for assessing neurological deficits. However, motor function after stroke is subject to a gre...

Cluster analysis on kinematic parameters of gait identified 3 clusters showing 3 distinct gait patterns in Dravet. The previously reported crouch pattern was confirmed as well as a highly functional gait pattern with only mild deformities. The third pattern is characterised by substantial rotational deformities in the transverse plane at the level...

Background and Aim: Patients suffering from bilateral vestibulopathy (BVP) experience severe balance deficits due to the underlying partial or complete vestibular loss, which is linked to a greater risk of falling (RoF)1,2. Fall-related injuries and fear of falling can result in a decline of social interaction and quality of life. Therefore predic...

Background and Aim: Bilateral vestibulopathy (BVP) is characterized by (in)complete vestibular function loss in both inner ears. Patients with BVP primarily experience unsteadiness when walking or standing, worsening in darkness and/or on uneven ground1,2. Thus, their balance mechanisms are disturbed, however, to which extent remains unclear. Ther...

INTRODUCTION AND PURPOSE: The Timed up and go test (TUG) is a very straightforward functional test to assess a child’s functional balance control during walking and is therefore frequently used in clinical practice. Nevertheless, to enhance its administration in preschool children, we developed a modified protocol. The aim of this study is therefor...

INTRODUCTION The diagnostic criteria for bilateral vestibulopathy (BVP) leave room for some variable amount of remaining vestibular function. Consequently, symptoms can be diverse1 leading to heterogeneity in functional consequences. OBJECTIVE To investigate whether clinical balance assessments, visual acuity and quality of life assessments diffe...

A better understanding of the coordinated activation patterns of the lower limbs, also known as muscle synergies, might help us improve assessment, goal setting and treatment plans. Therefore, it is necessary to gain insight in the number of muscle synergies and the distribution of muscle weightings that are present during walking after stroke

Background: Clinical laboratory testing of locomotor disorders is challenging in patients with intellectual disability (ID). Nevertheless, also in this population gait analysis has substantial value as motor problems are common. To promote its use, adequate protocols need to be developed and the impact on clinical decision making needs to be docum...

Background Dravet Syndrome is a rare developmental and epileptic encephalopathy characterised by epileptic seizures, cognitive impairment and motor disorders. Gait is markedly impaired and could benefit from targeted intervention to improve quality of life for patient and caregivers. Objective To establish the state of the art regarding gait devi...

Purpose: The aim of this systematic review was to determine the number of muscle synergies and the distribution of muscle weightings in stroke patients during gait. Material and Methods: This review is registered on PROSPERO (number: CRD42018088701) and is written following the PRISMA guidelines. A systematic search was conducted using following da...

For product developers that design near-body products, virtual mannequins that represent realistic body shapes, are valuable tools. With statistical shape modeling, the variability of such body shapes can be described. Shape variation captured by statistical shape models (SSMs) is often polluted by posture variations, leading to less compact models...

PURPOSE: Results on reliability and normative data for the Timed Up and Go test (TUG) in children who are developing typically are systematically reviewed. SUMMARY OF KEY POINTS: Six different TUG protocols are presented for which normative data are available for ages 3 to 18 years. TUG time is consistent within and between raters and sessions and...

Aim The aim of this study is to describe the course of motor development in children with Dravet syndrome. Method Forty‐three participants (21 males, 22 females; mean age at last assessment 53.89mo±42.50mo) met the inclusion criteria of having a confirmed diagnosis of Dravet syndrome and presence of data on motor development. All data between 1985...