1. Balance and gait changes in preclinical stages of neurodegenerative movement disorders - Commonalities, specificities, open questions and future steps
Joan O'Keefe¹, Anat Mirelman², Winfried Ilg³, Jeffrey Hausdorff²
¹Rush University Medical Center , ²Tel Aviv Sourasky Medical Center, ³Hertie Institute for Clinical Brain Research
Work over the past decades has demonstrated that the neuropathological processes involved in most neurodegenerative movement disorders begins years before clinical diagnosis. Recent advances in the potential benefit of neuroprotective interventions in these movement disorders have driven the awareness of the critical importance of early identification of prodromal balance and gait markers in pre-clinical disease stages, when far fewer cells and neural pathways are affected, and neuroprotective interventions are likely to be much more effective. Since movement changes in balance and gait have been identified in many different movement disorders several years before clinical disease manifestation, a gradual degradation of motor control mechanisms in this preclinical stage is likely. A more detailed understanding of these degrading control mechanisms will be crucial for the conception, design, and evaluation of clinical efficacy of neuroprotective interventions and motor rehabilitation programs. These hypotheses lead to specific questions regarding future balance and gait research. In particular, which motor tests are optimal to reveal preclinical motor dysfunction and which motor features can we use to: (i) identify and characterize motor alterations that are specific to individual movement disorders, and (ii) quantitatively describe the preclinical decline in motor performance. Furthermore, these prodromal balance and gait markers will potentially be combined with other risk factors (e.g. genetic, molecular, age, sex, cognition) and non-motor biomarkers in order to increase the sensitivity and specificity for the identification of at risk populations and the accuracy of estimations of clinically manifested disease onset. In this symposium, recent studies will be presented describing putative preclinical changes in gait and postural control of three neurodegenerative diseases: Parkinson's disease (PD), spinocerebellar ataxia (SCA) and Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS). The aim of the symposium is to describe the state of the art in this field and to identify similarities and differences across these three disorders in order to describe and further establish a framework for future preclinical gait and balance research in neurodegenerative disorders. The interactive scientific exchange will include discussions of the optimal choice of motor markers across the presented neurodegenerative movement disorders and complementary research in other movement disorders.
2. Using smart technology in the prevention of age-related decline in balance, strength, physical activity and behavioral complexity
Jorunn Helbostad1, Beatrix Vereijken¹, Michael Schwenk², Ionescu Anisoara¹, Elisabeth Boulton³, Sabato Mellone⁴
¹Norwegian University of Science and Technology, ²Robert Bosch Hospital, ³University of Manchester, ⁴University of Bologna
Balance, strength and physical activity are important factors for healthy ageing and for preventing age-related decline in function. Additionally, complexity in behavior is observed to decline with increased age and with age-related disease, and it is hypothesized that maintaining complexity in behavior may contribute to the prevention of functional decline. In order to be effective, preventive interventions should be targeting important risk factors for age-related functional decline, be tailored to the need and preferences of the older adult, and be designed to change behavior to a healthier life style over time. Use of mobile technology is the future, also for older adults! Smartphones and smartwatches are used by an increasing number of people in general and older adults in particular. Because the systems can send and receive wireless information and communicate with external servers, they can act as suitable platforms for the delivery of individualized interventions with direct feedback to the user. A plethora of mobile health applications have been, and are currently being, developed for the private market. However, most are targeting younger adults and are focused on cardiovascular health. Furthermore, few of them are research-based, which is mandatory if they are to contribute to solve future challenges related to health problems. In this symposium, we will present how mobile technology such as smartphones and smartwatches can be used to monitor behavior and to personalize and deliver an intervention. The intervention is based on the LiFE concept and will target balance, strength, and physical activity by giving advice on how to integrate task-oriented activities in the daily life situations of each individual person. We will also focus on how the technology can be used to develop self-assessment tools for assessment of physical function in older age, and how such information can be used to tailor interventions.
3. Transcranial direct current stimulation (tDCS): a research and rehabilitative tool for gait and postural control.
Brad Manor¹, Moria Dagan², Diego Kaski³, Talia Herman²
¹Harvard Medical School, ²Tel Aviv University, ³Imperial College London
The ability to maintain gait and postural control, especially when simultaneously performing additional cognitive and/or motor tasks, depends upon a complex control system that includes sensory, motor and cognitive brain networks. As such, many of the gait and postural control deficits linked to aging and disease stem at least in part from alterations in brain structure and function that impair its capacity to modulate activity within the appropriate networks. Transcranial direct current stimulation (tDCS) is a non-invasive and safe means of modulating cortical excitability. It is, therefore, not surprising that this technology is rapidly gaining in popularity as: 1) a research tool to identify and understand the cortical control of gait and postural control (by establishing cause-effect relationships between modulation of cortical excitability and movement outcomes), and 2) a rehabilitative tool with promise to enhance gait and postural control by inducing long-term, beneficial changes in brain function. Promising evidence now exists in each of these areas from studies in healthy adults and in those suffering from a range of movement disorders. Brad Manor, PhD, will provide an overview of tDCS technology, its recent application to gait and postural control research efforts, and specific work by his group demonstrating the transient effects of a single session of tDCS, and longer-term effects of a 10-day tDCS intervention, on dual task gait and posture in older adults. Moria Dagan, MS, a doctoral student under the guidance of Jeff Hausdorff, PhD, will present on the effects of "multi-focal" tDCS on freezing of gait and other cognitive-motor outcomes in Parkinson's disease, thereby providing insights into state-of-the-art tDCS delivery and its application to neurological disorders. Finally, Diego Kaski, MD PhD, will present a series of pilot studies examining the effects of tDCS on multiple age-related movement disorders, including Parkinson's disease, cerebral small vessel disease and stroke, with particular emphasis of the potential for tDCS to serve as an adjunct therapy to established interventions. An interactive scientific exchange, moderated by Tali Herman, PhD, will then discuss the potential neurophysiological mechanisms that drive the observed benefits of tDCS. The session will conclude with an attempt to obtain a group consensus of the most important limitations and gaps in knowledge that must be addressed in future research in order for tDCS to gain additional traction in the study and rehabilitation of gait and postural control.
Tuesday, June 27
3:30 – 5:15
1. (E)motion: The effect of emotion on human posture and gait control in health and illness
Danielle Bouman5, Brad Fawver¹, Liam Satchell², Laura Avanzino³, Jeffrey Staab⁴
¹University of Utah, ²University of Portsmouth, ³University of Genoa, ⁴Mayo Clinic, 5MOVE Research Institute
Evidence from diverse fields of research indicate that motion and emotion are interconnected. This symposium will bring together multiple lines of research surrounding the topic of emotion and its effect on human posture and gait in both healthy and clinical populations. The link between emotion and movement was established by Darwin in his classical work on The expression of emotion in man and animals. This relationship between emotion and gait and posture has since been investigated in several ways. Most recently, whole-body movement paradigms have been employed to define this connection. The essence of this research lies in studying how we control our body within time and space in the context of socially and evolutionary relevant stimuli which elicit emotions. Theoretical underpinnings of emotion-modulated posture and gait specify that emotions are embodied in the body, meaning that not only the brain is involved in emotional processes, but the body as well. This embodied cognition perspective lies at the core of this topic and connect all four presentations within the symposium. How gait and posture and emotion are intertwined will be discussed within four presentations by specialized researchers who each have their own approach. These unique perspectives will give the audience a broad overview of the interaction between human movement and emotion. The first two presentations will deal with the impact of emotion on human movement in the healthy populations. Dr. Brad Fawver will discuss the relatively new field of how emotion influences parameters of posture and gait, summarizing the empirical and theoretical perspective of his own work and that of others. Dr. Liam Satchell will add a public safety perspective, discussing his novel work on how other-directed negative emotions and aggression affect healthy gait and how observing an individual's gait can offer information on that person's emotion. The final two presentations will discuss emotion in pathological human movement. Dr. Laura Avanzino will review work on the influence of emotion on gait in Parkinson disease. Dr. Jeffrey Staab will complete the presentations by providing clinical applications that stem from his model on the interaction between anxiety and disorders of posture and gait. By using an electronic polling app, the audience will be engaged in a scientific exchange with the four presenters, giving room for both questions and comments that will help advance this interesting field of emotion and human movement research.
2. Implementation research in balance, mobility and fall prevention: How do we move the evidence into action?
Kathryn Sibley4, Stephen Lord¹, Debra Rose², Chris Todd³
¹Neuroscience Research Australia, ²California State University, Fullerton, ³University of Manchester, 4University of Manitoba
The traditional bench to bedside pipeline is inefficient at getting research into action, taking approximately 17 years to put established evidence into real-world practice. The result is substandard health care and a great deal of research waste that does not help the people to the extent to which it purports. Implementation research is an emerging field that studies methods to promote the systematic uptake of clinical research findings and other evidence-based practices into routine practice, and as such, to improve the quality of health care. Many aspects of ongoing posture and gait research have implications for physical functioning and daily life, but challenges in applying this research have been reported throughout the literature. As such, there is significant opportunity to apply new implementation theories, methodologies and interventions to the application of balance, mobility and falls evidence. In turn, studying implementation in such community and rehabilitation contexts can advance this new science. This symposium will incorporate an international perspective to gait and balance implementation research, highlighting four case examples from four new and established researchers from North America, Europe, and Australia. The symposium will be structured around an established implementation process model, the Knowledge-to-Action Framework (Graham et al. 2006), providing the audience with a practical guide for moving from primary research to broad uptake. Speaker presentations will explore how this framework can be used to design a balance and mobility research program that begins with the end in mind, development of evidence-based guidelines, design, evaluation, and facilitation of evidence-based programming in clinical and community settings, and the use of psychological theories and technology to promote behavior change among individuals and health professionals. Discussion will explore the role of researchers in the knowledge-to-action process, how to influence policy, and extending the reach of evidence-based initiatives.
3. Peeking inside the brain ? How to study the neural control of walking?
Noel Keijsers3, Vivian Weedersteyn4, Brett Fling¹, Dan Ferris²
¹Colorado State University, ²University of Michigan, 3Sint Maastenskliniek, 4Radboud University Medical Centre
Studies of (impaired) human gait mainly focus on the kinetics and kinematics of gait whereas understanding the neural control of gait might be even more important. So far, the neural control of human posture and gait is still not completely understood, with most of our knowledge originating from animal studies. In the last decades, there has been a rapid increase of studies using neuroimaging techniques ( (f)MRI, fNIRS and EEG) to assess the neural control of walking in humans. These studies have greatly increased our understanding of neural control in gait and balance. The purpose of this symposium is to present the pros and cons of each of these neuroimaging techniques and to discuss the latest insights these have yielded into the neural control of walking. The first presentation focusses on (f)MRI and will provide insight into the structural and functional brain circuitry differences that accompany balance and gait impairment in patients with neurodegenerative diseases like Parkinson's disease. Recently, advanced MR techniques have been utilized in the research setting as a biomarker for disease progression and therapeutic intervention efficacy. However, the main disadvantage of fMRI is that it is not yet possible to measure brain activity during actual walking. More recently, EEG and fNIRS have been used to measure cortical activity during actual walking on a treadmill. A disadvantage of these techniques is that they cannot accurately measure activity of deeper brain areas. However, these techniques have shown undisputable evidence for cortical involvement in human gait. The second presentation will start addressing the potential and pitfalls of fNIRS. Subsequently, recent work will be discussed on the role of prefrontal cortex and motor cortex in (complex) gait using fNIRS. The third presentation will address the application of EEG. It is only in the past decade that EEG has emerged as a research tool for studying the neural control of walking, thanks to both technological advances and to the development of techniques for removing motion artifacts. These developments will be discussed, as well as the insights that EEG studies have yielded into cortical activity in relation to specific phases of the gait cycle and different walking modalities. Finally, the potential clinical applications of EEG will be elaborated on. In the final discussion with the audience, the (future) role of these techniques in human posture and gait research will be discussed, as well as their present and future application in clinical settings.
Wednesday, June 28
11:00 – 1:00
1. Vestibular and cerebellar control of posture and gait - Neurophysiology and Clinical Applications
Roman Schniepp¹, Max Wühr¹, Winfried Ilg², Klaus Jahn³
¹Ludwig-Maximillians Universität München, ²Eberharnd-Karls Universität Tübingen, ³Schoen Klinik
Vestibular feedback information is essential to maintain dynamic balance during posture and during locomotion. Consequently, a disturbance or loss of sensory feedback sources results in an impaired dynamic postural stability and a higher risk to fall. A key site for vestibular information integration is the cerebellum. Disorders of the cerebellum may lead to both, impaired dynamic postural control and dysregulation of intra- and interlimb coordination. The proposed symposium covers the broad spectrum of identifying the basic control and interaction principles for vestibular and cerebellar posture and gait control. Alongside to this, novel imaging and neurophysiological markers for assessing vestibule-cerebellar postural and locomotion controls will be presented and their clinical applicability will be discussed. The second part of the project will focus on new therapeutic paradigms for vestibular and cerebellar gait disorders, e.g. vestibular stimulation paradigms that has recently been demonstrated to improve dynamic walking stability in patients with vestibular hypofunction. Moreover, virtual reality based and exergaming based rehabilitation strategies for patients with ataxia will be outlined. The symposium is created as an interactive discussion platform aiming a multidisciplinary review of the current status quo and future directions of both, clinical and scientific perspectives in the field. This is the reason for the multi-professional selection of the speakers with neuroscientists with technical background (WI, MW) and clinical scientists (KJ and RS).
2. Gamification to invoke behavioural changes. New challenges for rehabilitation in the daily living environment
Edouard Auvinet3, Nina Skjæret Maroni¹, Claudine Lamoth², Dag Svanaes1
¹NTNU University, ²University of Groningen, 3Imperial College
Traditional computer based exergaming have great potential to be used as a tool to increase physical activity and provide specific rehabilitation exercise. One limitation however, is that by using a computer based game the player does not directly interact with the living environment, making it difficult to create long-term behavioral changes. However, emerging technologies provide new possibilities for location-based exergames, so called ubiquitous gaming, that can take place in both a virtual gaming world and in a real-life environment simultaneously (e.g. PokémonGo or augmented reality glasses). This gamification of rehabilitation activities in living environment raises new challenging and exciting questions which will be addressed in the current symposium. For instance, how can we use gamification principles in the living environment to increase physical activity and support rehabilitation? And how can we ensure that interest, presence, and adherence to such gamification solutions is maintained over a longer period of time in order to reach potential exercise and rehabilitation goals? The current symposium will be composed of three keynote speakers presenting their experiences in different aspects of exergaming and gamification research with concluding remarks from the chair followed up by a gamified question and answer session with the audience. To bring the gamification aspect into the symposium we encourage the audience to download an app as this will be used to illustrate and facilitate the discussion at the end of the symposium.
3. Muscle synergy analysis: a promising tool for diagnosis and evaluation of balance and gait control deficits in people with neurological disorders.
Digna de Kam4, Andrew Sawers¹, Jessica Allen², Katherine Steele³
¹University of Illinois at Chicago, ²Emory University, ³University of Washington, 4 Radboud University Medical Center
Deficits in muscle coordination due to neurological disorders or aging can result in pronounced impairments in balance and movement. The quality of human movement is typically assessed with clinical performance tests that can gage an individual's impairment level and help guide treatment decisions. However, quantifying patient-specific impairments and understanding the functional impact of changes in muscle coordination remain challenging. Routine assessment of muscle coordination during functional tests may assist in diagnosis and develop individually tailored therapeutic interventions. Muscle synergy analysis has emerged as a promising analysis technique that can provide quantitative insight into muscle coordination patterns. It uses factorization algorithms to decompose multi-channel electromyograms into groups of muscles (i.e., synergies) that are activated in synchrony with fixed relative gains. Previous work has demonstrated that a reduction in the number of independently controlled muscle synergies is related to impaired function and may reflect poor flexibility of motor output (i.e. motor selectivity). Hence, muscle synergy analysis may provide clinically relevant information about muscle coordination. In this symposium we will present novel results showing that muscle synergy analysis could be potentially valuable in the clinical management of balance and gait deficits. We will first demonstrate that people after stroke have pronounced deficits in their recruitment of muscle synergies for postural control in the paretic leg. These deficits resulted in direction-specific postural instability (i.e. larger sway) when balance was perturbed by a moveable platform. Second, we will show that following slip-like balance perturbations while walking, individuals who fell in response to the perturbation used fewer muscle synergies than individuals who recovered. Third, we will demonstrate that the ability to recruit a common set of synergies across balance and gait tasks is associated with better motor performance and improvement during rehabilitation. Finally, we will show that children with cerebral palsy demonstrate similar changes in synergy structure and complexity as adult stroke survivors. These deficits are associated with poorer functional performance and rehabilitation outcomes. Together, these findings demonstrate that muscle synergy analysis reveals clinically relevant information about muscle coordination deficits during balance and gait in a wide variety of clinical populations. Hence, it is a promising tool to further develop and prescribe individual tailored balance and gait rehabilitation programs in individuals with central nervous system disorders and older adults.
Thursday, June 29
3:30 – 5:15
1. “Good vibrations” or are they? Is the activation of skin a worthwhile endeavour for wearable devices and interventions?
Tim Inglis4, Christopher Nester¹, Leah Bent², Paul Zehr³, Kristen Hollands1
¹University of Salford, ²University of Guelph, ³University of Victoria, 4University of British Columbia
Sensory signals from foot skin provide important information regarding body orientation relative to gravity, the support surface (e.g. slippery floor) and perturbations (trips, sudden acceleration). This cutaneous feedback is known to affect balance and gait outcomes. Sensory deficits occur with ageing and in many pathologies (e.g. diabetes, stroke), with known deficits to full recovery of balance and mobility. To date, our limited ability to stimulate and record thresholds from individual mechanoreceptors during functional tasks has restricted our insight on the link between foot sensation and task performance. Recently developments in the ability to activate skin during walking provide support for skin contributions in the control of walking and balance. Despite an emerging evidence base there has been rapid growth in sensory assistive devices and footwear which purport to enhance postural stability. Given this commercial growth in parallel with variable empirical support it is timely for ISPGR to consider: 1. integrated evidence from state-of-the-art techniques to support a role for skin in the control of balance and gait 2. opportunities for future research in the development of footwear and related devices and interventions This symposium will consider the evidence for the role of skin in the control of balance and gait, at the peripheral, and central neurological levels as well as from behavioural and biomechanical perspectives. The focus will be to explore skin as a source of functional sensory input. Four speakers will engage the audience in the science of the skin in the context of locomotion. Specific topics will examine the cutaneous implications of orthotics and footwear use, reflect on what we know regarding distribution and activation of cutaneous mechanoreceptors, and discuss cutaneous reflexes in gait. Discussion will focus on the central underlying question of the symposium: is skin sensation a significant contributor to the control of balance and gait? Is skin sensation an appropriate and feasible target for wearable technologies and rehabilitation interventions? What future research is required to improve, not only our understanding of the role of skin sensation in balance and gait, but to test and improve product concepts and subsequently clinical evaluation and demonstration of care pathway benefits?
2. Digging into data: What sensor signals from real-world falls can tell us
Jochen Klenk, Luca Palmerini¹, Omar Aziz², Lars Schwickert³
¹University of Bologna, ²Simon Fraser University, ³Robert-Bosch-Hospital
Falls are a major cause of injury and disability in older people. Until now only little objective evidence is available for how and why falls occur in this population. Existing knowledge and assumptions are mostly based on descriptive faller and proxy reports or simulated in-lab data. Real-world fall events measured by body-worn sensors can help to improve the understanding of fall events. However, these events are rare and hence challenging to capture. The FARSEEING consortium and associated partners have compiled the world-largest database of currently more than 200 validated real-world falls from older people measured with sensors, to bridge this gap. In the symposium we will present the first results using this unique dataset. The analyses cover pre-fall and falling phase, impact, as well as resting and recovery phase. The first presentation will focus on pre-fall and falling phase. Qualitative and quantitative parameters describing movements of the human body have been extracted, including, for example, pre-fall activities, initial and final fall direction, and maximum vertical acceleration. Furthermore, based on the data, reported and measured variables have been compared to assess reporting validity. Two presentations will cover different approaches of fall detection. In the first of these approaches, a complete system for fall detection will be presented. This is based on automatic algorithms that can learn the characteristic patterns and features of real-world falls. The functioning and real-life performance of this system will be presented. Moreover, all the issues that were encountered during the design and testing of such system will be presented and discussed. Among them, problematic signals, sensors' technical limitations, and choice of a standard evaluation criteria. The second presentation will focus on a machine learning approach - an alternate to traditional threshold-based methods - for automatic fall detection. We will share the results of our machine learning algorithm on the real-world fall and non-fall datasets, and discuss future steps for further improvements. Besides direct consequences due to the impact of a fall, the inability to get up after falls is a common life threatening condition in older people. Yet, little is known about the resting and recovery phase including successful recovery and falls with no recovery provoking long lies. Therefore, the fourth presentation will analyze different kinematic features from inertial sensors describing these phases and compare falls with successful and unsuccessful recovery. Furthermore, real-world measurements will be compared with those from younger and older adults measured in-lab. The results will sharpen the picture and thereby help to detect and understand critical incidents that require an automatic fall alarm to be sent. Finally, we aim to discuss our findings from real-world fall signals with the audience and try to derive implications and future analytic directions.
3. Can electrophysiology enhance our understanding and treatment of gait and posture in ageing and neurodegeneration?
Meir Plotnik¹, Simon Lewis¹, Jesse Jacobs², Evyatar Arad³
¹Sheba Medical Center, ²Liberty Mutual Research Institute for Safety, ³Sheba Medical Center
The measurement of brain activity during human walking is an emerging paradigm in the study of impaired and healthy gait and posture. Its virtues are palpable as it allows observations of supra-spinal neural processes. Specifically, electroencephalography (EEG) provides information about cortical activity. The objective of this symposium is to address the research and the implications associated with gait and posture related EEG signals. Historically, not many attempts were made to record EEG during walking. Recording EEG signals during walking is indeed a methodological challenge, particularly because mechanical forces applied on the scalp electrodes cause the recorded voltage to change regardless of cortical activity. Recommended methodologies for reducing these movement artifacts (MA) will be described, followed by an evaluation of several state-of-the-art computational tools for removing MA from EEG data. Three schemes of research employing EEG measurements during gait and postural tasks in participants with Parkinson's disease (PD) will be presented. In the first, EEG potentials are recorded prior to external perturbations and voluntary stepping. Results confirmed a lack of postural modulation from persons with PD, while exhibiting enhanced EEG modulation. Thus, impaired postural modulation with PD is not due to impaired neural modulation, but perhaps due to greater influence of preparatory cortical activity to maintain unmodulated postural behavior. In the second scheme, we compared inter- and intra-hemispheric phase synchronization (PS) levels and asymmetry (SA) of EEG signals between participants with and without PD during bilateral motor tasks, including walking. The group with PD exhibited significantly higher levels of inter-hemispheric PS and lower SA. The inter-hemispheric hyper synchronization may reflect a compensatory mechanism. We will discuss the potential of these findings and similar approaches to identify cortical dynamics related to gait impairments in PD. In the third scheme, we describe the use of EEG with virtual reality (VR) gait paradigms in combination with functional neuroimaging. The results depict neural correlates of freezing of gait (FOG) in PD. Ambulatory EEG signals may also be a biomarker of FOG and could perhaps predict FOG events. Single cell recordings taken during Deep Brain Stimulation (DBS) surgery in patients performing VR may promote our understanding of the interplay between cortical and sub-cortical events during FOG. In the future, it might be possible to harness real-time neurophysiological data in conjunction with closed loop DBS to reduce FOG in PD. A moderated discussion of open questions with the audience will follow, e.g., benefits and concerns regarding the use of wearable devices that record EEG; how can we learn more about other cerebral gait- and posture-related activity that is not directly reflected in EEG; methodological challenges related to recording and analyzing EEG that we still need to overcome.