Advanced Technologies for the Rehabilitation of Gait and Balance Disorders

This chapter gives an overview of the role played by the postural control system in the production of postural tone, stability and orientation. Sensory inputs are integrated at the level of the central nervous system, and postural responses, that are generated by the spinal and supraspinal centers, can be selected according to prior experience, the degree of postural stabilization, and the environment. Since human upright stance is an unstable condition, several diseases affecting the peripheral and central nervous system can lead to different degrees of balance impairment. In order to create a link between physiology of postural control and disease, a brief description of the main pathophysiological mechanisms underlying abnormalities of the postural control system in common diseases of the nervous system is also given.

The need of evidence-based medicine is a key factor in the current clinical rehabilitative approach. A randomized controlled trial (RCT) is a rigorous scientific methodology used to test the efficacy and efficiency of a service in healthcare‚ such as a new technology‚ methodology‚ treatment or drug therapy. RCTs are becoming a milestone to establish novel rehabilitation approaches. Indeed‚ the findings of a well-designed RCT influence the decision making process in healthcare‚ the international evidence-based clinical pathways guidelines‚ and ultimately‚ the formulation of national public health policies. The aim of this chapter is to describe the rigorous methodology that should be followed to design a RCT to demonstrate the efficacy of a novel rehabilitation intervention. The chapter is organized in four sections. The first section describes the main characteristics of an RCT (i.e. the randomization and the comparison with a control group) explaining its importance. The second section highlights the ethical issues that raises studying human subjects. The third describes the possible source of bias that should be considered designing an RCT and finally the fourth present the step by step procedure to follow in the design of an RCT reporting also a clinical example of an ongoing RCT.

The concept that “not all balance disorders are the same” well express the complexity of balance control, from which derives that the wide variety of balance problems, determining the cause of a balance disorder and what treatment options are the most appropriate, can be difficult. The fact that balance disorders can occur from a wide range of causes explains the interest from a wide variety of disciplines. This interest in the assessment of balance has led to the development of a variety of different techniques for measuring balance. It is important to take in mind that the choice of the appropriate evaluation tools depends on the disease, since the information collected from these tests does not bear the same meaning. To date, no consensus exists about which specific tools should be preferred to assess balance, especially in patients with neurological disease. However, both functional and system assessment should be considered as the two faces of the same coin to identify the presence of balance disturbances, and then to determine the underlying causes. This chapter will focus on the main approaches to the evaluation of balance disorders, briefly describing the most widely used clinical and functional scales according to the ICF framework outcomes, as well as summarizing the main instrumental approaches for the assessment.

Recovery of walking function is one of the main objectives in stroke rehabilitation. This is a challenging goal that can be addressed with specific rehabilitation interventions that must be preceded by careful evaluations to identify the relevant gait problems. Selecting appropriate outcome measures to assess this recovery is complex because of patient-related factors such as the heterogeneity of the stroke etiology, severity of symptoms and spontaneous recovery. Despite these heterogeneous factors, a number of approaches might help both clinicians and researchers to select appropriate outcome measures for their respective settings. In this chapter, we present a comprehensive overview of the approaches that can be used to select outcome measures to evaluate the effects of gait-training interventions in patients with stroke.

The vestibular and the ocular motor systems are very important for providing clear vision and good balance control. Accordingly the clinical examination of these two systems is able to suggest the possible reasons for an imbalance disorder, and the location of the dysfunction responsible for that imbalance. Here we will report the features and the pathophysiology of several kind of acquired nystagmus (peripheral, gaze evoked, rebound, down-beat, up-beat, pendular, dissociated nystagmus in internuclear ophthalmoplegia and periodic alternating nystagmus). We will also describe how to perform and to understand two simple clinical tests, the head impulse test and the head shaking test.

Clinical evaluation has an irreplaceable role in patient diagnosis and care but the need for objective measurements is constantly increasing. Equipment for the evaluation and treatment of impaired balance can currently be found on the market, although most of them are stabilometric non computerized footplates. More specifically, computerized dynamic posturography (CDP) started to be developed in the 70s by Louis Nashner, Anne Shumway-Cook and colleagues. Their studies created a theoretical background and they are rightly recognized as the pioneers of posturography. This chapter uses their model to describe the complexity of human behavior in regulating balance and suggests how test results can be turned into protocolos for treatment.

Gait and balance impairments are known to be omnipresent among the general elderly population, and especially among elderly people with neurological diseases (see Segev-Jacubovski et al. in Expert Rev Neurother 11:1057–1075, [1] for a review).

Falls are associated with many adverse health outcomes, including injury, fractures, debility and death. Attention must be focused on neurological diseases as a major and increasing risk factor for falls: in fact, stance problems and gait disturbances are frequent symptoms in these clinical conditions. In addition, prevention of fractures is necessary and is aimed at reducing the risk of falling and preventing the development of osteoporosis. Screening is the first step in preventing future falls and major injuries that can result from falling. A multifactorial fall assessment on a patient is required, followed by appropriate treatment: given the multifactorial nature of many falls, this often requires an interdisciplinary approach which may include medical treatment, physiotherapy, occupational therapy, dietetic support and clinical psychology interventions for anxiety and fear of falling.

Falls in the elderly may have adverse physical, medical, psychological, social and economic consequences. Falls in older adults are a significant public health concern, especially as more than 30% of this section of the population experience one or more falls each year. To date there has been no exhaustive review that has fully captured the various aspects of this problem (epidemiology, aetiology and prevention), although there is evidence to suggest that it is an issue that deserves attention. The aim of this chapter is to analyse, through a literature review, the following aspects: risk factors for falls in the elderly, strategies to prevent them, clinical and multifactorial assessment of patients at risk of falls, and the use of technology to boost fall prevention.

Parkinson's disease (PD) is a neurodegenerative disease for which there is currently no definitive cure. Rehabilitation therapy is increasingly used as an adjuvant of pharmacological and neurosurgical treatments and is mainly addressed to the management of walking and balance disorders. Numerous studies have shown the association between cognitive deficits and gait or balance performance of patients with PD. Various approaches integrating cognitive and motor aspects of rehabilitation (cueing training, dual-task training, motor imagery, action observation, augmented feedback and virtual reality) have been recently proposed. Such approaches share a solid pathophysiological background of enhanced plasticity and have been shown to induce significant benefits improving gait ability, reducing fall risk, ameliorating dexterity and quality of life.

Dystonia is a movement disorder that consists of sustained or intermittent muscle contractions leading to abnormal movements or sustained postures. The spectrum of dystonia is heterogeneous, as a result of the involvement of different body regions, the range of different patterns of body distribution, and the different etiologies (environmental factors, hereditary or sporadic neuronal dysfunction, neurodegenerative disease). The age at onset, body distribution, temporal pattern, and associated clinical manifestations are the main features that differentiate the various types of dystonia.

Walking recovery is one of the most important outcomes of neurorehabilitation in patients affected by stroke. Despite the effectiveness of current interventions, great steps forward still need to be made in order to improve the variability of response to rehabilitation treatments. A neurorehabilitation approach integrating cognitive-motor interventions with sensory input would help to improve the efficacy of rehabilitation interventions. Consideration should also be given to the need combine conventional techniques and innovative new technologies, so as to improve, in particular, the outcome of more severe patients who are less responsive to conventional approaches.

Cerebellar disorders (which include congenital, hereditary and acquired conditions) lead to several symptoms that may vary with the cause but typically include ataxia. The term ataxia (meaning “lack of order” in ancient Greek) refers to a lack of motor coordination, although growing evidence indicates that the cerebellum also contributes to regulation of certain non-motor features such as linguistic, cognitive and affective functions. Degenerative cerebellar ataxias, which have several different causes, are a significant group of disorders with an estimated prevalence ranging from 5.2 to 18.5 per 100,000 inhabitants [2, 33]. The typical cerebellar motor syndrome includes a wide range of features such as dysmetria, asynergia or dyssynergia, a- or dysdiadochokinesia, tremor, oculomotor abnormalities, speech disturbances, hypotonia and abnormalities of posture and gait (for a review see Bodranghien et al. [3]). Gait and balance disorders are crucial features of cerebellar ataxias, having a great influence on patients’ independence in daily life activities, quality of life and risk of falls [11, 28]. On these bases, and also considering the impact of these conditions in terms of economic costs and health-related quality of life [21], one of the main areas of neurorehabilitation intervention in patients with ataxia should be the treatment of gait and balance abnormalities. Over the last decade, evidence has emerged indicating that rehabilitation can improve postural and gait functions in cerebellar ataxia [15, 17, 18] and suggesting a potential role for neurorehabilitation in delaying the loss of independent walking.

In this chapter we highlight the main characteristics of gait and balance in multiple sclerosis, and the assessment and rehabilitation treatment of these disorders. The main scientific evidence on the rehabilitation treatment is described, with a focus on the innovative approaches and technologies. Finally, the prognostic factors on rehabilitation outcome are discussed.

Neuropathies are characterized by a sensorimotor deficit of the extremities, especially the lower limbs. According to the clinical signs, they can be divided into motor, sensory or trophic forms. With regard to the sensory forms, the main disorders are subjective and objective sensory disorders without motor impairment. Ataxic neuropathies are severe deep sensory disorders that, in turn, cause balance and walking disorders, with a reduction of distal sensitivity on tuning fork testing and greater imbalance with eyes closed (Romberg sign).

In 1700 BC, the Edwin Smith Papyrus, an ancient Egyptian medical text, described spinal cord injury (SCI) as an “ailment not to be treated.” (Silva et al. in Progress in neurobiology 2014;114:25–57, [1]) SCI can actually be defined as a lesion that occurs in any portion of the spinal cord and results in complete or incomplete impairment of motor, sensory and autonomic functions below the level of the injury [1]. The aetiology of SCI may be traumatic (TSCI) or non-traumatic (NTSCI).

Gait analysis (GA), or the computerized multifactorial (3D kinematics, kinetics and electromyography) evaluation of walking, is becoming increasingly widespread in clinical settings. GA is a means of evaluating walking ability for the purposes of arriving at an exhaustive diagnosis, of better characterizing the functional limitations of a patient with a certain pathology, and of evaluating the efficacy of rehabilitation treatments. Nowadays, there is growing recognition of the importance of measuring and analyzing gait variability, and GA is becoming increasingly accepted and used in rehabilitation and in clinical research. In the current era of evidenced-based medicine, continuous development of quality, which includes the careful measurement and recording of results, contributes to more efficient application of diagnostic procedures and interventions and to a reduction of expenditure on unnecessary procedures. In this context, GA is a fundamental tool for characterizing gait patterns in quantitative terms.

Spinal cord injury (SCI) is a traumatic event with a global incidence of 23 cases per million, representing 180,000 cases per annum worldwide. Recovery of locomotion is a main priority for spinal cord-injured patients. In addition to overcoming the obvious mobility and social issues related to the inability to stand or walk, regular ambulation may profoundly combat secondary medical problems associated with lack of weight-bearing activity in SCI patients. Lower limb exoskeletons (EXOs) may be devised as an ambulation device, as a rehabilitation tool or may be aimed at allowing both objectives living. Regarding rehabilitation, it is worth noticing that EXOs also provide a perfect environment for precise assessing of rehabilitation protocols and effects. Different is the case of EXO for mobility, where the old wheelchair is still largely winning the challenge: existing exoskeletons have limitations with respect to affordability, size, weight, speed, and efficiency, which may reduce their functional application. In all functional areas (velocity, safety, portability, acceptance as well as autonomy in the ADL) none of today EXOs can compete with the performances of an average wheelchair. However, EXO usage requires learning, and brain changes associated with tool usage introduce the human in the loop concept, a key aspect of clinical relevance for EXO usage. At present, interesting data on the biological mechanisms and rehabilitation relevance of embodiment are providing hints for guiding rehabilitation. In this chapter, these challenges will be presented from a clinical rehabilitation perspective and expectations and critics discussed.

Today’s concepts of motor learning address the demand for adequate therapy solutions with a task-specific approach. Since the 1990s, robot-assisted gait training (RAGT) has become a promising approach, alongside conventional rehabilitation, for treating gait disturbances in patients with neurological disease. RAGT devices enable the patient to practice an intensive, repetitive and assisted gait-like movement and have been found to improve mobility and independence in activities of daily living (Sale et al. in Eur J Phys Rehabil Med 48:111–21, 2012, [31]). On the basis of their driving principles, robotic devices for gait rehabilitation can be divided into two categories: exoskeleton and end-effector robots (Mehrholz and Pohl in J Rehabil Med 44:193–9, 2012, [20]). The former, extensively described elsewhere in this book, consist of treadmill-centered technology combined with an exoskeleton and a body weight support system. The latter represent an alternative approach in which footplates are used to guide the feet and thereby reproduce the gait trajectory.

In the last years, several evidences have demonstrated that starting rehabilitation in Intensive Care Units is a safe and feasible approach for patients affected by a severe Acquired Brain Injury (ABI). Moreover, the integration of the rehabilitative treatment in the acute care was shown to improve patients’ functional outcome and to reduce the risk of secondary complications. Since verticalization was reported to improve the level of arousal and awareness of brain injured patients, our group has recently evaluated the feasibility, safety and effectiveness of the very early use of a tilt table with an integrated robotic stepping device on patients affected by ABI hospitalized in a NeuroICU.

Stroke disease involves an increasing number of subjects due to the aging population. In clinical practice‚ the presence of widely accessible rehabilitative interventions to facilitate the patients’ motor recovery‚ especially in the early stages after injury when wider improvement can be gained‚ is crucial to reduce social and economical costs. The functional electrical stimulation (FES) has been investigated as a tool to promote locomotion ability in stroke patients. Particular attention was given to FES delivered during cycling‚ which is recognized as a safe and widely accessible way to provide a FES-based rehabilitative intervention in the most impaired subjects. In this chapter the neurophysiological basis of FES and its potential correlates to facilitate the long-term reorganization at both cortical and spinal level have been discussed. A discussion on clinical evidence and possible future direction is also proposed.

Functional electrical stimulation has been applied for more than half a century to restore and support gait in patients after stroke or after spinal cord injury. Most prevalent are assistive systems for the correction of drop foot in stroke patients using either surface or implanted stimulation technology. For therapeutical use in clinical environments, multi-channel FES systems are often employed in combination with robotic devices or partial body weight support during walking on a treadmill. The restoration of gait in spinal cord injured people is also an ongoing research topic. New implantable stimulation systems and hybrid approaches that combine powered exoskeletons and FES are under investigation. Inertial sensor technology, electromyographic sensing, and advanced feedback control are predicted to be key technologies of future FES systems that allow a more patient and situation-specific gait support.

The nociceptive withdrawal reflex (NWR) can be used for supporting gait as the spinal stepping generator circuits can also be triggered by robust afferent input [36]. This has been utilised in many assistive functional electrical stimulation devices since the first reports by Liberson [32] who found a functional benefit when stimulating electrically the peroneal nerve during the swing phase. The NWR response is an integrated movement generated by a coordinated activation of several muscles in the limb when the body receives a potentially tissue damaging stimulus. The NWR is generated to ensure adequate and sufficient withdrawal while maintaining balance and ensuring continuation of the ongoing motor programs [4, 41, 49]. This obviously leads to involvement of the contralateral limb to ensure upright posture and balance control. During rhythmic movements like gait, the spinal pattern generators are involved in reflex modulation as the reflex responses are strongly modulated by the phases of the gait cycle [17, 56].

Postural control has been defined as the ability to maintain, achieve or restore a state of balance during any posture or activity (van Diest et al. in J Neuroeng Rehabil 10:101, [1]; Pollock et al. in Clin Rehabil 14:402–406, [2]). Appropriate postural control is an absolute pre-requisite for activities of daily living and requires several different motor skills to be effective. To maintain a stable upright stance, with adaptive strategies for orientation and balance, information processed through the somatosensory (70%), visual (10%) and vestibular (20%) systems needs to be integrated (Horak in Age Ageing 35(Suppl 2):ii7–ii11, [3]; Laughton et al. in Gait Posture 18:101–108, [4]), and a complex interplay between sensory and motor systems (Bekkers et al. in Front Hum Neurosci 8:939, [5]) is required in order to control the multisegmental body system and interlimb coupling (Jancová in Acta Med Hradec Král Univ Carol Fac Med Hradec Král 51:129–137, [6]).

Gait is one of the motor tasks most affected in Parkinson’s disease (PD), due to a deficit of internal rhythmic signals that interferes with motor pathways (Currà et al. in JAMA 12:646–654, 2004 [1]).

In the last decades, non-invasive brain stimulation (NIBS) has evolved to become a valuable tool in both basic and clinical neuroscience. Various methods of transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) have been widely used for diagnostic, prognostic and even therapeutic applications in a broad range of neurological and psychiatric disorders. The rationale for using NIBS techniques lies in the possibility to modulate, in a targeted manner, the activity of different cerebral and cerebellar cortical regions, as well as the functional connections between these areas and distant brain regions also including subcortical structures. The neural circuitry involved in the different aspects of gait control is very complex and includes, along with the basal ganglia-cortical loops, the cerebellum and structures of the brainstem and the spinal cord. This is why different approaches of NIBS have been suggested for treatment of gait disorders in a variety of neurological disorders including Parkinson’s disease, stroke, cerebellar ataxia, multiple sclerosis, cerebral palsy and spinal cord injury. This review will collate the available knowledge on the physiology of gait and balance control, focusing on the ways in which the use of NIBS may contribute to the understanding and treatment of gait disorders.

The adult paralytic foot or drop foot is a secondary related foot deformity, which usually arises due to neurogenic damage (Kunst et al. in Stroke 42:2126–2130, 2011; Truelsen et al. in European Journal of Neurology 13:581–598, 2006). The lack of neural innervation of the muscles, which play a major role in ankle dorsiflexion—M. tibialis anterior, Mm. peronei, M. extensor digitorum longus, and M. extensor halluces longus—can cause a secondary malposition of the foot. As a dorsiflexion of the ankle cannot be actively provoked, this leads to a domination of the flexors and as a secondary outcome to a shortening of these muscles and their tendons. Similarly, it may also lead to a malposition in supination (www.mayoclinic.org/diseases-conditions/foot-drop/basics/definition/con-20032918).

Drop foot is a common problem following neurological conditions such as stroke, multiple sclerosis (MS), traumatic brain injury (TBI), incomplete spinal cord injury (iSCI) and cerebral palsy (CP). Between 20 and 30% of patients entering neurological rehabilitation suffer from drop foot. Typically, drop foot is caused by weakness of the ankle dorsiflexors leading to a lack of foot elevation during the swing phase of gait, which is often accompanied by a tendency towards varus deviation at the ankle due to muscular imbalance. In addition, spasticity of the ankle plantarflexors may worsen equinovarus deviation as a result of muscle stiffness, contracture and pathological co-contraction. Drop foot leads to an abnormal gait pattern, decreased walking speed, limited endurance walking and increased fall risk. All these factors can limit mobility, independence and social participation leading to reduced quality of life.

This chapter provides an overview of the achieved results with the existing neuroprostheses (NPs) and discusses some of the challenges of this technology which is currently facing to reorganize the brain by creating new neural pathways to regain body function due to brain lesions‚ as tumors‚ stroke‚ traumatic brain injury‚ spinal cord lesion‚ and sensory processing disorders among others; that produce motor disabilities. Neuroprostheses with myoelectric control (motor NPs) have a high potential for restoring or improving motor function as a result of applying Functional Electrical Stimulation (FES) to selected nerves and/or muscles. FES tries to mimic the central nervous system to attain sensory function or muscle activation. Individuals are able to increase their range of motion‚ their reaching ability‚ improve their overall gait and stability‚ and to diminish their spastic pattern. Therefore‚ the main challenge of motor NPs is to achieve the muscle synergies that would result in the desired movement. The burst sequence to apply FES seems to be the key to achieving them. The use of NPs in rehabilitation is often called Functional Electrical Therapy (FET). The stimulation pattern integrated in FET is timed to mimic the sequence of muscle activation in able-bodied subjects. FET is not only for therapeutic purposes but also for assistive activation that enhances neuroplasticity. The review summarizes who could benefit from the new technologies and what are the limitations of the neuroprostheses available today. It is presented the state-of-the-art of the basic architecture of FES used for electrical stimulation of the central nervous system and stimulation of peripheral sensory-motor systems. As well‚ the types of stimulation electrodes either through surface electrodes attached to the skin over nerves‚ percutaneous interface with the target or through electrodes implanted in close proximity to nerves are presented. Examples of motor neuroprostheses technologies include foot-drop and postural NPs‚ vestibular control implant‚ sensory/motor prosthetics‚ as well as‚ specialized software and hardware which support the function of autonomous nervous system‚ increase mobility‚ or improve gait and balance capacities. The coupling of a neuroprosthesis with systems as a Brain–Computer Interface (BCI) based on Electroencephalography signal (EEG) or biofeedback by Electromyography signal (EMG) to record‚ for example muscle activity is explored as an option to the control of motor neuroprostheses. The fact that the user learned to control the BCI in a comparatively short time indicates that this method may also be an alternative approach for clinical purposes to enhance neuroplasticity and sensory patterns. Clinical applications of FES devices‚ and NPs as consequence‚ require extraordinary‚ diverse‚ lengthy and intimate collaborations among basic scientists‚ engineers and clinicians. In this review‚ the most important physiological principles are shown regarding the neuroprosthetics approach and emphasize the role of electrical stimulation in order to achieve desired functional outcomes or to reduce medical problems such as‚ walking disorders‚ spasticity‚ or vertigo. Full restoration function with the current technologies is unlikely in the near future‚ continued research and development in neuroprostheses technology will likely result in a substantial improvement in the quality of life of disabled individuals.

It is well known that with a delay a lesion of the central nervous system (CNS) involving senso-motor networks in the brain or cervical or thoracic spinal cord will lead to an Upper Motor Neuron Syndrome (UMNS) caudal of the lesion. Clinically UMNS could be detected by increased resistance against passive movement during rest position (defined by Lance [22]), enhanced tendon reflexes [12, 28, 38], pyramidal signs and flexor-reflexes [12, 28], Co-contraction [12, 38], spastic dystonia [12, 38], and result in disturbed posture, slowed motor performance with decreased dexterity and coordination difficulties named spastic movement disorder (SMD, [13]).

Spasticity is a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks, caused by hyperexcitability of the stretch reflex (Lance in Symposium synopsis. Year Book Medical Publishers, Miami, FL, 1980, [1]). It is a common entity that is estimated to affect 35% of people post stroke (Welmer et al. in Cerebrovasc Dis 21(4):247–253, 2006, [2]), 40% of people post spinal cord injury (Noreau et al. in Am J Phys Med Rehabil [Internet] 79(6):526–535, 2000, [3]), and 50% of people post traumatic brain injury (Wedekind and Lippert-Grüner in Brain Inj [Internet] 19(9):681–684, 2005, [4]). It is also a condition associated with high morbidity that increases pain/discomfort levels, impairs daily living functioning, self-image and self-esteem, and, most of all, impairs mobility and gait.

Spasticity is a positive sign of upper motor neuron syndrome, which may interfere with motor function, leading to the need for pharmacological and rehabilitation interventions. Accurate prognostic indicators would be helpful in order to achieve adequate planning of spasticity management. The treatment goals of spasticity management usually include: drug potentiation, restoration of biomechanics, improvement of motor control, strengthening of weak muscles, integration of functional activities and, improvement of endurance. The optimal combination of rehabilitation techniques and medical management may improve outcomes in spasticity treatment.

Epidural spinal cord stimulation has a long history of application as a neuromodulation method for the relief of intractable pain and for improving motor control in various motor disorders. In spinal cord injury specifically, epidural stimulation of the lumbar spinal cord can effectively control severe and diffuse spasticity, without further deteriorating residual voluntary motor control. With appropriate parameters, the stimulation can also generate rhythmic activity and extension in paralyzed legs as well as enable or facilitate residual voluntary lower-limb movements. The development of transcutaneous spinal cord stimulation, a non-invasive method working through surface electrodes with similar neuromodulatory effects, allows for a wide clinical application of this technique in contemporary rehabilitation programs. While also providing background information on historical and recent developments in the field as well as on the neurophysiological mechanisms of spinal cord stimulation, this chapter provides practical information for professionals interested in using electrical neuromodulation in the rehabilitation of individuals after spinal cord injury.

Advances in the therapy of patients with neurological disorders have resulted in a large and growing population of subjects with dysfunction and deformity of the extremities secondary to a central nervous system lesion (upper motor neuron syndrome, UMNS). Traumatic brain injuries (TBIs) and cerebral vascular accidents (CVAs), or strokes, can have profound effects both on the patient and on society. Stroke is currently the third leading cause of mortality and is a common cause of long-term disability, generating increasing annual healthcare costs. Approximately 60% of these patients survive, and half of them may have residual hemiparesis. Due to the central nervous system damage, stroke patients show muscle weakness, abnormal muscle tone, and disorders of balance and posture control, which lead to difficulty controlling movements, limb spasticity and limb deformities (Keenan et al. in J Neuro Rehabil I2:119–143, 1999 [1]; Banks in Clin Orthop Relat Res 122:70–76, 1977 [2]). Limb deformities are commonly the result of both static and dynamic phenomena. The former include heterotopic ossification, fracture malunion and soft tissue contractures, and the latter weakness, spasticity, rigidity and impaired motor control. In more than 80% of hemiplegic patients, equinovarus foot deformity (EVFD), resulting in abnormal walking patterns, is the main factor limiting post-stroke gait (Lin et al. in Arch Phys Med Rehabil 87:562–568, 2006 [3]). It usually results from spasticity of the plantar flexor and invertor muscles, associated with a deficit of the dorsiflexors, their antagonists. Specifically, deformity of the foot can be seen in the presence of combined spasticity of several different muscles, including the gastrocnemius, soleus, tibialis anterior (TA), tibialis posterior (TP), flexor hallucis longus (FHL), and flexor digitorum longus (FDL), while associated weakness can be recorded in the peroneal muscles. Foot deformities interfere with toe clearance in the swing phase, with correct pre-positioning of the foot at the end of the swing phase, with loading of the stance leg, and with ankle stability during the stance phase (Keenan et al. in J Neuro Rehabil I2:119–143, 1999 [1]). Consequently, neurological patients with EVFD are often unable to walk unassisted, requiring either an orthotic device or crutches (Keenan et al. in Foot Ankle 5:35–41, 1984 [4]).