Archive for February, 2017

[Abstract] Safety and Tolerability of Transcranial Direct Current Stimulation to Stroke Patients – A Phase I Current Escalation Study.

Highlights

tDCS currents >2 mA have not been investigated in stroke patients.

This phase I dose escalation study establishes safety of up to 4 mA in stroke patients.

No predefined major response was noted at any current level.

Skin temperature did not rise, and skin barrier function remained intact.

Transient skin redness without injury was a common finding irrespective of dose level.

Abstract

Background and Objective

A prior meta-analysis revealed that higher doses of transcranial direct current stimulation (tDCS) have a better post-stroke upper-extremity motor recovery. While this finding suggests that currents greater than the typically used 2 mA may be more efficacious, the safety and tolerability of higher currents have not been assessed in stroke patients. We aim to assess the safety and tolerability of single session of up to 4 mA in stroke patients.

Methods

We adapted a traditional 3+3 study design with a current escalation schedule of 1>>2>>2.5>>3>>3.5>>4 mA for this tDCS safety study. We administered one 30-minute session of bihemispheric montage tDCS and simultaneous customary occupational therapy to patients with first-ever ischemic stroke. We assessed safety with pre-defined stopping rules and investigated tolerability through a questionnaire. Additionally, we monitored body resistance and skin temperature in real-time at the electrode contact site.

Results

Eighteen patients completed the study. The current was escalated to 4 mA without meeting the pre-defined stopping rules or causing any major safety concern. 50% of patients experienced transient skin redness without injury. No rise in temperature (range 26°C-35°C) was noted and skin barrier function remained intact (i.e. body resistance >1 kΩ).

Conclusion

Our phase I safety study supports that single session of tDCS with current up to 4 mA is safe and tolerable in stroke patients. A phase II study to further test the safety and preliminary efficacy with multi-session tDCS at 4 mA (as compared with lower current and sham stimulation) is a logical next step.

Source: Safety and Tolerability of Transcranial Direct Current Stimulation to Stroke Patients – A Phase I Current Escalation Study

, , , ,

Leave a comment

[ARTICLE] The effects of functional electrical stimulation on muscle tone and stiffness of stroke patients – Full Text PDF

Abstract

[Purpose] The purpose of this study was to determine the effects of functional electrical stimulation on muscle tone and stiffness in stroke patients.

[Subjects and Methods] Ten patients who had suffered from stroke were recruited. The intervention was functional electrical stimulation on ankle dorsiflexor muscle (tibialis anterior). The duration of functional electrical stimulation was 30 minutes, 5 times a week for 6 weeks. The Myoton was used a measure the muscle tone and stiffness of the gastrocnemius muscle (medial and lateral part) on paretic side.

[Results] In the assessment of muscle tone, medial and lateral part of gastrocnemius muscle showed differences before and after the experiment. Muscle stiffness of medial gastrocnemius muscle showed differences, and lateral gastrocnemius muscle showed differences before and after the experiment. The changes were greater in stiffness scores than muscle tone.

[Conclusion] These results suggest that FES on ankle dorsiflexor muscle had a positive effect on muscle tone and stiffness of stroke patients.

INTRODUCTION

Muscle tone is defined as the resistance of muscle being passively lengthened1) . Abnormal muscle tone occurs in disorders of central nervous system and can affect up to two-thirds of patients with stroke2) . Especially, it is a common motor disorder following stroke, which may require rehabilitation3) . A hypertonus state leads to involuntary muscle contractions that interfere with the normal movements of the arms and legs, restrict the range of motion of joints, and lower extremity the functions of daily living, thereby restricting the functional recovery of patients4) .

Yan and Hui-Chan reported that functional electrical stimulation (FES) may be able to normalize muscle tone in affected ankle plantar flexors5) . FES is a popular post-stroke gait rehabilitation intervention. FES is typically delivered to ankle dorsiflexors to correct foot drop during the swing phase6) . FES is applied on the tibialis anterior muscle to enhance coordination capability during the gait cycle, and to increase the range of motion of the ankle joint and walking speed, thus improving gait quality7) . FES appears to enhance balance control during walking and, thus, effectively management foot drop in stroke patients8) . Cho et al. reported that treadmill training while FES was applied to the gluteus medius and tibialis anterior muscles increased lower limb muscle strength and improved balance and gait9) . Most previous studies assessed muscle strength and gait ability. However, few studies have assessed muscle tone and stiffness. Therefore, we investigated the influence of FES on muscle tone and stiffness in stroke patients.

Stroke survivors show significantly higher resistance torque and joint stiffness10) . Muscle stiffness, which is defined as a change in passive tension per unit change in length, is an indication of a muscle’s passive resistance to elongation11) . Ankle stiffness is associated with difficulty walking due to an asymmetric posture and a loss of balance and motor control12) . Limited ankle joint dorsiflexion is caused by calf muscle (gastrocnemius and soleus muscles) stiffness and soft contracture13) . Owing to an increase of muscle tension in the gastrocnemius muscle, stroke patients cannot actively control dorsiflexion, and foot drop tends to occur14) .

In this study, we hypothesized that FES applied to the ankle dorsiflexor (tibialis anterior) may reduce muscle tone and stiffness of the gastrocnemis muscle (medial and lateral part) in stroke patients.

Download Full Text PDF

, , , ,

Leave a comment

[Abstract] Robotic Devices to Enhance Human Movement Performance.

Abstract

Robotic exoskeletons and bionic prostheses have moved from science fiction to science reality in the last decade. These robotic devices for assisting human movement are now technically feasible given recent advancements in robotic actuators, sensors, and computer processors. However, despite the ability to build robotic hardware that is wearable by humans, we still do not have optimal controllers to allow humans to move with coordination and grace in synergy with the robotic devices. We consider the history of robotic exoskeletons and bionic limb prostheses to provide a better assessment of the roadblocks that have been overcome and to gauge the roadblocks that still remain. There is a strong need for kinesiologists to work with engineers to better assess the performance of robotic movement assistance devices. In addition, the identification of new performance metrics that can objectively assess multiple dimensions of human performance with robotic exoskeletons and bionic prostheses would aid in moving the field forward. We discuss potential control approaches for these robotic devices, with a preference for incorporating feedforward neural signals from human users to provide a wider repertoire of discrete and adaptive rhythmic movements.

Source: Robotic Devices to Enhance Human Movement Performance: Kinesiology Review: Vol 6, No 1

, , , , , ,

Leave a comment

[ARTICLE] Short-term effects of physiotherapy combining repetitive facilitation exercises and orthotic treatment in chronic post-stroke patients – Full Text PDF

Abstract.

[Purpose] This study investigated the short-term effects of a combination therapy consisting of repetitive facilitative exercises and orthotic treatment.

[Subjects and Methods] The subjects were chronic post-stroke patients (n=27; 24 males and 3 females; 59.3 ± 12.4 years old; duration after onset: 35.7 ± 28.9 months) with limited mobility and motor function. Each subject received combination therapy consisting of repetitive facilitative exercises for the hemiplegic lower limb and gait training with an ankle-foot orthosis for 4 weeks. The Fugl-Meyer assessment of the lower extremity, the Stroke Impairment Assessment Set as a measure of motor performance, the Timed Up & Go test, and the 10-m walk test as a measure of functional ambulation were evaluated before and after the combination therapy intervention.

[Results] The findings of the Fugl-Meyer assessment, Stroke Impairment Assessment Set, Timed Up & Go test, and 10-m walk test significantly improved after the intervention. Moreover, the results of the 10-m walk test at a fast speed reached the minimal detectible change threshold (0.13 m/s).

[Conclusion] Short-term physiotherapy combining repetitive facilitative exercises and orthotic treatment may be more effective than the conventional neurofacilitation therapy, to improve the lower-limb motor performance and functional ambulation of chronic post-stroke patients.

 

INTRODUCTION

The mobility of many stroke survivorsislimited, and most identify walking as a top priority for rehabilitation1) . One way to manage ambulatory difficulties is with an ankle-foot orthosis (AFO) or a foot-drop splint, which aims to stabilize the foot and ankle while weight-bearing and lift the toes while stepping1) . In stroke rehabilitation, various approaches, including robotic assistance, strength training, and task-related/virtual reality techniques, have been shown to improve motor function2) . The benefits of a high intensity stroke rehabilitation program are well established, and although no clear guidelines exist regarding the best levels of intensity in practice, the need for its incorporation into a therapy program is widely acknowledged2) . Repetitive facilitative exercises (RFE), which combine a high repetition rate and neurofacilitation, are a recently developed approach to rehabilitation of stroke-related limb impairment2–5) . In the RFE program, therapists use muscle spindle stretching and skin-generated reflexes to assist the patient’s efforts to move an affected joint5) . Previous studies have shown that an RFE program improved lower-limb motor performance (Brunnstrom Recovery Stage, foot tapping, and lower-limb strength) and the 10-m walk test in patients with brain damage3) . An AFO is an assistive device to help stroke patients with hemiplegia walk and stand. A properly prescribed AFO can improve gait performance and control abnormal kinematics arising from coordination deficits6) . Gait training with an AFO has been also reported to improve gait speed and balance in post-stroke patients7, 8) . Therefore, we hypothesized that short-term physiotherapy combining RFE and orthotic treatment would improve both lower-extremity motor performance and functional ambulation. The present study aimed to confirm the efficacy of a combination therapy consisting of RFE for the hemiplegic lower limb and gait training with AFO.

Download Full Text PDF

 

, , , , , , , ,

Leave a comment

[ARTICLE] Validity of gait asymmetry estimation by using an accelerometer in individuals with hemiparetic stroke – Full Text PDF

Abstract.

[Purpose] The purpose of this study was to evaluate the validity of estimating step time and length asymmetries, using an accelerometer against force plate measurements in individuals with hemiparetic stroke.

[Subjects and Methods] Twenty-four individuals who previously had experienced a stroke were asked to walk without using a cane or manual assistance on a 16-m walkway. Step time and length were measured using force plates, which is the gold standard for assessing gait asymmetry. In addition to ground reaction forces, trunk acceleration was simultaneously measured using an accelerometer. To estimate step time asymmetry using accelerometer data, the time intervals between forward acceleration peaks for each leg were calculated. To estimate step length asymmetry using accelerometer data, the integration of the positive vertical accelerations following initial contact of each leg was calculated. Asymmetry was considered the affected side value divided by the unaffected side value.

[Results] Significant correlations were found between the accelerometer and the force plates for step time and length asymmetries (rho=0.83 and rho=0.64, respectively).

[Conclusion] An accelerometer might be useful for assessing step time and length asymmetries in individuals with hemiparetic stroke, although improvements are needed for estimating the accuracy of step length asymmetry.

Download PDF

, , , , , ,

Leave a comment

[WEB SITE] Study offers novel principle to reroute neurons for brain repair

Restorative neuroscience, the study to identify means to replace damaged neurons and recover permanently lost mental or physical abilities, is a rapidly advancing scientific field considering our progressively aging society. Redirecting immature neurons that reside in specific brain areas towards the sites of brain damage is an appealing strategy for the therapy of acute brain injury or stroke. A collaborative effort between the Center for Brain Research of Medical University of Vienna and the National Brain Research Program of Hungary/Semmelweis University in Budapest revealed that some mature neurons are able to reconfigure their local microenvironment such that it becomes conducive for adult-born immature neurons to extensively migrate. Thus, a molecular principle emerges that can allow researchers to best mobilize resident cellular reserves in the adult brain and guide immature neurons to the sites of brain damage.

The adult brain has limited capacity of self-repair

In the aging Western society, acute brain damage and chronic neurodegenerative conditions (e.g. Alzheimer’s and Parkinson’s diseases) are amongst the most debilitating diseases affecting hundreds of millions of people world-wide. Nerve cells are particularly sensitive to microenvironmental insults and their loss clearly manifests as neurological deficit. Since the innate ability of the adult human brain to regenerate is very poor and confined to its few specialized regions, a key question in present-day neurobiology is how to establish efficient strategies that can replace lost neurons, guide competent cells to the sites of injury and facilitate their functional integration to regain lost functionality. “Cell replacement therapy” thus offers frontline opportunities to design potent therapeutic interventions.

Neurons drive neurons: a new concept integrating brain activity with repair

Only two regions of the postnatal mammalian brain are known to retain their intrinsic potential to allow the generation of new neurons throughout life: the olfactory system decoding smell and the hippocampus acting as a key hub for memory encoding and storage. In humans, the generation of new neurons in the olfactory system rapidly ceases during early childhood. “Which are the processes that disallow this innate regenerative process in the human brain and how can dormant progenitors be reinstated to produce new neurons and guide those towards brain areas that require repair?” is a central yet unresolved question for brain repair strategies.

For neuronal migration, the widely-accepted concept is that support cells called astroglia are of primary importance to promote the movement of adult-born neurons through chemical signals and physical interactions. The new study involving researchers from the Department of Molecular Neurosciences of the Center for Brain Research goes well beyond these known frontiers through the discovery that the migration of new-born neurons requires resident, differentiated nerve cells to “clear their path” by digesting away some of the glue that fills the space between nerve cells. This process is dependent on the activity of resident neurons, thus suggesting the integration of the ancient developmental process of active cell movement with the integrative capacity and activity patterns of the brain. “By realizing that differentiated neurons are critical operators in this process we finally lay our hands on an “on switch” which we can use to produce a molecular landing strip for migrating neuroblasts to home in at areas of critical need” says Alán Alpár, senior author of the study.

Opportunities for restorative neuroscience

Tibor Harkany, Professor of Molecular Neurosciences at the Medical University of Vienna goes one step further “We mapped the entire molecular machinery used by differentiated neurons to make way for their migrating adult-born replacements. This clearly offers a pharmacological concept to reroute neurons in sufficient quantities for neurorepair once damage occurs. Even though distances can be considerably long, we are confident that molecular means exist to tackle these challenges”.

Brain activity defines therapeutic success?

The realization that differentiated neurons hold the key to directional cell migration is of enormous significance since they are wired into the brain circuitry, receive information from not only adjacent but also far-away regions and are activated by these specific connections at precisely given times. Consequently, migration controlled by the newly described specific neuronal subset can be aligned with brain activity, or conversely, with inactivity as evoked by neuronal loss during brain diseases. “To identify the physiological stimuli and stressors, which activate these guide-neurons will herald a new and exciting opportunity for regenerative neuroscience” adds Tomas Hökfelt, Guest Professor at the Center for Brain Research.

Like many other studies at the Department of Molecular Neurosciences, the European Research Council (ERC) and the European Molecular Biology Organisation (EMBO) frontier research programs funded this project. Alán Alpár’s work is supported by the National Brain Research Program of the Hungarian Academy of Sciences.

Source: Study offers novel principle to reroute neurons for brain repair

, , , , ,

Leave a comment

[ARTICLE] Electrical somatosensory stimulation followed by motor training of the paretic upper limb in acute stroke: study protocol for a randomized controlled trial | Trials – Full Text

Abstract

Background

Upper limb paresis is one of the most frequent and persistent impairments following stroke. Only 12–34% of stroke patients achieve full recovery of upper limb functioning, which seems to be required to habitually use the affected arm in daily tasks. Although the recovery of upper limb functioning is most pronounced during the first 4 weeks post stroke, there are few studies investigating the effect of rehabilitation during this critical time window. The purpose of this trial is to determine the effect of electrical somatosensory stimulation (ESS) initiated in the acute stroke phase on the recovery of upper limb functioning in a nonselected sample of stroke patients.

Methods/design

A sample of 102 patients with upper limb paresis of varying degrees of severity is assigned to either the intervention or the control group using stratified random sampling. The intervention group receives ESS plus usual rehabilitation and the control group receives sham ESS plus usual rehabilitation. The intervention is applied as 1 h of ESS/sham ESS daily, followed by motor training of the affected upper limb. The ESS/sham ESS treatment is initiated within 7 days from stroke onset and it is delivered during hospitalization, but no longer than 4 weeks post stroke. The primary outcome is hand dexterity assessed by the Box and Block Test; secondary outcomes are the Fugl-Meyer Assessment, hand grip strength, pinch strength, perceptual threshold of touch, degree of pain, and modified Rankin Scale score. Outcome measurements are conducted at baseline, post intervention and at 6-month follow-up.

Discussion

Because of the wide inclusion criteria, we believe that the results can be generalized to the larger population of patients with a first-ever stroke who present with an upper limb paresis of varying severity. On the other hand, the sample size (n = 102) may preclude subgroup analyses in such a heterogeneous sample. The sham ESS treatment totals a mere 2% of the active ESS treatment delivered to the intervention group per ESS session, and we consider that this dose is too small to induce a treatment effect.

Background

Stroke is ranked as the third largest cause of disease burden globally [1], causing substantial physical, psychological and financial demands on patients, families, and societies at large [2, 3, 4]. Upper limb paresis is one of the most frequent impairments following stroke and affects 48–77% of patients in the acute stroke phase [5, 6, 7]. Moreover, upper limb paresis has been identified as a major obstacle to regaining independence in activities of daily living (ADLs) [8]. In fact, only 12–34% of the patients achieve full functional recovery of the affected upper limb at 6 months post stroke [9, 10]. This represents a considerable challenge since near complete functional recovery is required to routinely involve the affected upper limb in performing ADLs [11].

Recovery of upper limb functioning is typically pronounced during the first month and subsequently levels off by 6 months post stroke [12, 13, 14]. Regaining hand dexterity (i.e., motor skills such as reaching, grasping, gripping, moving and releasing objects) is often achieved already within the first 4 weeks, implying that there may be a critical time window for recovery of upper limb functioning [9, 10] during which rehabilitation efforts may maximize functional recovery. However, there are few studies investigating the effect of motor rehabilitation methods in the initial weeks after stroke.

Electrical stimulation (ES) is one of the methods that have been used to facilitate recovery of upper limb functioning following stroke. ES can induce a muscle contraction, or it can be a somatosensory stimulation below the motor threshold [15]. The majority of studies using ES have been conducted in chronic stroke and, therefore, it remains unknown to what extent ES applied in the acute phase after stroke could affect the recovery of upper limb functioning. Also, these investigations have largely focused on ES that induces muscle contraction. In healthy persons, the application of low-intensity ES with no or small motor responses to peripheral hand nerves [16, 17, 18, 19, 20], forearm muscles [21] or the whole hand [22, 23] elicits an increase in the cortical excitability of the representations that control the stimulated body parts, which seems to outlast the stimulation period itself [18, 21, 23]. It has been hypothesized that increasing the amount of somatosensory input may enhance the motor recovery of patients following stroke [24]. Recent data on acute, subacute and mostly chronic stroke patients suggest that a single 2-h session of ESS to the peripheral hand nerves leads to transient improvement of pinch force, movement kinematics and upper limb motor skills required for ADL performance [25, 26, 27, 28, 29, 30, 31]. However, ESS was only used in conjunction with motor training in one of these studies [29]. Interestingly, there is some evidence that multiple sessions of ESS to the peripheral hand nerves, in conjunction with motor training, might improve motor skills of the paretic upper limb in subacute [32, 33] and chronic stroke patients [34], and, moreover, that these positive results seems to be long lasting [34]. However, the effect of ESS in conjunction with motor training has never been investigated in acute stroke patients. It is noteworthy that ESS is benign in nature, causes patients minimal discomfort and adverse effects (itch and blushing), is relatively inexpensive and can easily be incorporated into clinical practice [35]. Therefore, it would be valuable to establish the effect of multiple sessions of ESS in conjunction with motor training in the restoration of upper limb functioning in the acute stroke phase.

The purpose of the present trial is to investigate the effect of multiple sessions of ESS treatment accompanied by motor training on the recovery of the affected upper limb following stroke. The ESS treatment is initiated in the acute stroke phase and each ESS session is immediately followed by motor training of the paretic upper limb. Specifically, we wish to address the following:

  1. (1)

    Does ESS treatment: (a) reduce motor and sensory impairments, (b) improve hand dexterity and (c) reduce disability at the end of the intervention period (short-term effect)?

  2. (2)

    Are the changes that can be observed at the end of the intervention period still present or improved at 6 months post stroke (long-term effect)?

Our hypothesis is that ESS treatment initiated in the acute stroke phase will improve paretic upper limb functioning as measured by the Box and Block Test (BBT) (primary outcome measure) at 6 months post stroke.

Continue —> Electrical somatosensory stimulation followed by motor training of the paretic upper limb in acute stroke: study protocol for a randomized controlled trial | Trials | Full Text

Fig. 2 Placement of the electrodes

, , , , , , , , ,

Leave a comment

[commentary] Gait and balance training using virtual reality is more effective for improving gait and balance ability after stroke than conventional training without virtual reality.

Commentary

Virtual reality technology, consisting of computer simulations to artificially generate sensory information in the form of a virtual environment that is interactive and perceived as similar to the real world, is recognised as a novel intervention tool in stroke rehabilitation. This timely systematic review addressed the effectiveness of virtual reality training on gait and balance using commonly assessed clinical outcome measures. The meta-analyses conducted on these outcomes all favoured virtual reality training when the time-dose was matched between balance and gait training, with and without virtual reality. Virtual reality-based rehabilitation should thus be considered to be more than an adjunct to conventional gait training, which is recommended by a recent update on stroke rehabilitation best practice.1

While virtual reality offers the opportunity to create unique and customisable interventions that are unavailable or readily accomplished in the real world, its clinical implementation may be challenging. Diverse virtual reality tools exist; they range from computer games (eg, Wii, Kinect) to high-end, immersive, and costly systems.2 The realism and ecological validity of a virtual environment could enhance training efficiency in virtual reality-based rehabilitation. A useful framework3 to guide clinical decision-making consists of three essential phases: (1) interaction between the user and the virtual environment, taking into account the personal and environmental characteristics; (2) transfer of skills learned from the virtual environment to the real world; and (3) participation in the real world and its affordances as a result of rehabilitation. The transfer of virtual reality-based gait and balance training to actual community ambulation should thus be considered. It should be assessed with mobility outcomes recorded in the community and during negotiation of actual environmental challenges, such as slopes and obstacles. Outcomes of participation, motivation and adherence to training should also be evaluated.
Provenance: Invited. Not peer-reviewed.

References

    • 3
    • Weiss PL, et al. In: Selzer ME, et al. (eds). Textbook of neural repair and neurorehabilitation. 2016;2:182–197.

Source: Gait and balance training using virtual reality is more effective for improving gait and balance ability after stroke than conventional training without virtual reality [commentary]

, ,

Leave a comment

[Report] A smart brace to support spasticity management in poststroke rehabilitation – Full Text PDF by Max Lammers

Executive Summary

This report covers the design of a product to help stroke survivors who are suffering from chronic spasticity manage their everyday activities.

In the Netherlands alone, 44.000 people suffer from a Cerebro-Vascular Accident (CVA) each year. A CVA, more commonly known as a stroke, results in brain trauma with afflictions such as paralysis, fatigue and spasticity. It is possible to recover some, if not all, motor function though intensive physiotherapy, which requires longterm stay at a rehabilitation clinic in severe cases. Due to limited room and staff, only 12% of stroke survivors end up rehabilitating in a clinic. The remaining survivors are sent home, and will to travel to the clinic 3-5 times per week for therapy as part of the outpatient rehabilitation.

Adjuvo Motion, a young start-up, aims to improve the situation of stroke survivors by bringing the rehabilitation center to their home through the Adjuvo Platform, which allows them to perform exercises in the context of virtual tasks. They proposed an assignment to extend their product portfolio with a Range of Motion assessment device that is suited for those suffering from spasticity.

Spasticity occurs in roughly 60% of stroke survivors with varying degrees of intensity. It is caused by the damaged parts of the brain sending conflicting signals to the muscles, causing them to contract. This inhibits the survivor’s ability to perform daily tasks, but can be solved temporarily with stretching exercises. A solution to compensate for these spastic forces using a passiveassist device was proposed at the start of this project. The project was divided into four stages: Analysis, Synthesis, Embodiment and Evaluation.

During the Analysis stage, interviews with a Physiotherapist and stroke survivor and literature studies regarding anatomy, the state of the art and relevant technologies were used to create a framework for the design of a smart passive-assist glove. Looking at competing products, there is a demand for passive assist and Range of Motion assessment functionalities, yet a combination of these in a single device is not yet present in the market.

During the Synthesis stage, the design problem of the passive assist device was split into three groups: Orthoses; the connections to the body, Passive Assist; the compensation medium, and RoM measurement; the sensing mechanism(s). These three groups were further split into sub-problems, the solutions to which were compiled into a Morphological Chart. By combining the solution within this chart, three promising concept designs were created: One upgrade to the existing sensor glove, one full integration of sensing and passive assist, and one passive assist glove with removable sensors.

To evaluate these concepts, eight criteria were established and weighted with the help of a physiotherapist. In order to create an objective assessment, the criteria were kept strictly quantitative and the three designs were first scored against the Raphael Smart Glove by Neofect using early prototypes. These scores were then used to evaluate the designs relative to each other, which resulted in an overall higher score for the concept with separable electronics. Making the sensor part of the brace removable allowed the product to be used during daily life as well as physiotherapy exercises, and proved a key benefit in keeping the product clean.

Based on the chosen design, four iterations of prototypes were made, which were tested with healthy subject. During this stage, it became clear that flex sensors are be best suited to create a range of motion assessment for spastic stroke patients, since it is less important to know how well they perform a task, and more important to know if they can actually perform it.

Based on a quantified use case, the four sub-assemblies; the Wrist Wrap, Finger Modules and Sensor Module, and their connections were materialized in the Embodiment design stage. When selecting production methods, the main challenge was a small batch size of 1000 units, which made conventional techniques for mass production, such as Injection Molding, less attractive. This stage ended in an assessment of the product’s production price and durability: The product would cost €250 to make, and would last for 2.5 years before the Velcro connection on the Wrist Wrap would become too weak to sustain the spasticity forces.

In the Evaluation stage, the product was evaluated on the seven most important requirements established during the analysis stage. For several of these, a user test was performed, again with healthy subject. While the Adjuvo Auxilius passed most theoretical requirements, the user tests on healthy subjects could not be used to draw any conclusions regarding its effectiveness on spastic stroke patients. However, since the product’s working principle is based on that of existing spasticity compensation products, the prediction is that the Auxilius will be an effective therapy supplement.

The result of this project is the Adjuvo Auxilius; a spasticitycompensation glove with modular sensors, which can be added to allow virtual (stretching) exercises through the Adjuvo Motion’s platform. The results of these exercises are used to create a remote assessment of the patients motor skills, and to adjust the therapy if needed.

Full Text PDF

, , , , , , , , , ,

Leave a comment

[Abstract] Strength of ~20-Hz Rebound and Motor Recovery After Stroke.

Background. Stroke is a major cause of disability worldwide, and effective rehabilitation is crucial to regain skills for independent living. Recently, novel therapeutic approaches manipulating the excitatory-inhibitory balance of the motor cortex have been introduced to boost recovery after stroke. However, stroke-induced neurophysiological changes of the motor cortex may vary despite of similar clinical symptoms. Therefore, better understanding of excitability changes after stroke is essential when developing and targeting novel therapeutic approaches.

Objective and Methods. We identified recovery-related alterations in motor cortex excitability after stroke using magnetoencephalography. Dynamics (suppression and rebound) of the ~20-Hz motor cortex rhythm were monitored during passive movement of the index finger in 23 stroke patients with upper limb paresis at acute phase, 1 month, and 1 year after stroke.

Results. After stroke, the strength of the ~20-Hz rebound to stimulation of both impaired and healthy hand was decreased with respect to the controls in the affected (AH) and unaffected (UH) hemispheres, and increased during recovery. Importantly, the rebound strength was lower than that of the controls in the AH and UH also to healthy-hand stimulation despite of intact afferent input. In the AH, the rebound strength to impaired-hand stimulation correlated with hand motor recovery.

Conclusions. Motor cortex excitability is increased bilaterally after stroke and decreases concomitantly with recovery. Motor cortex excitability changes are related to both alterations in local excitatory-inhibitory circuits and changes in afferent input. Fluent sensorimotor integration, which is closely coupled with excitability changes, seems to be a key factor for motor recovery.

Source: Strength of ~20-Hz Rebound and Motor Recovery After Stroke – Feb 04, 2017

, , , , , , ,

Leave a comment

%d bloggers like this: