Posts Tagged hand function

[Abstract] Analyzing finger interdependencies during the Purdue Pegboard Test and comparative activities of daily living


Study Design

Bench and cross-sectional study.


Information obtained from dexterity tests is an important component of a comprehensive examination of the hand.

Purpose of the Study

To analyze and compare finger interdependencies during the performance of the Purdue Pegboard Test (PBT) and comparative daily tasks.


A method based on the optoelectronic kinematic analysis of the precision grip style and on the calculation of cross-correlation coefficients between relevant joint angles, which provided measures of the degree of finger coordination, was conducted on 10 healthy participants performing the PBT and 2 comparative daily living tasks.


Daily tasks showed identifiable interdependencies patterns between the metacarpophalangeal joints of the fingers involved in the grip. Tasks related to activities of daily living resulted in significantly higher cross-correlation coefficients across subjects and movements during the formation and manipulation phases of the tasks (0.7-0.9), whereas the release stage produced significantly lower movement correlation values (0.3-0.7). Contrarily, the formation and manipulation stages of the PBT showed low finger correlation across most subjects (0.2-0.6), whereas the release stage resulted in the highest values for all relevant movements (0.65-0.9).


Interdependencies patterns were consistent for the activities of daily living but differ from the patterns observed from the PBT.


The PBT does not compare well with the whole range of finger movements that account for hand performance during daily tasks.

via Analyzing finger interdependencies during the Purdue Pegboard Test and comparative activities of daily living – Journal of Hand Therapy


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[VIDEO] Henry Hoffman Q&A Video Series: Why SaeboStim Micro? – YouTube

Published on Oct 16, 2017

Saebo, Inc. is a medical device company primarily engaged in the discovery, development and commercialization of affordable and novel clinical solutions designed to improve mobility and function in individuals suffering from neurological and orthopedic conditions. With a vast network of Saebo-trained clinicians spanning six continents, Saebo has helped over 100,000 clients around the globe achieve a new level of independence.
In 2001, two occupational therapists had one simple, but powerful goal – to provide neurological clients access to transformative and life changing products.
At the time, treatment options for improving arm and hand function were limited. The technology that did exist was expensive and inaccessible for home use. With inadequate therapy options often leading to unfavorable outcomes, health professionals routinely told their clients that they have “reached a plateau” or “no further gains can be made”. The founders believed that it was not the clients who had plateaued, but rather their treatment options had plateaued.
Saebo’s commitment – “No Plateau in Sight” – was inspired by this mentality; and the accessible, revolutionary solutions began.
Saebo’s revolutionary product offering was based on the latest advances in rehabilitation research. From the SaeboFlex which allows clients to incorporate their hand functionally in therapy or at home, to the SaeboMAS, an unweighting device used to assist the arm during daily living tasks and exercise training, “innovation” and “affordability” can now be used in the same sentence.
Over the last ten years, Saebo has grown into a leading global provider of rehabilitative products created through the unrelenting leadership and the strong network of clinicians around the world. As we celebrate our history and helping more than 100,000 clients regain function, we are growing this commitment to affordability and accessibility even further by making our newest, most innovative products more accessible than ever.


via Henry Hoffman Q&A Video Series: Why SaeboStim Micro? – YouTube

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[Abstract] Outcome measurement of hand function following mirror therapy for stroke rehabilitation: A systematic review


  • Current studies on mirror therapy after stroke are not consistent in the assessment tools that are used to determine hand function.
  • Outcome measures used in the included studies are not fully reflective of the International Classification of Functioning, Disability and Health.
  • Most outcome measures used in the included studies are rated by the therapist and have determined validity, reliability, and responsiveness; however, responsiveness is the least investigated psychometric property.
  • Integrating a combination of measures that are psychometrically sound and reflective of the International Classification of Functioning, Disability and Health should be considered for assessment of hand function after mirror therapy after stroke.


Study Design

Systematic review.


Mirror therapy is a treatment used to address hand function following a stroke. Measurement of outcomes using appropriate assessment tools is crucial; however, many assessment options exist.

Purpose of the Study

The purpose of this study is to systematically review outcome measures that are used to assess hand function following mirror therapy after stroke and, in addition, to identify the psychometric and descriptive properties of the included measures and through the linking process determine if the outcome measures are representative of the International Classification of Functioning, Disability and Health (ICF).


Following a comprehensive literature search, outcome measures used in the included studies were linked to the ICF and analyzed based on descriptive information and psychometric properties.


Eleven studies met inclusion criteria and included 24 different assessment tools to measure hand or upper limb function. Most outcome measures used in the selected studies (63%) were rated by the evaluating therapist. Thirteen outcome measures (54%) linked to the ICF body function category and 10 measures (42%) linked to activities and participation. One outcome measure was linked to not defined, and all other ICF categories were not represented. A majority of outcome measures have been assessed for validity, reliability, and responsiveness, but responsiveness was the least investigated psychometric property.


Current studies on mirror therapy after stroke are not consistent in the assessment tools used to determine hand function. Understanding of study outcomes requires analysis of the assessment tools. The outcome measures used in the included studies are not representative of personal and environmental factors, but tools linking to body functions and activities and participations provide important information on functional outcome.


Integrating a combination of measures that are psychometrically sound and reflective of the ICF should be considered for assessment of hand function after mirror therapy after stroke.

via Outcome measurement of hand function following mirror therapy for stroke rehabilitation: A systematic review – Journal of Hand Therapy

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[ARTICLE] Effectiveness of Mirror Therapy in Rehabilitation of Hand Function in Sub-Acute Stroke – Full Text


Aim: Three quarters of strokes occur in the region supplied by the middle cerebral artery. As a consequence, the upper limb will be affected in a large number of patients. Purpose of the study is to examine the effectiveness of mirror therapy in rehabilitation of hand function in sub-acute stroke.

Methodology: An experimental study design, 30 subjects with sub-acute stroke with impaired hand function randomly allocated 15 subjects into each experimental group and conventional group. Both groups received conventional physiotherapy. The experimental group in addition, received Mirror Therapy program of 30 repetition of each exercises per day for 5 days in a week for 4 weeks (total = 20 sessions). Hand functions were measured using Upper extremity motor activity log (UE MAL) and Action research arm test (ARAT) before and after 4 week of intervention.

Results: Results of the study suggested that both the experimental and conventional group had a significant improvement in hand function (AROM, functional task with objects, object manipulation), however experimental group showed significantly more improvement than conventional group, providing Mirror Therapy with conventional treatment is more effective than conventional treatment alone.

Conclusion: Mirror therapy with conventional physiotherapy brings more improvement in hand function than conventional physiotherapy alone.


World Health Organization [WHO; Stroke; 1989] defines the clinical syndrome of stroke as ‘rapidly developed clinical signs of focal (or global) distribution of cerebral function with symptoms lasting more than 24 hours or longer or leading to death, with no apparent cause other than vascular origin’.

Prevalence rates reported for stroke or CerebroVascular Accident (CVA) worldwide vary between 500 to 800 per 100,000 population [N.K. Sehi et al 2007] with about 20 million people suffer from stroke each year; out of that 5 million will die as a consequences and 15 million will survive with long term disabilities of varied spectrum. Many surviving stroke patients will often depends on other people‘s continuous support to survive.

Stroke is the most common cause of chronic disability [1]. Of survivors, an estimated one third will be functionally dependent after 1 year experiencing difficulty with activities of daily living (ADL), ambulation, speech, and so forth [2]. Cognitive impairment occurs frequently after stroke, commonly involving memory, orientation, language, and attention. The presence of cognitive impairment in patients with stroke has important functional consequences, independent of the effects of physical impairment (T K Tatemichi et al 1994).

Recovery of function after stroke may occur, but it is unclear whether interventions can improve function beyond the spontaneous process. In particular, recovery of hand function plateaus in about 1 year, and common knowledge is that the patient will remain at that level for the rest of his or her life [3,4]. Typically in such situations, upper arm function is better than that in the hand [5]. An emerging concept in neural plasticity is that there is competition among body parts for territory in the brain [6-11].

Several studies have been conducted to examine the recovery of the hemiplegic arm in stroke patients. Up to 85% of patients show an initial deficit in the arm. Three to six months later, problems remain in 55% to 75% of patients [12-15]. While recovery of arm function is poor in a significant number of patients. Three quarters of strokes occur in the region supplied by the middle cerebral artery [16]. As a consequence, the upper limb will be affected in a large number of patients. Functional recovery of the arm includes grasping, holding, and manipulating objects, which requires the recruitment and complex integration of muscle activity from shoulder to fingers.

Functional brain imaging studies of healthy subjects suggest that excitability of the primary motor cortex ipsilateral to a unilateral hand movement is facilitated by viewing a mirror reflection of the moving hand [17]. Reorganization of motor functions immediately around the stroke site (ipsilesional) is likely to be important in motor recovery after stroke, and a contribution of other brain areas in the affected hemisphere is also possible. Activation when a subject is doing motor tasks can also occur in the bilateral inferior parietal area, the supplementary motor area, and in the premotor cortex. Furthermore, central adaptations occur in networks controlling the paretic as well as the nonparetic lower limb after stroke [18].

The aim of this study is to find the effect of mirror therapy in rehabilitation of hand function in sub-acute stroke. […]


Continue —> Effectiveness of Mirror Therapy in Rehabilitation of Hand Function in Sub-Acute Stroke

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[ARTICLE] Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors – Full Text

Various robotic exoskeletons have been proposed for hand function assistance during activities of daily living (ADL) of stroke survivors. However, traditional exoskeletons involve the use of complex rigid systems that impede the natural movement of joints, and thus reduce the wearability and cause discomfort to the user. The objective of this paper is to design and evaluate a soft robotic glove that is able to provide hand function assistance using fabric-reinforced soft pneumatic actuators. These actuators are made of silicone rubber which has an elastic modulus similar to human tissues. Thus, they are intrinsically soft and compliant. Upon air pressurization, they are able to support finger range of motion (ROM) and generate the desired actuation of the finger joints. In this work, the soft actuators were characterized in terms of their blocked tip force, normal and frictional grip force outputs. Combining the soft actuators and flexible textile materials, a soft robotic glove was developed for grasping assistance during ADL for stroke survivors. The glove was evaluated on five healthy participants for its assisted ROM and grip strength. Pilot test was performed in two stroke survivors to evaluate the efficacy of the glove in assisting functional grasping activities. Our results demonstrated that the actuators designed in this study could generate desired force output at a low air pressure. The glove had a high kinematic transparency and did not affect the active ROM of the finger joints when it was being worn by the participants. With the assistance of the glove, the participants were able to perform grasping actions with sufficient assisted ROM and grip strength, without any voluntary effort. Additionally, pilot test on stroke survivors demonstrated that the patient’s grasping performance improved with the presence and assistance of the glove. Patient feedback questionnaires also showed high level of patient satisfaction and comfort. In conclusion, this paper has demonstrated the possibility of using soft wearable exoskeletons that are more wearable, lightweight, and suitable to be used on a daily basis for hand function assistance of stroke survivors during activities of daily living.


The ability to perform basic activities of daily living (ADL) impacts a person’s quality of life and independence (Katz, 1983Andersen et al., 2004). However, an individual’s independence to perform ADLs is jeopardized due to hand motor impairments, which can be observed in patients with neurological disorders such as stroke. In order to improve hand motor functions in terms of strength and range of motion (ROM) (Kutner et al., 2010), stroke survivors undergo rehabilitation programs comprising repetitive practice of simulated ADL tasks (Michaelsen et al., 2006). Normally, patients undergo rehabilitation exercises in a specialized rehabilitation center under the guidance of physiotherapists or occupational therapists. However, due to increasing patient population, it is foreseen that there will be a shortage of physiotherapists to assist in the rehabilitative process. Thus, there will be comparatively less therapy time, which will eventually lead to a slower recovery process for the patients. Over the past decade, technological developments in robotics have facilitated the rehabilitative process and have shown potential to assist patients in their daily life (Maciejasz et al., 2014). One example of such a device is the hand exoskeleton, which is secured around the hand to guide and assist the movement of the encompassed joints. However, due to the complexity of the hand, designing a hand exoskeleton remains a challenging task.

Traditional hand exoskeletons involve the use of rigid linkage-based mechanisms. In this kind of mechanism, rigid components, such as linear actuators, rotary motors, racks, and pinions as well as rigid linkages are normally involved (Worsnopp et al., 2007Rotella et al., 2009Martinez et al., 2010). To assist hand movements that have high degrees of freedom (DOFs), traditional exoskeletons can be incorporated with a substantial number of actuators to achieve the requirement. However, this means that their application is limited due to the increasing bulkiness for higher DOFs. Therefore, these devices are normally restricted in clinical settings and not suitable for performing home therapy. Additionally, their rigidity, weight and constraint on the non-actuated DOFs of the joints pose complications. As a result, the level of comfort and safety of patients is reduced. In view of this, there is an apparent need for the development of exoskeletons that may be used in both clinical and home settings. A lightweight and wearable exoskeleton may allow patients to bring back home to continue daily therapy or to serve as an assistive device for the ADLs.

The development of wearable robotic exoskeletons serves to provide an alternative approach toward addressing this need. Instead of using rigid linkage as an interface between the hand and the actuators, wearable exoskeletons typically utilize flexible materials such as fabric (Sasaki et al., 2004Yap et al., 2016a) and polymer (Kang et al., 2016), driven by compliant actuators such as cables (Sangwook et al., 2014Xiloyannis et al., 2016) and soft inflatable actuators (Polygerinos et al., 2015dYap et al., 2016c). Therefore, they are more compliant and lightweight compared to the rigid linkage-based mechanism. Cable-driven based exoskeletons involve the use of cables that are connected to actuators in the form of electrical motors situated away from the hand (Nilsson et al., 2012Ying and Agrawal, 2012Sangwook et al., 2014Varalta et al., 2014). By providing actuations on both dorsal and palmar sides of the hand, bi-directional cable-driven movements are possible (Kang et al., 2016). These cables mimic the capability of the tendons of the human hand and they are able to transmit the required pulling force to induce finger flexion and extension. However, the friction of the cable, derailment of the tendon, and inaccurate routing of the cable due to different hand dimensions can affect the efficiency of force transmission in the system.

On the other hand, examples of the soft inflatable actuators are McKibben type muscles (Feifei et al., 2006Tadano et al., 2010), sheet-like rubber muscles (Sasaki et al., 2004Kadowaki et al., 2011), and soft elastomeric actuators (Polygerinos et al., 2015b,cYap et al., 2015); amongst which, soft elastomeric actuators have drawn increasing research interest due to their high compliance (Martinez et al., 2013). This approach typically embeds pneumatic chamber networks in elastomeric constructs to achieve different desired motions with pressurized air or water (Martinez et al., 2012). Soft elastomeric actuators are highly customizable. They are able to achieve multiple DOFs and complex motions with a single input, such as fluid pressurization. The design of a wearable hand exoskeleton that utilizes soft elastomeric actuators is usually simple and does not require precise routing for actuation, compared to the cable-driven mechanism. Thus, the design reduces the possibility of misalignment and the setup time. These properties allow the development of hand exoskeletons that are more compliant and wearable, with the ability to provide safe human-robot interaction. Additionally, several studies have demonstrated that compactness and ease of use of an assistive device critically affect its user acceptance (Scherer et al., 20052007). Thus, these exoskeletons provide a greater chance of user acceptance.

Table 1 summarizes the-state-of-art of soft robotic assistive glove driven by inflatable actuators. Several pioneer studies on inflatable assistive glove have been conducted by Sasaki et al. (2004)Kadowaki et al. (2011) and Polygerinos et al. (2015a,b,c). Sasaki et al. have developed a pneumatically actuated power assist glove that utilizes sheet-like curved rubber muscle for hand grasping applications. Polygerinos et al. have designed a hydraulically actuated grip glove that utilizes fiber-reinforced elastomeric actuators that can be mechanically programmed to generate complex motion paths similar to the kinematics of the human finger and thumb. Fiber reinforcement has been proved to be an effective method to constrain the undesired radial expansion of the actuators that does not contribute to effective motion during pressurization. However, this method limits the bending capability of the actuators (Figure S1); as a result, higher pressure is needed to achieve desired bending.

Table 1. Hand assistive exoskeletons driven by inflatable actuators.

This paper presents the design and preliminary feasibility study of a soft robotic glove that utilizes fabric-reinforced soft pneumatic actuators. The intended use of the device is to support the functional tasks during ADLs, such as grasping, for stroke survivors. The objectives of this study were to characterize the soft actuators in terms of their force output and to evaluate the performance of the glove with healthy participants and stroke survivors. The glove was evaluated on five healthy participants in order to determine the ROM of individual finger joints and grip strength achieved with the assistance of the glove. Pilot testing with two stroke survivors was conducted to evaluate the feasibility of the glove in providing grasping assistance for ADL tasks. We hypothesized that with the assistance of the glove, the grasping performance of stroke patients improved.

Specific contributions of this work are listed as follows:

(a) Presented fabric-reinforcement as an alternative method to reinforce soft actuators, which enhanced the bending capability and reduced the required operating pressure of the actuators,

(b) Utilized the inherence compliance of soft actuators and allowed the actuators to achieve multiple motions to support ROM of the human fingers,

(c) Integrated elastic fabric with soft actuators to enhance the extension force for finger extension,

(d) Designed and characterized a soft robotic glove using fabric-reinforced soft actuators with the combination of textile materials, and

(e) Conducted pilot tests with stroke survivors to evaluate the feasibility of the glove in providing functional assistance for ADL tasks.

Design Requirements and Rationale

The design requirements of the glove presented in this paper are similar to those presented by Polygerinos et al. (2015a,b,c) in terms of design considerations, force requirements, and control requirements. For design considerations, weight is the most important design criterion when designing a hand exoskeleton. Previous studies have identified the threshold for acceptable weight of device on the hand, which is in the range of 400–500 g (Aubin et al., 2013Gasser and Goldfarb, 2015). Cable-driven, hydraulic, and pneumatic driven mechanisms are found to be suitable options to meet the criteria. To develop a fully portable system for practical use in home setting, reduction in the weight of the glove as well as the control system is required. The total weight of the control system should not exceed 3 kg (Polygerinos et al., 2015a,b,c). In this work, the criteria for the weight of the glove and control system are defined as: (a) the weight of the glove should be <200 g, and (b) the weight of the control system should be <1.5 kg.

Considering the weight requirement, hydraulic systems are not ideal for this application, as the requirement of a water reservoir for hydraulic control systems and actuation of the actuators with pressurized water will add extra weight to the hand. The second consideration is that the hand exoskeleton should allow fast setup time. Therefore, it is preferable for the hand exoskeleton to fit the hand anatomy rapidly without precise joint alignment. Compared to cable-driven mechanisms, soft pneumatic actuators are found to be more suitable as they allow rapid customization to different finger length. Additionally, they do not require precise joint alignment and cable routing for actuation as the attachment of the soft pneumatic actuators on the glove is usually simple. Therefore, in this work, pneumatic mechanisms were selected. Using pneumatic mechanism, Connelly et al. and Thielbar et al. have developed a pneumatically actuated glove, PneuGlove that is able to provide active extension assistance to each finger while allowing the wearer to flex the finger voluntarily (Connelly et al., 2010Thielbar et al., 2014). The device consists of five air bladders on the palmar side of the glove. Inflation of the air bladders due to air pressurization created an extension force that extends the fingers. However, due to the placement of the air bladders on the palmar side, grasping activities such as palmar and pincer grasps were more difficult. Additionally, this device is limited to stroke survivors who are able to flex their fingers voluntarily.

In this work, the soft robotic glove is designed to provide functional grasping assistance for stroke survivors with muscle weakness and impairments in grasping by promoting finger flexion. While the stroke survivors still preserve the ability to modulate grip force within their limited force range, the grip release (i.e., hand opening) is normally prolonged (Lindberg et al., 2012). Therefore, the glove should assist with grip release by allowing passive finger extension via reinforced elastic components, similar to Saeboflex (Farrell et al., 2007) and HandSOME (Brokaw et al., 2011). The elastic components of these devices pull the fingers to the open hand state due to increased tension during finger flexion. Additionally, the glove should generate the grasping force required to manipulate and counteract the weight of the objects of daily living, which are typically below 1.07 kg (Smaby et al., 2004). Additionally, the actuators in the glove should be controlled individually in order to achieve different grasping configurations required in simulated ADL tasks, such as palmar grasp, pincer grasp, and tripod pinch. For the speed of actuation, the glove should reach full grasping motion in <4 s during simulated ADL tasks and rehabilitation training.

For the actuators, we have recently developed a new type of soft fabric-reinforced pneumatic actuator with a corrugated top fabric layer (Yap et al., 2016a) that could minimize the excessive budging and provide better bending capability compared to fiber-reinforced soft actuators developed in previous studies (Polygerinos et al., 2015c,d). This corrugated top fabric layer allows a small initial radial expansion to initiate bending and then constrains further undesired radial expansion (Figure 1). The detailed comparison of the fiber-reinforced actuators and fabric-reinforced actuators can be found in the Supplementary Material.



Figure 1. (A) A fabric-reinforced soft actuators with a corrugated fabric layer and an elastic fabric later [Actuator thickness, T= 12 mm, and length, L = 160 mm (Thumb), 170 mm (Little Finger), 180 mm (Index & Ring Fingers), 185 mm (Middle Finger)]. (B) Upon air pressurization, the corrugated fabric layer unfolds and expands due to the inflation of the embedded pneumatic chamber. Radial budging is constrained when the corrugated fabric layer unfolds fully. The elastic fabric elongates during air pressurization and stores elastic energy. The actuator achieves bending and extending motions at the same time. (C) A bending motion is preferred at the finger joints (II, IV, VI). An extending motion is preferred over the bending motion at the finger segments (I, III, V) and the opisthenar (VII).

Continue —>  Frontiers | Design and Preliminary Feasibility Study of a Soft Robotic Glove for Hand Function Assistance in Stroke Survivors | Neuroscience

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[ARTICLE] Soft Robotic Haptic Interface with Variable Stiffness for Rehabilitation of Neurologically Impaired Hand Function – Full Text

The human hand comprises complex sensorimotor functions that can be impaired by neurological diseases and traumatic injuries. Effective rehabilitation can bring the impaired hand back to a functional state because of the plasticity of the central nervous system to relearn and remodel the lost synapses in the brain. Current rehabilitation therapies focus on strengthening motor skills, such as grasping, employ multiple objects of varying stiffness so that affected persons can experience a wide range of strength training. These devices have limited range of stiffness due to the rigid mechanisms employed in their variable stiffness actuators. This paper presents a novel soft robotic haptic device for neuromuscular rehabilitation of the hand, which is designed to offer adjustable stiffness and can be utilized in both clinical and home settings. The device eliminates the need for multiple objects by employing a pneumatic soft structure made with highly compliant materials that act as the actuator of the haptic interface. It is made with interchangeable sleeves that can be customized to include materials of varying stiffness to increase the upper limit of the stiffness range. The device is fabricated using existing 3D printing technologies, and polymer molding and casting techniques, thus keeping the cost low and throughput high. The haptic interface is linked to either an open-loop system that allows for an increased pressure during usage or closed-loop system that provides pressure regulation in accordance to the stiffness the user specifies. Preliminary evaluation is performed to characterize the effective controllable region of variance in stiffness. It was found that the region of controllable stiffness was between points 3 and 7, where the stiffness appeared to plateau with each increase in pressure. The two control systems are tested to derive relationships between internal pressure, grasping force exertion on the surface, and displacement using multiple probing points on the haptic device. Additional quantitative evaluation is performed with study participants and juxtaposed to a qualitative analysis to ensure adequate perception in compliance variance. The qualitative evaluation showed that greater than 60% of the trials resulted in the correct perception of stiffness in the haptic device.


The human hand is a complex sensorimotor apparatus that consists of many joints, muscles, and sensory receptors. Such complexity allows for skillful and dexterous manual actions in activities of daily living (ADL). When the sensorimotor function of hand is impaired by neurological diseases or traumatic injuries, the quality of life of the affected individual could be severely impacted. For example, stroke is a condition that is broadly defined as a loss in brain function due to necrotic cell death stemming from a sudden loss in blood supply within the cranium (Hankey, 2017). This event can lead to a multitude of repercussions on sensorimotor function, one of which being impaired hand control such as weakened grip strength (Foulkes et al., 1988Duncan et al., 1994Nakayama et al., 1994Jørgensen et al., 1995Wilkinson et al., 1997Winstein et al., 2004Legg et al., 2007). Other potential causes of impaired hand function include cerebral palsy, multiple sclerosis, and amputation. Therefore, effective rehabilitation to help patients regain functional hand control is critically important in clinical practice. It has been shown that recovery of sensory motor function relies on the plasticity of the central nervous system to relearn and remodel the brain (Warraich and Kleim, 2010). Specifically, there are several factors that are known to contribute to neuroplasticity (Kleim and Jones, 2008): specificity, number of repetition, training intensity, time, and salience. However, existing physical therapy of hand is limited by the resource and accessibility, leading to inadequate dosage and lack of patients’ motivation. Robot-assisted hand rehabilitation has recently attracted a lot of attention because robotic devices have the advantage to provide (1) enriched environment to strengthen motivation, (2) increase number of repetition through automated control, and (3) progressive intensity levels that adapts to patient’s need (for review, see Balasubramanian et al., 2010).

Specifically, haptic interfaces and variable stiffness mechanisms are usually incorporated into robotic rehabilitation devices to provide varying difficulties by adjusting force output or stiffness. For example, the LINarm++ is a rehabilitative device that appropriates variable stiffness actuators with multimodal sensors to provide changing resistance in a physical environment in which users performs arm movement (Malosio et al., 2016Spagnuolo et al., 2017). This device also encompasses a functional electrical stimulation system which has been shown to promote motor recovery in upper limb rehabilitation (Popović and Popović, 2006). The Haptic Knob is a device that trains stroke patients’ grasping movements, and wrist pronation and supination motions by rotating a dial that is able to produce forces and torques up to 50 N and 1.5 Nm, respectively, depending on the patient’s level of impairment (Lambercy et al., 2009). The GripAble is a handheld rehabilitative device that allows the patient to squeeze, lift, and rotate to play a video game with increasing difficulty and gives feedback through vibration in response to the patient’s performance (Mace et al., 20152017). The MIT-MANUS, a planar rehabilitation robot, also has a hand-module that converts rotary motions to linear motions, and in turn allows for controllable impedance in the device (Masia et al., 2006). In addition, pneumatic particle jamming systems have been designed to provide users with haptic feedback by changing the stiffness and geometry of the surface the user presses on with their fingertips (Stanley et al., 2013Genecov et al., 2014). These devices and systems, however, are either costly and bulky due to complex mechanical design or have limited range of stiffness due to passive mechanical components.

To overcome these limitations, this paper proposes the design of a novel pneumatically actuated soft robotics-based variable stiffness haptic interface to support rehabilitation of sensorimotor function of hands (Figure 1). Soft robotics is a rapidly growing field that utilizes highly compliant materials that are fluidic actuated to effectively adapt to shapes and constraints that traditionally rigid machines are unable to Majidi (2014) and Polygerinos et al. (2017). Several soft-robotics devices have been developed to provide assistance to stroke patients, but none of these has been designed as resistive training devices. An example of an existing device includes the use of soft actuators that bend, twist, and extend through finger-like motions in a rehabilitative exoglove to be worn by stroke patients (Polygerinos et al., 2015a,bYap et al., 2017). A variable stiffness device that employs soft-robotics allows a greater range of stiffness to be implemented since there is minimal or no impedance to the initial stiffness of the device. In addition, soft robotics methods allow devices to be manufactured with lowered cost and have much less complexity, thus suitable to be used not only inpatient but also outpatient hand rehabilitative services (Taylor et al., 1996Godwin et al., 2011).


Figure 1. The prototyped soft haptic variable stiffness interface with a hand grasping it.

In Section “Materials and Methods” of this paper, the materials and methods employed in designing and fabricating the soft robotic haptic interface are described, including the design criteria of the prototype. This section also describes the methodology for a stiffness perception test on healthy participant with the proposed device. In addition, the overall closed-loop control system of the device to provide pressure regulation is presented in this section. Section “Results” describes the preliminary results obtained from characterization of the device’s varying stiffness in response to changing pressure inputs, and the subjective evaluation of perceived stiffness obtained from test participants. Finally, Section “Discussion” includes an overall discussion of open question and future research directions. […]

Continue —>  Frontiers | Soft Robotic Haptic Interface with Variable Stiffness for Rehabilitation of Neurologically Impaired Hand Function | Robotics and AI

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Background: Hand dysfunction is a common problem of stroke patients and it is the main cause of impairment of the upper limb. Finding new method to improve hand performance will decrease the disability of chronic stroke patients. Aim of the study: to study the effect of bilateral hand training with weight on the non paretic hand on the hand performance and time of performance in chronic stroke patients.

Materials and Methods: Thirty left chronic stroke patients participated in this study. The patients were assigned randomly into two equal groups. Group one (G1) received unilateral hand training and group two (G2) received bilateral hand training with weight on non affected hand. Both groups assessed two times before starting training program and after two months of training by Fugl meyer assessment scale, Wolf motor function test and hand dynamometer for the motor performance, time of performance and hand grip respectively.

Results: the patients in G2 showed significant improvement in the hand performance (P<.0001) and significant decrease in the time of performance (P<.001) and also significant improvement of hand grip (P<.0001).

Conclusion: Bilateral hand movement with weight on the non affected hand has a significant effect on improving hand performance and decreasing the time of performance and increasing hand grip than unilateral hand movement.

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[BLOG POST] SaeboFlex Helps Client Regain Hand Function 23 Years After Stroke

SaeboFlexStroke survivor exhibits remarkable improvement in hand function more than two decades after stroke, disproving theories that recovery window is limited to 6 months. 

Charlotte, N.C. – Tuesday, July 25, 2017 – Until recently, researchers believed that if a stroke survivor exhibited no improvement within the first 6 months, then he or she would have little to no chance of regaining motor function in the future. This assumed end of recovery is called a plateau. However, a groundbreaking new article published in the Journal of Neurophysiology discusses a stroke patient’s remarkable improvement decades after suffering a stroke at the age of 15. Doctors Peter Sörös, Robert Teasell, Daniel F. Hanley, and J. David Spence formally dismiss previous theories that stroke recovery occurs within 6 months, reporting that the patient experienced “recovery of hand function that began 23 years after the stroke.”

The patient’s stroke resulted in paralysis on the left side of his body, rendering his left hand completely nonfunctional, despite regular physical therapy. More than twenty years after his stroke, the patient took up swimming when his doctor recommended he lose weight. A year later, he began to show signs of movement on his affected side and returned to physical therapy. Therapists fitted the patient with the SaeboFlex, a mechanical device shown to improve hand function and speed up recoveryand, after only a few months of therapy, he began picking up coins with his previously nonfunctional hand. He also saw notable improvement in hand strength and control with the SaeboGlove, a low-profile hand device recently patented by Saebo.

Functional MRI studies showed the reorganization of sensorimotor neurons in both sides of the patient’s brain more than two decades after his stroke, resulting in a noticeable recovery in both hemispheres and improved motor function. “The marked delayed recovery in our patient and the widespread recruitment of bilateral areas of the brain indicate the potential for much greater stroke recovery than is generally assumed,” the doctors reported. “Physiotherapy and new modalities in development might be indicated long after a stroke.”

“This article highlights what we have seen for the last 15 years with many of our clients,” states Saebo co-founder, Henry Hoffman. “Oftentimes, stroke survivors are told that they have plateaued and no further progress is possible. We believe it is not the client that has plateaued but failed treatment options have plateaued them. In other words, traditional therapy interventions that lack scientific evidence can be ineffective and can actually facilitate the plateau.”

“The SaeboFlex device is a life-changing treatment designed for clients that lack motor recovery and function,” Hoffman continues. “Whether the client recently suffered a stroke or decades later, they can immediately begin using their hand with this device and potentially make significant progress over time. I agree with the authors that the neurorehabilitation community needs to take a hard look at traditional beliefs with respect to the window of recovery following stroke. It is my hope that this article will spark more interest by researchers to investigate upper limb function with clients at the chronic stage using Saebo’s hand technology.”

The abstract and article in its entirety can be viewed at the Journal of Neurophysiology’s website,

If you are suffering from limited hand function or have been told you have plateaued, then schedule a call with a Saebo Specialist or click here to get started on the road to recovery.

via SaeboFlex Helps Client Regain Hand Function 23 Years After Stroke | Saebo

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[Abstract] The effect of kinesiotaping on hand function in stroke patients: A pilot study


Upper extremity motor impairment is one of the most prevalent problems following stroke. Considering the functional importance of the upper extremity in the daily life, the purpose of this study was to investigate the effect of kinesiotaping (KT) on hand function and spasticity in individuals following a stroke. Eight individuals who had experienced a stroke, with their age ranging from 47 to 66, participated in this pretest-posttest clinical study. An I- strip of tape was placed on the extensor muscles of the forearm. Primary outcome measures were the Modified Modified Ashwoth Scale, Box and Block test, and Nine Hole Peg test. At the immediate assessment, there were significant differences between two hand function tests scores. Secondary assessment was done after one week and the results showed significant differences between two hand function test scores. There was no significant change in flexor muscles spasticity after the intervention. This pilot study indicated that KT in the direction of the extensor muscles could result in better hand function in stroke patients.

Source: The effect of kinesiotaping on hand function in stroke patients: A pilot study – Journal of Bodywork and Movement Therapies

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[Abstract] Design and Test of a Closed-Loop FES System for Supporting Function of the Hemiparetic Hand Based on Automatic Detection Using the Microsoft Kinect Sensor

This paper describes the design of a FES system automatically controlled in a closed loop using a Microsoft Kinect sensor, for assisting both cylindrical grasping and hand opening. The feasibility of the system was evaluated in real-time in stroke patients with hand function deficits. A hand function exercise was designed in which the subjects performed an arm and hand exercise in sitting position. The subject had to grasp one of two differently sized cylindrical objects and move it forward or backwards in the sagittal plane. This exercise was performed with each cylinder with and without FES support. Results showed that the stroke patients were able to perform up to 29% more successful grasps when they were assisted by FES. Moreover, the hand grasp-and-hold and hold-and-release durations were shorter for the smaller of the two cylinders. FES was appropriately timed in more than 95% of all trials indicating successful closed loop FES control. Future studies should incorporate options for assisting forward reaching in order to target a larger group of stroke patients.

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