Posts Tagged dexterity

[Abstract] Neural coordination of bilateral power and precision finger movements

Abstract

The dexterity of hands and fingers is related to the strength of control by cortico‐motoneuronal connections which exclusively exist in primates. The cortical command is associated with a task‐specific, rapid proprioceptive adaptation of forces applied by hands and fingers to an object. This neural control differs between “power grip” movements (e.g., reach and grasp of a cup) where hand and fingers act as a unity and “precision grip” movements (e.g., picking up a raspberry) where fingers move independently from the hand. In motor tasks requiring hands and fingers of both sides a “neural coupling” (reflected in bilateral reflex responses to unilateral stimulations) coordinates power grip movements (e.g., opening a bottle). In contrast, during bilateral precision movements, such as playing piano, the fingers of both hands move independently, due to a direct cortico‐motoneuronal control, while the hands are coupled (e.g., to maintain the rhythm between the two sides). While most studies on prehension concern unilateral hand movements, many activities of daily life are tackled by bilateral power grips where a neural coupling serves for an automatic movement performance. In primates this mode of motor control is supplemented by a system that enables the uni‐ or bilateral performance of skilled individual finger movements.

Source: https://onlinelibrary.wiley.com/doi/abs/10.1111/ejn.14911?af=R

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[Abstract] Neural coordination of bilateral power and precision finger movements

Cover imageAbstract

The dexterity of hands and fingers is related to the strength of control by cortico‐motoneuronal connections which exclusively exist in primates. The cortical command is associated with a task‐specific, rapid proprioceptive adaptation of forces applied by hands and fingers to an object. This neural control differs between “power grip” movements (e.g., reach and grasp of a cup) where hand and fingers act as a unity and “precision grip” movements (e.g., picking up a raspberry) where fingers move independently from the hand.

In motor tasks requiring hands and fingers of both sides a “neural coupling” (reflected in bilateral reflex responses to unilateral stimulations) coordinates power grip movements (e.g., opening a bottle). In contrast, during bilateral precision movements, such as playing piano, the fingers of both hands move independently, due to a direct cortico‐motoneuronal control, while the hands are coupled (e.g., to maintain the rhythm between the two sides).

While most studies on prehension concern unilateral hand movements, many activities of daily life are tackled by bilateral power grips where a neural coupling serves for an automatic movement performance. In primates this mode of motor control is supplemented by a system that enables the uni‐ or bilateral performance of skilled individual finger movements.

via Neural coordination of bilateral power and precision finger movements – Dietz – – European Journal of Neuroscience – Wiley Online Library

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[Abstract] An Automated Game-Based Variable-Stiffness Exoskeleton for Hand Rehabilitation – Full Text PDF

Abstract

In this paper, we propose and demonstrate the functionality of a novel exoskeleton which provides variable resistance training for human hands. It is intended for people who suffer from diminished hand strength and low dexterity due to non-severe forms of neuropathy or other ailments. A new variable-stiffness mechanism is designed based on the concept of aligning three different sized springs to produce four different levels of stiffness, for variable kinesthetic feedback during an exercise. Moreover, the design incorporates an interactive computer game and a flexible sensor-based glove that motivates the patients to use the exoskeleton. The patients can exercise their hands by playing the game and see their progress recorded from the glove for further motivation. Thus the rehabilitation training will be consistent and the patients will re-learn proper hand function through neuroplasticity. The developed exoskeleton is intrinsically safe when compared with active exoskeleton systems since the applied compliance provides only passive resistance. The design is also comparatively lighter than literature designs and commercial platforms.

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via An Automated Game-Based Variable-Stiffness Exoskeleton for Hand Rehabilitation – Volume 9, No. 4, April 2020 – IJMERR

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[ARTICLE] A modified standardized nine hole peg test for valid and reliable kinematic assessment of dexterity post-stroke – Full Text

Abstract

Background

Impairments in dexterity after stroke are commonly assessed by the Nine Hole Peg Test (NHPT), where the only outcome variable is the time taken to complete the test. We aimed to kinematically quantify and to compare the motor performance of the NHPT in persons post-stroke and controls (discriminant validity), to compare kinematics to clinical assessments of upper extremity function (convergent validity), and to establish the within-session reliability.

Methods

The NHPT was modified and standardized (S-NHPT) by 1) replacing the original peg container with an additional identical nine hole pegboard, 2) adding a specific order of which peg to pick, and 3) specifying to insert the peg taken from the original pegboard into the corresponding hole of the target pegboard. Eight optical cameras registered upper body kinematics of 30 persons post-stroke and 41 controls during the S-NHPT. Four sequential phases of the task were identified and analyzed for kinematic group differences. Clinical assessments were performed.

Results

The stroke group performed the S-NHPT slower (total movement time; mean diff 9.8 s, SE diff 1.4), less smoothly (number of movement units; mean diff 0.4, SE diff 0.1) and less efficiently (path ratio; mean diff 0.05, SE diff 0.02), and used increased scapular/trunk movements (acromion displacement; mean diff 15.7 mm, SE diff 3.5) than controls (P < 0.000, r ≥ 0.32), indicating discriminant validity. The stroke group also spent a significantly longer time grasping and releasing pegs relative to the transfer phases of the task compared to controls. Within the stroke group, kinematics correlated with time to complete the S-NHPT and the Fugl-Meyer Assessment (rs 0.38–0.70), suggesting convergent validity. Within-session reliability for the S-NHPT was generally high to very high for both groups (ICCs 0.71–0.94).

Conclusions

The S-NHPT shows adequate discriminant validity, convergent validity and within-session reliability. Standardization of the test facilitates kinematic analysis of movement performance, which in turn enables identification of differences in movement control between persons post-stroke and controls that may otherwise not be captured through the traditional time-based NHPT. Future research should ascertain further psychometric properties, e.g. sensitivity, of the S-NHPT.

Background

Impaired upper limb dexterity is evident as in many as 45–70% of the stroke victims one year post-stroke [12]. Such impairment is often evaluated in clinics by performance of the Nine Hole Peg Test (NHPT) [3], which is a frequently used dexterity task in many clinical populations [4567]. The NHPT equipment consists of a container with nine small pegs and a target pegboard with nine holes. Performance of the NHPT requires the pegs to be picked up from the container one-by-one unimanually and transferred and inserted into the holes of the pegboard until it is filled, upon which the pegs are returned unimanually to the container. The test is performed as quickly as possible and the only outcome variable is the total time to complete the task. Consequently, motor performance is currently not analyzed during the NHPT despite potentially providing valuable information relating to upper limb dexterity, especially among persons with a neurological dysfunction.

Among persons with stroke, the NHPT is considered reliable [8], valid [7910], and sensitive to change [71011]. Nevertheless, and despite overall good test-retest reliability post-stroke, low test-retest reliability has been found in persons post-stroke who have spasticity in the affected hand [8]. Further, the measurement errors are large; the minimal detectable change of the NHPT is estimated to 33 s for an individual post-stroke, and even doubled in the presence of spasticity [8]. The measurement properties of computer-assisted assessments of NHPT in virtual environments have been investigated with promising results [1213]. However, high intra-subject variation indicates that haptic and virtual reality technologies are more demanding for a stroke population and for instance require more practice trials prior to the actual test than when performing a conventional NHPT.

Advantages of the NHPT include the simple, cheap and easily portable equipment as well as the test being easy to administer and time-efficient [710]. There are, however, some drawbacks when testing persons post-stroke. First, the outcome score of the test is based solely on the time for task accomplishment [14]. Hence, a time reduction of the NHPT in rehabilitation of a person post-stroke may represent either a true motor recovery (i.e. performing movement patterns in a similar way as before the stroke) or compensation (performing different movement patterns than prior to the stroke) [15]. Compensatory strategies are common during upper limb tasks post-stroke, and thus plausible in a fine manipulative task like the NHPT. Secondly, the current NHPT test procedure may provide unreliable results for repeated measures or group comparisons as there is no standardized procedure with regard to the order in which the pegs are inserted into the target holes. To increase the stringency of the NHPT, we modified and standardized the test, which we henceforth refer to as the Standardized Nine Hole Peg test (S-NHPT). The experimental setup with two pegboards was in analogy with that of a study exploring three different methods of completing the NHPT, focusing on comparisons to tests in a virtual setting [12]. However, we have standardized the experimental setup even further by stipulating the order in which the pegs should be transferred.

Kinematic assessments may detect changes in movement performance that are not captured by only considering the time taken to complete the NHPT [14], and provide objective measures that may be more sensitive and not vulnerable to ceiling effects [16]. Recent research calls for parameters indicating quality of movements in persons post-stroke by means of kinematic analysis in order to better understand motor recovery [141517]. However, a test of fine upper limb fine dexterity like the NHPT has not been investigated. Our modifications and standardization enabled our first aim to kinematically characterize S-NHPT performance in a group of persons post-stroke and compare it to that of a non-disabled control group (discriminant validity). A second aim was to determine the convergent validity of the S-NHPT by comparing kinematics (movement time, peak speed, number of movement units, reach-grasp ratio, path ratio, acromion vertical displacement and trunk displacement) to the total movement time and to other clinical assessments (the Fugl-Meyer Assessment, the Stroke Impact Scale and grip strength). A third aim was to establish the within-session reliability of the S-NHPT, i.e., the consistency of the hand trajectories during the nine pick-up and transfer movements of the test.[…]

 

Continue —-> A modified standardized nine hole peg test for valid and reliable kinematic assessment of dexterity post-stroke | Journal of NeuroEngineering and Rehabilitation | Full Text

 

Fig. 1Experimental setup and movement phases. a) Marker positions used for the calculations of the kinematic variables. Markers displayed with a dot in the center of the marker were positioned on the trunk. The enlarged pegboard shows the standardized order of which peg to pick and which hole to fill, referred to as the “vertical row strategy”. The S-NHPT consists of 9 pegs (3.8 cm long, 0.64 cm wide) and two pegboards (12.7 cm × 12.7 cm) with 9 holes (0.70 cm wide) spaced 3.2 cm apart. The two pegboards were attached to a wooden panel with a distance of 18 cm between the center holes of the pegboards. The arrow indicates the direction of the movement. b) The velocity of the index finger marker in the medial direction displays the events defining the transfer phases Peg Transfer (positive curve) and Hand Return (negative curve). The manipulative phases Peg Grip and Peg In Hole are between those transfer movements (see Methods)

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

Abstract

Study Design

Bench and cross-sectional study.

Introduction

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.

Methods

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.

Results

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).

Discussion

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

Conclusions

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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[ARTICLE] Combined treatment of botulinumtoxin and robot-assisted rehabilitation therapy on poststroke, upper limb spasticity: A case report – Full Text

Abstract

Rationale: Spasticity is a major complication after stroke, and botulinumtoxin A (BoNT-A) injection is commonly used to manage focal spasticity. However, it is uncertain whether BoNT-A can improve voluntary motor control or activities of daily living function of paretic upper limbs. This study investigated whether BoNT-A injection combined with robot-assisted upper limb therapy improves voluntary motor control or functions of upper limbs after stroke.

Patient concerns: Two subacute stroke patients were transferred to the Department of Rehabilitation.

Diagnoses: Patients demonstrated spasticity in the upper extremity on the affected side.

Interventions: BoNT-A was injected into the paretic muscles of the shoulder, arm, and forearm of the 2 patients at the subacute stage. Conventional rehabilitation therapy and robot-assisted upper limb training were performed during the rehabilitation period.

Outcomes: Manual dexterity, grip strength, muscle tone, and activities of daily living function were improved after multidisciplinary rehabilitation treatment.

Lessons: BoNT-A injection in combination with multidisciplinary rehabilitation treatment, including robot-assisted arm training, should be recommended for subacute spastic stroke patients to enhance appropriate motor recovery.

1 Introduction

Upper limb spasticity is a common complication following stroke, occurring in 20% to 40% of stroke survivors.[1] As upper limb spasticity, joint contractures, and pain limit the voluntary motor control of the arm and hand, the functions of which are essential for the activity of daily living (ADL), ADL dependencies, including hygiene, dressing, and positioning, can be exacerbated.[2]

Injection of botulinumtoxin A (BoNT-A), which is commonly used in the management of focal spasticity in the chronic phase of stroke, reduces muscle tone and passive range of motion. However, it is unclear whether BoNT-A can improve voluntary motor control or ADL functions of upper limbs.[3]

Recently, task-specific high-intensity training with a multidisciplinary team approach has become an important concept in stroke rehabilitation therapy, and robot-assisted arm training (RAT) has been shown to allow well tolerated and intensive task-specific repetitive training of the paretic arm.[4] However, multidisciplinary rehabilitation therapies using RAT in combination with BoNT-A injection have rarely been applied to subacute poststroke spasticity. Thus, we report on 2 cases showing the beneficial effects of RAT in combination with BoNT-A injection on upper limb spasticity in the subacute phase of stroke. […]

Continue —> Combined treatment of botulinumtoxin and robot-assisted reha… : Medicine

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[ARTICLE] Role of Practice And Mental Imagery on Hand Function Improvement in Stroke Survivors – Full Text

Abstract

Objective: The purpose of this study was to evaluate the Role of Practice and Mental Imagery on Hand function improvement in stroke survivors

Method: We conducted systematic review of the previous studies and searched electronic databases for the years 1995 to 2016, studies were selected according to inclusion criteria, and critical appraisal was done for each study and summarized the use of mental practice for the improvement in hand function in stroke survivors.

Results: Studies differed in the various aspects like intervention protocols, outcome measures, design, and patient’s characteristics. The total number of practice hours to see the potential benefits from mental practice varied widely. Results suggest that mental practice has potential to improve the upper extremity function in stroke survivors.

Conclusion: Although the benefits of mental practice to improve upper extremity function looks promising, general guidelines for the clinical use of mental practice is difficult to make. Future research should explore the dosage, factors affecting the use of Mental Practice, effects of Mental Therapy alone without in combination with other interventions.

Introduction

Up to 85% stroke survivors experience hemi paresis resulting in impaired movement of the arm, and hand as reported by Nakayama et al. Loss of arm function adversely affects quality of life and functional motor recovery in affected upper extremity.

Sensorimotor deficits in the upper limb, such as weakness, decreased speed of movement, decreased angular excursion and impaired temporal coordination of the joints impaired upper-limb and trunk coordination.

Treatment interventions such as materials-based occupations constraint-induced movement therapy modified constraint-induced movement therapy and task-related or task-specific training are common training methods for remediating impairments and restoring function in the upper limb.

For the improvement of upper and lower functions, physical therapy provides training for functional improvement and fine motor. For most patients such rehabilitation training has many constraints of time, place and expense, accordingly in recent studies, clinical methods such as mental practice for improvement of the upper and lower functions have been suggested.

Mental practice is a training method during which a person cognitively rehearses a physical skill using motor imagery in the absence of overt, physical movements for the purpose of enhancing motor skill performance. For example, a review of the duration of mental movements found temporal equivalence for reaching; grasping; writing; and cyclical activities, such as walking and running.

Evidence for the idea that motor imagery training could enhance the recovery of hand function comes from several lines of research: the sports literature; neurophysiologic evidence; health psychology research; as well as preliminary findings using motor imagery techniques in stroke patients.

Much interest has been raised by the potential of Motor Practice of Motor task, also called “Motor Imagery” as a neuro rehabilitation technique to enhance Motor Recovery following Stroke.

Mental Practice is a training method during which a person cognitively rehearsals a physical skill using Motor Imagery in the absence of Physical movements for the purpose of enhancing Motor skill performance.

The merits of this intervention are that the patient concentration and motivation can be enhanced without regard to time and place and the training is possible without expensive equipment.

Researchers have speculated about its utility in neurorehabilitation. In fact, several review articles examining the impact of mental practice have been published. Two reviews examined stroke outcomes in general and did not limit their review to upper-extremity–focused outcomes. Both articles included studies that were published in 2005 or earlier.

Previous reviews, however, did not attempt to rate the studies reviewed in terms of the level of evidence. Thus, in this review, we determined whether mental practice is an effective intervention strategy to remediate impairments and improve upper-limb function after stroke by examining and rating the current evidence. […]

Continue –>  Role of Practice And Mental Imagery on Hand Function Improvement in Stroke Survivors | Insight Medical Publishing

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[ARTICLE] Effects of repeated vibratory stimulation of wrist and elbow flexors on hand dexterity, strength, and sensory function in patients with chronic stroke: a pilot study – Full Text PDF

Abstract.

[Purpose] The aim of this study was to investigate the effects of repeated vibratory stimulation to muscles related to hand functions on dexterity, strength, and sensory function in patients with chronic stroke.

[Subjects and Methods] A total of 10 stroke patients with hemiplegia participated in this study. They were divided into two groups: a) Experimental and b) Control, with five randomly selected subjects for each group. The experimental group received vibratory stimulation, while the control group received the traditional physical therapy. Both interventions were performed for 30 minutes each session, three times a week for four weeks.

[Results] There was a significant within-group improvement in the box and block test results in both groups for dexterity. Grip strength improved in both groups but the improvement was not statistically significant.

[Conclusion] The vibratory stimulation activated the biceps brachii and flexor carpi radialis, which increased dexterity to grasp and lift the box and block from the surface. Therefore, repeated vibratory stimulation to muscles related to hand functions improved hand dexterity equality to the traditional physical therapy in patients with chronic stroke.

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[Abstract] Assessment of the Ipsilesional Hand Function in Stroke Survivors: The Effect of Lesion Side 

Background

The aim of this study was to examine the effect of the side of brain lesion on the ipsilesional hand function of stroke survivors.

Methods

Twenty-four chronic stroke survivors, equally allocated in 2 groups according to the side of brain lesion (right or left), and 12 sex- and age-matched healthy controls performed the Jebsen-Taylor Hand Function Test (JTHFT), the Nine-Hole Peg Test (9HPT), the maximum power grip strength (PwGSmax) test, and the maximum pinch grip strength (PnGSmax) test. Only the ipsilesional hand of the stroke survivors and both hands (left and right) of the controls were assessed.

Results

PwGS max and PnGS max were similar among all tested groups. Performances in JTHFT and 9HPT were affected by the brain injury. Individuals with left brain damage showed better performance in 9HPT than individuals with right brain damage, but performance in JTHFT was similar.

Conclusions

Individuals after a brain injury have the capacity to produce maximum strength preserved when using their ipsilesional hand. However, the dexterity of their hands and digits is affected, in particular for stroke individuals with right brain lesion.

Source: Assessment of the Ipsilesional Hand Function in Stroke Survivors: The Effect of Lesion Side – Journal of Stroke and Cerebrovascular Diseases

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[VIDEO] New Hope For Stroke Victims – YouTube

 

Δημοσιεύτηκε στις 9 Σεπ 2016

According to a clinical trial, a new form of electrical stimulation therapy can help rewire the brain and restore some dexterity to a hand that’s been paralyzed by stroke. In the experimental therapy, patients use their good hand to help their brain regain control over the paralyzed hand. A sensored glove, worn on the patient’s good hand, sends signals to electric stimulators attached to the paralyzed hand. The inert muscles are then prompted to mirror the movements of the functioning hand while patients think about opening both hands at the same time,
Research is still underway, but so far almost all patients who received the new therapy have felt an improvement.
http://www.upi.com/Health_News/2016/0…
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This video was produced by YT Wochit News using http://wochit.com

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