Design and Performance Evaluation of a Hybrid Hand Exoskeleton for Hand Opening/Closing

2021 ◽  
Author(s):  
Muhammad Ahsan Gull ◽  
Shaoping Bai ◽  
Jakob Blicher ◽  
Tobias Stærmose
Keyword(s):  
Ring Finger ◽  
Middle Finger ◽  
Dorsal Side ◽  
Normal Hand ◽  
Hand Exoskeleton ◽  
And Performance ◽  
Flex Sensors ◽  
Exoskeleton Design ◽  
Lateral Sclerosis ◽  
Hand Opening

Abstract Finger extensor muscle weakness and flexor hypertonia are the most commonly reported issues among patients suffering from amyotrophic lateral sclerosis (ALS). Moreover, the relative hyperflexion of the wrist and the fingers has limited their ability to open the hand and interact with the external environment voluntarily. In this work, a hybrid hand exoskeleton is developed to prevent the relative hyperflexion of the fingers and wrist and facilitate the users in their functional hand opening by compensating the flexor hypertonia. This exoskeleton, combining a passive device with the soft extra muscle (SEM) glove, assists users in normal hand opening/closing required for some basic activities of daily living. The paper presents kinematic and static models of passive hand exoskeleton design. Moreover, the proposed design is tested and evaluated by comparing the volunteer hand opening with the exoskeleton assistance using the flex sensors attached on the dorsal side of the middle finger, ring finger, and thumb with both healthy subjects and patients.

scholarly journals Independent home use of a brain-computer interface by people with amyotrophic lateral sclerosis

Neurology ◽  
2018 ◽  
Vol 91 (3) ◽  
pp. e258-e267 ◽  
Author(s):  
Jonathan R. Wolpaw ◽  
Richard S. Bedlack ◽  
Domenic J. Reda ◽  
Robert J. Ringer ◽  
Patricia G. Banks ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Amyotrophic Lateral Sclerosis ◽  
Brain Computer Interface ◽  
Computer Interface ◽  
It Use ◽  
Technical Problems ◽  
Rapid Disease Progression ◽  
And Performance ◽  
Lateral Sclerosis

ObjectiveTo assess the reliability and usefulness of an EEG-based brain-computer interface (BCI) for patients with advanced amyotrophic lateral sclerosis (ALS) who used it independently at home for up to 18 months.MethodsOf 42 patients consented, 39 (93%) met the study criteria, and 37 (88%) were assessed for use of the Wadsworth BCI. Nine (21%) could not use the BCI. Of the other 28, 27 (men, age 28–79 years) (64%) had the BCI placed in their homes, and they and their caregivers were trained to use it. Use data were collected by Internet. Periodic visits evaluated BCI benefit and burden and quality of life.ResultsOver subsequent months, 12 (29% of the original 42) left the study because of death or rapid disease progression and 6 (14%) left because of decreased interest. Fourteen (33%) completed training and used the BCI independently, mainly for communication. Technical problems were rare. Patient and caregiver ratings indicated that BCI benefit exceeded burden. Quality of life remained stable. Of those not lost to the disease, half completed the study; all but 1 patient kept the BCI for further use.ConclusionThe Wadsworth BCI home system can function reliably and usefully when operated by patients in their homes. BCIs that support communication are at present most suitable for people who are severely disabled but are otherwise in stable health. Improvements in BCI convenience and performance, including some now underway, should increase the number of people who find them useful and the extent to which they are used.

scholarly journals Comparable behaviour of ring and little fingers due to an artificial reduction in thumb contribution to hold objects

2020 ◽  
Author(s):  
Banuvathy Rajakumar ◽  
Varadhan SKM
Keyword(s):  
Normal Force ◽  
Safety Margin ◽  
Ring Finger ◽  
Middle Finger ◽  
Human Hand ◽  
Mechanical Advantage ◽  
Free Condition ◽  
Normal Forces ◽  
Fixed Condition ◽  
Little Finger

AbstractBackgroundThe human hand plays a crucial role in accomplishing activities of daily living. The contribution of each finger in the human hand is remarkably unique in establishing object stabilization. According to the mechanical advantage hypothesis, the little finger tends to exert a greater normal force than the ring finger during a supination moment production task to stabilize the object. Similarly, during pronation, the index finger produces more normal force when compared with the middle finger. Hence, the central nervous system employs the peripheral fingers for torque generation to establish the equilibrium as they have a mechanical advantage of longer moment arms for normal force. In our study, we tested whether the mechanical advantage hypothesis is supported in a task in which the contribution of thumb was artificially reduced. We also computed the safety margin of the individual fingers and thumb.MethodologyFifteen participants used five-finger prismatic precision grip to hold a custom-built handle with a vertical railing on the thumb side. A slider platform was placed on the railing such that the thumb sensor could move either up or down. There were two experimental conditions. In the “Fixed” condition, the slider was mechanically fixed, and hence the thumb sensor could not move. In the “Free” condition, the slider platform on which the thumb sensor was placed could freely move. In both conditions, the instruction was to grasp and hold the handle (and the platform) in static equilibrium. We recorded tangential and normal forces of all the fingers.ResultsThe distribution of fingertip forces and moments changed depending on whether the thumb platform was movable (or not). In the free condition, the drop in the tangential force of thumb was counteracted by an increase in the normal force of the ring and little finger. Critically, the normal forces of the ring and little finger were statistically equivalent. The safety margin of the index and middle finger did not show a significant drop in the free condition when compared to fixed condition.ConclusionWe conclude that our results does not support the mechanical advantage hypothesis at least for the specific mechanical task considered in our study. In the free condition, the normal force of little finger was comparable to the normal force of the ring finger. Also, the safety margin of the thumb and ring finger increased to prevent slipping of the thumb platform and to maintain the handle in static equilibrium during the free condition. However, the rise in the safety margin of the ring finger was not compensated by a drop in the safety margin of the index and middle finger.

scholarly journals Grasp Posture Control of Wearable Extra Robotic Fingers with Flex Sensors Based on Neural Network

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 905 ◽  
Author(s):  
Joga Dharma Setiawan ◽  
Mochammad Ariyanto ◽  
M. Munadi ◽  
Muhammad Mutoha ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Neural Network ◽  
Haptic Feedback ◽  
Control Method ◽  
Middle Finger ◽  
Object Manipulation ◽  
Robotic System ◽  
Robotic Motion ◽  
Trained Neural Network ◽  
Flex Sensors ◽  
Robotic Fingers

This study proposes a data-driven control method of extra robotic fingers to assist a user in bimanual object manipulation that requires two hands. The robotic system comprises two main parts, i.e., robotic thumb (RT) and robotic fingers (RF). The RT is attached next to the user’s thumb, while the RF is located next to the user’s little finger. The grasp postures of the RT and RF are driven by bending angle inputs of flex sensors, attached to the thumb and other fingers of the user. A modified glove sensor is developed by attaching three flex sensors to the thumb, index, and middle fingers of a wearer. Various hand gestures are then mapped using a neural network. The input data of the robotic system are the bending angles of thumb and index, read by flex sensors, and the outputs are commanded servo angles for the RF and RT. The third flex sensor is attached to the middle finger to hold the extra robotic finger’s posture. Two force-sensitive resistors (FSRs) are attached to the RF and RT for the haptic feedback when the robot is worn to take and grasp a fragile object, such as an egg. The trained neural network is embedded into the wearable extra robotic fingers to control the robotic motion and assist the human fingers in bimanual object manipulation tasks. The developed extra fingers are tested for their capacity to assist the human fingers and perform 10 different bimanual tasks, such as holding a large object, lifting and operate an eight-inch tablet, and lifting a bottle, and opening a bottle cap at the same time.

Modified Littler flap for sensory reconstruction of large thumb pulp defects

2018 ◽  
Vol 43 (5) ◽  
pp. 546-553 ◽  
Author(s):  
Hui Wang ◽  
Xiaoxi Yang ◽  
Chao Chen ◽  
Bin Wang ◽  
Wei Wang ◽  
...  
Keyword(s):  
Donor Site ◽  
Ring Finger ◽  
Middle Finger ◽  
Donor Site Morbidity ◽  
Digital Nerve ◽  
Level Of Evidence ◽  
Dorsal Branch ◽  
Ulnar Aspect ◽  
Monofilament Test

The Littler flap has been widely used to repair large pulp defects of the thumb; however, several complications have occurred frequently. In order to reduce these issues, the modified Littler flap innervated by the dorsal branch of the proper digital nerve and the proper digital nerve from the ulnar aspect of the middle finger or the radial aspect of the ring finger were devised in 16 consecutive cases. At the donor site, the defect of the proper digital nerve was repaired with a nerve graft from the proximal portion of the ipsilateral dorsal branch of the proper digital nerve. At the final follow-up, the scores for the static two-point discrimination test, Semmes–Weinstein monofilament test and total active motions in both recipient and donor fingers were nearly normal. This modified Littler flap provides a simple and reliable alternative for treatment of large defects of the thumb pulp with low donor-site morbidity. Level of Evidence: IV

The Sparthan Three-Dimensional Printed Exo-Glove: A Preliminary Evaluation of Performance Via Case Study

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Tomás A. Georgiou ◽  
Davide Asnaghi ◽  
Alva Liang ◽  
Alice M. Agogino
Keyword(s):  
Light Intensity ◽  
Daily Living ◽  
Low Cost ◽  
Three Dimensional ◽  
Preliminary Evaluation ◽  
Evaluation Of Performance ◽  
3D Printed ◽  
Hand Exoskeleton ◽  
And Performance

This paper describes the development and testing of a low-cost three-dimensional (3D) printed wearable hand exoskeleton to assist people with limited finger mobility and grip strength. The function of the presented orthosis is to support and enable light intensity activities of daily living and improve the ability to grasp and hold objects. The Sparthan Exoskeleton prototype utilizes a cable-driven design applied to individual digits with motors. The initial prototype is presented in this paper along with a preliminary evaluation of durability and performance efficacy.

Avulsion Of The Ring Finger Flexor Digitorum Profundus Tendon: An Experimental Study

HAND ◽  
1978 ◽  
Vol os-10 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Paul R. Manske ◽  
Peggy A. Lesker
Keyword(s):  
Experimental Study ◽  
Breaking Strength ◽  
Ring Finger ◽  
Middle Finger ◽  
Frequent Occurrence ◽  
Flexor Digitorum Profundus ◽  
Flexor Digitorum ◽  
Flexor Digitorum Profundus Tendon

Summary The results of an experimental study of the breaking strength of the tendon-bone junction of the flexor digitorum profundus tendon in cadaver specimens indicates a significantly weaker insertion of the ring finger compared to the middle finger. This explains in part the more frequent occurrence of avulsion of the ring finger profundus tendon as observed clinically.

An anatomic study of flexor tendon sheaths: a cadaveric study

2009 ◽  
Vol 34 (6) ◽  
pp. 762-765 ◽  
Author(s):  
J. M. FUSSEY ◽  
K. F. CHIN ◽  
N. GOGI ◽  
S. GELLA ◽  
S. C. DESHMUKH
Keyword(s):  
Flexor Tendon ◽  
Index Finger ◽  
Ring Finger ◽  
Middle Finger ◽  
Tendon Sheath ◽  
Water Soluble ◽  
Anatomic Study ◽  
Patterns Of Communication ◽  
Flexor Tendon Sheath ◽  
Spread Of Infection

Previous descriptions of the pattern of communication between the digital flexor tendon sheaths have been largely based on imaging studies. An anatomic study on 12 cadaveric hands was conducted using water soluble dye and directly observed patterns of communication between the digital flexor tendon sheaths and the radial and ulnar bursae. Four out of twelve specimens (33%) demonstrated a communication between the radial and ulnar bursae. The ulnar bursa communicated with the ring finger flexor sheath in two specimens, and the index finger flexor sheath in two specimens. One hand (8.3%) showed communication between the middle finger tendon sheath and radial bursa and between the index finger flexor tendon sheath and radial bursa. These findings show a considerable level of variation in communicating patterns between the synovial sheaths of the hand and wrist. Clinicians should be aware of the possibility of variations to the classical presentation of spread of infection through the digital flexor sheaths.

Modified “On-Top-Plasty” Technique for Restoring Length to Amputation Stumps

2002 ◽  
Vol 27 (3) ◽  
pp. 265-269 ◽  
Author(s):  
V. PISTRE ◽  
P. PELISSIER ◽  
A. BALLANGER ◽  
D. MARTIN ◽  
J. BAUDET
Keyword(s):  
Proximal Phalanx ◽  
Ring Finger ◽  
Middle Finger ◽  
Proximal Interphalangeal Joint ◽  
Interphalangeal Joint ◽  
Middle Phalanx ◽  
Secondary Procedure ◽  
Amputation Stumps ◽  
Amputation Stump ◽  
Middle Ring

Five patients were successfully treated with a modified “on-top-plasty” technique, in which a finger stump is lengthened by transfer of an adjacent amputation stump with a reverse blood flow fingerstump. This technique can be performed in the acute phase or as a secondary procedure. A conventional on-top-plasty can be performed by transfer of a partially amputated index or ring finger to the “top” of the proximal phalanx of an amputated middle finger. Alternatively, the transferred part may be used in an intercalated fashion to reconstruct the middle phalanx, using a prosthesis to reconstruct the proximal interphalangeal joint. The results, complications and disadvantages of the technique are reported. We propose this procedure for the reconstruction of the middle ring finger when a free microneurovascular toe-to-hand transfer is contraindicated or refused by the patient.

The Superficial Anastomosis on the Palm of the Hand between the Ulnar and Median Nerves

1991 ◽  
Vol 16 (5) ◽  
pp. 511-514 ◽  
Author(s):  
G. P. FERRARI ◽  
A. GILBERT
Keyword(s):  
Median Nerve ◽  
Ring Finger ◽  
Middle Finger ◽  
The Other ◽  
Sensory Innervation ◽  
Digital Nerve ◽  
The Third ◽  
Palmar Surface ◽  
Communicating Branch ◽  
Palm Of The Hand

The communications between the median and ulnar innervated territories on the palm of the hand have been studied anatomically and microscopically. A communicating branch is well appreciated but its description has had little emphasis in anatomical or surgical literature. 50 cadaveric palms were dissected in both sexes and an anastomotic branch was found in 45 hands. In 43 of them it originated proximally from the ulnar nerve and proceeded distally to enter the third common digital nerve; in the other two hands it left the median nerve to reach the fourth common digital nerve. By microscopic dissection we have seen that the ulnar fibres of the anastomotic branch which join the median nerve may contribute to the sensory innervation of the radial half of the ring finger and ulnar side of the middle finger on its palmar surface. We have therefore described a cutaneous area on the palm where care must be taken to avoid surgical damage to this branch.

scholarly journals REGRESSION ANALYSIS TO DETERMINE STATURE FROM HAND ANTHROPOMETRY AMONG ILOCANO POPULATION IN PHILIPPINES FOR PERSON IDENTIFICATION

2021 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
T.Nataraja Moorthy
Keyword(s):  
Ring Finger ◽  
Middle Finger ◽  
Size Analysis ◽  
Human Hand ◽  
Regression Equations ◽  
Person Identification ◽  
Left Hand ◽  
Length Measurements ◽  
The Right ◽  
Hand Length

Stature determination aids the person identification during forensic investigation. The human hand research is the current topic of interest among forensic scientist, forensic medicine experts and anthropologists. Based on sample size analysis, the study involved consented 60 males and 60 females, age ranged from 18 to 55 years old. Stature and hand lengths measurements were made with Stadiometer and Vernier Calipers for analysis.  From each participant, ten hand length measurements, five from left and five from right hands were taken. The five length measurements in left hand are the inter-distance between the distal traverse crease of the wrist (LH) and tip of thumb (T), index finger (I), middle finger (M), ring finger (R) & little finger (L), as abbreviated LHT, LHI, LHM, LHR and LHL. Similarly, the right hand lengths indicated as RHT, RHI, RHM, RHR, and RHL.  The data were statistically analyzed by using SPSS software, version 23 and column chart. The information about age, gender, name, and place of origin of the participants was coded for easy reference. This study finally developed regression equations to determine stature from hand anthropometry among Ilocano population in Philippines for person identification

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