Diminished capacity to modulate motor activation patterns according to task contributes to thumb deficits following stroke

Triandafilou, Kristen M.; Fischer, Heidi; Towles, Joseph D.; Kamper, Derek G.; Rymer, William Z.

doi:10.1152/jn.00936.2010

Cited by 25 publications

(17 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A recent study assessed the maximum thumb-tip forces of stroke survivors with severe or moderate hand impairment and in age-matched subjects with no neurological deficits [6]. The maximum active isometric thumb-tip forces that could be produced were recorded for each of 6 intended directions: distal, proximal, adduction, abduction, flexion, extension.…”

Section: Design Requirementsmentioning

confidence: 99%

“…Compared to the other digits, the thumb also has disproportionately large cortical representation, both in motor cortex [2] and sensory cortex [3], thereby contributing to its superior precision of proprioception [4] and independence of movement [5]. The thumb can also generate the strongest forces of any of the digits [6]. Not surprisingly, the thumb is involved in more than 50% of hand functions [7].…”

Section: Introductionmentioning

confidence: 99%

“…Precise examination of motor control of the thumb is challenging due to its large number of actuating muscles and its non-orthogonal, non-intersecting rotational axes [13, 14]. Thumb involvement may differ from that of the fingers, in terms of relative strength deficits [6] and reflex abnormalities [15], for example.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Design and evaluation of an actuated exoskeleton for examining motor control in stroke thumb

et al. 2016

Self Cite

View full text Add to dashboard Cite

Chronic hand impairment is common following stroke. This paper presents an actuated thumb exoskeleton (ATX) to facilitate research in examining motor control and hand rehabilitation. The ATX presented in this work aims to provide independent bi-directional actuation in each of the 5 degrees-of-freedom (DOF) of the thumb using a novel flexible shaft based mechanism that has 5 active DOF and 3 passive DOF. A prototype has been built and experiments have been conducted to measure the allowable workspace at the thumb and evaluate the kinematic and kinetic performance of the ATX. The experimental results show that the ATX is able to provide individual actuation at all 5 thumb joints with high joint velocity and torque capacities. Further improvement and future work are discussed.

show abstract

Section: Design Requirementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design and evaluation of an actuated exoskeleton for examining motor control in stroke thumb

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…While a number of mechanisms contribute to varying degrees to the diminished motor control, such as contracture 1 , muscle atrophy 2,3 , spasticity 4 , and excessive coactivation 5 , weakness plays a fundamental role 6 . This weakness is especially noticeable in the hand where isometric force generation can be reduced by 80% or more 7,8 . We have observed that force deficits during isokinetic movements are even greater 9 .…”

Section: Introductionmentioning

confidence: 99%

Analysis of muscle fiber conduction velocity during finger flexion and extension after stroke

Conrad

Qiu

Hoffmann

et al. 2017

Topics in Stroke Rehabilitation

Self Cite

View full text Add to dashboard Cite

Background Stroke survivors experience greater strength deficits during finger extension than finger flexion. Prior research indicates relatively little observed weakness is directly attributable to muscle atrophy. Changes in other muscle properties, however, may contribute to strength deficits. Objectives This study measured muscle fiber conduction velocity in a finger flexor and extensor muscle to infer changes in muscle fiber type after stroke. Methods Conduction velocity was measured using a linear EMG surface electrode array for both extensor digitorum communis and flexor digitorum superficialis in 12 stroke survivors with chronic hand hemiparesis and 5 control subjects. Measurements were made in both hands for all subjects. Stroke survivors had either severe (n=5) or moderate (n=7) hand impairment. Results Absolute muscle fiber conduction velocity was significantly lower in the paretic hand of severely impaired stroke patients compared to moderately impaired patients and healthy control subjects. The relative conduction velocity between the two hands, however, was quite similar for flexor muscles across all subjects and for extensor muscles for the neurologically intact control subjects. However, muscle fiber conduction velocity for finger extensors was smaller in in the paretic as compared to the non-paretic hand for both groups of stroke survivors. Conclusions One explanation for reduced conduction velocity may be a type II to type I muscle fiber, especially in extrinsic extensors. Clinically, therapists may use this information to develop therapeutic exercises targeting loss of type II fiber in extensor muscles.

show abstract

“…Even after stroke survivors regain the ability to open their hands, functionality may remain limited due to a variety of impairments affecting task performance. For example, diminished capacity to voluntarily modulate muscle activities [15,16] or abnormal interactions between hand flexors and proximal muscles [17] can result in abnormal hand kinematics and kinetics, which may further lead to reduced workspaces [18], abnormal joint coordination [19], and misguided force at the thumb tip [15] and fingertip(s) [20]. Even if rigorous training could be performed with the help of skilled therapists, it would be labor-intensive and expensive, imposing a significant economic burden on patients.…”

Section: Introductionmentioning

confidence: 99%

Development of a Biomimetic Hand Exotendon Device (BiomHED) for Restoration of Functional Hand Movement Post-Stroke

Lee

Landers

Park

2014

IEEE Trans. Neural Syst. Rehabil. Eng.

104

View full text Add to dashboard Cite

Significant functional impairment of the hand is common among stroke survivors and restoration of hand function should be prioritized during post-stroke rehabilitation. The goal of this study was to develop a novel biomimetic device to assist patients in producing complex hand movements with a limited number of actuators. The Biomimetic Hand Exoskeleton Device (BiomHED) is actuated by exotendons that mimic the geometry of the major tendons of the hand. Ten unimpaired subjects and four chronic stroke survivors participated in experiments that tested the efficacy of the system. The exotendons reproduced distinct spatial joint coordination patterns similar to their target muscle-tendon units for both subject groups. In stroke survivors, the exotendon-produced joint angular displacements were smaller, but not significantly different, than those of unimpaired subjects (p = 0.15–0.84). Even with limited use of the BiomHED, the kinematic workspace of the index finger increased by 63–1014% in stroke survivors. The device improved the kinematics of the tip-pinch task in stroke survivors and resulted in a significant reduction in the fingertip-thumb tip distance (17.9 ± 15.3 mm). This device is expected to enable effective ‘task-oriented’ training of the hand post-stroke.

show abstract

Diminished capacity to modulate motor activation patterns according to task contributes to thumb deficits following stroke

Abstract: Triandafilou KM, Fischer HC, Towles JD, Kamper DG, Rymer WZ. Diminished capacity to modulate motor activation patterns according to task contributes to thumb deficits following stroke.

Cited by 25 publications

References 36 publications

Design and evaluation of an actuated exoskeleton for examining motor control in stroke thumb

Design and evaluation of an actuated exoskeleton for examining motor control in stroke thumb

Analysis of muscle fiber conduction velocity during finger flexion and extension after stroke

Development of a Biomimetic Hand Exotendon Device (BiomHED) for Restoration of Functional Hand Movement Post-Stroke

Contact Info

Product

Resources

About