Force control and degree of motor impairments in chronic stroke

Lodha, Neha; Naik, Sagar K.; Coombes, Stephen; Cauraugh, James H.

doi:10.1016/j.clinph.2010.04.005

Cited by 96 publications

(110 citation statements)

References 78 publications

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“…We also examined the standard deviation and coefficient of variation of force production across target levels (5%, 25% and 50%). Although both the mean amplitude and the standard deviation of force output increased with an increase in target force level [28,29], the coefficient of variation decreased, revealing a relative increase in variability at low relative to high target forces, which is consistent with previous evidence [30].…”

Section: Discussionsupporting

confidence: 80%

(343) Dose-response effect of isometric force production on the perception of pain

Coombes¹,

Misra²

2014

The Journal of Pain

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Isometric contractions can influence the way that we perceive pain, but conclusions on the dose-response effect of force amplitude on pain perception are limited because previous studies have not held the duration of force contractions constant while varying force amplitude. To address this issue we designed an experiment that allowed us to accurately guide the amplitude of an isometric pinch grip force contraction on a trial-by-trial basis, while a thermal pain eliciting stimulus was simultaneously delivered for the same duration to the non-contracting hand. Our results show that an increase in the amplitude of force produced by one hand corresponded with a decrease in pain perception in the opposite hand. Our observations provide novel evidence that the centralized inhibitory response that underlies analgesia is sensitive to and enhanced by stronger isometric contractions.

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Section: Discussionsupporting

confidence: 80%

(343) Dose-response effect of isometric force production on the perception of pain

Coombes¹,

Misra²

2014

The Journal of Pain

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“…Lodha and colleagues (37) reported increased variability [coefficient of variation (CV)] and regularity (approximate entropy) in isometric wrist/ finger extension force in nine stroke subjects 4 mo to 12 yr post-onset. They also found that force variability and regularity at moderate force levels were more increased among patients with lower Fugl-Meyer motor scores in the affected upper extremity.…”

mentioning

confidence: 99%

Force control of quadriceps muscle is bilaterally impaired in subacute stroke

Chow

Stokić

2011

Journal of Applied Physiology

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Chow JW, Stokic DS. Force control of quadriceps muscle is bilaterally impaired in subacute stroke. J Appl Physiol 111: 1290-1295, 2011. First published September 1, 2011 doi:10.1152/japplphysiol.00462.2011.-We tested the hypothesis that force variability and error during maintenance of submaximal isometric knee extension are greater in subacute stroke patients than in controls and are related to motor impairments. Contralesional (more-affected) and ipsilesional (less-affected) legs of 33 stroke patients with sufficiently high motor abilities (62 Ϯ 13 yr, 16 Ϯ 2 days postinjury) and the dominant leg of 20 controls (62 Ϯ 10 yr) were tested in sitting position. After peak knee extension torque [maximum voluntary contraction (MVC)] was established, subjects maintained 10, 20, 30, and 50% of MVC as steady and accurate as possible for 10 s by matching voluntary force to the target level displayed on a monitor. Coefficient of variation (CV) and root-meansquare error (RMSE) were used to quantify force variability and error, respectively. The MVC was significantly smaller in the more-affected than less-affected leg, and both were significantly lower than in controls. The CV was significantly larger in the more-affected than less-affected leg at 20 and 50% MVC, whereas both were significantly larger compared with controls across all force levels. Both moreaffected and less-affected legs of patients showed significantly greater RMSE than controls at 30 and 50% MVC. The CV and RMSE were not related to the Fugl-Meyer motor score or to the Rivermead Mobility Index. The CV negatively correlated with MVC in controls but only in the less-affected leg of patients. It is concluded that isometric knee extension strength and force control are bilaterally impaired soon after stroke but more so in the more-affected leg. Future studies should examine possible mechanisms and the evolution of these changes. force steadiness; force variability; force accuracy; knee extension strength; hemiparesis NEGATIVE EFFECTS OF STROKE on motor function are well documented, including reduced strength and slower rate of torque generation (8), deficits in postural control during quiet standing (22), abnormal muscle activation patterns during gait (35), impaired manual tracking (9), and grip force control (5). Strength testing after stroke typically involves measurement of force (torque, power) during maximal voluntary effort. This is in stark contrast to the actual use of muscles in daily activities, which requires production of submaximal and finely graded forces.Force control generally refers to the ability to produce accurate and steady muscle output under static or dynamic conditions. Characteristics of force control have been extensively studied in the elderly (16,25). When asked to maintain a submaximal isometric force, especially at a low level [i.e., Յ10% of maximum voluntary contraction (MVC)], older healthy subjects show greater force variability than young adults in various muscles (63). Force (targeting) error is also greater in elderly com...

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“…Force variability has been used to quantify the stability control of digit force, thus serving as an indicator of precision performance [7,27]. Greater variability of digit force was observed in men compared with women [14], in the nondominant hand compared with the dominant [13], and in the elderly (60-69 years) compared with the young (20-29 years) [38].…”

Section: Introductionmentioning

confidence: 99%

“…Greater variability of digit force was observed in men compared with women [14], in the nondominant hand compared with the dominant [13], and in the elderly (60-69 years) compared with the young (20-29 years) [38]. However, few studies have examined how abnormal sensory functions affect force variability [9,27], especially during five-digit grasping [45]. The synergies among the various roles of the fingers, which are described by the force relationships among thumb-finger pairs [8,24,36], may provide insights into the coordination that occurs among the involved and intact digits of patients with CTS.…”

Section: Introductionmentioning

confidence: 99%

Is the Control of Applied Digital Forces During Natural Five-digit Grasping Affected by Carpal Tunnel Syndrome?

Chen

Jou

Lin

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background The impaired sensory function of the hand induced by carpal tunnel syndrome (CTS) is known to disturb dexterous manipulations. However, force control during daily grasping configuration among the five digits has not been a prominent focus of study. Because grasping is so important to normal function and use of a hand, it is important to understand how sensory changes in CTS affect the digit force of natural grasp. Questions/purposes We therefore examined the altered patterns of digit forces applied during natural five-digit grasping in patients with CTS and compared them with those seen in control subjects without CTS. We hypothesized that the patients with CTS will grasp by applying larger forces with lowered pair correlations and more force variability of the involved digits than the control subjects. Specifically, we asked: (1) Is there a difference between patients with CTS and control subjects in applied force by digits during lift-hold-lower task? (2) Is there a difference in force correlation coefficient of the digit pairs? (3) Are there force variability differences during the holding phase? Methods We evaluated 15 female patients with CTS and 15 control subjects matched for age, gender, and hand dominance. The applied radial forces (F r ) of the five digits were recorded by respective force transducers on a cylinder simulator during the lift-hold-lower task with natural grasping. The movement phases of the task were determined by a video-based motion capture system. Results The applied forces of the thumb in patients with CTS (7 ± 0.8 N; 95% CI, 7.2-7.4 N) versus control subjects (5 ± 0.8 N; 95% CI, 5.1-5.3 N) and the index finger in patients with CTS (3 ± 0.3 N; 95% CI, 3.2-3.3 N) versus control subjects (2 ± 0.3 N; 95% CI, 2.2-2.3 N) observed throughout most of the task were larger in the CTS group (p ranges 0.035-0.050 for thumb and 0.016-0.050 for index finger). In addition, the applied force of the middle finger in patients with CTS (1 ± 0.1 N; 95% 3-1.4 N) versus the control subjects (2 ± 0.2 N; 95% CI, 1.9-2.0 N) during the lowering phase was larger in CTS group (p ranges 0.039-0.050). The force correlations of the thumb-middle finger observed during the lowering phase in the patients with CTS (0.8 ± 0.2; 95% CI, 0.6-0.9) versus the control subjects (0.9 ± 0.1; 95% CI, 0.8-1.0; p = 0.04) were weaker in the CTS group. The thumb-little finger during holding in the patients with CTS (0.5 ± 0.2; 95% CI, 0.3-0.7) versus the control subjects (0.8 ± 0.2; 95% CI, 0.6-0.9; p = 0.02), and the lowering phase in the patients with CTS (0.6 ± 0.2; 95% CI, 0.3-0.8) versus the control subjects (0.9 ± 0.1; 95% CI, 0.8-1.0; p = 0.01) also were weaker. The force variabilities of patients with CTS were greater in the CTS group than in the control subjects: in the thumb ([0.26 ± 0.11 N, 95% CI, Conclusions Patients with CTS grasped with greater digit force associated with weaker correlation and higher variability on specific digits in different task demands. These altered patterns in daily graspi...

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Force control and degree of motor impairments in chronic stroke

Cited by 96 publications

References 78 publications

(343) Dose-response effect of isometric force production on the perception of pain

(343) Dose-response effect of isometric force production on the perception of pain

Force control of quadriceps muscle is bilaterally impaired in subacute stroke

Is the Control of Applied Digital Forces During Natural Five-digit Grasping Affected by Carpal Tunnel Syndrome?

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