Effects of age and gender on finger coordination in MVC and submaximal force-matching tasks

Shinohara, Minoru; Sheng, Li; Kang, Ning; Zatsiorsky, Vladimir M.; Latash, Mark L.

doi:10.1152/japplphysiol.00643.2002

Cited by 140 publications

(176 citation statements)

References 60 publications

(119 reference statements)

Supporting

Mentioning

152

Contrasting

Unclassified

Order By: Relevance

“…All subjects that participated in the studies with ramp force production (Latash et al 2001Shim et al 2003;Shinohara et al 2003Shinohara et al , 2004, including the authors of this paper, noticed that it was relatively easy to keep the total force constant or changing at a constant rate. In contrast, a change between these two regimes, e.g.…”

Section: Discussionmentioning

confidence: 97%

“…As a result, the relatively high variance in the finger force space results in a much lower variance of the total force. As in earlier studies Shinohara et al 2003;Shim et al 2003), we quantified this effect with an index ΔV reflecting the difference between the sum of the variances of individual digit forces and the variance of the total force; ΔV showed reproducibly high values over the steady-state phase of the task. The ramp-phases, however, presented a strikingly different picture.…”

Section: Emergence and Disappearance Of Multi-finger Synergiesmentioning

confidence: 99%

“…Recent series of studies have addressed the emergence of multi-finger synergies in isometric ramp force production tasks (Shim et al 2003;Shinohara et al 2003Shinohara et al , 2004. Within those studies, synergies were defined as covariations of forces produced by individual fingers that reduced the variance of the total force across repetitive attempts at the task.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The emergence and disappearance of multi-digit synergies during force-production tasks

et al. 2005

Self Cite

View full text Add to dashboard Cite

We analyzed patterns of covariation among forces produced by the five digits of the human hand during tasks that required the production of a pattern of the total force consisting of ramp-up, constant force, and ramp-down segments with the time of the ramps ranging from 0 to 3000 ms. Patterns of the variance of the total force and the sum of the variances of individual digit forces were compared over sets of 12 trials at each task. The initiation of the ramp-up segment was associated with positive covariation of digit forces. Negative covariation among digit forces (force-stabilizing synergies) emerged after a critical time of 600-800 ms, which was only weakly dependent on the ramp time. These synergies persisted over the steady-state phase. A quantitative index of digit force covariation was introduced; it showed a drop about 100 ms before initiation of the ramp-down phase; we termed this phenomenon "anticipatory covariation" (ACV). The ramp-down phase was associated with rapid disappearance of the force-stabilizing synergy over a time period that ranged from 0 to 600 ms and scaled strongly with the duration of the force ramp. Thumb-virtual finger synergies showed qualitatively similar behavior to the multi-finger synergies (virtual finger is an imagined digit whose action is mechanically equivalent to the action of the four fingers). We conclude that abrupt changes in a time profile of total force are associated with transient destabilization of the total force. Changes in force-stabilizing synergies may occur in preparation to changes in the total force.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Emergence and Disappearance Of Multi-finger Synergiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The emergence and disappearance of multi-digit synergies during force-production tasks

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…When a person tries to produce a certain level of force or a certain time profile of force with several fingers pressing together in parallel, the variability of the total force across repetitive trials is typically smaller than what one could expect based on the magnitudes of variability of individual finger forces Scholz et al 2002;Shim et al 2003a;Shinohara et al 2003). This observation suggests that commands to individual fingers do not vary independently across trials but rather they are organized by the central nervous system (CNS) into a synergy with the purpose to minimize deviations of the total force from its desired value or from a time series of values.…”

Section: Introductionmentioning

confidence: 99%

Hierarchies of synergies: an example of two-hand, multi-finger tasks

2006

Self Cite

View full text Add to dashboard Cite

We explored the ability of the central nervous system (CNS) to assemble synergies stabilizing the output of sets of effectors at two levels of a control hierarchy. Specifically, we asked a question: can the CNS organize both two-hand and within-a-hand force stabilizing synergies in a simple two-hand force production task that involves two fingers per hand? Intuitively, one could expect a positive answer; that is, forces produced by each hand are expected to co-vary negatively across trials to bring down the total force variability, while forces produced by each finger within-a-hand are expected to co-vary negatively to reduce the variability of that hand's contribution to the total force. The subjects were instructed to follow a trapezoidal time profile with the signal corresponding to the force produced by a set of instructed fingers in one-hand tasks with two-finger force production and in two-hand tasks with involvement of both symmetrical and asymmetrical finger pairs in the two hands. Finger force co-variation across trials was quantified and used as an index of stabilization of the force produced by all the instructed fingers, and of the force produced by finger pairs within-a-hand. No major differences were seen between the dominant and the non-dominant hand and between the twohand tasks with symmetrical and asymmetrical finger involvement. Stronger synergies were seen in the index-middle finger pair as compared to the ring-little finger pair. The main result of the study is the significantly weaker or even lacking two-finger force stabilizing synergies within-a-hand during two-hand tasks while such synergies were present in one-hand tasks. This observation points at a potential limitation in the ability of the CNS to organize synergies at two levels of a control hierarchy simultaneously. It also allows suggesting a hypothesis on two types of synergies in the human motor repertoire, well-practiced synergies that form a library serving as the foundation for all novel actions, and freshly assembled synergies.

show abstract

“…Rate coding occurs over a narrower range of forces in older adults (Barry et al, 2007). In addition, the hand muscles of older adults are disproportionately weaker when compared to young groups and therefore higher levels of muscle activation are required to achieve the same force (Shinohara et al, 2003b). These findings indicate some of the potential reasons that older adults could have difficulty with force modulation tasks when compared to young adults.…”

mentioning

confidence: 95%

Aging effects on the control of grip force magnitude: An fMRI study

Noble

Eng

Kokotilo

et al. 2011

Experimental Gerontology

View full text Add to dashboard Cite

Functional neuroimaging techniques have allowed for investigations into the mechanisms of agerelated deterioration in motor control. This study used functional Magnetic Resonance Imaging (fMRI) to investigate age related differences in the control of grip force magnitude. Using an event-related design, fMRI scans were completed on 13 older adults, and 13 gender matched younger adults, while using their dominant hand to squeeze a rubber bulb for 4s at 10%, 40% or 70% of their maximum voluntary contraction. Both groups were able to match the relative force targets, however the older adults produced significantly lower levels of absolute force. fMRI analysis consisted of a 1) region of interest (ROI) approach to detect differences in selected motor areas within brain and 2) a voxel-wise whole brain comparison to find areas of differential activation that were not defined a priori between the older and younger group. The ROI analysis revealed that despite producing lower levels of absolute force, the older adults showed higher levels of activity predominantly in subcortical structures (putamen, thalamus and cerebellum) when compared to the younger group. The older adults also showed higher levels of activity in the ipsilateral ventral premotor cortex. A total of 19 of the 22 ROIs analyzed showed a significant main effect of the required force-level. In the majority of the ROIs that showed a significant force effect there were no significant differences in the magnitude of the blood-oxygen-level-dependent (BOLD) signal between the 10% and 40% conditions but a significantly higher BOLD signal in the 70% condition, suggesting that the modulation of brain activation with grip force may not be controlled in a linear fashion. It was also found that the older adult group demonstrate higher levels of activation in 7 areas during a force production task at higher force levels using a voxelwise analysis. The 7 clusters that showed significant differences tended to be areas that are involved in visual-spatial and executive processing. The results of this study revealed that older adults require significantly higher activation of several areas to perform the same motor task as younger adults. Higher magnitudes of the BOLD signal in older adults may represent a compensatory pattern to counter age related deterioration in motor control systems.Corresponding Author: Janice J. Eng, PT, OT, Ph.D., Professor, Department of Physical Therapy, University of British Columbia, 212-2177 Wesbrook Mall, Vancouver, BC, Canada V6T 1Z3, Janice.Eng@ubc.ca, Phone: IntroductionThe normal aging process leads to several declines of the motor system that are related to changes within the central nervous system, peripheral nervous system and the musculoskeletal system (Seidler et al., 2010). These changes have the potential to lead to decreased motor performance with aging, which has been observed in the forms of decreased coordination, increased movement variability, slower movements and difficulties with balance and gait (Seidler et al., 2...

show abstract

Effects of age and gender on finger coordination in MVC and submaximal force-matching tasks

Cited by 140 publications

References 60 publications

The emergence and disappearance of multi-digit synergies during force-production tasks

The emergence and disappearance of multi-digit synergies during force-production tasks

Hierarchies of synergies: an example of two-hand, multi-finger tasks

Aging effects on the control of grip force magnitude: An fMRI study

Contact Info

Product

Resources

About