Precision in isometric precision grip force is reduced in middle-aged adults

Inserm, UMR_S 742, ANiM, 75005, Paris France.
Experimental Brain Research (Impact Factor: 2.04). 11/2008; 193(2):213-24. DOI: 10.1007/s00221-008-1613-4
Source: PubMed


We investigated age related changes in the control of precision grip in 29 healthy adults spanning early adulthood to middle age (21-67 years). Subjects performed a visually guided, isometric precision grip ramp-and-hold force-tracking task. Target force levels were 3, 6, and 9 N. Precision and performance of force regulation was quantified. Larger errors were made during the ramp than during the hold phase. Age correlated positively with the amount of error at the lowest (3 N) force level in both phases. Force onsets were systematically earlier in middle-aged subjects and the average slope of the force during the ramp decreased with increasing age. The results show that precision during low grip force control decreases already during middle age and those subjects may modify their force generation strategies to compensate for early and subtle degenerative changes in the motor system before decline in grip strength is apparent.

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Available from: Pavel Lindberg, Jul 18, 2015
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    • "Force control and bimanual coordination performance change with increasing age. For example, older adults are less able to accurately modulate and time their force output during dynamic force modulation tasks with sinusoidal targets from middle-adulthood onward (Lindberg et al., 2009; Vieluf et al., 2013; Voelcker-Rehage, Reuter, Vieluf, & Godde, 2013). In a bimanual force maintenance task with asymmetric force levels, Hu and Newell (2011c) demonstrated higher absolute force errors and higher variability for older than for younger adults. "
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    ABSTRACT: ABSTRACT The authors examined age-related differences in fine motor control during a bimanual coordination task. The task required the modulation of fingertip forces in the precision grip according to a visually presented sinusoidal antiphase pattern (force range 2-12 N; frequency 0.2 Hz). Thirty-four right-handed participants of three age groups (young, early middle-aged, and late middle-aged) practiced 30 trials of the task. Accuracy and variability of relative timing and relative forces at minima and maxima of the sine wave were analyzed for hand-hand and hand-stimulus couplings and compared between age groups. Analysis showed for relative timing and force weaker hand-hand than hand-stimulus coupling as well as lower accuracy and higher variability for minima as compared to maxima. Further, we analyzed practice effects by comparing the first and last trials and characterized the course of practice by detecting the transition of a steeper to a shallower acquisition slope for the different age groups. Late middle-aged participants demonstrated poorer performance than both other groups for all parameters. All groups improved performance to a similar amount. However, an age-related difference in acquisition strategy is visible. Late middle-aged participants seemed to have focused on improvement of force amplitude, whereas young and early middle-aged focused on timing.
    Full-text · Article · Nov 2014 · Journal of Motor Behavior
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    • "Extending previous findings (e.g., Cole 1991; Galganski et al. 1993), we revealed that age-related differences in precision grip performance (TWR, rRMSE) in all task conditions became visible already in late middle-aged adults younger than 65 years of age. Our findings are in line with Lindberg et al. (2009) demonstrating lower force modulation abilities in precision grip tasks for middle-aged as compared to young adults. One might argue that agerelated differences are influenced by a lower MVC of late middle-aged adults (Kapur et al. 2010; Sosnoff and Newell 2006b). "
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    ABSTRACT: It has been repeatedly shown that precise finger force control declines with age. The tasks and evaluation parameters used to reveal age-related differences vary between studies. In order to examine effects of task characteristics, young adults (18-25 years) and late middle-aged adults (55-65 years) performed precision grip tasks with varying speed and force requirements. Different outcome variables were used to evaluate age-related differences. Age-related differences were confirmed for performance accuracy (TWR) and variability (relative root mean square error, rRMSE). The task characteristics, however, influenced accuracy and variability in both age groups: Force modulation performance at higher speed was poorer than at lower speed and at fixed force levels than at force levels adjusted to the individual maximum forces. This effect tended to be stronger for older participants for the rRMSE. A curve fit confirmed the age-related differences for both spatial force tracking parameters (amplitude and intercept) and for one temporal parameter (phase shift), but not for the temporal parameter frequency. Additionally, matching the timing parameters of the sine wave seemed to be more important than matching the spatial parameters in both young adults and late middle-aged adults. However, the effect was stronger for the group of late middle-aged, even though maximum voluntary contraction was not significantly different between groups. Our data indicate that changes in the processing of fine motor control tasks with increasing age are caused by difficulties of late middle-aged adults to produce a predefined amount of force in a short time.
    Full-text · Article · Oct 2012 · Experimental Brain Research
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    • "Most earlier studies addressed age-related changes in the characteristics of grip force during holding or manipulation of the hand-held objects. In particular, elderly persons are known to show excessive grip force magnitudes (Cole, 1991; Cole & Beck, 1994; Cole et al., 1999; Danion, Descoins, & Bootsma, 2007; Diermayr, McIsaac, & Gordon, 2011; Gilles & Wing, 2003; Kinoshita & Francis, 1996; Lindberg, Ody, Feydy, & Maier, 2009), commonly quantified as an increase in the safety margin, which is the proportion of grip force above the threshold level for slippage (Burstedt, Flanagan, & Johansson, 1999; Johansson & Westling, 1984; Pataky, Latash, & Zatsiorsky, 2004). An impairment of multi-digit synergies related to stabilization of grip force has also been documented (Kapur et al., 2010; Shim et al., 2004; Shinohara, Latash et al., 2003; Shinohara Li et al., 2003; Shinohara et al., 2004). "
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    ABSTRACT: We investigated age-related differences in finger coordination during rotational hand actions. Two hypotheses based on earlier studies were tested: higher safety margins and lower synergy indices were expected in the elderly. Young and elderly subjects held a handle instrumented with five six-component force sensors and performed discrete accurate pronation and supination movements. The weight of the system was counterbalanced with another load. Indices of synergies stabilizing salient performance variables, such as total normal force, total tangential force, moments produced by these forces, and total moment of force were computed at two levels of a hypothetical control hierarchy, at the virtual finger-thumb level and at the individual finger level. At each level, synergy indices reflected the normalized difference between the sum of the variances of elemental variables and variance of their combined output, both computed at comparable phases over repetitive trials. The elderly group performed the task slower and showed lower safety margins for the thumb during the rotation phase. Overall, the synergy indices were not lower in the elderly group. In several cases, these indices were significantly higher in the elderly than in the younger participants. Hence, both main hypotheses have been falsified. We interpret the unexpectedly low safety margins in the elderly as resulting from several factors such as increased force variability, impaired feed-forward control, and the fact that there was no danger of dropping the object. Our results suggest that in some natural tasks, such as the one used in this study, healthy elderly persons show no impairment, as compared to younger persons, in their ability to organize digits into synergies stabilizing salient performance variables.
    Full-text · Article · Jan 2012 · Human movement science
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