Mentally represented motor actions in normal agingI. Age effects on the temporal features of overt and covert execution of actions

Abstract

The present study examines the temporal features of overt and covert actions as a function of normal aging. In the first experiment, we tested three motor tasks (walking, sit-stand-sit, arm pointing) that did not imply any particular spatiotemporal constraints, and we compared the duration of their overt and covert execution in three different groups of age (mean ages: 22.5, 66.2 and 73.4 years). We found that the ability of generating motor images did not differentiate elderly subjects from young subjects. Precisely, regarding overt and covert durations, subjects presented similarities for the walking and pointing tasks and dissimilarities for the stand-sit-stand task. Furthermore, the timing variability of imagined movements was always greater compared to actual movements and was of the same amount in the three groups of age. In the second experiment, we investigated the effect of age (three groups with mean ages: 22, 64.8 and 73.2 years) upon temporal characteristics of covert and overt movements involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). During overt execution young and elderly subjects respected Fitts's law despite the fact that movement speed progressively decreased with age. Thus, while execution is deteriorated, the motor preparation process is still intact in old age, and follows well-known laws of biological motions. For covert execution, movement speed progressively decreased with age but elderly subjects did not respect Fitts's law. This suggests that the generation and control of motor intentions that consciously do not come to execution, particularly those concerning complex motor actions are progressively perturbed in the aging brain.

Ageing of internal models: from a continuous to an intermittent proprioceptive control of movement

“…Personnier et al 2008;Skoura et al 2005). However, the absence of end-point differences in goaldirected aiming movements to visual target (e.g.…”

“…Indeed, although it was against an increased cognitive cost and additional neural resources, previous studies showed that older adults were able to reach levels of proprioceptive control of movement comparable to those of young adults (Batavia et al 1999;Boisgontier et al 2012;Deshpande et al 2003;Goble et al 2012a, b;Heuninckx et al 2008;Marks 1996;Pickard et al 2003). However, on the basis of the differences observed in motor imagery (Personnier et al 2010(Personnier et al , 2008Skoura et al 2005) and kinematic studies (Elliott and Hansen 2010;Goggin and Meeuwsen 1992;ReyRobert et al 2012; Seidler-Dobrin and Stelmach 1998), we hypothesised that (2) older adults were not able to reach the same level of end-point performance as the young adults in the fast speed condition due to the temporal constraints, making it impossible to use additional sub-movements to compensate for the presumably altered internal models. We also hypothesised that (3) older adults required a greater number of corrective sub-movements reflecting an intermittent control movement used to compensate for a presumed alteration of the internal models.…”

“…The alteration of internal models in adult ageing has been experimentally assessed using different methods. One of these methods is motor imagery (Personnier et al 2008(Personnier et al , 2010Skoura et al 2005). In this method, a subject internally simulates a movement without moving his limbs or activating the muscles involved in the execution of this movement.…”

Maze test: an instrument to evaluate age-related cognitive and motor changes in humans

“…The older adults had lower scores than those of the younger individuals in the first analysis and a significantly greater decline in task performance after 48h, suggesting that the older adults did not manage to preserve a functional motor skill as well as the young adults did (TUNNEY et al, 2004). According to the literature the findings cited may be related to problems of inhibitory control of a competing motor memory or to some aspects of action representation such as the intention to move or motor predictions (BROSSEAU; POTVIN; ROULEAU, 2007), which also become progressively fragile with age (SKOURA et al, 2005).…”

Interference of action perception on action production increases across the adult life-span

“…In action production, increasing age is accompanied by less precise motor planning (Reuter et al, 2015), less interhemispheric inhibition (Talelli, Waddingham, Ewas, Rothwell, & Ward, 2008), and reduced sensorimotor control of actions (Seidler & Stelmach, 1995). With respect to action perception, the accuracy of action prediction (Diersch, Cross, Stadler, Schütz-Bosbach, & Rieger, 2012), imagination (Personnier, Kubicki, Laroche, & Papaxanthis, 2010;Personnier, Paizis, Ballay, & Papaxanthis, 2008;Saimpont, Mourey, Manckoundia, Pfitzenmeyer, & Pozzo, 2010;Skoura, Papaxanthis, Vinter, & Pozzo, 2005), and the perception of the personal action range (Gabbard, Caçola, & Cordova, 2011) decreases from younger to older adults.…”