PT  - JOURNAL ARTICLE
AU  - Chang Ye
AU  - Seyed Saman Saboksayr
AU  - William Shaw
AU  - Rachel O. Coats
AU  - Sarah L. Astill
AU  - Gonzalo Mateos
AU  - Ioannis Delis
TI  - A Tensor Decomposition Uncovers the Effect of Ageing on Muscle and Grip-Load Force Couplings During Grasping
AID  - 10.1101/2022.02.25.482040
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.02.25.482040
4099  - http://biorxiv.org/content/early/2022/03/01/2022.02.25.482040.short
4100  - http://biorxiv.org/content/early/2022/03/01/2022.02.25.482040.full
AB  - Do motor patterns of grasp-to-lift movements change as a result of ageing? Previous studies often relied on simple temporal and kinetic variables to unveil differences caused by ageing, yet their neuromuscular origins remain largely unknown. Here we employed a bimanual grasping protocol with younger and older adults and combined measurements of muscle activity with grip and load forces to provide a window into the neuromuscular strategies underlying effective grasping. We introduced a tensor decomposition to identify patterns of muscle activity and grip-load force ratios while also characterising their temporal profiles and relative activation across object weights and participants of different age groups. This approach extracted the motor components underpinning object grasping across participants. We then probed age-induced changes in these components. A classification analysis revealed two motor components that are differentially recruited between the two age groups. Linear regression analyses further showed that advanced age and poorer manual dexterity can be predicted by the coupled activation of forearm and hand muscles which is associated with high levels of grip force. Our findings suggest that ageing may induce stronger muscle couplings in distal aspects of the upper limbs, and a less economic grasping strategy to overcome age-related decline in manual dexterity.Competing Interest StatementThe authors have declared no competing interest.