A Modified Reach-to-Grasp Task in a Supine Position Shows Coordination Between Elbow and Hand Movements After Stroke.

Kate Broome,Ashlee Dunn,Jason Kulk,Irene Hudson,Huiqiao Tian,Kaitlyn Potter,Tom Zeffiro,Gavin Cooper,Paulette Van Vliet,Jameen Arm

doi:10.3389/fneur.2019.00408

Abstract

Objective: A modified reach-to-grasp task has been developed for the purpose of investigating arm-hand coordination in a supine position in the functional magnetic resonance imaging environment. The objective of this study was to investigate the kinematics of the reach-to-grasp task, in stroke and healthy participants.Design: Observational cohort study.Setting: Movement laboratory.Participants: Ten stroke participants and 10 age-matched healthy participants performed 10 repetitions of the modified reach-to-grasp task in two conditions—a natural condition and a standardized condition in a splint.Intervention: Not applicable.Main Outcome Measures: Kinematic variables of start time of transport, start time of aperture, movement duration, time of peak velocity (PV), percentage time of PV, peak deceleration (PD), percentage time of PD, peak aperture (PA), time of PA, and percentage time of PA were recorded. The correlation between key events in the grasp and transport trajectories were investigated. Performance between conditions and groups were compared.Results: Both groups demonstrated a significant correlation between the start time of aperture and the start time of transport and between the time of PA and PV in both conditions. A significant correlation was found between the time of PA and the PD in both conditions for the healthy group, but in neither condition for the stroke group. Movements by participants with stroke had a significantly longer movement duration, a smaller PV, and an earlier absolute time of PV and PD, and an earlier percentage time of PV and PD. They also had a smaller aperture than healthy participants. Wearing the splint resulted in a significantly higher PV, later absolute and percentage time of PV, PD, and PA, and a smaller PA compared to moving without the splint. The timing of transport variables time to peak velocity and time to peak deceleration, were strongest determinants of movement duration.Conclusion: The modified reach-to-grasp movement performed without the constraint of the splint, demonstrates similar motor control and coordination between the grasp and transport components of reach-to-grasp as in seated reach-to-grasp. This provides a new task that may be used to explore reach-to-grasp in the fMRI environment.

Highlights

77% of people with stroke experience impaired coordination of their upper limb [1]
The mean percentage times of these kinematic parameters follow the same pattern as the absolute times, except for the healthy natural condition, where the % peak aperture preceded % peak velocity
Our recommendation is to have participants perform the movement without the splint, since wearing it caused differences in key kinematic variables compared to the natural condition

Summary

Introduction

77% of people with stroke experience impaired coordination of their upper limb [1]. Coordination is defined as an ability to maintain a context-dependent and phase-dependent cyclical relationship between different body segments or joints in both spatial and temporal domains [2]. A key functional movement of the upper limb is the ability to reach and grasp an object, how this ability is affected following stroke is of great interest. Investigations of reach-to-grasp typically study reaching movements performed in a sitting position, sitting does not suit all research environments, such as for example the fMRI environment. The primary objective of this study was to investigate the kinematics of a reach-tograsp task, performed in supine, in a group of people with stroke and a group of healthy individuals. The kinematics of reach to grasp include a transport of the hand phase describing the movement of the hand toward the object, driven by extrinsic factors such as the location of the object [3, 4], and a grasp component describing the shaping of the hand to reflect the intrinsic factors such as size and shape of the object to be picked up [3, 4]

Methods

Results

Discussion

Conclusion