Implicit development of gaze strategies support motor improvements during action encoding training of prosthesis use

Abstract

Background: Action observation training has been suggested to facilitate motor improvements in the lives of persons with neural injury. Previous studies have shown that for persons with upper limb amputation, matched limb training, where prosthesis users emulate each other, has shown promise above mismatched training where a prosthesis user emulates actions of a person with sound limbs (most commonly that of a therapist). Objective: The mechanism underlying the matched limb training benefit is unclear. Gaze strategies may reveal unique patterns between matched and mismatched training which could explain improvements in motor function in matched limb training. Methods: Twenty persons with sound limbs were trained on how to use a prosthesis simulator using matched or mismatched limb training in a single session. Eye movements were recorded during the training phase. Kinematics were recorded as persons performed the task. Results: Gaze patterns showed differences between the training groups. The mismatched group demonstrated a higher probability of gaze on the path between the start and end of the action, while the matched group demonstrated a significantly higher probability of focusing on the elements of the path of the action and a trend of focusing on the shoulders. Kinematics also revealed overall improvements in motor control for the matched group. Conclusions: This study proposes a putative mechanism that may explain improvements in matched limb training through shifting gaze strategies. Further work is needed to understand whether implicit visual strategies seen during matched limb training might encourage motor learning during functional training with prostheses.

Emergence of perceptuomotor relationships during paleolithic stone toolmaking learning: intersections of observation and practice

“…Work on the role of gaze in motor control and learning has largely focused on action planning and execution 12 , 22 , 23 or goal inference (e.g. 24 ), At least one recent study 25 has reported gaze variation’s effects on observational learning of a novel task (prosthesis use). Bayani et al found that eye movements tracking action path and bodily effector rather than the action start and endpoints during demonstration was associated with more efficient kinematics during execution.…”

A scoping review of the application of motor learning principles to optimize myoelectric prosthetic hand control

“…For example, Cusack et al 85 showed that those who trained to use a prosthesis by observing and imitating the movements of prosthesis users were able to execute actions with reduced movement variability, compared to those who trained by observing and imitating the movements of intact limbs. Bayani et al 86 reported similar findings, with greater kinematic improvements following training involving action observation of a prosthesis user compared to action observation of an intact limb. Eye-tracking measures also revealed that different gaze strategies underpinned the kinematic differences, with those observing intact limbs directing their gaze primarily to the start and end points of the observed action, and those observing prosthesis use directing their gaze towards the path of the prosthesis in action and the shoulders.…”

A scoping review of eye tracking metrics used to assess visuomotor behaviours of upper limb prosthesis users

“…All studies quantitatively assessed the behaviour of participants using eye tracking technology. Ten studies consisted of a cross-sectional design [ 3 , 15 – 23 ], 3 studies included a repeated-measures study design [ 21 , 24 , 25 ], 2 were crossover studies [ 26 , 27 ], and 4 were case studies [ 25 , 28 – 30 ]. Of the included literature, 1 was a conference paper [ 23 ] and 2 were dissertations [ 16 , 20 ].…”

“…The simulated device used myoelectric signals to control a terminal device that bypassed the anatomic hand. Alternatively, a simulated body-powered prosthesis was employed in one study [ 15 ] and a myoelectrically-controlled virtual reality arm was used in another study [ 20 ] with participants who had intact arms. Figure 2 summarizes the type of prosthetic device and level of amputation of participants.…”

“…Dual tasks were performed with and without vibration Adding vibrotactile feedback reduced task performance time in a dual task activity performed by myoelectric prosthesis users. There was no effect of adding vibrotactile feedback on gaze behaviour Bayani et al (2019) [ 15 ] To identify gaze strategies that develop implicitly during matched and mismatched limb training during action observation Head-mounted (Pupil Labs, binocular, Berlin, Germany) Percent fixation Movement time, number of errors, type of errors, peak height, peak velocity, peak lateral trunk movement, variability in lateral trunk movement and smoothness The task involved reaching and grasping for a disc and transporting it over a barrier to be placed in an open slot. Participants watched an instruction video performed either by an actor with a body-powered prosthesis (matched) or with the anatomic limb (mismatched).…”