Robotic Upright Stand Trainer (RobUST)
A novel cable-driven robotic upright stand trainer (RobUST) has been designed and validated in adults without SCI to provide trunk perturbations and standing balance assistance-as-needed through trunk and pelvic force fields (Khan et al. 2019c; Luna et al. 2020). RobUST has also been shown to be a potential training device for upright postural control in one individual with SCI, resulting in complete functional independence and the ability to stand and ambulate independently (Santamaria et al. 2021). There have been recent studies providing some evidence for the use of this device in participants with SCI.
Discussion
Two studies by Bowersock et al. (2023, 2024) provided the foundation for the pre-post study of Rejc et al. (2024a), which included six individuals with chronic SCl who had been implanted with a spinal cord epidural stimulation (scES) unit for the recovery of motor function. The RobUST, a motorized cable-driven device that can provide assistance as needed and deliver controlled perturbation forces at the trunk and pelvis, was used for upright postural training (Rejc et al. 2024a). After an average of 80 sessions, robotic postural training re-enabled and/or largely improved the participants’ ability to control steady standing, self-initiated trunk movements and upper limb reaching movements while standing with free hands, receiving only external assistance for pelvic control (Rejc et al. 2024a); but not in sitting balance outcomes (Rejc et al. 2024b). These improvements were associated with neuromuscular activation pattern adaptations above and below the lesion, suggesting that the human spinal cord below the level of injury can generate meaningful postural responses when its excitability is modulated by scES, and can learn to improve these responses (Rejc et al. 2024a). However, longitudinal studies involving more participants and populations with different injury severity are needed to test this hypothesis (Rejc et al. 2024a).
Conclusions
There is level 4 evidence (from 2 pre-post studies: Rejc et al. 2024a; Rejc et al. 2024b) that 80 sessions (1 h/day; 5 days/week) of robotic postural stand training with the RobUST device (a motorized cable driven device that can provide assistance as needed and deliver controlled perturbation forces at the trunk and pelvis), which included periods of standing with steady trunk control, self-initiated trunk and arm movements, and trunk perturbations; re-enables and/or largely improves the participants’ ability to control steady standing, self-initiated trunk movements and upper limb reaching movements while standing with free hands, but does not improve sitting balance performance in people with chronic and motor complete tetraplegia who are already implanted with a scES unit for the recovery of motor function.
