Rehabilitation robots are expected to save time, money, and expand access to some physical therapies. Moreover, robots can perform certain actions that human therapists cannot which may open up novel possibilities that improve upon current practice. Here, we investigated the effects of assistance and resistance within the electromechanical delay between muscle activation and muscle contraction during arm extension; reactions faster than any human therapist could achieve. We found that robotic assistance within the electromechanical delay dramatically increases muscle activation (68.97 ± 80.05%, SE = 0.021; p = 0.007). This result is surprising since all previous literature shows that muscle activation either decreases or does not change when participants receive assistance. In the context of rehabilitation, this could solve a tradeoff between providing patient assistance and sufficiently challenging the patient to improve neuromotor function. Traditionally, rehabilitation programs gradually reduce the amount of assistance as the patient improves over time to maintain sufficient muscle activation for neuronal repair. Instead, robotic assistance within the electromechanical delay may offer a new solution that enables therapists to provide assistance while simultaneously, challenging patients by causing elevated muscle activation.
Authors: Dzewaltowski A., and Malcolm P.