Effects of Robot-Assisted Therapy for the Upper Limb After Stroke

BACKGROUND: Robot technology for poststroke rehabilitation is developing rapidly. A number of new randomized controlled trials (RCTs) have investigated the effects of robot-assisted therapy for the paretic upper limb (RT-UL). OBJECTIVE: To systematically review the effects of poststroke RT-UL on measures of motor control of the paretic arm, muscle strength and tone, upper limb capacity, and basic activities of daily living (ADL) in comparison with nonrobotic treatment. METHODS: Relevant RCTs were identified in electronic searches. Meta-analyses were performed for measures of motor control (eg, Fugl-Meyer Assessment of the arm; FMA arm), muscle strength and tone, upper limb capacity, and basic ADL. Subgroup analyses were applied for the number of joints involved, robot type, timing poststroke, and treatment contrast. RESULTS: Forty-four RCTs (N = 1362) were included. No serious adverse events were reported. Meta-analyses of 38 trials (N = 1206) showed significant but small improvements in motor control (~2 points FMA arm) and muscle strength of the paretic arm and a negative effect on muscle tone. No effects were found for upper limb capacity and basic ADL. Shoulder/elbow robotics showed small but significant effects on motor control and muscle strength, while elbow/wrist robotics had small but significant effects on motor control. CONCLUSIONS: RT-UL allows patients to increase the number of repetitions and hence intensity of practice poststroke, and appears to be a safe therapy. Effects on motor control are small and specific to the joints targeted by RT-UL, whereas no generalization is found to improvements in upper limb capacity. The impact of RT-UL started in the first weeks poststroke remains unclear. These limited findings could mainly be related to poor understanding of robot-induced motor learning as well as inadequate designing of RT-UL trials, by not applying an appropriate selection of stroke patients with a potential to recovery at baseline as well as the lack of fixed timing of baseline assessments and using an insufficient treatment contrast early poststroke.