## 4 Discussion
### Treatment Interventions  
This review evaluates and reports the treatment modalities used in robot-assisted rehabilitation in children. Robotic devices can provide specific treatment features that foster recovery and neuroplasticity [13]. These devices allow performing highly repetitive, intensive, and task-oriented training, thus fostering the neuroplasticity process [15]. Notably, a recent meta-analysis on gait rehabilitation in children with CP has suggested that the body of literature for gait training has presented several limitations, including potentially insufficient duration, intensity, and total amount of gait training, which may have negatively biased the results [2]. Furthermore, the use of technology may combine purely motor rehabilitation with cognitive-behaviour exercises. Children can interact with the systems performing problem-solving activities, receiving rewards and maximizing their engagement. Indeed, robotic devices have been reported to provide a means of emotional expression for individuals with cognitive, physical, communication, or social impairments [61]. Above all, the interactive modalities provided by some devices and the combination of robotic tasks with VR environments may promote higher focus and attention, fun, and challenge. All these characteristics are of paramount importance in paediatric rehabilitation, and, all together, maximize cognitive engagement, thus stimulating the child's active, voluntary participation and neuroplasticity [33; 61]. Following the classification of architecture of robotic devices, the treatment interventions of the included studies can be roughly divided into two groups: rehabilitation treatments involving the whole lower limb and gait [27; 28; 30; 31; 32; 33; 34; 41; 42; 44; 50; 53; 54], and intervention targeted to specific joints like knee or ankle [30; 36; 39; 40; 43; 45; 46; 47; 51; 52; 55; 56; 57]. Although the importance of the features of robotic devices for rehabilitation, our analysis suggested that rehabilitation protocols are highly heterogeneous in terms of treatment duration, ranging from one [41] to 60 sessions [26] and duration of each session ranging from eight [41; 51] to 75 min [52]. Moreover, in a limited number of studies, the difficulty level of the treatment was adjustable to the patient's needs. Lastly, the assistance modality that characterizes the patient-machine interaction was often not reported or was limited to passive or active modalities. However, recent works on robot-assisted rehabilitation have suggested that the assistive modality could be the ideal strategy for fostering neuroplasticity [13]. Along with assistance modality, type of feedback provided, the number of repetitions executed, and control system used should also be specified when describing the rehabilitation intervention. Improving the reporting of the treatment and performing more complex and intensive rehabilitation protocols is crucial for taking full advantage of the available robotic devices. The methodological quality of the studies included is low to moderate, with only 10 RCTs. The limited quality of evidence affects the attempt to synthesize the effectiveness of robot-assisted neurorehabilitation in these subjects, and future RCTs should provide solid rehabilitation protocols and technical descriptions. However, some common pattern in studies that used similar devices and treatment modalities can be found. Specifically, intervention using robot for gait rehabilitation, such as Lokomat and Gait-Trainer, showed patients' improvement in functional gait parameters like speed and endurance [28; 29; 31; 32; 34; 49; 50; 54]. In contrast, single-joint devices generally showed improvements in active and passive joint-specific movement features, like muscle strength or spasticity [36; 40; 43; 45; 52; 55; 56; 57]. From a clinical perspective, therefore, clinicians should be aware of technical difference between different devices and choose the most appropriate one (when possible) accordingly.